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Hall B Monday 14:00-16:00 784. Preliminary In-Vivo Bone Quantification Results Using MR and PQCT Victor Rakesh Lazar1, Gary P. Liney2, David J. Manton1, Peter Gibbs1, Martin Lowry1, Celia L. Gregson3, Joern Rittweger4, Sue Steel5, Chris Langton6, J H. Tobias3, Lindsay W. Turnbull1 1Centre for MR Investigations, University of Hull, Hull, North Humberside, United Kingdom; 2Radiotherapy Physics, University of Hull, Hull, North Humberside, United Kingdom; 3Academic Rheumatology, University of Bristol, Bristol, United Kingdom; 4Excercise and Sports Medicine, Manchester Metropolitan University, Manchester, United Kingdom; 5Centre for Metabolic Bone Disease, Hull Royal Infirmary, Hull, North Humberside, United Kingdom; 6School of Physical and Chemical Sciences, Queensland University of Technology, Australia Bone quantification is commonly measured using DEXA and pQCT. Research in MRI and MRS have shown promising potential in the quantification of bones. Our work was based on using these ideas in a clinical setting on individual patients. The work was involved in a High Bone Mass (HBM) study program to identify individuals affected with a genetic condition of LRP–5. pQCT data was collected from 169 individuals from the HBM study. 43 people were selected for MRI and MRS acquisition from the total pQCT population. Preliminary results from these investigations have been explained in this abstract. 785. Software Tools for MR and PQCT Bone Quantification Victor Rakesh Lazar1, Gary P. Liney2, David J. Manton1, Peter Gibbs1, Martin Lowry1, Celia L. Gregson3, Joern Rittweger4, Sue Steel5, Chris Langton6, J H. Tobias3, Lindsay W. Turnbull1 1Centre for MR Investigations, University of Hull, Hull, North Humberside, United Kingdom; 2Radiotherapy Physics, University of Hull, Hull, North Humberside, United Kingdom; 3Academic Rheumatology, University of Bristol, Bristol, United Kingdom; 4Excercise and Sports Medicine, Manchester Metropolitan University, Manchester, United Kingdom; 5Centre for Metabolic Bone Disease, Hull Royal Infirmary, Hull, United Kingdom; 6School of Physical and Chemical Sciences, Queensland University of Technology, Australia Peripheral Quantitative Computed Tomography (pQCT) and Dual Energy X-Ray Absorptiometry (DEXA) are the current gold standards for the measurement of bone density and structure, in the research and clinical setting respectively. However, Magnetic Resonance Imaging (MRI) and unsuppressed 1H Magnetic Resonance Spectroscopy (MRS) can also offer several advantages including the ability to quantify bone marrow content and structure. In-house software was developed to process and evaluate cortical and trabecular bone structure, marrow composition and vertebrae segmentation using data from MRI/MRS and structural details from pQCT. 786. Characterization of Bone Explants by Magnetic Resonance Microscopy Ingrid E. Chesnick1, Carol B. Fowler1, Francis A. Avallone2, Kimberlee Potter1 1Department of Biophysics, Armed Forces Institute of Pathology Annex, Rockville, MD, United States; 2Department of Genitourinary Pathology, Armed Forces Institute of Pathology, Washington, DC, United States MRI studies of tissue engineered constructs prior to implantation clearly demonstrate the utility of the MRI technique for monitoring the bone formation process. However, in our studies of osteoblast-seeded scaffolds, implanted on the chorioallantoic membrane of a chick embryo, we have found that the presence of angiogenic vessels and fibrous tissue around the implant can confound MRI findings of bone deposition. On-going studies support the use of targeted contrast agents for studying mineral deposition and blood vessel infiltration in tissue engineered scaffolds post-implantation. Yusuf Abu Tayeb Bhagat1, Chamith S. Rajapakse1, James H. Love1, Michael J. Wald1, Jeremy F. Magland1, Alexander C. Wright1, Hee Kwon Song1, Felix W. Wehrli1 1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, PA, United States The detection of subtle microstructural trabecular bone (TB) alterations such as the conversion of plates to rods requires adequate signal-to-noise ratio (SNR), which governs achievable spatial resolution and scan time. Increased SNR may enhance detection sensitivity for microstructural changes in treatment studies. Here, the reproducibility of TB quantitative parameters was investigated using a new 3D fast-spin-echo technique at 7.0T. The imaging and analysis protocol is shown to provide highly reproducible measures of scale, topology and mechanical parameters related to TB microstructure. Performance improvements relative to earlier work are attributed to enhanced SNR, motion control and correction, and improved registration techniques. 788. Studying the Effect of Different Biomaterials on Healing Process in Bone Injury Model Using Microscopic MRI and Micro CT May Abdel Hamid Taha1, Sarah L. Manske2, Erika Kristensen3, Jaymi T. Taiani4, Roman Krawetz5, Ying Wu, Steven K. Boyd6, John Robert Matyas7, Derrick E. Rancourt5, Jeffery F. Dunn1 1Radiology, University of Calgary, Calgary, Alberta, Canada; 2Kinesiology; 3Mechanical and Manufacturing Engineering; 4 Medical Sciences; 5Departments of Oncology, Biochemistry & Molecular Biology and Medical Genetics; 6Mechanical and Manufacturing Engineering; 7Comparative Biology and Experimental Medicine in Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada The objective of this study was to investigate the effect of different biomaterials on bone healing in vivo in a mouse model of bone injury. These materials; matrigel, purecol gel and hydroxyapatite (HA) are potential matrices to support stem cells. Optimized in vivo MR microscopy and micro computed tomography were used to assess fracture repair. In addition, MRI images and µCT scans were compared at the same time point, to show the difference between them in revealing the actual stage of healing. 789. Traditional Bone Structural Parameters on Different Resolutions in Magnetic Resonance Imaging June-Goo Lee1,2, Gyunggoo Cho1, Youngkyu Song1, Jong Hyo Kim2, Namkug Kim3 1Division of Proteome Research/Bio-Magnetic Resonance Research Center, Korea Basic Science Institute, Cheongwon-Gun, Chungcheongbuk-Do, Korea, Republic of; 2Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul, Korea, Republic of; 3Department of Radiology, Asan Medical Center, University of Ulsan, Seoul, Korea, Republic of Our study focused on the development of robust image processing algorithm on low resolution μ-MR bone image 790. Advanced Image Analysis Techniques of New High-Resolution Images of the Proximal Femur in the Presence of Red and Yellow Bone Marrow Using Local Bone Enhancement Fuzzy Clustering Jenny Folkesson1, Julio Carballido-Gamio1, Dimitrios C. Karampinos1, Patrick Koon2, Suchandrima Banerjee2, Eric Han2, Thomas M. Link1, Sharmila Majumdar1, Roland Krug1 1Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States; 2Applied Science Laboratory, GE Heathcare, Menlo Park, CA, United States With the advent of new MR hardware and pulse sequences it is now possible to image the small trabecular structure of deeper seated regions like the proximal femur with high spatial resolution in a clinically feasible scan time. We employ a novel partial membership bone segmentation technique (BE-FCM) technique that enhances bone segmentation compared to an established dual thresholding method in the presence of signal variations due to different marrow types. We demonstrate that the new image acquisition and analysis framework enables trabecular bone analysis in the deeply situated femoral head, something which has been previously unfeasible in vivo. 791. Bone Marrow Fat Fraction Mapping in the Proximal Femur in Vivo Using IDEAL Gradient Echo Imaging Dimitrios C. Karampinos1, Huanzhou Yu2, Ann Shimakawa2, Eric T. Han2, Thomas M. Link1, Sharmila Majumdar1, Roland Krug1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States There is some evidence that osteoporosis is associated with increased marrow fat content as well as an accelerated conversion from red marrow to yellow (fatty) marrow with age. In this work, we investigated the marrow fat composition in the proximal femur in vivo using IDEAL gradient echo imaging. 3-point IDEAL FGRE hip images of six healthy subjects were acquired and water-fat separation was performed using multi-peak IDEAL. The average fat fraction and standard deviation were determined in three different regions of interest (femoral head, greater trochanter and neck). Significant differences in marrow fat content were identified between the three regions for all subjects. 792. 1H MRS to Detect Biochemical Degenaration of the Vertebral Bone Marrow in Gaucher Disease Simona Ortori1, Michela Tosetti2, Marzio Perri3, Margherita Marchetti1, Gabriele Caproni1, Laura Biagi2, Mirco Cosottini4, Virna Zampa1, Giuliano Mariani3, Carlo Bartolozzi1 1Divisione di Radiologia Diagnostica ed Interventistica, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy; 2MR Laboratory, Stella Maris Scientific Institute, Pisa, Italy; 3Divisione di Medicina Nucleare, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy; 4Dipartimento di Neuroscienze, Università di Pisa, Pisa, Italy Gaucher disease is the most prevalent inherited, lysosomial storage disease and results in a deficient level of activity of β-glucocerebrosidase, a membrane-bound lysosomal enzyme. This deficiency leads to accumulation of the lipid glucocerebroside in the lysosomes of monocytes and macrophages, called Gaucher cells. The symptoms and pathology of Gaucher disease result from the accumulation of Gaucher cells in various organ system, including vertebral bodies. To evaluate the biochemical process underlying the infiltration of Gaucher cells, 1H-MRS has been acquired on vertebral bone marrow in patients affected by Gaucher disease, highlighting a significant reduction of fat content of any age range 793. Characterization of Trabecular Orientation in Chicken Femur by Multi-Directional SPENT (Sub-Pixel Enhancement of Non-Uniform Tissue) Bailiang Chen1, Bernard Siow2, David Carmichael1,3, Freddy Odille2, Roger Ordidge1, Andrew Todd-Pokropek1 1Medical Physics and Bioengineering, University College London, London, United Kingdom; 2Centre for Medical Image Computing, University College London, London, United Kingdom; 3Institute of Neurology , University College London, London, United Kingdom The recently proposed SPENT sequence can provide direction specific information based on the sub-voxel structural uniformity of a sample. Analogous to diffusion tensor imaging, given a voxel with a local anisotropic structure (e.g. trabecular bone), it is possible to characterize the orientation of sub-pixel micro-structure by applying SPENT with multiple directions. A 6-direction SPENT series was applied to a chicken femur head in order to characterize its trabecular bone orientation by reconstructing a 2D tensor in each voxel. Both tensor statistics and eigensystems were computed and showed good qualitative agreement with data from a subsequent micro-CT acquisitions. 794. The Effect of Freezing on Measurements of Trabecular Bone Structure Based on NMR Spectroscopy Viktoria Prantner1, Hanna Isaksson1, Johanna Närväinen2, Eveliina Lammentausta3, Olli HJ Gröhn2,4, Jukka S. Jurvelin1 1Department of Physics, University of Kuopio, Kuopio, Finland; 2A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland; 3Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 4Biomedical Imaging Unit, University of Kuopio, Kuopio, Finland NMR is a potential tool for the assessment of trabecular bone structure. Since trabecular bone provides a negligible NMR signal, the indirect evaluation of the trabecular bone structure is based on the analysis of water and fat components in the bone marrow. Earlier studies have revealed that freezing affects the bone marrow structure, suggesting there may be changes in the molecular structure. The aim of the current study is to investigate the effect of freezing on trabecular bone and bone marrow, as assessed by NMR spectroscopy. 795. Performance of Two Spin-Echo Sequences for Quantitative Structure Analysis of Trabecular Bone Michael Jeffrey Wald1, Jeremy Francis Magland1, X. Edward Guo2, Felix Werner Wehrli1 1Laboratory for Structural NMR Imaging, University of Pennsylvania Medical Center, Philadelphia, PA, United States; 2Bone Bioengineering Laboratory, Columbia University, New York, United States The performance of two spin-echo based pulse sequences for imaging trabecular bone microstructure are evaluated at 1.5T in seven fixed, cadaveric distal tibia specimens. SNR efficiency and sensitivity of image-derived trabecular bone structural parameters to variations in bone quality as assessed by µCT were investigated. Inter- pulse sequence correlations suggest similar structural sensitivity, while comparisons to µCT reveal good sensitivity but large deviations in absolute values between modalities. 796. Ultra-Short TE (UTE) Imaging of Skull and a Quantitative Comparison of Skull Images Obtained from MRI and CT Liya Wang1, Xiaodong Zhong2, Longjiang Zhang3, Diana Tiwari1, Hui Mao1 1Department of Radiology and Emory Center for Systems Imaging, Emory University School of Medicine, Atlanta, GA, United States; 2MR R&D Collaborations, Siemens healthcare, Atlanta, GA, United States; 3Department of Radiology, Jinlin Hospital and Nanjing University College of Clinical Medicine, Nanjing, Jiangsu, China This study provided a quantitative evaluation of skull images obtained using UTE MRI and a direct comparison to those from CT. The skull thickness measured from UTE images showed good agreement with those obtained from CT images in different slices. There is also a good correlation between the thickness measurements obtained from CT and UTE images. Signal intensity based evaluation showed that there is no statistical difference between UTE and CT images in outer, inner layer and diploe of the skull. The comparison of bone UTE MRI and CT of skull suggests that UTE images match closely with CT images. 797. MR Imaging Detects Impaired Angiogenesis and Trabecular Bone Formation During Endochondral Bone Growth Mediated Through PKBalpha/Akt1 in Gene Dosage Dependent Manner Katrien Vandoorne1, Jeremy Magland2, Vicki Plaks1, Inbal E. Biton3, Amnon Sharir4,5, Elazar Zelzer4, Felix Wehrli6, Brian A. Hemmings7, Alon Harmelin3, Michal Neeman1 1Biological Regulation, Weizmann Institute, Rehovot, Israel; 2Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, United States; 3Veterinary Resources, Weizmann Institute, Rehovot, Israel; 4Molecular Genetics, Weizmann Institute, Rehovot, Israel; 5The Laboratory of Musculoskeletal Biomechanics and Applied Anatomy, Koret School of Veterinary Medi, Hebrew University of Jerusalem, Rehovot, Israel; 6Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, Israel; 7Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland Since infiltration of the newly formed blood vessels is required for endochondral bone formation, and PKBalpha/Akt1 mediates intracellular signaling of angiogenesis, we postulated that a vascular deficiency at the site of the long bones could contribute indirectly to impaired bone development in PKBalpha/Akt1 deficient mice. Our study demonstrated using macromolecular DCE-MRI in vivo and ex vivo µCT and µMRI, vascular and bone developmental defects in PKBalpha/Akt1 null mice, and remarkably also in heterozygous mice, lacking a single copy of the gene. 798. Water and Fat Suppressed Proton Projection MRI (WASPI) Study on Bone Specimens After Proton-Deuteron Exchange Haihui Cao1,2, Jerome L. Ackerman, 2,3, Guangping Dai, 2,3, Mirko Hrovat4, Melvin J. Glimcher, 2,5, Yaotang Wu, 2,5 1Department of Orthopedic Surgery, Children's Hospital , Boston, MA, United States; 2Harvard Medical School, Boston, MA, United States; 3Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; 4Mirtech, Inc, Brockton, MA, United States; 5Department of Orthopedic Surgery, Children's Hospital, Boston, MA, United States Questions have arisen as to the nature of the molecular species giving rise to the short-T2 proton signal in Water- and fat-suppressed proton projection MRI (WASPI), a noninvasive means to image bone. In this study we use deuterium exchange to identify the source of proton signal in WASPI. 799. Quantification of Bound and Mobile Water in Human Cortical Bone by 1H and 2H Magnetic Resonance Henry H. Ong1, Alexander C. Wright1, Felix W. Wehrli1 1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States Magnetic resonance is a powerful tool for non-destructive study of bone water, which can provide insight into bone micro- and nanostructure. However, the MR signal of bone is comprised of several proton populations including collagen-associated water, and water within the pore space (Haversian and lacuno-canalicular system). We hypothesize that water in pores is predominantly free and water in the bone matrix is predominantly associated with collagen. Using 2H exchange and inversion recovery experiments, we estimated porosity in human cortical bone and found it to agree with micro-CT based volumetric measurements with a significant fraction being collagen-associated. 800. MR Spin Behavior During RF Pulses: T2 Vs. T2' Relaxation Michael Carl1, Nikolaus Szeverenyi2, Mark Bydder2, Eric Han1, Graeme Bydder2 1GE Healthcare, Waukesha, WI, United States; 2University of California, San Diego We investigated the behavior of the MR magnetization vector during RF pulses in the presence of rapid transverse relaxation caused by either amplitude loss or spin dephasing. We found that different tissues with the same T2* may generate different responses to RF pulses, dependent on whether the relaxation is dominated by a homogeneously or inhomogeneously broadened linewidth and RF optimization may hence require explicit knowledge of the intrinsic T2 and T2* of the tissue. 801. Multi-Modality Imaging of Bone Marrow Edema-Like Lesions and Associated Cartilage in Osteoarthritic Patients Daniel Kuo1, Joseph Schooler1, Janet Goldenstein1, Sarmad Siddiqui1, Swetha Shanbhag1, Jean-Baptiste Pialat1, Andrew Burghardt1, Sharmila Majumdar1, Michael Ries2, Galateia Kazakia1, Xiaojuan Li1 1Musculoskeletal Quantitative Imaging Research (MQIR), Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States Osteoarthritis (OA) is a complex disease that affects both cartilage and bone. Bone marrow edema-like lesions (BMEL) are important in studying OA, but knowledge about them is limited. In this study, we take a multi-modality imaging approach, examining MR T1ñ and T2 values of BMEL-associated cartilage plus structure and composition of BMEL tissue using high resolution peripheral quantitative computed tomography (HR-pQCT) imaging and Fourier transform infrared (FTIR) spectroscopy. Our results indicate that regions of BMEL are associated with more advanced cartilage degeneration and that there is a localized imbalance in bone formation and mineralization specific to BMEL regions. 802. Perfusion Abnormalities of Bone Marrow Edema-Like Lesions in Knees with Anterior Cruciate Ligament Injury Using Dynamic Contrast-Enhanced MRI Jin Zuo1, Sharmila Majumdar1, Xiaojuan Li1 1Radiology and Biomedical Imaging, Univ. of California, San Francisco, San Francisco, CA, United States Anterior cruciate ligament (ACL) tear is a common knee injury, and is a risk factor of post-traumatic osteoarthritis (OA). The disease is frequently associated with bone marrow edema-like (BMEL) lesions which exhibit as an area of high signal intensity in T2-weighted, fat-saturated fast spin echo MR images. BMEL is also commonly seen in OA and has been associated with disease progression and pain in OA. However, the knowledge on the pathophyisiology and significance of BMEL in ACL-injured knees is very limited. Dynamic contrast enhanced MRI (DCE-MRI) can probe bone marrow and subchondral bone perfusion as well as fluid dynamics. Impaired perfusion in bone may lead to cartilage degeneration. A recent study showed bone marrow abnormalities were associated with BME in OA. The aim of this study is to apply DCE MRI to evaluate bone marrow perfusion in patients with ACL tears, and to compare the perfusion patterns between BMEL region and normal appearing bone marrow region. Kai-Yu Ho1, Houchun H. Hu2, Krishna S. Nayak2, Patrick M. Colletti3, Christopher M. Powers1 1Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, United States; 2Department of Electrical Engineering, University of Southern California, Los Angeles, CA, United States; 3Department of Radiology, University of Southern California, Los Angeles, CA, United States The purpose of this study was to investigate the influence of running on patellar water content and bone marrow edema (BME) in individuals with and without patellofemoral pain (PFP). Using the IDEAL protocol, two subjects with PFP and 2 pain-free controls were evaluated. Each subject underwent a pre-running MR scan, a 40-min moderate effort running, and a post-running MR scan. Our data showed that in persons with PFP, content and volume of local BME increases post-running. Additionally, the PFP subjects demonstrated increased water content of the bone marrow region post-running while the controls showed no changes in water content. 804. Using 18F NaF PET/CT to Image Increased Bone Activity in Patellofemoral Pain: Correlation with MRI Christine Elizabeth Draper1, Michael Fredericson1, Thor F. Besier1, Gary S. Beaupre2, Scott L. Delp1, Andrew Quon1, Garry E. Gold1 1Stanford University, Stanford, CA, United States; 2VA Palo Alto Health Care System, Palo Alto, CA, United States Articular cartilage deterioration is associated with the development of osteoarthritis. Cartilage health depends upon the integrity of the underlying subchondral bone and there may be abnormalities in bone metabolic activity that accompany structural defects in bone and cartilage. 18F NaF PET/CT enables bone metabolic activity to be visualized. We compared metabolic abnormalities detected using PET/CT with structural defects seen using MRI. We found that regions of increased bone metabolic activity do not always correlate with cartilage damage or bone marrow edema, indicating that 18F NaF PET/CT may image bone abnormalities prior to the development of structural damage seen using MRI. 805. Improved Fat-Suppression for Unspoiled GRASS Imaging of the Knee Using Multi-Peak IDEAL Chemical Shift Fat-Water Separation Richard Kijowski1, Catherine Debra Hines2, Huanzhou Yu3, Scott Brian Reeder1,2 1Radiology, University of Wisconsin, Madison, WI, United States; 2Medical Physics, University of Wisconsin, Madison, WI, United States; 3GE Healthcare, Applied Science Laboratory, Menlo Park, CA, United States This study was performed to demonstrate improvements in the quality of fat-suppression for unspoiled GRASS imaging of the knee using multi-peak fat spectral modeling and IDEAL fat-water separation. An IDEAL-GRASS sequence was performed at 3.0T on the knees of 10 asymptomatic volunteers. The IDEAL-GRASS images were reconstructed using a single-peak method and a multi-peak method that more accurately models the NMR spectrum of fat. Multi-peak IDEAL-GRASS had significantly greater (p<0.001) suppression of bone marrow signal and significantly higher (p<0.001) CNR between cartilage and bone marrow than single-peak IDEAL-GRASS. 806. Tissue Repair Differentiation Using T2 Multicomponents: Investigation in Tissue-Engineered Bone Regeneration Marine Beaumont1, Marc G. DuVal2, Yasir Loai3, Walid A. Farhat3, George K. Sándor2, Hai-Ling Margaret Cheng1,4 1The Research Institute and Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada; 2Department of Oral and Maxillofacial Surgery, University of Toronto, Toronto, Ontario, Canada; 3Division of Urology, The Hospital for Sick Children, Toronto, Ontario, Canada; 4Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada Tissue repair plays a key role in successful tissue regeneration and involves various simultaneous processes. In bone regeneration, bone growth in a defect occurs only in the absence of early fibrous scar formation or collapse of surrounding tissues into the defect. In this study, a tissue-engineered construct is inserted into a defect in the rabbit calvarium to provide a 3-dimensional resorbable scaffold that maintains a space for bone growth. Multicomponent T2 measurements are performed to characterize and differentiate tissue repair from normal construct resorption. Hall B Tuesday 13:30-15:30 807. High-Resolution MRI at 7 T of Local Strains in the Intervertebral Disc Alexander C. Wright1, Jonathon Yoder2, Nicholas Tustison3, James Gee3, Felix W. Wehrli1, Dawn M. Elliott2 1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States; 3Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States We have quantified local strains in a bovine tail intervertebral disc by imaging it with a Helmholtz-pair local transmit coil with a decoupled 4-element re-ceive phased array in a whole-body 7 T MRI scanner. The image data were of exceptional quality and were processed by an advanced algorithm to yield high-resolution strain maps in the axial and sagittal planes of the disc. 808. Quantitative Measurement of Bone Marrow Composition and Bone Structure Using Simultaneous Acquisition of Fat Fraction and T2* with Multiple-Echo Gradient-Echo Method in the Normal Volunteers and Hematological Disease Patients Eito Kozawa1, Waka Mizukoshi1, Naoko Nishi1, Yasuo Sakurai1, Noriko Tanaka1, Fumiko Kimura1 1Saitama Medical University, International Medical Center, Hidaka-shi, Saitama, Japan We illustrate its use for measuring lumbar spine of fat fraction and T2* in normal volunteers and malignant hematological disease patients group with multiple echo gradient echo images (MEGE). Fat fractions of MEGE vs. MR spectroscopy (MRS), and T2* vs. each group were analyzed by linear regression method and Mann-Whitney rank test. Fat fraction values of MEGE and MRS show very good agreement. T2* values vs. each group showed significant difference (p<0.05). In conclusion, MR determination of those parameters could be used to assess and diagnose a deficiency in marrow composition and bone structure using fat fraction and T2*. 809. Higher Lumbar Bone Mineral Density Is Associated with Narrowed Intervertebral Disc Space, But Not Higher Hip Bone Mineral Density: A Study in 359 Elderly Subjects Using an 8-Level MRI Based Disc Degeneration Grading System. Yi Xiang Wang1, J F. Griffith1, W L. Kwok2, C S. Leung2, H T. Ma2,3, D K. Yeung1, A T. Ahuja1, P C. Leung2 1Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong; 2Jockey Club Centre for Osteoporosis Care and Control, The Chinese University of Hong Kong, Prince of Wales Hospital; 3Department of Electronic and Information Engineering, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, China The correlation between osteoporosis and intervertebral disc degeneration in the spine is not fully understood. In this study the relationship between BMD and disc narrowing is analysed in 359 healthy elderly subjects. The results show there was no significant relationship between hip BMD and intervertebral disc space narrowing. With 48 male subjects who had both DXA and QCT, except disc L1/L2, lumbar disc were more likely to have a narrowed space when lumbar BMD was higher. This observed association could be lumbar spine BMD specific since hip BMD better represents systemic BMD. 810. Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) Imaging of the Cervical Spine: Clinical Efficiency Compared with Conventional MR Tsyh-Jyi Hsieh1,2, Twei-Shiun Jaw1,3, Yu-Ting Kuo1,3, Ming-Lun Chiu1, I-Chan Chiang1, Gin-Chang Liu1,3 1Department of Radiology, School of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan, Kaohsiung, Taiwan; 2Department of Medical Imaging, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Taiwan, Kaohsiung, Taiwan; 3Department of Medical Imaging, Kaohsiung Medical University Hospital, Taiwan, Kaohsiung, Taiwan T2-weighted (T2W) iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) ¡V fast spin echo (FSE) imaging can provide good uniformity of fat suppression, but the clinical efficiency is not evaluated. The purpose of this work was to evaluate the clinical efficiency of T2W IDEAL FSE imaging of the cervical spine, compared with conventional fat-saturated T2W FSE, including quantitative measurements of SNR and SNR efficiency and qualitative scoring of diagnostic image quality and fat suppression. 811. In Vivo Measurement of Relaxation Time of Water and N-Acetyl in Intervertebral Disc Using MR Spectroscopy Jin Zuo1, Xiaojuan Li1, John Kurhanewicz1, Sharmila Majumdar1 1Radiology and Biomedical Imaging, Univ. of California, San Francisco, San Francisco, CA, United States Intervertebral disc degeneration (IVDD) related back pain affects about 80% in the general population during the life-time. Traditional imaging techniques rely on disc morphology while actual disc degeneration begins with internal biochemical and biomechanical changes. Proton magnetic resonance spectroscopy (1H-MRS) is a powerful non-invasive tool that has been used for the assessment of metabolites in tissues. Previously, 1H-MRS on a clinical 3T magnetic resonance (MR) scanner has demonstrated the feasibility of using short-echo water suppressed point-resolved spectroscopy (PRESS) for evaluating biochemical changes in cadaveric bovine and human discs. In these studies the degradation of bovine discs, induced by papain digestion, and the prevalent degeneration in cadaveric discs as assessed with Pfirrmann grading was correlated to spectra measures. In this study, we performed single voxel MRS technique in intervertebral discs from healthy volunteers and T1 and T2 relaxation times of water peak and N-acetyl peak of proteoglycan (PG) in the healthy discs were measured. As dehydration and loss of PG are the two primary consequences of disc degeneration, relaxation times may potentially change with degeneration, and quantification of relaxation times might provide valuable information related to disc degeneration. 812. HR-MAS Spectroscopy of Human Intervertebral Disc Tissue Demonstrates the Lactate/N-Acetyl Ratio as a Potential Marker for Painful Degenerative Disc Disease Rahwa Berhanu Iman1, Serena Hu2, Lynn DeLosSantos1, John Claude3, James Peacock3, Sharmila Majumdar1, John Kurhanewicz1 1Radiology, University of California, San Francisco, San Francisco, CA, United States; 2Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA; 3NociMed, Redwood City, CA The intervertebral disc is thought to be a primary source of low back pain, which is difficult to evaluate clinically. To determine whether chemical biomarkers can discriminate painful from non-painful degenerated discs, ex vivo long echo-time 1H (HR-MAS) spectroscopy data were acquired from intervertebral disc tissue and correlated with a clinical assessment of pain. The relative ratios of the lactate/N-acetyl provide a significant discrimination of painful from non-painful degenerated discs. Although there is a clear need for a larger patient cohort study to validate these findings, the lactate/N-acetyl ratio could provide a potential marker for painful disc degeneration. Hall B Wednesday 13:30-15:30 813. Improved Sodium MRI of the Human Knee with Projection Acquisition in the Steady State at 4.7 Tesla Alexander Watts1, Robert Stobbe1, Adrian Tsang1, Christian Beaulieu1 1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada Sodium MRI of knee cartilage is a possible diagnostic method for osteoarthritis, but low signal strength in vivo results in poor quality images. A steady state approach (shorter TR, longer excitation pulse widths) to 3D twisted projection image acquisition may improve sodium SNR by increased averaging over a constant scan time and SAR of 6 W/kg. Simulations predicted a 42% increase in SNR for steady state over ‘fully relaxed’ parameters while a 26+/-5% increase was determined experimentally for sodium in human knee cartilage (n=9). Partial volume effects with synovial fluid and/or relaxation parameter differences may be responsible for this disagreement. 814. Impact of Different Coils on Biochemical T2 and T2* Relaxation Time Mapping of Articular Cartilage Goetz Hannes Welsch1,2, Sebastian Apprich1, Tallal Charles Mamisch3, Marius Mayerhoefer1, Stefan Zbyn1, Siegfried Trattnig1 1MR Center, Department of Radiology, Medical University of Vienna, Vienna, Austria; 2Department of Trauma and Orthopaedic Surgery, University Hospital of Erlangen, Erlangen, Germany; 3Department of Orthopaedic Surgery, University of Basel, Basel, Switzerland The aim of the present initial study was to assess T2 and T2* relaxation time values of patella cartilage in healthy volunteers using three different coils (i) eight-channel knee coil; ii) eight-channel multi-purpose coil; iii) surface coil) at 3.0 Tesla MRI. The mean as well as the zonal T2 and T2* values revealed, in most of the cases, significant differences in between the respective coils. These differences were a little less pronounced in the T2* measurements, compared to the T2 evaluations. The present results demonstrate that biochemical T2 and T2* mapping is highly dependent on the utilized coil. 815. dGEMRIC Evaluation 9 to 20 Years After Autologous Chondrocyte Implantation in the Knee Barbro Danielson1, Haris Vasiliadis2, Maria Ljungberg3, Sowmya Vijayakumar4, Nitya Krishnan4, Deborah Burstein4, Lars Peterson5, Brian McKeon6 1Musculoskeletal Section, Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden; 2Molecular Cell Biology and Regenerative Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden; 3Radiation Physics, University of Gothenburg, Gothenburg, Sweden; 4Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, United States; 5Orthopedics, Sahlgrenska University Hospital, Sweden; 6New England Baptist Hospital, Boston, United States The study assessed the long-term status of isolated cartilage lesions in the knee after ACT using dGEMRIC. Scans were obtained from 31 patients (5 bilateral lesions) total of 36 lesion sites, representing an f/u period of 9.5 to18.5 years post-implant. The dGEMRIC Index of the implant was greater than 90% of the value of the dGEMRIC Index for surrounding native tissue in 70% of cases, even more than 10 years after the implantation. 816. Individual Joint Loading Type Affects Human Cartilage Composition as Measured by Biochemical MRI Sannamari Lepojärvi1, Marianne Haapea1, Tatu Kokkonen2, Juha Isolehto3, Ilkka Kiviranta4,5, Miika T. Nieminen1,6 1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Radiology, Helsinki University Hospital, Helsinki, Finland; 3Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland; 4Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland; 5Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland; 6Department of Medical Technology, University of Oulu, Oulu, Finland Joint loading is dependent on the individual loading type. The aim of this study was to investigate the effect of individual, biomechanically determined joint loading type on biochemical properties of load-bearing articular cartilage in the knee joint, as measured by T2 relaxation time mapping and delayed gadolinium enhanced MRI of cartilage (dGEMRIC) in 37 asymptomatic healthy volunteers. The biochemical composition of cartilage is related to the characteristic loading type of individual subjects while the cartilage constituents may vary with physical performance. Cartilage constituents may be altered with exercise and adapt to individual loading conditions in daily-life activities or joint-loading exercise. 817. Comparison of SPGR and Balanced SSFP for Sodium Knee Imaging Ernesto Staroswiecki1,2, Neal Kepler Bangerter3, Garry Evan Gold1, Brian Andrew Hargreaves1 1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States; 3Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States Early degenerative changes in human articular cartilage are usually accompanied by proteoglycan depletion. Sodium MRI has been shown to correlate with proteoglycan concentration in the tissue. In order to track sodium signal in cartilage, contributions from synovial fluid should be minimized. Here we studied the contrast between fluid and cartilage generated by SPGR and balanced SSFP sequences. We acquired images of phantoms and volunteers at 3T with both sequences and a range of flip angles. Fluid was significantly attenuated on SPGR images with a large flip angle when compared with SSFP data, while the cartilage signal was minimally affected. 818. Age-Related Diffusion Patterns in Intervertebral Disc Degeneration Zhongping Zhang1, Queenie Chan2, Marina Portia Anthony1, Kenneth MC Cheung3, Mina Kim1 1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China; 2Philips Healthcare, Hong Kong, China; 3Division of Spine Surgery, Department of Orthopaedics and Traumatology, Faculty of Medicine, The University of Hong Kong, Hong Kong, China Intervertebral disc (IVD) degeneration is an age-related condition which is associated with a loss of matrix molecules resulting in an alteration of the biochemical and biomechanical tissue properties. Shedding light on age-related matrix alterations may help improve our understanding of the regulatory mechanisms involved during IVD degeneration. In the present work, we conducted diffusion tensor imaging (DTI) for investigating the diffusion patterns of human IVDs. Our results show that DTI-derived metrics can sensitively assess age-related matrix alterations, which may potentially be a useful biomarker in monitoring degenerative disc disease. 819. Prospective Image Registration for Automated Scan Prescription of Follow-Up Knee Images Janet Goldenstein1,2, Joseph Schooler1, Jason C. Crane1, Eugene Ozhinsky1,2, Julio Carballido-Gamio1, Sharmila Majumdar1 1Department of Radiology and Biomedical Imaging, UC San Francisco, San Francisco, CA, United States; 2Joint Graduate Group in Bioengineering, UC Berkeley/UC San Francisco, San Francisco, CA, United States Consistent scan prescription for MRI of the knee is very important for accurate comparison and quantitative analysis of images in a longitudinal study. This study demonstrates the feasibility of using a mutual information based method to register MR images of the knee without segmentation and automatically determine the follow-up scan prescription. This registration method is performed only on the distal femur and is not affected by the proximal tibia or soft tissues. Results show an improvement with registration in the coefficient of variation for cartilage thickness, cartilage volume, and T2 relaxation measurements. 820. Evaluation of the Ability of Delayed Gadolinium-Enhanced MRI (DGEMRIC) to Detect Change in Cartilage Characteristics Among Individuals with Knee Osteoarthritis (OA) Receiving a Collagen Hydrolysate Formulation Nitya Krishnan1, Timothy McAlindon2, Melynn Nuite, Kimberly Carr, Deborah Burstein1,3, Lori Lyn Price, Klaus Flechsenhar4 1Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, United States; 2Division of Rheumatology, Tufts Medical Center, Boston, MA, United States; 3Health Sciences and Technology , Harvard Medical School, Boston, MA, United States; 4Research & Development, Gelita AG, Eberbach, Germany A pilot study was performed to determine if dGEMRIC or T2-mapping could detect changes in knee cartilage among participants treated with collagen hydrolysate (Fortigel®) versus placebo. A randomized, double-blind, 24-week clinical trial included 30 participants with symptomatic knee OA. Half received 10 grams collagen hydrolysate orally. The dGEMRIC index was able to discriminate between treatment and placebo groups in the tibial regions with an increase in dGEMRIC in the active arm. The sample size was small, and so these data are preliminary. 821. In-Vivo Assessment of Collagen Fiber Arrangement in Articular Cartilage with 7T MRI Nikita Garnov1, Gregor Thörmer1, Wilfried Gründer2, Robert Trampel3, Robert Turner3, Thomas Kahn1, Harald Busse1 1Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany; 2Institute of Medical Physics and Biophysics, Leipzig University, Leipzig, Germany; 3Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany The collagen fiber network determines the biomechanical properties of articular cartilage. It has been shown that the ultrastructure of the cartilage can be assessed by means of T2-weighted high-resolution MRI in vitro. With the recent introduction of ultra-high field whole-body scanners, this approach may also be applied to human in-vivo studies. We describe a method to non-invasively assess the fiber structure of knee cartilage and present first results on three healthy volunteers at 7T. High-resolution in-vivo cartilage MRI is considered a helpful and relatively simple tool to evaluate the integrity of the collagen network and general condition. Tuomas Svärd1, Tomos G. Williams2, Eveliina Lammentausta1, Yang Xia3, Miika T. Nieminen4 1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2School of Cancer, Enabling Science and Technology, The University of Manchester, United Kingdom; 3Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI, United States; 4Department of Medical Technology, University of Oulu, Oulu, Finland T2 relaxation time in articular cartilage could provide an early biomarker of cartilage quality in disease. T2 measures are dependent on the orientation of collagen fibrils with respect to the B0 field. Variation in joint positioning has a detrimental effect on the reproducibility of T2. In a study of three volunteers, imaged five times each, the variation in orientation of load-bearing femoral joint surfaces was determined using an Active Appearance Model of the distal femur bone. Simulations revealed that the variation in T2 due to joint positioning is acceptable (0.1-4.7ms) compared to the expected elevation related to pathological changes. Tuomas Svärd1, Martti Lakovaara2, Harri Pakarinen2, Ilkka Kiviranta3, Eveliina Lammentausta1, Jukka Jurvelin4, Osmo Tervonen1,5, Risto Ojala1, Miika T. Nieminen1,6 1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Orthopaedic Surgery, Oulu University Hospital, Oulu, Finland; 3Department of Orthopaedics and Traumatology, Helsinki University Hospital; 4Department of Physics, University of Eastern Finland, Kuopio, Finland; 5Department of Diagnostic Radiology, University of Oulu, Oulu, Finland; 6Department of Medical Technology, University of Oulu, Oulu, Finland The study aimed to determine the usability of biochemical MRI methods, namely T2 relaxation time mapping and dGEMRIC, for detecting early mechanical and visually graded cartilage alterations in vivo, as determined by arthroscopic indentation stiffness measurements and arthroscopic grading, respectively, in 15 subjects. T2 and dGEMRIC values showed a trend with cartilage defect severity, however, no statistical significance was reached. Further, T2 was negatively correlated (r≈-0.6, p<0.05) with cartilage stiffness at several ROIs of the medial compartment. The results suggest that biochemical MRI measurements may be related to information on the mechanical and structural integrity of cartilage. 824. T2 Maps and Diffusion-Weighted Imaging of Knee Cartilage with a DESS Sequence at 3T Ernesto Staroswiecki1,2, Kristin Lee Granlund1,2, Marcus Tedrow Alley1, Garry Evan Gold1, Brian Andrew Hargreaves1 1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States Detailed visualization of articular cartilage is a challenge that requires advanced MRI techniques. In order to detect early changes of osteoarthritis, we require contrast mechanisms capable of showing biochemical properties of cartilage like T2-mapping and diffusion-weighted-imaging. Here we study the diffusion sensitivity of the T2 maps of cartilage generated with a DESS sequence, and present a method for generating T2-weighted and diffusion-weighted images, together with T2 maps and relative-ADC maps of cartilage via two sequential DESS acquisitions with different gradient amplitudes. 825. Assessment of Subchondral Bone Marrow Lipids in OA Patients at 3T Ligong Wang1, Nouha Salibi2, Gregory Chang, Michael Recht, Ravinder R. Regatte 1NYU Langone Medical Center, New York, NY, United States; 2Siemens Medical Solutions, Malvern, PA, USA This work reported the saturated lipid signals and unsaturated lipid indices in different compartments of femoral-tibial bone marrow in OA patents at 3T. There were significant differences among different compartments of femoral-tibial bone marrow only at 2.03 ppm for saturated lipids (P < 0.002). The tibia has relatively higher saturated lipids compared to the femur. The femur has a relatively higher unsaturated lipid index compared to the tibia. Juhani Multanen1, Eveliina Lammentausta2, Risto Ojala2, Ilkka Kiviranta3, Arja Häkkinen4, Ari Heinonen4, Miika T. Nieminen2,5 1Department of Health Sciences, Jyväskylä University, Jyväskylä, 40014, Finland; 2Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 3Unit of Orthopaedics and Traumatology, Helsinki University, Helsinki, Finland; 4Department of Health Sciences, Jyväskylä University, Jyväskylä, Finland; 5Department of Medical Technology, University of Oulu, Oulu, Finland The radiological definition of Kellgren/Lawrence (K/L) for classifying osteoarthritis (OA) gives no insight into the status of articular cartilage, the key factor of early pathological changes of OA. The objective of the current study was to determine whether a relationship exists between the K/L grade and the dGEMRIC index of subjects with early OA (K/L grade 1 or 2). The present results show that the dGEMRIC index is significantly shorter in subjects with K/L grade 2 (N=41) as compared to subjects with grade 1 (N=22). The dGEMRIC index was not, however, correlated with the WOMAC pain score. 827. Bound Pool Fractions Correlate with Proteoglycan and Collagen Content in Articular Cartilage Nikola Aleksandar Stikov1, Kathryn E. Keenan2, John Mark Pauly1, R. Lane Smith3, Robert F. Dougherty4, Garry E. Gold, 3,5 1Electrical Engineering, Stanford University, Stanford, CA, United States; 2Mechanical Engineering, Stanford University, Stanford, CA, United States; 3Orthopaedic Surgery, Stanford University, Stanford, CA, United States; 4Psychology, Stanford University, Stanford, CA, United States; 5Radiology, Stanford University, Stanford, CA, United States In this abstract, a novel method for imaging cartilage is proposed. A quantitative magnetization transfer technique called bound pool fraction (BPF) mapping is applied to human ex vivo knee specimens, and correlations with macromolecular content in articular cartilage are presented. BPFs are positively correlated with proteoglycan content, and negatively correlated with collagen content in articular cartilage.
828. Longitudinal Analysis of Articular Cartilage for Microfracture and Mosaicplasty Procedures Using Quantitative T1rho and T2 MRI William Wyant Schairer1, Alexander A. Theologis1, Sharmila Majumdar1, Xiaojuan Li1, Benjamin Ma1 1University of California, San Francisco, San Francisco, CA, United States A longitudinal MRI analysis was performed on patients with focal cartilage defects of the femur who received either mosaicplasty or microfracture surgical treatment. We examined T1rho and T2 changes at 3-months and 1-year. Additionally, we performed a laminar analysis to compare the superficial and deep cartilage at the repair site and in the surrounding normal tissue. 829. Effect of Tear of the Medial Meniscus on T2 Relaxation Time of Articular Cartilage Risto Ojala1, Antero Saviluoto1, Ilkka Hannila1, Marianne Haapea1, Osmo Tervonen1,2, Miika T. Nieminen1,3 1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Diagnostic Radiology, University of Oulu, Oulu, Finland; 3Department of Medical Technology, University of Oulu, Oulu, Finland Meniscal tears are known to increase the risk of osteoarthritis (OA). To assess whether they influence the composition and structure of articular cartilage, T2 relaxation time of medial weight-bearing tibio-femoral cartilage was measured and compared between 20 patients with a tear in medial meniscus and 20 asymptomatic controls. A tear in medial meniscus resulted in significantly longer T2 values in most of the superficial and deep load-bearing medial femoro-tibial cartilage when compared to controls. T2 mapping may provide a sensitive tool to detect early signs of OA. 830. Multi-Component T2* Relaxation of Knee Cartilage Under UTE Acquisitions Yongxain Qian1, Ashley A. Williams2, Constance R. Chu2, Fernando E. Boada1 1MR Research Center, Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States This work presents new observations of T2* decay of multiple components on human knee cartilage explants with ultrashort echo time (UTE) acquisitions on a clinical 3T MRI scanner. Four types of T2* decay (mono-, bi-, tri-, and non-exponential) in cartilage explants were detected. Multi-component T2* decays were mapped on a pixel-by-pixel basis, permitting examination of the spatial distribution of T2* relaxations in cartilage. 831. Regional Relations Within the Medial Meniscus of the Knee Joint - Assessed with DGEMRIC Georg Scheurecker1,2, Marius Mayerhöfer3, Katja Pinker3, Stephan Domayer4, Siegfried Trattnig1,3 1MR Centre of Excellence, Medical University Vienna, Vienna, Austria; 2CT/MRT Institut am Schillerpark, Linz, Upper Austria, Austria; 3Radiology, Medical University Vienna, Vienna, Austria; 4Orthopedic Surgery, Medical University Vienna, Vienna, Austria A standard dGEMRIC protocol for the knee can be used to assess regional relations within the medial meniscus. We found statistically significant different relations of the red with the white zone and of the surface with the core area of the posterior horn between healthy volunteers versus patients after a cartilage repair surgery. This is most probably due to an adaption to different loading patterns of the meniscus in patients after Matrix-associated cartialge transplantation (MACT) versus healthy volunteers. 832. High-Resolution 1H/23Na MR Imaging of Knee Articular Cartilage Using Dual-Tuned Knee Coil at 7T Jung-Hwan Kim1, Chan Hong Moon1, Alessandro Furlan1, Bumwoo Park1, Tiejun Zhao2, Kyongtae Ty Bae1 1University of Pittsburgh, Pittsburgh, PA, United States; 2MR Research Support, Siemens Healthcare, Pittsburgh, PA, United States We acquired high-resolution proton and sodium images at 7T using dual-tuned 1H/23Na coil and 3D ultra-short-echo spiral trajectory sequence and quantitatively analyzed the distribution of sodium signals at different compartments of the knee cartilage. The images demonstrated excellent SNR and resolution of proton and sodium in vivo that allowed us to perform quantitative analysis of the cartilage morphology as well as characterization of cartilage quality. 833. Preliminary Evaluation of Potential Disease Modification by Hylan G-F 20 (Synvisc®) Using DGEMRIC Pottumarthi Prasad1, Wei Li1, Thomas Schnitzer2, Nitya Krishnan3, Deborah Burstein3 1NorthShore University HealthSystem, Evanston, IL, United States; 2Feinberg School of Medicine, Northwestern University, Chicago, IL, United States; 3Radiology, Beth Israel Deaconess Medical Center, Boston, MA, United States Treatment of osteoarthritis remains to be symptom modification, although the concept of disease modification is currently evolving. Hylan G-F 20 has been shown to demonstrate disease modifying effects, even though it is currently approved for symptom modification. We have performed preliminary evaluation to see if dGEMRIC can detect changes in patients treated with Hylan G-F 20 in a small number of subjects. While we observed little change, we believe this may be due to the relatively advanced disease status. This is in general agreement with other published human trials using joint space width as an outcome measure. 834. Variable Fiber Orientations of Knee Cartilages Investigated by Zonal T2* Measurements with Automatic Segmentation Ping-Huei Tsai1, Hsaio-Wen Chung1, Guo-Shu Huang2 1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 2Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan Osteoarthritis (OA) is a common disease in aged people, which results in degeneration of the articular cartilage and the meniscus. The purpose of this study is to propose an efficient image segmentation method based on the 2D fussy C-means (FCM) algorithm to facilitate MR T2* measurements, and to investigate the zonal difference of knee cartilages at variable fiber orientations. 835. Comparison of T1ρ, T2 Mapping, and Sodium MRI of Osteoarthritic Cartilage in Vivo Melissa Ann Vogelsong1, Ernesto Staroswiecki2, Brian A. Hargreaves, Eric Han3, Jill A. Fattor4, Anne L. Friedlander5, Omer Shah6, Jacquie M. Beaubien7, Garry E. Gold 1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA; 3GE Healthcare Global Applied Sciences Laboratory, Menlo Park, CA; 4Stanford Center on Longevity, Stanford, CA; 5VA Palo Alto Healthcare Center, Palo Alto, CA; 6Georgetown University School of Medicine, Washington, DC; 7Psychology, Stanford University, Stanford, CA Several imaging techniques are currently being investigated for use in visualizing cartilage biochemistry. T2 mapping is thought to assess water content and collagen structure while sodium imaging reflects proteoglycan content, however precisely what affects T1ρ relaxation remains unclear. We imaged 9 knees of patients with osteoarthritis and measured T2 and T1ρ relaxation times as well as sodium signal from corresponding ROIs. No correlation was found between T1ρ relaxation and sodium signal, however there was a moderate correlation between T1ρ and T2 relaxation. T1ρ may therefore depend on a complex interaction of macromolecules rather than proteoglycan content alone. 836. Relaxation Along Fictitious Field (RAFF) Contrast in Bovine Articular Cartilage Timo Liimatainen1, Mikko Nissi2,3, Miika T. Nieminen4,5, Shalom Michaeli6, Michael Garwood6, Olli Gröhn7 1Department of Biotechnology and Molecular Medicine, University of Kuopio, Kuopio, Finland; 2Department of Physics, University of Kuopio, Kuopio, Finland; 3Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 5Department of Medical Technology, University of Oulu, Oulu, Finland; 6Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 7Department of Neurobiology, University of Kuopio, Kuopio, Finland Possibility of measuring the physicochemical properties of cartilage proteoglycans could help diagnosis and monitoring of osteoarthritis. Relaxation along a fictitious field (RAFF) was optimized to detect proton exchange between water and proteoglycans (–OH groups), and its applicability for cartilage imaging was studied using Bloch-McConnell simulations and cartilage samples. Relaxation measurements with optimized RAFF provided better CNRs between deep and intermediate and between deep and superficial cartilage than continuous wave T1ρ corresponding to increasing proteoglycan content towards bone. The RAFF rate constant is suggested as a potential biomarker for cartilage degeneration, also for in vivo imaging. 837. Quantification of Age Dependent Molecular Changes in Guinea Pig OA Model Using T1ρ MRI Matthew Fenty1, Victor Babu Kassey1, George Dodge2, Ari Borthakur1, Ravinder Reddy1 1Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania School of Medicine, Philadelphia, PA, United States; 2Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States T1ρ MRI is sensitive to molecular changes in cartilage, which have been shown to occur early in osteoarthritis. Dunkin-Hartley guinea pigs spontaneously develop osteoarthritis within 9 months of age. This study quantifies the age dependent degeneration of cartilage in the guinea pig stifle using T1ρ MRI with detailed correlation using histology and immunohistochemistry. 838. Sequential Change of Rat Cartilage and Subchondral Bone with Experimental Osteoarthritis Investigated by Quantitative T2* Measurements Ping-Huei Tsai1, Ming-Chung Chou2, Ming-Huang Lin3, Chien-Yuan Lin3, Hsaio-Wen Chung1, Herng-Sheng Lee4, Guo-Shu Huang2 1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 2Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; 3Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan; 4Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan Osteoarthritis (OA) is a disease related to the degeneration of cartilage, pathological change of subchondral bone (SB) and so force, which may leads to a series of inflammation and pain responses. The purpose of this study is to investigate the relationships among cartilage, menisci and SB with the progression of OA by MR T2* measurements. 839. Compromised Perfusion in Femoral Head of Normal Wistar Rats: Distinctive Perfusion MRI Evidence of Contrast Wash-Out Delay Yi Xiang Wang1, M Deng1, H T. Ma2,3, Y F. Zhang4, J F. Griffith1, T C. Kwok4, A T. Ahuja1 1Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong; 2Jockey Club Centre for Osteoporosis Care and Control, The Chinese University of Hong Kong, Prince of Wales Hospital; 3Department of Electronic and Information Engineering, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, China; 4Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital Clinical studies have shown femoral head has a poorer blood supply compared to femoral neck and femoral shaft. It has been suggested that delayed wash-out in DCE MRI suggests tissue blood stasis or outflow obstruction. In this study, the DCE MRI wash-out characteristics in femoral head of normal rats were investigated, and comparison was made to those of proximal and distal femoral diaphysis, distal femoral epiphysis, proximal tibial epiphysis, proximal tibial diaphysis. After the initial fast wash-in phase, for femoral head a continuous further slow wash-in was observed, while other sites showed a wash-in phase followed by a wash-out phase. 840. Z-Spectroscopy with Phase Alternating Irradiation (ZAPI) in Articular Cartilage Mikko Johannes Nissi1,2, Miika Tapio Nieminen3,4, Olli Heikki Gröhn5, Johanna Närväinen5 1Department of Physics, University of Kuopio, Kuopio, Finland; 2Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; 3Department of Medical Technology, University of Oulu, Oulu, Finland; 4Department of Diagnostic Radiology, Oulu University Hospital , Oulu, Finland; 5Department of Neurobiology, A.I. Virtanen Institute for molecular Medicine, University of Kuopio, Kuopio, Finland Exchange between collagen and bulk water in cartilage has been observed earlier in Magnetization transfer (MT) experiments. In the present study, the suitability of a recently introduced MT method, alternating phase irradiation Z-spectroscopy (ZAPI), in characterization of MT and T2 distribution in bovine cartilage was investigated. Use of alternating phase (AP) irradiation in ZAPI provides a unique possibility for T2 filtering by adjusting the pulse parameters. ZAPI was used for Z-spectroscopy and T2 filtered on-resonance MT of cartilage samples and the dependence of these parameters as a function of cartilage depth was analyzed. 841. Measurement of T1 Relaxation Time in Articular Cartilage Using SWIFT Mikko Johannes Nissi1,2, Lauri Juhani Lehto3, Curtis Andrew Corum4, Djaudat Idiyatullin4, Olli Heikki Gröhn5, Miika Tapio Nieminen6,7 1Department of Physics, University of Kuopio, Kuopio, Finland; 2Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; 3Department of Biotechnology and Molecular Medicine, University of Kuopio, Kuopio, Finland; 4CMRR, University of Minnesota, Minneapolis, MN, United States; 5Department of Neurobiology, A.I. Virtanen Institute for molecular Medicine, University of Kuopio, Kuopio, Finland; 6Department of Medical Technology, University of Oulu, Oulu, Finland; 7Department of Diagnostic Radiology, Oulu University Hospital , Oulu, Finland Spins with sub-millisecond T2 relaxation times are virtually invisible in conventional MRI. Signal from articular cartilage is typically low due to effective dipolar coupling. In this study, T1 maps of articular cartilage were measured using the recently introduced SWIFT method, which is capable of acquiring signal from virtually all spins, with a T2 sensitivity limit around few microseconds. The feasibility and performance of SWIFT for T1 measurements was compared to conventional FSE method. SWIFT had better SNR performance especially in cartilage layers with short T2. The T1 values measured using SWIFT were comparable to those measured with FSE sequence. 842. Multiexponential T2 Relaxation Analysis to Assess the Development of Engineered Cartilage Onyi Irrechukwu1, Remy Roque1, David Reiter1, Richard Spencer1 1National Instiute on Aging, National Institutes of Health, Baltimore, MD, United States The objective of this study was to use multiexponential analysis of T2 relaxation data to monitor the development of engineered cartilage. Chondrocyte-seeded collagen constructs were studied after 1-4 weeks of culture. Four water compartments were consistently detected; however, an additional compartment, T21-2, emerged in week 4. The two most slowly relaxing components, T23 and T24, loosely associated with macromolecules, decreased with macromolecular synthesis. T22 was assigned to PG monomers and the appearance of T21-2 was consistent with aggregation of these monomers. T21 was assigned to collagen-bound water and its fraction size decreased in week 4, an indication of scaffold degradation. 843. DTI of the Human Patellar Cartilage Ex Vivo at 1.5T: Comparisson with 17.6 T and Patterns of Disease José G. Raya1, Lucianna Filidoro1, Andreas Kellerer2, Olaf Dietrich1, Elisabet Mützel3, Maximilian F. Reiser2, Peter Jakob4, Christian Glaser2 1Josef Lissner Laboratory for Biomedial Imaging, Departmentof Radiology, University of Munich, Munich, Germany; 2Department of Clinical Radiology, University of Munich; 3Department of legal medicine, University of Munich, Germany; 4Departmentof experimental physics 5, University ofWuerzburg, Germany DTI of the articular cartilage has been restricted to ultra-high fields (>7T) and small samples because of the short T2 and high resolution needed. The aim of this work was to demonstrate the value of DTI of the cartilage performed ex vivo on a 1.5T scanner and to characterize the patterns of pathology. Excised human patellar cartilage (n=25) has been examined at 1.5T. Additionally, six samples have been imaged at 17.6T. DTI parameters were very similar at both field strengths. Imaging the whole cartilage plate allowed identifying different patterns of pathology: focal lesions, alterations of the subchondral bone and osteophytes. 844. Improved Specificity of Cartilage Matrix Assessment Using Multiexponential T2 Parameter Maps with Validation by Fourier-Transform Infrared Spectroscopic Imaging David A. Reiter1, Remy A. Roque1, Ping-Chang Lin1, Onyi Irrechukwu1, Nancy Pleshko2, Richard G. Spencer1 1National Institute on Aging, National Institutes of Health, Baltimore, MD, United States; 2Department of Mechanical Engineering, Temple University, Philadelphia, PA, United States We sought to improve the specificity of cartilage matrix assessment through localized multiexponential T2 analysis permitting the mapping of matrix associated water compartments. Maps of MR-derived proteoglycan- (PG) bound water fractions (wPG) showed differences between young and mature cartilage; these differences were consistent with biochemically-derived PG content and Fourier-transform infrared spectroscopic imaging (FT-IRIS) derived PG content. Good spatial correspondence was observed between wPG maps and FT-IRIS-derived PG maps normalized by water content, demonstrating the potential of this approach to detect and map PG in degraded cartilage. 845. The Macromolecular 1H NMR Lineshape in Cartilage Gil Navon1, Uzi Eliav1 1School of Chemistry, Tel Aviv University, Tel Aviv, Israel The analysis of the magnetization transfer contrast under incomplete saturation of the macromolecules (common in clinical setups) requires the knowledge of the macromolecular spectral lineshape. In previous studies this information was retrieved by fitting the MTC data to models where the lineshape characteristic was kept as a free parameter. In the current study we present a method that is a combination of double and zero quantum filtering for measuring the macromolecular lineshape. A demonstration of the method is given for the macromolecular fraction of articular cartilage. The lineshape is Gaussian with width at half height of 27.3 kHz. 846. High-Resolution DTI to Study Articular Cartilage Dehydration Cesare E. M. Gruber1,2, Silvia Capuani, 12, Giovanni Giulietti3, Tommaso Gili, 1,3, Bruno Maraviglia1,4 1Physics, SAPIENZA University of Rome, Rome, Italy; 2Physics, CNR-INFN SOFT, Rome, Italy; 3MARBILab, Enrico Fermi Center, Rome, Italy; 4Neuroimaging Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy T2-w scans and DTI were used to monitor degradation processes in cartilage samples due to dehydration. T2-w measures did not provide useful information. Conversely, DTI revealed a decrease of MD and an increase of FA over the first 48hrs, thus suggesting a reduction of water content and a consequent increase of collagen fibril density. More interestingly, increased MD and decreased FA were observed between 48 and 60hrs. This finding likely reflects degeneration of proteoglycans. These experimental observations propose a new model to investigate the pathophysiology of osteoarthritis, and might prompt a new MRI approach for diagnostic purposes in humans. 847. Dynamic Contrast-Enhanced MRI: A Valuable Non-Invasive Tool to Evaluate Tissue Perfusion of Free Flaps? Claudia Fellner1, Ernst M. Jung1, Stefan Feuerbach1, Lukas Prantl2 1Institute of Radiology, University Medical Center Regensburg, Regensburg, Germany; 2Department of Traum and Plastic Surgery, University Medical Center Regensburg, Regensburg, Germany The aim of this study was to evaluate the perfusion of free flaps using DCE MRI. DCE covering the whole flap was performed in 11 patients. Signal increase over time in normally perfused flaps was similar to the reference tissue; there was no significant difference depending on the position within the flap. In flaps with compromised perfusion the increase was significantly lower than in the reference tissue. Normalized signal increase in adequately perfused flaps and flaps with compromised perfusion showed a significant difference. DCE MRI may be a valuable non-invasive tool to evaluate tissue perfusion of the complete free flap. 848. Application of the Dice Similarity Coefficient (DSC) for Failure Detection of a Fully-Automated Atlas Based Knee MRI Segmentation Method Karl G. Baum1, Edward Schreyer1, Saara Totterman1, Joshua Farber1, Jose Tamez-Peña1, Patricia González1 14Qimaging, LLC, Rochester, NY, United States Quantitative analysis of MRI images is providing new insight into and sensitivity to detect osteoarthritic progression, but is encumbered with the time, cost and variability associated with manual or semi-automated segmentation. To address this, a fully-automated knee MRI segmentation and analysis method was developed and validated. Although the method has proven to be robust, in a small percentage of cases (< 2%) underlying image quality or other anomalies may produce poor segmentation results. This study examines the feasibility of using the Dice Similarity Coefficient (DSC) as an objective, reproducible and automated method of accurately detecting segmentation failure. 849. High Resolution Bilateral Hip Joint Imaging at 7 Tesla Using Fast Multi-ROI B1 Shim Methods Jutta Ellermann1,2, Ute Goerke2, Pierre-Francois Van de Moortele2 1University of Minnesota Medical School, Minneapolis, MN, United States; 2Center for Magnetic Resonance Research, Minneapolis, MN, United States Recent advances in orthopedic surgery allow for successful treatment of subtle developmental, often bilaterally occurring hip joint abnormalities. Femoroacetabular impingement (FAI) typically causes labral tears and chondral lesions. Clinical unilateral studies at 1.5 and 3T often use intraarticular Gadolinium. In this preliminary study, we demonstrate that high resolution, high contrast/noise images can be obtained at 7 T without contrast enhancement, both hips being imaged simultaneously despite of transmit B1 distortion at very high field. Key components include the use of a transceiver RF coil array together with fast, low SAR B1+ shim methods, which could become standard components in 7T imaging protocols. Hall B Thursday 13:30-15:30
850. Three and Four Point Dixon
Comparison at 3T: in Vitro and in Vivo 1King's College London, London, United Kingdom; 2King's College Hospital, London, United Kingdom; 3Guy's and St Thomas' Hospital, London; 4Imaging Sciences, King's College London In this study, 3 and 4-point Dixon MRI methods were compared at 3T in phantoms with known compositions of fat and water and compared to fat-water ratios from localised MRS in the calf muscle from eight healthy volunteers.In vitro, both 3 and 4 point Dixon techniques investigated correlated well with the fat content of the phantoms. In vivo, the 4 point Dixon technique with a 1 or 1.22 ms ÄTE appears to be the more reliable technique for intra muscular fat quantification. 851. Feasibility and Reproducibility of MR Fat-Fraction Measurements in Muscle Using Iterative Signal Decomposition with a Multifrequency Fat Signal Model Beatrijs Henriette Aleid Wokke1, Clemens Bos2, Holger Eggers2, Andrew G. Webb3, Hermien E. Kan3 1Neurology, Leiden University Medical Centre, Leiden, Netherlands; 2Philips Healthcare, Best, Netherlands; 3Radiology, Leiden University Medical Centre, Leiden, Netherlands MRI is finding increasing importance in the follow up of muscle diseases in which there is fatty muscle infiltration. Techniques such as multiecho chemical shift-based water-fat separation are highly useful because they provide quantitative values for fat fractions. Despite the presence of multiple peaks in the fat spectrum, the fat fraction is usually obtained through a single peak model. Multipeak correction should improve the obtained fat fraction. In this study we validate that correction for multiple fat peaks does indeed improve quantification of fat fractions in vitro and is applicable to, and highly reproducible in, muscle studies in vivo. 852. Test-Retest Reproducibility of MTR, T2 and 3-Point Dixon Fat Quantification Methods in Muscle MRI Chris David James Sinclair1,2, Jasper M. Morrow1, Tarek A. Yousry1,2, Xavier Golay2, John S. Thornton1,2 1MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London WC1N 3BG, United Kingdom; 2National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom We performed a test-retest reproducibility study of histogram metrics in the thigh and calf muscles of 8 healthy individuals. Quantitative maps of MT ratio, T2 relaxation time and 3-point Dixon fat-fraction were acquired from each subject twice with a between scan interval of 14 days. The inter-scan reproducibility of the fitted histogram peak position was evaluated using intra-class correlation coefficients and Bland-Altman plots. No systematic differences were noted and most variability could be attributed to differences between individuals, providing confidence that similar implementation of these methods may be used as potential markers of neuromuscular disease in patient groups. 853. Muscle Fat Infiltration in Limb Girdle Muscular Dystrophy 2I: A Comparison of Qualitative T1w and Quantitative Dixon Imaging Kieren Grant Hollingsworth1, Tracey A. Willis2, Anna Coombs3, Anna Mayhew2, Michelle Eagle2, Andrew Mark Blamire1, Volker Straub2 1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; 2Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; 3SFC Brain Imaging Research Centre, Edinburgh University, Edinburgh, United Kingdom LGMD2I leads to muscle wasting, necrosis, and fat infiltration. Future trials of therapy require robust measures of fat infiltration and infiltration pattern to determine whether muscle deterioration can be arrested. T1w imaging and 3-point Dixon was performed at calf and thigh for 13 diagnosed LGMD2I patients and 6 age-matched controls. A 6-point scale assessment and region-of-interest quantitative analysis of calf and thigh muscles in one cross-section were performed. Generally, thigh muscles were more fat infiltrated than the calf muscles. Qualitative and quantitative measures were significantly correlated, though there was considerable overlap of fat percentages at the lower qualitative grades. 854. Testing the Efficacy of Therapeutic Approaches with in Vivo 1H MRS of Intramyocellular Lipids in the Rat Skeletal Muscle Heiko G. Niessen1, Michael Neumaier1, Thomas Kaulisch1, Corinna Schoelch2, Detlef Stiller1 1In-Vivo Imaging Unit, Dept. of Drug Discovery Support, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, BW, Germany; 2Dept. of Cardiometabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, BW, Germany Intramyocellular lipids (IMCL) have been identified as important marker for insulin resistance in type 2 diabetes. We used in vivo MRS to evaluate the efficacy of a CB1-receptor antagonist on the muscle lipid content. MR measurements were performed using a custom-made Helmholtz coil set-up for signal reception. After a significant reduction of IMCL content upon treatment, reservoirs almost completely recover within two weeks after treatment. In addition to significant differences between control and treated rats, different time points can be distinguished by their IMCL content. IMCL data correlate with body fat content, body weight and other biochemical parameters. 855. Optimization of Spectroscopy-Based Diffusion Measurements of Intramyocellular Lipids Vaclav Brandejsky1, Roland Kreis1, Chris Boesch1 1Department of Clinical Research, University of Bern, Bern, Switzerland Intramyocellular lipids (IMCL) are related to insulin resistance and are an important substrate for the muscular metabolism. Studies of diffusion properties of these lipids in vivo may contribute to the understanding of their physiological role. However, due to low diffusion coefficients, very strong gradients are required leading to motion artifacts. Cardiac pulsations induce additional signal variations. This study aimed at optimizing parameters for diffusion measurements by MR spectroscopy in skeletal muscle. It was found that both physiologic triggering and independent phase corrections of individual spectra is essential to obtain correct diffusion measurements for IMCL in vivo. 856. Muscle Spectroscopy Shows IMCL, Creatine and Choline Are Biomarkers for Adolescent Type 1 Diabetes Thomas WJ Ash1, Guy B. Williams1, Fiona Regan2, Sally Georgia Harding1, Tero Saukkonen2, David B. Dunger2, T Adrian Carpenter1, Alison Sleigh1 1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom; 2Department of Paediatrics, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom Using machine learning (support vector machines) we construct a model that classifies soleus muscle spectra of adolescents into Type 1 diabetes / control groups with 95% accuracy in leave one out tests. This is an improvement on previous analysis of the data using solely IMCL peak area calculations which achieves 84% accuracy. The model confirms that IMCL height increases in type one diabetics, as well as showing that creatine and choline peaks are broadened in the type 1 diabetic group. Francisco Ortiz-Nieto1, Jan Weis1, Lars Johansson1,2, Håkan Ahlström1 1Department of Radiology, University Hospital, Uppsala, Sweden; 2Astra Zeneca R&D The purpose of this study was to determine and compare EMCL and IMCL content in the calf and thigh muscles of normal male and female volunteers using high spatial resolution MRSI. A common feature for both genders was higher total fat content in the thigh muscles compared with the calf. The mean IMCL level was, however, higher in the calf muscles. No significant differences in lipid concentrations of correspondent VOIs were found between genders. The high-spatial-resolution MRSI technique enables a more detailed study of muscle lipid distribution. Hall B Monday 14:00-16:00 858. Creatine Methylene Group and PCr Observed by Interleaved 1H/31P MRS During Muscle Exercise Martin Meyerspeer1,2, Roberta Kriegl3, Ewald Moser1,4 1Biomedical Technology and Physics, Vienna Medical University, Vienna, Austria; 2High Field MR Centre of Excellence, Vienna Medical University, Austria; 3Siemens Austria; 4High Field MR Centre of Excellence, Vienna Medical University, Vienna, Austria Data were measured with interleaved dynamic localised 1H and 31P spectroscopy, following PCr and Cr2 signal during ischaemic rest, exercise and recovery of human calf muscle.
859. Post-Ischemic Stenosis and Reperfusion Studied by Dynamic 31P MRS and Functional Imaging Albrecht Ingo Schmid1,2, Martin Andreas3, Martin Meyerspeer2,4, Ewald Moser1,4, Michael Wolzt1 1Dpt. of Clinical Pharmacology, Medical University of Vienna, Wien, Austria; 2MR Center of Excellence, Medical University of Vienna, Wien, Austria; 3Department of Cardiac Surgery, Medical University of Vienna, Wien, Austria; 4Center of Biomedical Engineering and Physics, Medical University of Vienna, Wien, Austria Post-ischemic stenosis is a common clinical finding, yet rarely studied by NMR. 31P MRS and BOLD sensitive EPI was measured (two days) in 11 male subjects, with and without 5min stenosis (cuff at 30mmHg below cystolic pressure) following 20min cuff (thigh), the last two minutes performing plantar flexion. During stenosis pH and PCr remained at post-ischemic levels, BOLD signal declined further. In conclusion, stenosis is a state in which oxygen supply is insufficient to start PCr recovery. 860. A 31P MRS Study of the Effects of Exercise-Induced Acidosis on Phosphocreatine Recovery Kinetics in Three Muscle Groups in a Single Cohort of Human Subjects Gwenael Layec1, Emil Malucelli2, Christophe Vilmen1, David Manners2, Kazuya Yashiro1, Claudia Testa2, Patrick J. Cozzone1, stefano Iotti2, David Bendahan1 1CRMBM UMR CNRS 6612, Marseille, France; 2Dipartimento di Medicina Interna, dell’Invecchiamento e Malattie Nefrologiche; Università di Bologna, Italy It is acknowledged that mitochondrial function can be assessed in vivo from PCr resynthesis during recovery period. Several studies have pointed out that end-of-exercise conditions could bias the characterization of mitochondrial function. The purpose of the present study was to analyze the relationship between end-of-exercise pH and PCr recovery rates in forearm, calf and thigh muscles in a single group of subjects in order to determine whether a common normalisation frame could be adopted for different muscles. Overall, our results clearly illustrate that, whatever the muscle investigated, low end-of exercise pH is systematically related to a slower PCr recovery kinetics. 861. Exercise Protocol and Muscular Fiber Type Composition Dependent Phosphocreatine Recovery in Health and Disease Marco Jauslin1, Anke Henning1, Ulrike Dydak2, Haiko Sprott3, Dieter Meier1, Hans H. Jung4, Peter S. Sándor4, Peter Boesiger1 1Institute for Biomedical Engineering, ETH and University Zürich, Zürich, Switzerland; 2School of Health Sciences, Purdue University, West Lafayette, IN, United States; 3Department of Rheumatology and Institute of Physical Medicine, University Hospital Zürich, Zürich, Switzerland; 4Department of Neurology, University Hospital Zürich, Zürich, Switzerland Differences in phosphocreatine recovery (represented by its time constant, normalized for pHmin) between controls and patients with mitochondrial encephalomyopathies (and migraine with aura) have been detected with 31P-MRS exercise protocols of both low and increasing intensity at low contraction frequency. By employing a protocol of high intensity and high contraction frequency these differences vanish, which may be explained by higher fractions of activated fast twitch fibers and interindividual variations in muscle fiber type composition in controls. Our observations therefore challenge the notion of absolute workload independence of PCr recovery due to different recovery characteristics of fast and slow twitch fibers. 862. Localised Versus Unlocalised Dynamic 31P MRS Acquisition in Exercising Human Muscle at 7T Martin Meyerspeer1,2, Ewald Unger1, Thomas Mandl1,2, Tom Scheenen3, Graham J. Kemp4, Ewald Moser, 2 1Center for Biomedical Technology and Physics, Vienna Medical University, Vienna, Austria; 2High Field MR Centre of Excellence, Vienna Medical University, Vienna, Austria; 3Dpt. of Radiology, Radboud University, Nijmegen, Netherlands; 4School of Clinical Science, Faculty of Medicine, University of Liverpool, Liverpool, United Kingdom The effect of localised versus non-localised 31P MRS on data acquired from aerobically exercising human gastrocnemius muscle is studied at ultra hight field. For localisation, a short TE single voxel spectroscopy MR sequence comprising adiabatic refocussing which allows high temporal resolution is used. From a series of exercise bouts of equal intensity we conclude that with localisation, PCr is depleted to a lower level, recovery from depletion is faster and no compartmentation of pH, manifest in a spliting of the Pi peak is observed, in contrast to non-localised 31P MRS. 863. Resting and Maximal Oxidative ATP Production Are Independent Parameters of Muscle Mitochondrial Function Douglas E. Befroy1, Ryan G. Larsen2, Michael A. Tevald2, Jane A. Kent-Braun2 1Yale University, New Haven, CT, United States; 2University of Massachusetts, Amherst, MA, United States Several MRS methods have been developed to investigate muscle mitochondrial function in-vivo. Although some studies have detected alterations in oxidative metabolism in the elderly and type-2 diabetes, others have discerned no effect. Resolving these disparities is confounded by differences in subject selection and muscle metabolic phenotype between studies, and by methodological differences between techniques. To establish whether correlated or independent parameters of mitochondrial metabolism are assessed by these methods, we have directly compared three 31P-MRS techniques: resting Pi → ATP flux, ischemic PCr decline and post-contraction PCr recovery, in a single muscle compartment in a group of healthy male subjects. 864. Exercise Ability Is Determined by Muscle ATP Buffer Content, Not Pi or PH Jeroen A.L. Jeneson1, Joep P. Schmitz1, Johannes H. van Dijk2, Dick F. Stegeman2, Peter A. Hilbers1, Klaas Nicolay1 1Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Clinical Neurophysiology, University Medical Center St Radboud, Nijmegen, Netherlands Muscle fatigue is a primary symptom in human myopathy. Its molecular basis remains hotly debated. We tested the in vivo significance of two leading hypotheses – i.e., Pi accumulation and muscle acidification – using bicycle ergometry, 31P MR spectroscopy and multi-channel surface electromyography. The experimental design allowed quasi-independent manipulation of intramuscular concentrations of Pi and H+ at the start of exercise. It was found that the ability of a subject to exercise against a supramaximal load maintaining a pedaling frequency of 80 rpm was neither affected by low intramuscular pH or high Pi but required a minimal phosphocreatine concentration of 5 mM. 865. Exercise-Induced Muscle Activities of the Trunk: Detectability of the Slight Impact Using Muscle Functional MRI Noriyuki Tawara1, Osamu Nitta2, Hironobu Kuruma2, Mamoru Niitsu3, Atsuto Hoshikawa1, Toru Okuwaki1, Akiyoshi Itoh4 1Department of Sports Medicine, Japan Institute of Sports Sciences, Tokyo, Japan; 2Department of Physical Therapy, Tokyo Metropolitan University, Tokyo, Japan; 3Department of Radiological Sciences, Tokyo Metropolitan University, Tokyo, Japan; 4NIHON University, Chiba, Japan Exercise-induced muscle activity is essential in sports medicine, especially for the trunk muscle. MRI can evaluate muscle activity; T2 of exercised muscle increases compared to that of rested muscle. Previous studies have proposed the muscle functional MRI (mfMRI), which visualizes muscle activity in enhanced activated muscle. However, the body parts that can be studied by mfMRI are limited to the limbs. In order to evaluate trunk muscle activity induced by exercise, we proposed and verified the feasibility of mfMRI using ultrafast imaging. This study evaluated the detectability of the slight impact on trunk muscle activity induced by acute exercises. 866. Detection of the Temporal Sequence of Muscle Recruitment During Cycling Exercise Using MRI Christopher Paul Elder1,2, Ryan N. Cook1,3, Ken L. Wilkens1, Marti A. Chance2, Otto A. Sanchez, 12, Bruce M. Damon, 12 1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 2Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States; 3Biomedical Engineering, Vanderbilt University, Nashville, TN, United States The purpose of this project was to use MRI to determine the temporal sequence of muscle recruitment during cycling by applying variable work rates during the pedal cycle and validate the imaging data using electromyography. Variable work rates were applied in two different distributions; the first increased post-exercise T2 in the extensors and flexors of the thigh, the second increased post-exercise T2 in the flexors only. Similar patterns were observed in the electromyography data, providing validation for the future use of the technique to fully characterize recruitment in individual muscles during cycling, along with applications to functional electrical cycling. 867. Motor Unit Loss in Aging Skeletal Muscle Is Not Accompanied by Increased Heterogeneity of the T2 Increase After Exercise. Theodore F. Towse1, Jill M. Slade2, Michael T. Andary3, Ronald A. Meyer1 1Physiology, Michigan State University, East Lansing, MI, United States; 2Radiology, Michigan State University, East Lansing, MI, United States; 3Physical Medicine And Rehabilitation, Michigan State University, East Lansing, MI, United States Loss of motor units is often compensated for by reinnervation of fibers from nearby axons, leading to unit reorganization and fiber-type clumping. Previous studies suggest that motor unit reorganization could result in increased heterogeneity of the T2 increase observed by MRI after moderate exercise. This study shows that, despite a 50% decrease in motor unit number in anterior tibial muscles of elderly vs. younger subjects, the heterogeneity of muscle T2 after exercise is no greater in elderly than in younger subjects. The results suggest that fiber reinnervation is not a dominant mechanism compensating for motor unit loss in muscles of elderly subjects. 868. Effect of Cholecalciferol Supplementation on Muscle Strength in Healthy Volunteers with Low Serum 25(OH)D: A Double Blind Randomized Placebo Controlled Trial Rajat Gupta1, Uma Sharma2, Nandita Gupta1, U Singh3, Randeep Guleria4, Naranamangalam R. Jagannathan2, Ravinder Goswami1 1Department of Endocrinology, All India Institute of Medical Sciences, New Delhi, Delhi, India; 2Department of NMR & MRI Facility, All India Institute of Medical Sciences, New Delhi, Delhi, India; 35Department of Physical Medicine and Rehabilitation, All India Institute of Medical Sciences, New Delhi, Delhi, India; 4Department of Medicine, All India Institute of Medical Sciences, New Delhi, Delhi, India Effects of six months cholecalciferol and calcium supplementation was investigated on the skeletal muscle strength and muscle energy metabolism using 31PMRS in healthy volunteers with low serum 25(OH)D in a double blind randomized placebo controlled trial. At six months, 25(OH)D levels, hand grip strength, gastrosoleus muscle strength, distance covered during six minute walk were significantly higher in cholecalciferol compared to placebo group (p=0.001). There were no significant differences in MIP, MEP and PCr/Pi ratio in the two groups at six months. Thus, improvement in muscle strength could be due to factors other than change in muscle energy metabolism. Hall B Tuesday 13:30-15:30 869. Short TR, Elongated Echo Time Spectroscopy (STREETS) of Muscle at 3 T. Giulio Gambarota1, Mark Tanner1, Rex D. Newbould1 1GlaxoSmithKline Clinical Imaging Center, London, United Kingdom The measurement of IMCL is hampered by the fact that IMCL resonances overlap with the much larger resonances of extramyocellular lipids (EMCL). Long echo time acquisition allows for a better discrimination of IMCL from EMCL, however, it to suffer from the low signal-to-noise ratio (SNR). In the current study, we show that with a the short TR of 600ms, a 50% improvement in SNR (compared to TR = 2s) is achieved in lipid spectra. 870. Sodium Concentration Quantification in Human Calf Muscle Using UTE Imaging at 7.0T Peter Linz1, Davide Santoro2, Wolfgang Renz, 2,3, Friedrich C. Luft4, Jens Titze1, Thoralf Niendorf2,4 1Department of Nephrology and Hypertension, University Clinic Erlangen-Nuernberg, Erlangen, Germany; 2Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany; 3Siemens Medical Solutions, Erlangen, Germany; 4Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany Sodium metabolism in muscle is changed in hypertensive animal models. With Na high field MRI and UTE-sequences Na-concentrations in human muscle can be studied at fast acquisition times. times. 871. Quantitative Magnetization Transfer in In Vivo Healthy Human Skeletal Muscle at 3T Chris David James Sinclair1,2, Rebecca S. Samson3, David L. Thomas4, Nikolaus Weiskopf5, Antoine Lutti5, John S. Thornton1,6, Xavier Golay, 2,6 1MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London WC1N 3BG, United Kingdom; 2Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London WC1N 3BG, United Kingdom; 3Department of Neuroinflammation, UCL Institute of Neurology, London WC1N 3BG, United Kingdom; 4Advanced MRI Group, UCL Medical Physics, London WC1N 3BG, United Kingdom; 5Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London WC1N 3BG, United Kingdom; 6National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom We applied a quantitative magnetization transfer model to healthy human muscle data in vivo to pave the way to its implementation in patients with neuromuscular diseases. The right lower leg of 10 subjects was imaged at 3T with an MT-prepared sequence with variable offset frequencies and amplitudes and accompanying T1 and B1 maps. A 2-pool MT model accounting for pulsed saturation was fitted to the data to obtain qMT parameters for normal muscle such as T2 of the restricted proton pool and the restricted pool fraction f, measured to be around 8%. 872. Immune Responses to Adeno Associated Virus Vectors in Canine Muscle Using MRI for Duchenne Muscular Dystrophy Donghoon Lee1, Martin Kushmerick1, Zejing Wang2, Stephen Tapscott2 1University of Washington, Seattle, WA, United States; 2Fred Hutchinson Cancer Research Center, Seattle, WA, United States One challenge of gene therapy, a promising treatment for Duchenne muscular dystrophy, is to understand immune responses to adeno associated virus (AAV) vectors used for gene delivery. Canine MR imaging was conducted to noninvasively monitor local inflammatory responses to AAV in dog muscle over time by measuring T2 values and volumes of the inflammatory areas. The volume increase of 33 ~ 150 % was monitored on semitendinosus muscle and the median T2 value was significantly higher at the sites of AAV injection (60.1 ± 5.4 ms) than those from the un-injected muscles (33.6 ± 0.5 ms) in the contra-lateral muscle. 873. Relaxation Parameters of N-Acetyl in Healthy and Osteo-Arthritic Cartilage - An High Resolution Magic Angle Spinning (HR-MAS) Study Keerthi Shet1, Sarmad Siddiqui2, John Kurhanewicz2, Xiaojuan Li1 1Radiology, University of California at San Francisco, San Francisco, CA, United States; 2Radiology, University of California at San Francisco, San Francisco , CA, United States Osteoarthritis (OA) is a degenerative joint disease that results in degradation and gradual loss of articular cartilage. Proteoglycan loss and alteration in the cartilage has been considered an important marker for detecting and measuring the progress of OA. The N-acetyl resonance observed in HR-MAS spectra arises from the proteoglycan content in cartilage. We aim to detect the changes in the mobility of the N-acetyl moiety due to the degradation process that occurs in OA as reflected in the relaxation parameters of the entity (T1 and T2). An increase in T2 relaxation time is observed in case of ex-vivo human osteo-arthritic cartilage samples. 874. Independent Component Analysis and Artifact Removal in Human Calf Muscle Functional MRI Nicole Damara Fichtner1,2, Ewald Moser1, Michael Wolzt2, Albrecht Ingo Schmid1,2 1MR Centre of Excellence, Medical University of Vienna, Vienna, Austria; 2Dept. of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria Human calf muscle functional magnetic resonance imaging data, taken while simulating ischemia and acquired using echo planar imaging, can have many artifacts, particularly those from motion. Using temporal independent component analysis (ICA) on this type of data is a novel technique for separating the time-courses into various components. We show that it is possible to separate and remove artifacts from physiologically relevant information using temporal ICA. The remaining components can mostly be associated with various physiological effects, including those related to ischemia. The removal of artifacts and separation into components will improve the ease of further statistical analysis. 875. Vastus Lateralis/vastus Medialis Cross-Sectional Area Ratio Impacts Presence and Degree of Knee Joint Abnormalities and Cartilage T2 Determined with 3T MRI – an Analysis from the Incidence Cohort of the Osteoarthritis Initiative Judong Pan1, Christoph Stehling2,3, Christina Muller-Hocker4, Benedikt Jakob Schwaiger5, John Lynch6, Michael Nevitt6 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA , United States; 2Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 3Department of Clinical Radiology, University of Muenster, Germany; 4Technical University of Munich, Germany; 5Ludwig-Maximilians University of Munich, Germany; 6Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States Quadriceps strength has been extensively studied in relationship to knee osteoarthritis (OA). However, the role of vastus lateralis and vastus medialis in OA remains unclear. We examined 176 non-symptomatic subjects with risk factors for OA selected from the Osteoarthritis Initiative incidence cohort using cartilage T2 mapping technique and 3 Tesla MRI morphological analyses. We found that higher vastus lateralis to medialis cross-sectional area ratio is associated with significantly lower cartilage T2 values and less morphological abnormalities detected by MRI. Our data suggested that vastus lateralis/medialis balance may play an important role in the pathogenesis of early OA. 876. Extra-Orbital Muscle T2 Relaxation Time and Clinical Activity in Thyroid Eye Disease Laura Mancini1,2, Rathie Rajendram3, Jimmy Uddin3, Richard W J Lee4, Geoffrey E. Rose3, Tarek Yousry1,2, Katherine Miszkiel1,3, John S. Thornton1,2 1Lysholm Dept Neuro-radiology, National Hospital for Neurology and Neurosurgery, Univ College London Hospitals NHS Foundation Trust, London, United Kingdom; 2Academic Neuroradiological Unit, Institute of Neurology, University College of London, London, United Kingdom; 3Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; 4Academic Unit of Ophthalmology, Clinical Science at South Bristol, University of Bristol, Bristol, United Kingdom This study shows that there is correlation between T2 relaxation values in the extra-orbital muscles of patients with thyroid eye disease and Clinical Activity Score (CAS). CAS is the ‘gold-standard’ measure of disease activity, considered to reflect the degree of orbital inflammation, while T2-weighted images are sensitive to changes in tissue water content concomitant with extra-orbital muscle inflammation. This study represents a validation of T2 measurements as outcome measures for studies of interventions in TED. T2 measures have therefore the potential to improve the quality of data reported in Randomised Control Trials. 877. In Vivo Detection of Deoxymyoglobin in Skeletal Muscle by 1H-MRS at 7T Katja Heinicke1,2, Ivan Dimitrov3,4, Jimin Ren3, Deborah Douglas3, Andrew G. Webb5, Craig R. Malloy3, Ronald G. Haller1,2 1Neuromuscular Center, Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX, United States; 2Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 3Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 4Philips Medical Systems, Cleveland, OH, United States; 5Department of Radiology, dC.J. Gorter High Field Magnetic Resonance Center, Leiden University Medical Center, Leiden, Netherlands 1H-magnetic resonance spectroscopy (1H-MRS) can be used to noninvasively determine oxygen tension in human skeletal muscle. The purpose of this pilot study was to investigate the feasibility to detect the deoxy-Mb signal in skeletal muscle using 1H-MRS in ultra-high fields (7 Tesla). Spectra were acquired on a whole-body 7T scanner using a single-loop linear T/R surface coil with 10-cm diameter. Deoxy-Mb signal was observed in calf muscle in three healthy subjects during ischemia with 160-240 mmHg cuff pressure applied above the knee. The study demonstrates the feasibility of measuring deoxy-Mb in skeletal muscle using 1H-MRS at 7T.
878. In Vivo Assessment of Ca2+-Related Glucose Homeostasis in Skeletal Muscle Using Manganese-Enhanced Magnetic Resonance Imaging Li-Wen Lee1,2, Po-Wah So3, Jimmy D. Bell1 1Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Hammersmith Hospital Campus, Imperial College London, London, United Kingdom; 2Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Chang Gung Univeristy College of Medicine, Chiayi, Taiwan, Taiwan; 3Preclinical Imaging Unit, King's College London, Institute of Psychiatry, James Black Centre, Denmark Hill Campus, London, United Kingdom Glucose homeostasis is regulated by β-cell insulin secretion, peripheral glucose uptake and hepatic glucose production. We applied manganese-enhanced magnetic resonance imaging (MEMRI), utilising Mn2+ as a surrogate marker for Ca2+, to assess Ca2+-related processes involved in glucose homeostasis. MEMRI was performed following i.p. glucose or vehicle and signal intensity (SI) measured to assess Mn2+ distribution. MEMRI showed a significant increase in SI in skeletal muscle and the pancreas following glucose challenge but not in the liver. Thus, MEMRI can be used to assess changes in skeletal muscle glucose uptake and β-cell insulin secretion in vivo. 879. Non-Uniform Diffusion Encoding Directions Schemes to Minimize Fiber Direction Uncertainty in Skeletal Muscle DTI Dimitrios C. Karampinos1, Christopher P. Hess1, Konstantinos Arfanakis2, Suchandrima Banerjee3, Eric T. Han3, Thomas M. Link1, Sharmila Majumdar1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States; 3Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States Fiber direction measurements in skeletal muscle DTI are limited by low precision because of the low SNR of muscle diffusion-weighted MRI and the low anisotropy of muscle diffusion tensor. However, in most skeletal muscles, fibers have a preferential orientation. In the present work, a priori assumptions about the dominant fiber orientation are used to derive non-uniform diffusion encoding schemes that minimize the elliptical cone of uncertainty. Simulations show that optimized schemes can decrease the fiber direction uncertainty up to 37% relative to uniform schemes. Preliminary in vivo results in the human tibialis anterior muscle are presented. 880. High-Resolution Skeletal Muscle Single-Shot DW-EPI with Optimized Stimulated-Echo Preparation and SENSE Dimitrios C. Karampinos1, Suchandrima Banerjee2, Kevin F. King3, Eric T. Han2, Thomas M. Link1, Sharmila Majumdar1 1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 3Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States Skeletal muscle DTI fiber reconstruction close to the aponeuroses is challenging because of partial volume effects. The spatial resolution of skeletal muscle single-shot DW-EPI is limited by the low SNR of muscle DWI and the high sensitivity of single-shot EPI to off-resonance effects. In the present work, eddy-current compensated diffusion-weighted stimulated echo preparation is used to increase SNR and is combined with SENSE to decrease the length of EPI readout. Theoretical results for the SNR efficiency of stimulated echo preparation with SENSE are derived and in vivo tensor maps of the calf muscles with an in plane resolution of 1.56x1.56 mm2 are presented. 881. Specific Changes in Water Diffusivity Due to Passive Shortening and Lengthening of the Thigh Muscles – a Diffusion Tensor Imaging Study Julien Gondin1, Virginie Callot2, Patrick J. Cozzone2, David Bendahan2, Guillaume Duhamel2 1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine , Université de la Méditerranée, Marseille, France; 2Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France We investigated whether the DTI metrics were sensitive enough to structural skeletal muscle fiber changes induced by both passive shortening and lengthening of the thigh muscles. Eight healthy male subjects were examined in a 1.5T whole-body MRI scanner. Images were randomly recorded from the mid-thigh region with the knee joint positioned at 0° and at 45°. Both the vastus lateralis and biceps femoris muscles showed changes in diffusion properties between the two positions whereas the DTI metrics of RF muscle were kept constant. We hypothesized that the specifc changes in water diffusivity observed in this study, reflect nonuniform microstructure changes among the thigh muscles due to their complex muscle-tendon architectures.
882. Assessment of Critical Limb Ischemia Using MRI Samuel Alberg Thrysoe1, Steffen Ringgaard, Khiem D. Hyunh2, William P. Paaske2 1MR-Center, Aarhus University Hospital Skejby, Aarhus, N, Denmark; 2Dept. of Vascular Surgery T, Aarhus University Hospital Skejby We used T2, T2*, and T2’ maps to assess critical limb ischemia (CLI) using MRI. Neither T2* nor T2’ were found to be able to discriminate patients with severe ischemia from normal controls. However, T2-values differed significantly (P=0.011, CI95=[5.6;29.7]) between patients (T2=57.4 ± 7.9 ms) and controls (T2=39.7 ± 3.3 ms). The observed difference is attributed to increased edema in patients suffering from CLI. 883. The Role of Diffusion Tensor Imaging in the Characterization of Myopathy Caused by Systemic Sclerosis – Initial Results Nina F. Schwenzer1,2, Christina Schraml1,2, Ina Kötter3, Jörg C. Henes3, Claus D. Claussen1, Fritz Schick2, Marius Horger1 1Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, BW, Germany; 2Department of Diagnostic and Interventional Radiology, Section on Experimental Radiology, University Hospital of Tübingen, Tübingen, BW, Germany; 3Department of Internal Medicine II, University Hospital of Tübingen, Tübingen, BW, Germany Systemic sclerosis is an autoimmune disease characterized by fibrosis, predominantly of the skin and vessels but also of internal organs and the skeletal muscle. Diffusion tensor imaging (DTI) is able to display diffusional characteristics of tissue. It seems plausible that water diffusivity within the muscle will change due to inflammation and subsequent fibrosis. Our results showed that the mean diffusivity increased in affected muscle groups while the fractional anisotropy did not change compared to healthy volunteers. This might be explained by the fact that the inflammatory processes affect mainly the perimysium of the muscle while the muscle fiber remains unchanged. Hall B Wednesday 13:30-15:30 884. Bloch Simulations of UTE, WASPI and SWIFT for Imaging Short T2 Tissues Michael Carl1, Jing-Tzyh Alan Chiang2, Eric Han1, Graeme Bydder2, Kevin King1 1GE Healthcare, Waukesha, WI, United States; 2University of California, San Diego Three specialized sequences designed to image short T2 tissues are Ultrashort TE (UTE) imaging, Water And Fat Suppressed Projection Imaging (WASPI), and SWeep Imaging with Fourier Transformation (SWIFT). We present theoretical work including Bloch simulations to investigate the T2 blurring characteristics of these three techniques. Simulated images obtained with WASPI and SWIFT show comparable T2 blurring, and slightly increased blurring with the UTE technique. 885. High Resolution Diffusion Tensor MRI of Rabbit Tendons and Ligaments at 11.7T Aman Gupta1,2, Weiguo Li1, Glenn T. Stebbins1,3, Richard L. Magin1, Vincent M. Wang1,2 1Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States; 2Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, United States; 3Department of Neurosciences, Rush University Medical Center, Chicago, IL, United States Low grade tendon and ligament injuries are challenging to delineate on conventional MRI. This study presents results of 11.74T DTI analyses of rabbit MCL ligament and SemiT tendon. FA and MD(x10-6 mm2/s) values for SemiTs (n=6) were 0.66 and 1388, respectively, and for MCLs (n=4) were 0.47 and 1255. 3D tractography graphically depicted the spatial distribution of parallel, well organized collagen bundles. To our knowledge, this is the first study that investigates the microstructure of these tissue types using 3D DTI at high magnetic field. High Field DTI provides more rigorous data regarding tissue structural integrity compared to conventional MRI. 886. Three-Dimensional MRI Assessment of Median Nerve Variability in the Carpal Tunnel Daniel Ross Thedens1, Jessica E. Goetz2, Nicole M. Kunze2, Thomas E. Baer2, Ericka Lawler2, Thomas D. Brown2 1Radiology, University of Iowa, Iowa City, IA, United States; 2Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, United States An important consideration in the evaluation of the biomechanics of the tendons and median nerve in the carpal tunnel is the normal range of variation in their conformation and relative arrangement within the tunnel under otherwise equivalent external conditions. The purpose of this study was to investigate the range of median nerve deformation and position within the tunnel over a series of imaging evaluations and following a set of specific pre-scan activities. The results demonstrate the complex motion and deformation of the median nerve in both neutral and flexed wrist positions. 887. Isotropic MRI of the Upper Extremity with 3D-FSE-Cube Lauren M. Shapiro1, Alicia M. Jenkins1, Kathryn J. Stevens1, Charles Q. Li1, Weitian Chen2, Anja C.S. Brau2, Brian A. Hargreaves1, Garry E. Gold3 1Radiology, Stanford University, Stanford, CA, United States; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 3Radiology, Bioengineering, Orthopedics, Stanford University, Stanford, CA, United States Two-dimensional fast spin-echo (2D-FSE) is commonly used to image the upper extremity, however it is limited by slice gaps, partial volume artifact and poor quality reformats. Three-dimensional fast spin-echo (3D-FSE-Cube) overcomes these limitations by acquiring isotropic data, allowing for reformations in oblique planes while decreasing exam time. Our study compared 2D-FSE with 3D-FSE-Cube at 3.0T in the upper extremity. 3D-FSE-Cube demonstrated similar or significantly higher signal-to-noise compared with 2D-FSE. 3D-FSE-Cube images were slightly worse than 2D-FSE with respect to blurring, artifacts, and overall image quality. 3D-FSE-Cube may improve visualization of complex upper extremity anatomy and make multiple 2D acquisitions unnecessary. 888. MR Temperature Measurements of Activities Outside the Magnet Using Image Registration and a Fixation Device Michael Bock1, Axel Joachim Krafft1, Florian Maier1, Hans H. Paessler2 1Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg, Germany; 2Center for Knee & Foot Surgery/Sports Trauma, ATOS Clinic, Heidelberg, Germany During sports activities such as skiing temperature changes of up to 10 K have been measured invasively. In this work we propose the use of MR temperature measurements in the knee where the thermal stimulation is performed outside the magnet. With a temperature-sensitive 3D FLASH sequence proton resonance frequency data are acquired before and after stimulation, and image co-registration is achieved with both a passive fixation device and an alignment post-processing algorithm to calculate phase difference maps. 889. Is There a Benefit from Rotating K-SPACE Sampling (BLADE) Vs. Conventional Cartesian K-SPACE Sampling (TSE) for Routine Shoulder MRI? Annie Horng1, Matthias Pietschmann2, Mike Notohamiprodjo1, Peter Müller2, Maximilian F. Reiser1, Christian Glaser1 1Department of Clinical Radiology, University Hospitals LMU Munich Campus Grosshadern, Munich, Bavaria, Germany; 2Department of Orthopedic Surgery, University Hospitals LMU Munich Campus Grosshadern, Munich, Bavaria, Germany Shoulder-MRI using conventional TSE sequences often exhibit artifacts resulting in non-diagnostic images due to involuntary patient movement. A recent developed multishot T2-weighted sequence based on rotating rectangular read-out of k-space data (BLADE) is supposed to reduce motion artifacts. This study compared BLADE to a conventional fat-saturated TSE sequence used in musculoskeletal radiology, revealing significant reduction of motion artifacts, improvement of image quality, depiction of anatomical detail and improved diagnostic confidence of anterior labral lesions. Thus BLADE provides a promising alternative for examination of young, critically ill or claustrophobic patients, who express a higher probability for motion artifacts. 890. In Vivo Conductivity Imaging of Human Knee Using 3 MA Imaging Current Hyung Joong Kim1, Young Tae Kim1, Woo Chul Jeong1, Atul Singh Minhas1, Tae Hwi Lee1, O Jung Kwon2, Eung Je Woo1 1Biomedical engineering, Kyung Hee University, Yongin, Gyeonggi, Korea, Republic of; 2Medicine, Sungkyunkwan University, Seoul, Korea, Republic of In Magnetic Resonance Electrical Impedance Tomography (MREIT), we measure induced magnetic flux density subject to multiple injection currents to reconstruct cross-sectional conductivity images. Newly developed multi-echo pulse sequence in MREIT is expected to provide a higher magnitude image SNR and lower noise level in magnetic flux density data. Injecting 3 mA imaging currents into the human knee, we collected induced magnetic flux density data using the multi-echo pulse sequence. Reconstructed conductivity images using the harmonic Bz algorithm show good contrast among different parts of the subcutaneous adipose tissue, muscle, synovial capsule, and bone inside the knee Hall B Thursday 13:30-15:30 891. Reduction of Metal Artifacts in Patients with Hip Joint Implants by Using Optimized Imaging Protocols Sven Månsson1, Gunilla Müller2, Daniel Alamidi3, Jonas Svensson1, Markus Müller2 1Medical Radiation Physics, Lund University, Malmö, Sweden; 2Radiology, Lund University, Malmö, Sweden; 3Radiation Physics, University of Gothenburg, Gothenburg, Sweden Metal-on-metal hip resurfacing implants are suitable for young, active patients. However, there are indications that these implants fail more frequently than traditional implants. An early diagnosis of prosthetic failure would be facilitated by artifact-reducing MRI protocols. The purpose of this study was to investigate to which extent metal artifacts can be reduced, in the worst case of a stainless steel implant, by optimizing routine imaging protocols. The result on a patient with hip joint implant showed that metal artifacts can be substantially reduced, thereby permitting anatomical details to be visualized closer to the implant. 892. MAVRIC Imaging Near Metal Implants with Improved Spatial Resolution and Reduced Acquisition Time Kevin M. Koch1, Matthew F. Koff2, Hollis G. Potter2, Kevin F. King1 1Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States; 2Hospital for Special Surgery, New York, United States A variety of enhancements to the MAVRIC technique are described and demonstrated to produce minimal artifact images with sub-millimeter resolution in the near vicinity of total joint replacements. Clinically feasible scan times are achieved by using k-space corner-cutting, partial Fourier, and autocalibrated parallel imaging undersampling acquisition strategies. MAVRIC images are shown to dramatically reduce susceptibility artifacts while maintaining diagnostically relevant spatial resolution when compared to established 2D-FSE arthroplasty images. 893. MRI Near Metallic Implants Using SEMAC: Initial Clinical Experience Garry E. Gold1, Shreyas S. Vasanawala2, Wenmiao Lu3, Christina A. Chen2, Weitian Chen4, John M. Pauly5, Kim Butts Pauly2, Stuart B. Goodman, Brian A. Hargreaves2 1Radiology, Bioengineering, Orthopaedic Surgery, Stanford University, Stanford, CA, United States; 2Radiology, Stanford University, Stanford, CA, United States; 3Electrical and Electronic Engineering, Nanyang Tech., Singapore; 4Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 5Electrical Engineering, Stanford University, Stanford, CA, United States MRI around metallic implants such as total joint replacements has been limited due to artifacts. Recently a new method for reducing artifact near metal called Slice Encoding for Metal Artifact Correction (SEMAC) was described. This work compares the clinical performance of SEMAC versus 2D-FSE in an initial population of symptomatic patients with metal implants. Clinical management was changed in a substantial number of cases. Hall B Monday 14:00-16:00 894. High Spatial Resolution 3D MRI of the Larynx Using a Dedicated TX/RX Phased Array Coil at 7.0T Tobias Frauenrath1, Wolfgang Renz2, Jan Rieger1, Andreas Goemmel3, Christoph Butenweg3, Thoralf Niendorf1,4 1Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany; 2Siemens Medical Solutions , Germany; 3Chair of Structural Statics and Dynamics, RWTH, Aachen, Germany; 4Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt University, Berlin, Germany MRI holds great potential for elucidating laryngeal and vocal fold anatomy together with the assessment of physiological processes associated in human phonation. However, MRI of human phonation remains very challenging due to the small size of the targeted structures, interfering signal from fat, air between the vocal folds and surrounding muscles and physiological motion. These anatomical/physiological constraints translate into stringent technical requirements in balancing, scan time, image contrast, immunity to physiological motion, temporal resolution and spatial resolution. Motivated by these challenges and limitations this study is aiming at translating the sensitivity gain at ultra-high magnetic fields for enhanced high spatial resolution 3D imaging of the larynx and vocal tract. To approach this goal a dedicated two channel TX/RX larynx coil is being proposed. 895. Real-Time Imaging of the Temporomanibular Joint Motion Based on Golden Ratio Radial MRI Andreas Johannes Hopfgartner1, Olga Tymofiyeva1, Philipp Ehses1, Kurt Rottner2, Julian Boldt2, Ernst-Jürgen Richter2, Peter Michael Jakob1 1Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany; 2Prosthodontics, Dental School, University of Würzburg, Würzburg, Bavaria, Germany Static or pseudo-dynamic MRI of the TMJ does not allow for full analysis of the disc deformation and displacement during the mandibular motion. The purpose of this study was to develop a dynamic MRI technique for measurement of the TMJ with an arbitrary reconstruction window. The method uses a radial trajectory with a constant azimuthal profile spacing of 111.246°. Two kinds of measurements were performed: opening and closing of the mouth and biting into a cooled chocolate-covered caramel. Reconstruction was performed with a sliding window method and a KWIC filter. The method is suitable for diagnosis and therapy planning. 896. Micro-Magnetic Resonance Imaging of Limb Development: Insights Into the Basis of Clubfoot Suzanne Louise Duce1 1College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom Clubfoot (CTEV) in humans is a malformation which affects about 4-in-1000 births; its aetiopathogenesis is unknown. We undertook a 3D μMRI study using 7.1T Bruker spectrometer, of a pma mouse model that has clubfoot-like hindfoot malformations. Wild-type and pma mouse musculoskeletal anatomy were compared. The pma hindfeet displays similar abnormalities (eg supination) to human CTEV. Embryonic hindfoot developmental studies showed initiation of pma hindfoot rotation is often delayed compared to wild-type, is slower and does not reach completion. If our results were extrapolated to humans, it supports the hypothesis that CTEV is due to incompletion foot rotation and angulation. 897. High-Resolution Interleaved Water-Fat MR Imaging of Finger Joints Wingchi Edmund Kwok1, Zhigang You1, Gwysuk Seo1, Christopher Ritchlin2, Johnny Monu1 1Department of Imaging Sciences, University of Rochester, Rochester, NY, United States; 2Allergy, Immunology and Rheumatology Division, University of Rochester, Rochester, NY, United States Insufficient resolution and chemical-shift artifacts in MRI of finger joints can hinder early diagnosis of arthritis. We used an interleaved water-fat (IWF) sequence and a dedicated RF coil to achieve high-resolution finger MRI without chemical-shift artifacts. A normal subject and six subjects with arthritis were studied. The high-resolution images revealed detailed structures of the finger joints. The IWF sequence gave more accurate depiction of subchondral bone thickness, and avoided false bone erosions shown in the regular sequence. It also allowed better visualization of ligaments and tendons. High-resolution IWF imaging should be useful for the diagnosis and treatment evaluation of arthritis.
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