Junchao Ma¹, Nan Yu¹, Ruifeng Wang¹, and Shaoyu Wang^2
1The Affiliated Hospital of Shaanxi University of Chinese Medicine, Xian Yang, China, ²MR Scientific Marketing Specialist Diagnostic Imaging Healthcare Greater China, Xi'an, China

Magnetic resonance imaging (MRI) is considered the best imaging method to evaluate the multifidus degeneration. The existing evaluation methods based on fat infiltration fraction (FSF) cannot fully reflect the muscle integrity and functional status. In order to obtain a tool for objective and continuous grading of multifidus degeneration. Fractal method was used to analyze the signal heterogeneity of multifidus. The fractal dimension of lumbar multifidus muscle（LMM） is closely related to LBP. The fractal dimension may be a reliable imaging marker for monitoring the degree of multifidus degeneration in symptomatic patients.

Mengyue Wang¹, Yin Shi¹, Weiqiang Dou², and Yuefen Zou^1
1Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²GE Healthcare, MR Research China, Beijing, China

  Many diseases can result in increased fatty infiltrations within muscles adjacent to lumbosacral plexus. However, the normal level of fat content in paraneural muscles is not clear within healthy people. In this study, we applied iterative decomposition of water and fat with echo asymmetry and least-squares estimation intelligent quantification (IDEAL-IQ) to measure fat fraction (FF) of paraneural muscles within healthy participants. We found that FF values of paraneural muscles in healthy people depend on gender and age. Therefore, both factors of gender and age need to be taken into account, when assessing the FF levels of muscles in diseases.

Lara Schlaffke¹, Martijn Froeling², Marlena Rohm¹, Johannes Forsting¹, Martin Tegenthoff¹, Matthias Vorgerd¹, and Robert Rehmann^1
1Neurology, BG UK Bergmannsheil, Bochum, Germany, ²Radiology, UMC Utrecht, Utrecht, Netherlands

Quantitative MRI-markers are essential for monitoring disease progression in late-onset pompe disease (LOPD). Using muscle diffusion tensor imaging (mDTI) and mDixon we evaluated differences in diffusion parameters in six thigh and seven calf muscles - with <10% and >10% fat-fraction - of 18 LOPD and 29 healthy controls (HC). Upper leg muscles with <10% fat-fraction showed significant differences in MD, RD, λ_1-3 and MD positively correlated with 6-MWT (p=0.003). mDTI reveals an increased diffusion restriction in muscles of LOPD-patients with and without fat-infiltration and could reflect structural changes prior to fatty degeneration.

Lara Schlaffke¹, Robert Rehmann¹, Martijn Froeling², and Johannes Forsting^1
1Neurology, BG UK Bergmannsheil, Bochum, Germany, ²Radiology, UMC Utrecht, Utrecht, Netherlands

Muscle diffusion tensor imaging is a quantitative magnetic resonance image (MRI) technique, which can provide information about muscular microstructure and integrity. Due to high intermuscular variability, the manual separation of the muscles is essential. Here, we have compared three methods, which allow assessing of diffusion properties of the thigh muscles. In each of the three investigated methods, two independent raters performed the muscle segmentation. We could show, that volume-based tractography proved to be the most reliable and robust method (ICC = 0.923-0.985) and has the advantage to achieve additional information about muscle architecture.

Laura Secondulfo¹, Joep J M Suskens², Ozgur Kilic², Valentina Mazzoli³, Mario Maas⁴, Hans J.L Tol², Aart Nederveen⁴, Melissa Hooijmans¹, and Gustav J Strijkers^1
1Biomedical Engineering and Physics, UMC Amsterdam, Location AMC, Amsterdam, Netherlands, ²Orthopedic Surgery, UMC Amsterdam, Location AMC, Amsterdam, Netherlands, ³Radiology, Lucas Center for Imaging, Stanford University, Stanford, CA, United States, ⁴Radiology and Nuclear Medicine, UMC, Amsterdam, Location AMC, Amsterdam, Netherlands

Hamstring injuries have high recurrence rates in elite athletes, which motivates the investigations in novel diagnostic methods for muscle injury and follow-up. Diffusion tensor imaging facilitates direct and indirect monitoring of the muscle condition and architecture. Fiber orientations and changes therein due to injury or training are considered a key parameter; however, the assessment over the full volume of an individual muscle is still difficult. Therefore, we developed a method to generate reproducible quantitative fiber-angle color maps of the whole volume of leg muscles, which proved sensitive to changes due to muscle stretch and a training intervention.

Melissa Tamara Hooijmans^1,2, Crystal L. Coolbaugh¹, Hannah L. Kilpatrick¹, Mark K George¹, and Bruce M Damon^1,3
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, ²Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers, Amsterdam, Netherlands, ³Department of Radiology and Radiological Sciences, Biomedical Engineering, and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, United States

In this study we explore the feasibility of using displacement fields to quantify whole muscle 3D strain patterns during submaximal voluntary contractions of the dorsiflexor muscles. Our results showed a consistent pattern, of large negative (shortening) and a large positive (lengthening) principal strains. Both the magnitude and pattern of strain agree with other studies performed during submaximal contractions which indicates the feasibility of this approach to quantify 3D strain. 

Dushyant Kumar¹, Deepa Thakuri¹, Blake Benyard¹, Hari Hariharan¹, Ravi Prakash Reddy Nanga¹, and Ravinder Reddy^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

Though oldest noninvasive imaging biomarker for creatine kinase (CK)  reaction in exercised muscle, phosphorous magnetic resonance spectroscopy (31PMRS) suffers from the poor resolution. The 2D creatine Chemical Exchange Saturation Transfer allows for the assessment of creatine recovery with excellent in plane spatial resolution, it was not possible to construct voxel wise parametric maps for recovery time constant due to low signal to noise ratio (SNR). Recently developed 3D implementation of CrCEST allowed for higher SNR and increased volumetric coverage and we exploit these two advantages in our novel non-local spatially regularized approach to reconstruct parametric map for recovery time constant.

Rengaraj Anantharaj¹, Jadegoud Yaligar¹, Giang Thi Thu Le¹, Venkatesh Gopalan¹, Sanjay Kumar Verma¹, Kavita Kaur¹, Kasthuri Thirumurugan², Johan G Eriksson^2,3, Brian Kennedy⁴, and S Sendhil Velan^1,2
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore, ²Singapore Institute for Clinical Sciences, A*STAR, Singapore, Singapore, ³Department of Obstetrics & Gynecology, National University of Singapore, Singapore, Singapore, ⁴Center for Healthy Aging, National University of Singapore, Singapore, Singapore

Aging associated loss of muscle mass leads  to metabolic diseases and compromised quality of life.  Increase in intramyocellular lipid (IMCL) and reduced skeletal muscle mass are associated with insulin resistance and diabetes.  Rapamycin increases muscle mass  by inhibiting  the mTOR signalling pathway.  In this study, we investigated IMCL metabolism and muscle mass in response to rapamycin intervention in an aging rodent model.  We observed significant reduction in IMCL along with increase in muscle mass indicating improved muscle metabolism with rapamycin intervention. Muscle differentiation gene, MyoD was upregulated and myostatin which is negative regulator of muscle growth factor was down regulated. 

Martin Schwartz^1,2, Petros Martirosian¹, Günter Steidle¹, Thomas Küstner^1,2,3, Bin Yang², Alto Stemmer⁴, Thorsten Feiweier⁴, Ludger Schöls^5,6, Matthis Synofzik^5,6, and Fritz Schick^1
1Section on Experimental Radiology, University Hospital of Tuebingen, Tuebingen, Germany, ²Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, ³School of Biomedical Engineering & Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom, ⁴Siemens Healthcare GmbH, Erlangen, Germany, ⁵Department Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, Tübingen & Center for Neurology, Tuebingen, Germany, ⁶German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany

Quantification of spontaneous mechanical activities in musculature like fibrillations or fasciculations is of high interest for the assessment of neuro-muscular function in normal and impaired subjects. The diagnostic assessment of neuromuscular disease focuses at specific muscular regions, and the measurement protocol was optimized in order to robustly quantify spontaneous activities in these areas. This work shows preliminary results regarding activity patterns of healthy and diseased subjects.

Ericky Caldas de Almeida Araujo^1,2, Harmen Reyngoudt^1,2, and Pierre G. Carlier^1,2
1NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France, ²NMR Laboratory, CEA/DRF/IBFJ/MIRCen, Paris, France

Although sensitive to disease activity, the mono-exponential muscle water T₂ is non-specific to the underlying dominant pathophysiological processes taking place in the different neuromuscular disorders. In this work we performed multi-exponential analysis of muscle water T2-relaxation data acquired in healthy subjects, Duchenne Muscular Dystrophy and Inclusion Body Myositis patients. T2-decay curves were obtained using ¹H NMR spectra acquired at different echo times. The results put in evidence a distinct water T2-relaxation behavior between inflammatory and dystrophic myopathies, supporting the hypothesis that a multi-exponential analysis of T2-relaxation data can reveal specific pathophysiological information that is missing from mono-exponential analysis.

Matt Farrow¹, John Biglands¹, Steven F Tanner¹, Elizabeth Hensor¹, Paul Emery¹, and Ai Lyn Tan^1
1University of Leeds, Leeds, United Kingdom

Rheumatoid arthritis can present with the loss of muscle mass and a decrease in strength and functional capability. This study demonstrates that Quantitative MRI can detect differences in the muscles of RA patients, whether they are newly diagnosed, in remission or with persistently active disease. Differences in T2, FF and muscle volume were apparent at diagnosis, suggesting muscle changes in RA occur early. Furthermore, despite RA treatment, patients in remission show worse MRI parameters and strength compared to healthy individuals, suggesting the muscles have pathology. This warrants attention in improving the muscle health throughout the spectrum of the RA continuum.

Usha Sinha¹, Vadim Malis², Edward Smitaman³, and Shantanu Sinha^3
1Physics, San Diego State University, San Diego, CA, United States, ²Physics, UC San Diego, La Jolla, CA, United States, ³Radiology, UC San Diego, La Jolla, CA, United States

Ultralow TE imaging of skeletal muscle enables the visualization of low T2* species. In skeletal muscle, the signal from the small fraction of short-T2 (T2^S) components are masked by the larger component long-T2 (T2^L) species. One method is to extract the short T2 components from subtracted images of a dual echo UTE sequence. However, the subtracted images invariably have residual signal from lipids due to the chemically shifted frequencies of signals produced by lipids. We integrate the fat fraction and T2^L extracted from MP-IDEAL sequence to the subtracted UTE images to extract the fibrosis fraction.

Ravneet Vohra¹, Guy Odom², Jeffrey S Chamberlain^2,3,4, and Donghoon Lee^1
1Radiology, University of Washington, Seattle, WA, United States, ²Neurology, University of Washington, Seattle, WA, United States, ³Medicine, University of Washington, Seattle, WA, United States, ⁴Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, WA, United States

Mutations in the X-linked dystrophin gene disrupts protein expression resulting in Duchenne muscular dystrophy (DMD), a neuromuscular disorder characterized by body-wide muscle cell degeneration. The mdx mouse model is one of the most commonly used animal models for DMD. Recombinant adeno-associated viral (rAAV) vector-mediated gene transfer represents a promising approach for DMD. Magnetic resonance has emerged as a noninvasive method in monitoring disease progression and treatment response for muscular dystrophy. The aim of this study was to elucidate the functional impact of micro-dystrophin on skeletal muscles using magnetic resonance imaging and spectroscopy.

Deepa Thakuri¹, Dushyant Kumar¹, Abigail Cember¹, Ravi Prakash Reddy Nanga¹, Lizbeth Novelo², Hari Hariharan¹, Joshua Baker², and Ravinder Reddy^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Rheumatology & Epidemiology, University of Pennsylvania, Philadelphia, PA, United States

Osteoarthritis (OA) is the leading cause of disability in adult and aging populations. Knee OA increases difficulty in the functional use of various upper and lower leg muscles. In the recent years, CrCEST technique has emerged as a potential imaging biomarker to study muscle metabolism and its application was shown in different systemic diseases like mitochondrial disorders. Here, we are particularly interested in exploring and investigating the correlation of knee OA with post exercise CrCEST increase.  

Manoj Kumar Sarma¹, Andres Saucedo¹, Daniel Kohanghadosh¹, Kavya Umachandran¹, Ely R. Felker¹, Christine H. Darwin², and M. Albert Thomas^1
1Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States, ²Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States

Increased intramyocellular and extramyocellular lipids (IMCL and EMCL), abdominal lipids and decreased lipid unsaturation ratios, are of prime interest in determining relationships of these changes to insulin sensitivity and progression to type 2 diabetes (T2DM). We acquired 6-point Dixon based MRI of abdomen and accelerated MR Spectroscopic Imaging in calf muscle. In the T2DM group, BMI correlated positively with visceral fat, total fat and hepatic fat fractions. In contrast, BMI correlated negatively with pancreatic fat fractions (body/tail) in age-matched healthy volunteers. Mostly association between IMCL unsaturation index and abdominal fat content was observed. Also, we found an excellent correlation between abdominal lipid accretion and calf muscle lipid infiltration in T2DM and healthy controls predominantly inside muscle fibers (IMCL).

Elka B Rubin¹, Valentina Mazzoli¹, Marianne Black¹, Arjun D Desai¹, Kate Young¹, Feliks Kogan¹, Ashwin Sreedhar¹, Dominic J Vincentini¹, Katelin A Knox¹, Tomoo Yamada¹, Andrew McCabe², Marc Safran¹, Sharmila Majumdar³, Hollis G Potter⁴, and Garry E Gold^1
1Stanford University, Stanford, CA, United States, ²Santa Clara University, Santa Clara, CA, United States, ³University of California San Francisco, San Francisco, CA, United States, ⁴Hospital for Special Surgery, New York, NY, United States

Basketball players place high loads on their knee joints that can lead to chronic knee injuries.  In this study, we used advanced MRI methods and a cluster analysis to longitudinally study cartilage structure and potential early degenerative changes in Division 1 (D1) basketball players and swimmers. Pre-season and post-season quantitative results indicate an increase in T₂ and T_1p relaxation times in the central compartment of the femoral cartilage in the basketball players compared to the swimmers. The results of this study suggest that microstructural changes in knee cartilage can occur in one season of D1 college play.

Valentina Mazzoli¹, Lauren Elizabeth Watkins¹, Elka Brooke Rubin¹, Brian Hargreaves¹, Feliks Kogan¹, and Garry Evan Gold^1
1Department of Radiology, Stanford University, Stanford, CA, United States

Mean Diffusivity (MD) and Fractional Anisotropy (FA) derived from DTI are a very promising biomarker of cartilage health. Many current implementations of DTI require high field scanners, and its feasibility utility at 3T is unclear. The aim of this study was to develop an optimized DTI acquisition and postprocessing protocol for the evaluation of femoral articular cartilage at 3T in a clinically feasible scan time, and to assess its repeatability and sensitivity to transient changes induced by exercise. Our results show that MD  and FA measurements at 3T are repeatable and robust to changes induced by exercise.

Hollis Crowder¹, Valentina Mazzoli², Marianne Black², Lauren Watkins³, Feliks Kogan², Brian Hargreaves⁴, Marc Levenston⁴, and Garry Gold^4
1Mechanical Engineering, Stanford University, Palo Alto, CA, United States, ²Radiology, Stanford University, Palo Alto, CA, United States, ³Bioengineering, Stanford University, Palo Alto, CA, United States, ⁴Stanford University, Palo Alto, CA, United States

To identify potential changes in cartilage hydration or microstructure resulting from exercise we compared global and regional T2 relaxation times of eleven female recreational runners and five controls at baseline, time 0, and time 60 minutes post-exercise. No significant difference in mean T2 relaxation times between the runner group and the control group were found at any time point in either global or regional analysis. Suspected changes in cartilage hydration or microstructure resulting from biomechanical running forces may not manifest in such a way that is detectable by global or regional T2 relaxation analysis compared to controls.

Marcelo Victor Wust Zibetti¹, Azadeh Sharafi¹, and Ravinder Regatte^1
1Radiology, NYU, New York, NY, United States

T1ρ-mapping using mono- or bi-exponential models usually require multiple spin-lock times (#TSLs). Choosing the optimal #TSLs for improved SNR, i.e. minimizing the Cramer-Rao lower bound (CRLB), is important. However, Gaussian statistics with CRLB usually lead to the repetition of longer TSLs and the minimum number of shorter TSLs. This choice is non-robust to large data acquisition errors caused by subject motion or other scan related problems that strongly affect quantitative parameters. To alleviate this problem, we propose a robust T1ρ-protocol based on optimized #TSLs using CRLB with robust statistics, and outlier-robust fitting method. 

Akshay Chaudhari¹, Quin Lu², Anna Wisser^3,4, Wolfgang Wirth^3,4, Garry E Gold¹, Brian A Hargreaves¹, and Felix Eckstein^3,4
1Stanford University, Stanford, CA, United States, ²Philips, San Francisco, CA, United States, ³Paracelsus Medical University, Salzburg, Austria, ⁴Chondrometrics GmbH, Ainring, Germany

Changes in cartilage morphology have shown to predict and monitor osteoarthritis progression with great sensitivity. However, the lack of a rapid and inexpensive MRI technique for imaging cartilage that can be implemented across vendors is a challenge in large multi-site clinical studies. In this work, we evaluate multi-vendor and scan-rescan reliability and explore left-right knee asymmetries of cartilage morphology measured using a rapid, 4-minute quantitative double-echo steady-state (qDESS) sequence. We demonstrate qDESS harmonization across vendors, which can produce high scan-rescan repeatability and high repeatability of left-right knee asymmetry of cartilage volume, surface area, and thickness metrics.

Halston J.C. Sandford¹, Marianne Black^2,3, Akshay S. Chaudhari², Arjun Desai^2,4, Feliks Kogan¹, Brian A. Hargreaves^2,4,5, Garry E. Gold^2,5,6, and Valentina Mazzoli^2
1Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States, ³Mechanical Engineering, Stanford University, Stanford, CA, United States, ⁴Electrical Engineering, Stanford University, Stanford, CA, United States, ⁵Bioengineering, Stanford University, Stanford, CA, United States, ⁶Orthopedic Surgery, Stanford University, Stanford, CA, United States

ACL-injured individuals, despite reconstructive surgery, have an increased risk of developing osteoarthritis and methods to identify early changes in cartilage are needed to allow implementation of treatment. Diffusion-weighted MRI (DWI) has been shown to provide information on femoral cartilage health. This study aims to assess the potential of DWI to detect early degenerative changes in articular cartilage following ACL reconstruction. We found that DWI shows elevated ADC values in both ACL-injured and contralateral knees compared with controls at baseline. DWI did not show significant changes in cartilage over time within 18 months of post-ACL-reconstructive surgery.

Robert L. Wilson¹, Nancy C. Emery², David M. Pierce^3,4, and Corey P. Neu^1
1Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States, ²Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States, ³Mechanical Engineering, University of Connecticut, Storrs, CT, United States, ⁴Biomedical Engineering, University of Connecticut, Storrs, CT, United States

Spatial gradients in articular cartilage structure trend toward homogeneity with onset and progression of osteoarthritis (OA). Exploiting MRI, we compared heterogeneous variations in tissue structure, and the corresponding function, to OA severity through the use of spatial first derivatives, herein termed functional gradient indices (FGIs), providing new biomarkers indicating tissue state. We evaluated FGI maps of MRI data visualizing osteochondral human explants and OAI subjects for relationships to OA severity. FGI data correlated significantly with tissue health, while traditional metrics did not. The sensitivity and versatility of FGI analysis suggests a novel biomarker with improved detection of early disease pathogenesis.

Quin Lu¹, Brian A Hargreaves², and Akshay S Chaudhari^2
1Clinical Science, Philips Healthcare NA, San Francisco, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States

Quantitative Double Echo Steady State (qDESS) is a fast 3D MRI sequence capable of simultaneous knee morphometry and T2 relaxometry. Compressed-sensing based acceleration methods are more and more readily available from major MRI vendors, and have the potential to further speed up qDESS and to provide greater clinical value. In this study, we investigate the feasibility of applying Philips Compressed SENSE (CS) to qDESS. We show that CS does not bias the T2 accuracy of qDESS. Our findings support the clinical application of CS accelerated qDESS for fast and quantitative MR knee assessment. 
 

Bernd A Jung¹, Onur Afacan², Till Lerch¹, Young-Jo Kim³, Tobias Kober^4,5,6, Michael Ith¹, Markus Klarhoefer⁷, and Florian Schmaranzer^1
1Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Bern, Switzerland, ²Dept of Radiology, Boston Children`s Hospital, Boston, MA, United States, <sup>3</sup>Dept of Orthopaedic Surgery, Boston Children`s Hospital, Boston, MA, United States, ⁴Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, ⁵Dept of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ⁶LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, ⁷Siemens Healthcare, Zuerich, Switzerland

Although commonly used for T1 mapping of hip cartilage, 3D dual flip angle (DFA) techniques are sensitive to flip angle variations related to B1 inhomogeneities. Therefore, the IR-based MP2RAGE technique was compared with a standard 3D DFA acquisition including B1 field mapping for T1 mapping of hip cartilage in a phantom study and in healthy volunteers at 3T. For the phantom study, a 2D IR-based sequence was additionally acquired to provide reference T1 maps. MP2RAGE resulted in more accurate T1 values with less regional variations compared to DFA method and therefore enables a more robust T1 mapping of hip cartilage.

Rafeek Thaha¹, Sandeep Panwar Jogi^1,2, Sriram Rajan³, Amit Mehndiratta^1,4, Anup Singh^1,4, and Dharmesh Singh^1
1Centre for Biomedical Engineering, Indian Institute of Technology, New Delhi, India, ²Biomedical Engineering, ASET, Amity University Haryana, Gurgaon, India, ³Mahajan Imaging Centre, New Delhi, India, ⁴Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, India

Quantitative MR parameters(such as T2-relaxation time) are sensitive to biochemical changes in the cartilage. The objective of the study was to evaluate the performance of different statistics parameters from T2 values of femur cartilage and normalized T2 map (Z-score T2 map) values for differentiating healthy vs OA patients as well as Early-OA (Grade-I and Grade-II), vs Risk-OA (Grade-III) patients. Multiple Statistic parameter from T2 map provided high accuracy in differentiation between healthy vs OA cartilage, while one of the static parameter of Z-score T2 map provided high accuracy in differentiation between early-OA vs Risk-OA. 

YUXI PANG^1
1Department of Radiology, University of Michigan, Ann Arbor, MI, United States

A self-compensated spin-locking (SL) scheme for quantitative R_1ρ dispersion in cartilage has been developed. The performance of this new method was evaluated by Bloch simulations and R_1ρ dispersion (with 6 SL RF strengths ranging from 50 to 1000 Hz) studies on agarose (1-4%, w/v) phantom and on one healthy human knee in vivo at 3T, with respect to three reported SL approaches. The simulated and experimental results indicate that the proposed SL method was less susceptible to B₀ and B₁ field artifacts for a wide range of SL strengths, and thus more suitable for quantitative R_1ρ dispersion in ordered tissue.

Mary Elizabeth Hall^1,2, Valentina Mazzoli², Marianne Black^1,2, Halston Sandford², Katherine Young², Daehyun Yoon², Bragi Sveinsson³, Akshay Chaudhari², Emily McWalter⁴, Feliks Kogan², Marc Levenston^1,2,5, Brian Hargreaves^2,5,6, and Garry Gold^2
1Mechanical Engineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States, ³Massachusetts General Hospital, Boston, MA, United States, ⁴Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ⁵Bioengineering, Stanford University, Stanford, CA, United States, ⁶Electrical Engineering, Stanford University, Stanford, CA, United States

This study evaluates apparent diffusion coefficient (ADC) as measured by a quantitative double echo steady state (qDESS) sequence as a biomarker for early osteoarthritis detection in articular cartilage in the femur and its correlation with ADC from a diffusion weighted echo planar (DWI-EPI) scan.  9 injured knees and contralateral knees of patients undergoing reconstruction surgery following anterior cruciate ligament tears were scanned with qDESS and DWI-EPI sequences up to 18 months post surgery.  There were no consistent patterns of qDESS ADC change on a global or regional basis in the femoral cartilage.  qDESS ADC did not correlate with DWI-EPI ADC.
 

Marianne S Black^1,2, Katherine A Young¹, Akshay S Chaudhari¹, Feliks Kogan¹, Bragi Sveinsson³, Emily J McWalter⁴, Garry E Gold^1,5, Marc E Levenston^1,2, and Brian A Hargreaves^1,5,6
1Radiology, Stanford University, Stanford, CA, United States, ²Mechanical Engineering, Stanford University, Stanford, CA, United States, ³Massachusetts General Hospital, Boston, MA, United States, ⁴Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ⁵Bioengineering, Stanford University, Stanford, CA, United States, ⁶Electrical Engineering, Stanford University, Stanford, CA, United States

There is a need to detect and quantify early osteoarthritic changes for the development of treatments for osteoarthritis progression.  ACL-injured subjects are at an increased risk of developing osteoarthritis, and T₂ is sensitive to the structure and composition of cartilage, including osteoarthritic change. This study used a quantitative DESS acquisition to obtain T₂ maps in 10 subjects 3-weeks, 3-months, 9-months, and 18-months after ACL reconstruction surgery and 10 controls at matched times. Our results show that T₂ cluster analysis was able to detect changes to the ACL-reconstructed cartilage as early as 3-months post-surgery and these differences persisted at 18-months.

Abdul Wahed Kajabi^1,2, Seyed Amir Mirmojarabian^1,2, Juuso Ketola¹, Timo Liimatainen^1,2, Miika T. Nieminen^1,2,3, Mikko J. Nissi⁴, and Victor Casula^1,2
1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, ²Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, ³Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland, ⁴Department of Applied Physics, University of Eastern Finland, Kuopio, Finland

In this study, multiparametric MRI was used to predict cartilage proteoglycan content and collagen fiber orientation, as measured by quantitative microscopy. Twenty osteochondral samples were obtained from stifle joints of ten Shetland ponies. Measurements of 14 different MRI parameters, including T₁, T₂, continuous wave T_1rho, adiabatic T_1rho and T_2rho, and T_RAFF were performed at 9.4 T. Three ensemble-based regression models (Gradient Boosting, Random Forest and Extra Trees) were used and the highest coefficients of determination (r²) were 0.77 for collagen orientation and 0.62 for proteoglycan content. These findings show that multiparametric MRI can be used to non-invasively estimate cartilage histology.

Yang Xia¹, Syeda Batool¹, and Mohammad Hammimi^1
1Physics, Oakland University, Rochester, MI, United States

This work aims to characterize the site-specific and depth dependent molecular and morphological structures in young rabbit femur cartilage, using quantitative µMRI (T2 relaxation) and Polarized light microscopy (PLM).

Xiaoshuai Chen¹, Ranxu Zhang¹, Xiaoyue Zhou², Esther Raithel³, and Jian Zhao^1
1The third Hospital of Hebei Medical University, Shijiazhuang, China, ²Siemens Healthineers Ltd, Shanghai, China, ³Siemens Healthcare, Erlangen, Germany

Once articular cartilage is damaged it cannot be readily repaired. However, to what extent marathon running causes cartilage damage to the knees is unclear. We quantitatively assessed the morphologic and T2* value changes in the knee cartilage of marathon runners using an automatic cartilage segmentation method. The cartilage volume, thickness, and T2* values of 21 sub-regions were quantitatively assessed. The results showed that the T2* value of knee cartilage increased right after running and recovered two months later, suggesting that the knee joint cartilage showed a degree of reversible change after marathon running.

Ping Zhang¹, Xiao Yue Zhou², Esther Raithel³, Xu Ran Zhang⁴, Xiao Shuai Chen⁴, Jian Ling Cui⁴, and Jian Zhao^4
1The third Hospital of Hebei Medical University, Shijiazhuang, China, ²MR Collaboration, Siemens Healthineers Ltd,Shanghai,China, ShangHai, China, ³Siemens Healthcare, Erlangen, Germany., Erlangen, Germany, ⁴radiology, The third Hospital of Hebei Medical University, Shijiazhuang, China

Manual cartilage segmentation is a time-consuming post-processing procedure, especially for clinical doctors. Automatic cartilage segmentation frees doctors from tedious computer work. Although there have been various automatic segmentation algorithms,  accurate automatic segmentation is still a challenge. In this study, we validated the automatic cartilage segmentation results of the knee joint using a 3D high-resolution DESS sequence. We found that the location of cartilage subregions, and the hydrarthrosis and cartilage degeneration may influence the accuracy of the segmentation. In order to derive more accurate results, a manual finetuning of the automatic segmentation was done. Automatic segmentation still saved considerable time.

Dimitri A Kessler¹, Joshua D Kaggie¹, James W MacKay^1,2, Scott McDonald³, Andrew Grainger¹, Alexandra R Roberts⁴, Robert L Janiczek⁵, Martin J Graves¹, and Fiona J Gilbert^1
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ²Norwich Medical School, University of East Anglia, Norwich, United Kingdom, ³Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, ⁴Independent Clinical Imaging Consultant, Munich, Germany, ⁵GlaxoSmithKline, Clinical Imaging, Philadelphia, PA, United States

We introduce a method to reliably determine changes in healthy knee cartilage composition after joint loading. Ten healthy participants were imaged before and after participant repositioning to determine the test-retest repeatability of T_1ρ and T­₂ relaxation time mapping. Additionally, nine healthy participants were imaged before and after a mild, dynamic stepping exercise. Three-dimensional surface analysis of patellar, femoral, and lateral and medial tibial cartilage was performed. The exercise surface data was thresholded with the determined measurement errors from the T_1ρ and T­₂ repeatability data to highlight cartilage regions experiencing reliable exercise-induced compositional changes.

Yuanyuan Liu^1,2, Weitian Chen³, Xin Liu¹, Hairong Zheng¹, Dong Liang^1,2, and Yanjie Zhu^1
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²Research center for Medical AI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ³Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, China

The quantitative 3D-T_1ρ mapping requires multiple T_1ρ-weighted images with different spin lock times (TSLs) to obtain the T_1ρ  map, which makes the acquisition time very long. In this work, a signal compensation strategy with low-rank plus sparse model (SCOPE) was used to reconstruct  T_1ρ-weighted images from  highly undersampled data. We provide the reconstructed images and the estimated T_1ρ maps at an acceleration factor up to 8.5 in fast 3D-T_1ρ cartilage imaging.

Ye Li¹, Guangbin Wang¹, Weibo Chen², and Aocai Yang^1
1Shandong Medical Imaging Research Institute,Shandong University, Jinan, China, ²Philips Healthcare, Shanghai, China

The current work evaluates the influence of compressed sensing accelerated imaging on the T1ρ mapping. Quantitative evaluation is done using quantitative T1ρ mapping for knee cartilage quantification. T1ρ quantification after CS-accelerated acquisition was compared with non-CS-accelerated acquisition for central patella cartilage.
 

Aurelien Destruel¹, Mingyan Li ¹, Craig Engstrom², Ewald Weber¹, Jin Jin^1,3,4, Rahel Heule⁵, Oliver Bieri⁶, Feng Liu¹, and Stuart Crozier^1
1School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, ²School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia, ³University of Southern California, Los Angeles, CA, United States, ⁴Siemens Healthcare Pty Ltd, Brisbane, Australia, ⁵High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ⁶Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland

The double-echo steady-state (DESS) sequence has been used successfully in 3T MRI imaging of the musculoskeletal system for segmentation of joint. However, in 3D-DESS images acquired at 7T MRI, a reduction in the contrast between tissues due to an increased diffusion sensitivity may complicate cartilage segmentation. Typically, the signals acquired with DESS are averaged without any pre-processing. However, these signals give different contrasts and have different noise behaviours. In this work, we improve the contrast-to-noise ratio (CNR) whilst preserving anatomical detail in high-resolution 7T DESS images through a new approach combining L1-norm denoising and p-norm combination of the echo signals.

Aurelien Destruel¹, Mingyan Li ¹, Ewald Weber¹, Jin Jin^1,2,3, Shekhar S Chandra¹, Jurgen Fripp⁴, Feng Liu¹, Stuart Crozier¹, and Craig Engstrom^5
1School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, ²Mark and Mary Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States, ³ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, Brisbane, Australia, ⁴CSIRO Health and Biosecurity, Herston, Australia, ⁵School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia

Advances in automatic segmentation of cartilage in hip joints has shown the need for high resolution and contrast in 3D sequences. In this work, double-echo steady-state (DESS) hip images from a healthy volunteer were compared at 3T and 7T. 3D-DESS with a resolution up to 0.4x0.4x0.6mm³ was acquired, and showed that the 7T images had superior anatomical detail, signal-to-noise ratio (SNR), contrast ratio (CR) and overall image quality. The improvements observed in 7T imaging of the hip have the potential to boost the performance of automated cartilage segmentation algorithms by reducing segmentation errors.

Sami Lehtovirta^1,2, Ahti Kemppainen^1,2, Marianne Haapea^2,3, Jaro Karppinen^2,4,5, Eveliina Lammentausta^2,3, Vesa Koivukangas⁶, Eero Kyllönen⁷, Mika Nevalainen^1,2,3, Anna-Maija Kauppila⁷, Victor Casula^1,2, and Miika T. Nieminen^1,2,3
1Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, ²Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland, ³Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland, ⁴Center for Life Course Health Research, University of Oulu, Oulu, Finland, ⁵Finnish Institute of Occupational Health, Oulu, Finland, ⁶Department of Surgery, Oulu University Hospital, Oulu, Finland, ⁷Department of Physical Medicine and Rehabilitation, Oulu University Hospital, Oulu, Finland

Obesity has become a worldwide phenomenon with nearly tripling since 1975: 13% of adults over 18 are obese. We set out to study articular cartilage of knee joint in obese individuals using T2 relaxation time. Our study population underwent Roux-en-Y gastric bypass operation and were compared with a control group of obese individuals in a 12-month follow-up. Our results suggest improved quality of cartilage in the lateral compartment of femoral cartilage after bariatric surgery. 

Andrew C. Yung¹, Valentin H. Prevost¹, Jane Desrochers², David Wilson², and Piotr Kozlowski^1
1UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, ²Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada

This work presents one of the first examples of ihMT imaging in cartilage, using ex vivo bovine knee specimens at 7 Tesla.  Protocol optimization experiments were performed to determine the optimal set of parameters (B_1rms, TR, frequency offset, centre frequency) to maximize the ihMTRex signal.  Cartilage-specific signal was observed, which may be related to residual dipolar order established by the highly ordered nature of collagen.

Andrew C Yung¹, Valentin H. Prevost¹, Jane Desrochers², Emily Sullivan², Piotr Kozlowski¹, and David Wilson^2
1UBC MRI Research Centre, University of British Columbia, Vancouver, BC, Canada, ²Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada

We investigated the use of magnetization transfer ratio MTR and ihMTRex as a potential surrogate of cartilage strain, using ex vivo cow knee specimens in a uniaxial compression rig.  On MTR and ihMTRex image volumes for several load levels, the cartilage strain and average MTR or ihMTRex for each column of pixels within the cartilage were calculated.  Normalized change in MTR showed a linear relation with strain throughout the tested range of deformation, whereas ihMTRex only showed response at the highest load levels.  These techniques may be an attractive alternative to T2 or T1ρ techniques to map cartilage strain.

Ashley A Williams^1,2, Jennifer Erhart-Hledik^1,2, Jessica L. Asay^2,3, Gordhan Mahtani^1,2, and Constance R. Chu^1,2
1Orthopaedic Surgery, Stanford University, Stanford, CA, United States, ²Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, United States, ³Mechanical Engineering, Stanford University, Stanford, CA, United States

Patellofemoral joint osteoarthritis (PFOA) following anterior cruciate ligament reconstruction (ACLR) is thought to arise, in part, due to increased external rotation of the tibia and decreased quadriceps strength that alter the tracking of the patella in the trochlear groove. In this study of 59 subjects 2 years after ACLR, higher cartilage UTE-T2* values were detected in ACLR knees with greater external tibial rotations and greater knee flexion moments assessed by gait analysis. This study provides evidence that UTE-T2* is sensitive to patellofemoral cartilage degeneration likely due to altered patellar tracking and quadriceps strength in knees at risk of PFOA. 

Florian Schmaranzer^1,2, Eduardo Novais², Young-Jo Kim², Tobias Kober^3,4,5, Bernd Jung¹, Sarah Bixby⁶, and Onur Afacan^6
1Department of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Inselspital Bern, Bern, Switzerland, ²Department of Orthopaedic Surgery, Harvard Medical School, Boston Children`s Hospital, Boston, MA, United States, <sup>3</sup>Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, <sup>4</sup>Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, <sup>5</sup>École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, <sup>6</sup>Department of Radiology, Harvard Medical School, Boston Children`s Hospital, Boston, MA, United States

Current standard techniques for T1 mapping of hip cartilage are affected by flip angle variations due to B1-field inhomogeneities at 3T. The aim was to prospectively compare a 3D MP2RAGE for T1 mapping of cartilage to a 2D-IR based reference standard in the patients with hip pain undergoing indirect MR arthrography. 3D MP2RAGE correlated well with the 2D-IR reference standard and showed a minor systematic bias. This supports the continued use of 3D MP2RAGE in patients undergoing joint preserving hip surgery with the goal to establish prognostic predictors to predict the success or failure of these interventions.

Laurel Hales¹ and Feliks Kogan^2
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States

Given the use of T1rho as a measure of cartilage health and an early indicator for osteoarthritis, it is important to understand the T1rho relaxation mechanism including its somewhat unexplained angular dependence. In the hope of finding a range of spin-lock frequencies (FSLs) with a decreased angular dependence, we generated T1rho maps of in-vivo femoral knee cartilage at various FSLs from 100Hz to 1kHz. We found a visible angular dependence in T1rho measurements for all FSLs including 1kHz. If there exists a range of FSL with little or no angular dependence it is higher than 1kHz.

Lauren Watkins¹, Valentina Mazzoli², Marianne Black³, Scott Uhlrich³, Brian Hargreaves^1,2,4, Garry Gold², and Feliks Kogan^2
1Bioengineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States, ³Mechanical Engineering, Stanford University, Stanford, CA, United States, ⁴Electrical Engineering, Stanford University, Stanford, CA, United States

Degradation of articular cartilage related to osteoarthritis is associated with changes in cartilage T2 relaxation times that may not be uniform across the cartilage surface. Analysis of changes in T2 times longitudinally or in response to mechanical loading can assist in detection of regions of cartilage damage. Here we examine the ability of cluster analysis to reflect transient changes in cartilage T2 times in response to acute loading. Osteoarthritic subjects who performed a squat exercise had a greater percent of the cartilage area with negative changes in T2 times compared to healthy and osteoarthritic subjects who did not exercise.

Sophia Kronthaler¹, Jürgen Rahmer², Peter Börnert², Alexandra S. Gersing¹, Benedikt J. Schwaiger¹, Roland Krug³, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine, Munich, Germany, ²Philips Research Laboratory, Hamburg, Germany, ³Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States

Imaging of the morphological and biochemical composition of the deep articular cartilage has important implications in the assessment of osteoarthritis. The deep cartilage layer has intrinsically short T₂* characteristics and ultra-short echo time (UTE) imaging techniques have been recently employed in the depiction of the deep cartilage layer morphology. UTE imaging is known to be affected by k-space trajectory errors. The purpose of the present work is to investigate the effect of trajectory errors in UTE imaging used for the depiction and relaxometry of deep articular knee cartilage. A GIRF-correction is applied to correct eddy-currents induced k-space trajectory errors.

Tony T Wong¹, Patrick Quarterman¹, Phuong Duong¹, Diego Jaramillo¹, Michael Liu¹, and Sachin R Jambawalikar^1
1Columbia University Medical Center, New York, NY, United States

Ultrashort echo time (UTE) T2* images of 20 sacroiliac joints were acquired in 10 asymptomatic volunteers. Each sacroiliac (SI) joint was segmented manually and divided into thirds (superior, middle, and inferior). Differences in mean UTE T2* values were assessed. Results demonstrated a mean UTE T2* value of 10.38 ± 0.62 ms in the SI joints. There was no statistical significance between right and left sides (p = 0.89), superior, middle, and inferior third regions (p = 0.86), or males and females (p = 0.47). Intra-observer variability with ICC ranged from 0.89-0.98. 

Jessica Bugeja^1,2, Ales Neubert^1,2, Shekhar Chandra¹, Jurgen Fripp², Craig Engstrom¹, and Stuart Crozier^1
1University of Queensland, Brisbane, Australia, ²CSIRO, Brisbane, Australia

QMRI sequences including T2  and T2*  mapping analyse biochemical changes of cartilage including the deterioration of the ECM and changes in water content for early diagnosis of hip OA prior to serious cartilage degradation. Longitudinal studies and clinical assessments with T2  and T2*  mapping rely on a high reproducibility of the tissue relaxation times for accurate diagnosis. We present a statistical analysis of the reproducibility of T2  and T2*  mapping of hip MR images. An automated cartilage segmentation method is used for the segmentation of FISP MR hip images and biochemical information is obtained from the T2  and T2*  images.

Umi Nabilah Ismail¹, Che Ahmad Azlan¹, Shasha Khairullah², Kuan Jin Lee³, Chai Hong Yeong⁴, Nur Farhayu Omar⁵, Mohammad Nazri M Shah¹, Raja Rizal Azman Raja Aman¹, Nicholas Jackson⁶, and Kwan Hoong Ng^1
1Biomedical Imaging Department, University of Malaya, Kuala Lumpur, Malaysia, ²Department of Medicine, University of Malaya, Kuala Lumpur, Malaysia, ³Singapore Bioimaging Consortium, A*STAR Research, Singapore, Singapore, ⁴School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, Subang Jaya, Malaysia, ⁵Department of Imaging, Universiti Putra Malaysia, Serdang, Malaysia, ⁶Department of Pathology, University of Malaya, Kuala Lumpur, Malaysia

Fat in bone marrow is stated to be regulated by the body haematopoietic needs. We explored this by measuring bone marrow fat fraction(FF) of healthy subjects and β-thalassaemia patients who required treatment to suppress their body haematopoietic needs. The results obtained from 1H-MR Spectroscopy suggested that information about marrow adipocytes may be useful in evaluating patients' treatment response.

Mahsa Talebi^1,2, Shahrokh Abbasi-Rad³, Malakeh Malekzadeh^1,4, Mohamad Shahgholi⁵, Kimia Foudeh⁵, and Hamidreza Saligheh Rad^1,2
1Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran, Tehran, Iran (Islamic Republic of), ²Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran, Tehran, Iran (Islamic Republic of), ³Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran, Brisbane, Australia, ⁴3Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran, Tehran, Iran (Islamic Republic of), ⁵Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran, Najaf Abad, Iran (Islamic Republic of)

Cortical bone porosity contributes to bone quality but is under the limit of the current clinical imaging modalities’ resolution. T1 value of water molecules residing in cortical bone pores is linked with their mobility. Since the changes in surface-to-volume ratio of the pores affect cortical bone mechanical properties, we assumed that free water T1 (T1,free) would model the mechanical properties of cortical bone. Variable flip angle, variable TR, and inversion recovery methods were used to quantify T1,free and their correlation with bone toughness was assessed. The results showed VFA T1,free could predict the cortical bone toughness (r = -0.63, p<0.01).

Kojiro Ono^1,2, Yasuhiro Oikawa³, Shinya Obara¹, and Hideaki Haneishi^2
1Radiology, Chiba Children's Hospital, Chiba, Japan, ²Center for Frontier Medical Engineering, Chiba University, Chiba, Japan, ³Orthopedics, Chiba Children's Hospital, Chiba, Japan

In this study, we reveal a scheme to evaluate the femoral head ischemia using optimized DCE-MRI for preoperative diagnosis in children with unstable SCFE. The consistency of the evaluation of DCE-MRI is verified through compare the cases which were classified as ischemia or normal after surgery. As a result, optimized DCE-MRI is a useful tool to detected femoral head ischemia in children with unstable SCFE, which allows doctors to plan a treatment strategy ahead of time. PEI and MTE using DCE-MRI contribute to an objective evaluation of the perfusion status.

 

Jingqi Zhu¹, Xueli Zhang¹, Yun Tu¹, Rui Tang¹, Rui Ji¹, Jilei Zhang², Ting Hua¹, and Guangyu Tang*^1
1Department of Radiology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China, ²Clinical Science, Philips Healthcare, Shanghai, China

Our study found that the differences of the parameters of mDIXON-Quant and IVIM-DWI [T₂*, fat fraction (FF) and f values] among three groups with varying bone mineral density (normal, osteopenic and osteoporotic) were statistically significant. The correlations of the T₂* and FF values with T-score were negative and the correlations of the D* and f values with T-score were positive. Our study implies that mDIXON-Quant and IVIM-DWI techniques were helpful to reflect the changes of vertebral marrow microenvironment of osteoporosis, which may provide valuable information for the assessment of the bone quality.

Minghui Tang¹, Ken Masuyama², Takayoshi Nakano³, and Toru Yamamoto^1
1Hokkaido University, Sapporo, Japan, ²Teine Keijinkai Hospital, Sapporo, Japan, ³Osaka University, Osaka, Japan

Collagen fibers in the healty cortical bone tends to align to the bone axis, and the degree of this orientation is one of dominant factors to determine bone strength. Because microscopic R₂* around a collagen fiber is anisotropic, we investigated how the UTE signal from mice femurs (normal and osteopetrotic) varies by changing the angle between the bone axis and B₀ for future MRI evaluation of bone strength. The angular dependence of UTE signal of a knockout osteopetrotic mouse decreased 1/5 of a normal mouse. This decrease reflects deterioration of collagen fiber orientation that is a pathological evidence of osteopetrosis.

Fan Qing¹, Ren Huipeng¹, Wang Xiaohu¹, Shen Tianbo¹, Wei Xiaocheng², and Ren Zhuanqin^1
1Baoji Central Hospital, Shaanxi Province, Baoji, China, ²GE Healthcare, MR Research China, Beijing, China

Despite the fact that diffusion MRI is well established in bone marrow as a valuable imaging modality, only a limited number of studies have investigated the intravoxel incoherent motion (IVIM) approach. In this study, bi-exponential IVIM was used to measure diffusion and perfusion fraction in lumbar vertebral bone marrow in 99 healthy subjects. The results demonstrated a gender-related variation in D and f while D* was an independent factor. Our findings may help to better understand the variation of water diffusion and perfusion imaging in lumbar vertebral bone marrow in-vivo with healthy and pathological condition.

Fan Qiuju¹, Tan Hui¹, Yang Zhen¹, Yu Nan¹, Yu Yong¹, Wang Shaoyu², Xue Yu³, and Li Yue^3
1Affiliated Hospital of Shaanxi University of Chinese Medicine, Shaanxi, China, ²MR senior scientific marketing specialist, Shaanxi, China, ³Shaanxi University of Chinese Medicine, Shaanxi, China

This study aimed to investigate the role of multi-echo Dixon technique and IVIM-DWI in assessing vertebral marrow changes among subjects with osteoporosis, osteopenia and normals. The multi-echo Dixon technique and IVIM-DWI were used to evaluate 26 healthy volunteers, 26 osteopenia patients and 24 osteoporosis patients. The FF, D and D* among osteoporosis, osteopenia and normals were significantly different.Furthermore,  we found that there was a statistically significant positive correlation between D value and T-score,while the D* value and FF were negatively correlated to the T-score.

Ying Li¹, Cuiping Ren¹, Jingliang Cheng¹, Jinxia Zhu², and Stephan Kannengiesser^3
1MRI, The first affiliated hospital of Zhengzhou university, Zhengzhou, China, ²MR Collaboration, Siemens Healthcare Ltd., Beijing, China, ³Siemens Healthcare GmbH, Erlangen, Germany

Osteoporosis is a systemic disease characterized by low bone mass with increased fracture risk. This work investigated and evaluated the role of the quantitative Dixon sequence in predicting the bone marrow fat on the lumbar spine, which might provide quantitative imaging parameters for accurately predicting fracture risk in patients with osteoporosis.

Jin Liu¹, Yajun Ma², Xiaojun Chen¹, Jianwei Liao¹, Wei Li¹, Yinghua Zhao³, Yijie Fang¹, Long Qian⁴, Jiang Du², and Shaolin Li^1
1Department of Radiology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Guangdong, China, ²University of California, San Diego, California, San Diego, CA, United States, ³The Tird Affiliated Hospital of Southern Medical University, Guangdong, China, ⁴MR Research, GE Healthcare, Beijing, China

The current study aims to assess the feasibility of proton density (PD) in the lumbar using 3D adiabatic inversion recovery prepared ultrashort TE cones (3D IR‐UTE‐Cones) sequence. In addition, the latent associations between the PD and BMD, age, gender, the oswestry disability index (ODI) were evaluated, respectively. It was concluded that proton density of trabecular bone can be applied in lumbar. Moreover, the proton density of lumbar were observed to correlate with BMD, age and ODI, which need further study to clarify this topic.

Sophia Kronthaler¹, Christof Böhm¹, Dominik Weidlich¹, Maximilian N. Diefenbach^1,2, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany, ²Division of Infectious Diseases and Tropical Medicine, Munich, Germany

Osteoporosis is characterized by a loss in bone mass and structural decrease of bone tissue which is leading to morbidity and an increased fracture risk. Fractures occur predominantly in areas with trabecular bone and the assessment of the bone volume and microstructural changes in the trabecular bone are therefore highly relevant in fracture prediction. The present study characterizes the decay of trabecularized bone marrow signal in multi-echo imaging sampling both UTEs and conventional TEs. A novel methodology is proposed for simultaneous cortical and trabecular bone imaging in the presence of bone marrow.

Brian Johnson¹, Ivan E. Dimitrov¹, Sandeep Ganji¹, and Molly Dempsey ^2
1Philips Healthcare, Gainesville, FL, United States, ²Texas Scottish Rite Hospital for Children, Dallas, TX, United States

Computed tomography (CT) is the current modality of choice for imaging bone yet it suffers from poor soft tissue contrast and utilizes ionizing radiation.  Unlike CT, MRI provides excellent soft-tissue contrast, but is limited in its ability to image bone.  Here, we describe FRACTURE (FFE Resembling A CT Using Restricted Echo-spacing), a novel 3D gradient-echo approach that offers MRI-based bone contrast to yield clinically relevant information for patient management. 

Dimitri Martel¹, Stephen Honig², and Gregory Chang^1
1Radiology, NYU Langone Health, New York, NY, United States, ²Osteoporosis Center, NYU Langone Health, New York, NY, United States

Osteoporosis (OP) is a disease of weak bone associated with an increased fracture risk. Recent studies using Chemical Shift Encoded MRI has been previously used to show differences in term of fat amount related to osteoporosis condition in spine and femur. 

The aim of our study is to use CSE-MRI in muscle, bone marrow and subcutaneous fat of the pelvic region in osteoporosis patient with varying degree of fracture risk.

Gerd Melkus^1,2, Kawan Rakhra^1,2, Reggie Taylor³, Katie Dinelle³, Stephen Dinning^4,5, and Paul Beaulé^5,6
1Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, ²Radiology, University of Ottawa, Ottawa, ON, Canada, ³Brain Imaging Centre, The Royal Hospital, Ottawa, ON, Canada, ⁴Nuclear Medicine, The Ottawa Hospital, Ottawa, ON, Canada, ⁵Medicine, University of Ottawa, Ottawa, ON, Canada, ⁶Orthopaedic Surgery, The Ottawa Hospital, Ottawa, ON, Canada

In this study subjects with asymptomatic FAI and healthy controls underwent PET-MRI to investigate hip bone activity (by [18F]-Sodium Fluoride (NaF) PET) and hip cartilage proteoglycan content (by MRI T1ρ mapping). The FAI subjects showed an increased [18F]-NaF uptake in the femoral head neck junction and in lateral area of the acetabulum, indicating increased bone remodelling. Hip cartilage T1ρ values were significantly higher in the anterior-lateral region for the FAI group, revealing a loss of proteoglycan with a possible connection to an early osteoarthritis stage. PET-MRI has potential to be a useful non-invasive tool to research FAI in vivo.  

Jan-Peter Grunz^1,2, Carsten Herbert Gietzen^1,2, Andreas Steven Kunz¹, Thorsten Alexander Bley¹, and Rainer Schmitt^1,2
1Institute of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany, ²Department of Diagnostic and Interventional Radiology, Rhön-Klinikum Campus Bad Neustadt, Bad Neustadt a. d. Saale, Germany

With the ability to non-invasively display different viability patterns in the scaphoid bone, contrast-enhanced MRI is a powerful tool for detection and staging of Preiser’s disease. To our best knowledge, this study includes the largest patient sample undergoing MRI for idiopathic osteonecrosis of the scaphoid to date, thus expanding the knowledge on this rare disease entity. Our results suggest that the size of scaphoid necrosis is considerably overestimated in unenhanced MRI because necrotic bone cannot be reliably differentiated from vascularized repair tissue. Influencing decision on therapy, the extent of osteonecrosis should consequently not be assessed without administration of contrast agent.

Enrico Soldati¹, Martine Pithioux², David Bendahan³, and Jerome Vicente^1
1IUSTI, AixMarseille, Marseille, France, ²ISM, AixMarseille, Marseille, France, ³CRMBM, AixMarseille, Marseille, France

With the aim of assessing bone microarchitecture, several studies have intended to use MRI but the issue of air bubbles artefacts has been very scarcely reported. In the present study, we assessed air bubbles-related artefacts in MR images of human bone samples and intended to design a protocol to eliminate them. The method was validated using TSE MRI at 3T and high-resolution X-ray micro tomography. Morphological parameters computed from MRI recorded with and without the air bubbles artefacts were compared to those obtained from X-ray micro tomography.

Jinliang Niu¹, Kaiyu Wang², Wenqi Wu¹, Tong Gong³, Jianting Li⁴, and Rong Zheng^4
1Shanxi Medical University Second Affiliated Hospital, Taiyuan, China, ²GE Healthcare, MR Research China, Beijing, Beijing, China, ³Sichuan Provincial People's Hospital, Chengdu, China, ⁴Shanxi Medical University, Taiyuan, China

Intravoxel incoherent motion diffusion-weighted MRI (IVIM) plays an important role in detecting and monitoring microstructure. It offers diffusion and perfusion information at the same time without contrast agents. In this work, we demonstrated IVIM parameters can discriminate the microstructure of marrow in younger women from men compared with the apparent diffusion coefficient (ADC) values. It may provide noninvasive methods for evaluating cellularity, vascular volume and blood velocity of bone marrow.

Saeed Jerban¹, Yajun Ma¹, Hyungseok Jang¹, behnam namiranian¹, Nicole Le², Hoda Shirazian¹, Mark Murphy³, Jiang Du¹, and Eric Y Chang^2
1Radiology, University of California, San Diego, San Diego, CA, United States, ²Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, ³Orthopaedic Service, VA San Diego Healthcare System, San Diego, CA, United States

Cortical bone porous microstructure can be potentially predicted by the total water density in bone. Comparing bone signal from a relatively fast ultrashort echo time MRI (UTE-MRI) scan against the signal of a known external reference (rubber eraser) enabled us to measure total water proton density (TWPD) in 135 cortical bone specimens from 37 donors. We observed significant correlations between bone TWPD and micro computed tomography (μCT) measures (porosity, pore size, and bone mineral density, (BMD)). This relatively fast MRI technique may aid diagnosing and monitoring bone diseases.

Fan Qiuju¹, Tan Hui¹, Yang Zhen¹, Yu Nan¹, Yu Yong¹, Wang Shaoyu², Xue Yu³, and Li Yue^3
1Affiliated Hospital of Shaanxi University of Chinese Medicine, Shaanxi, China, ²MR senior scientific marketing specialist, Shaanxi, China, ³Shaanxi University of Chinese Medicine, Shaanxi, China

This study aimed to assess the association between the magnetization transfer ratio (MTR) value and bone mineral density (BMD) in lumbar vertebral among normal, osteopenia and osteoporosis. The MT technique was used to evaluate 26 healthy volunteers, 26 osteopenia patients and 24 osteoporosis patients. The MTR in the osteoporotic, osteopenic, and normal BMD groups were statistically significant differences. Therefore, MT technique  provide quantitative information about the contribution of macromolecules., which can be used as a non-invasive quantitative monitoring MRI tool for osteoporosis progression.

Pianpian Chen¹, Weiyin Vivian Liu², and Yunfei Zha^3
1Hospital of Stomatology Wuhan University, Wuhan, China, ²MR Research, GE Healthcare, Beijing, China, ³Renmin Hospital of Wuhan University, Wuhan, China

We quantitatively evaluate the microvascular permeability of lumbar marrow changes in alloxan-induced diabetic rabbits using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) . And to investigate whether texture analysis based on permeability parameter K^trans map of DCE-MRI can be used to assess the fine alterations of lumbar marrow structures in early-stage diabetic rabbits.

Our results confirm that texture analysis parameters based on DCE-MRI quantitative parameter K^trans map are feasible to identify the early-stage fine changes of lumbar marrow structure in diabetic rabbits.

Yang Xia¹, Farid Badar¹, and Sarah Salem^1
1Physics, Oakland University, Rochester, MI, United States

Correlated application of high-resolution MRI T2 of intact rabbit knee joints with the aid of bone density properties measured by isotropic high-resolution µCT. The combined multi-model study will aid in the understanding of the relationship between underlying bone-density changes and osteoarthritic cartilage in joint degeneration.

Malakeh Malekzadeh¹, Shahrokh Abbasi-Rad ², Mohammad Bagher Shiran¹, Mojgan Asadi³, Mehdi Shamsi⁴, Navid Tofighi Rad⁴, and Hamidreza Saligheh Rad^5
1Iran University of Medical Science, Tehran, Iran (Islamic Republic of), ²Quantitative Medical Imaging Systems Group, Tehran, Iran (Islamic Republic of), ³Tehran University of Medical Science, Tehran, Iran (Islamic Republic of), ⁴Laleh Hospital, Tehran, Iran (Islamic Republic of), ⁵Tehran University of medical science, Tehran, Iran (Islamic Republic of)

This study deals with assessing the ability of current clinical measures of bone to model the systematic age-related alteration of bone during aging and where does MRI stand as a new modality. Fifty Healthy volunteers with an average age of 44.53 ±7.95 were enrolled based on oral interviews and blood tests. Quantitative measurements were performed by various modalities for lumbar spine, forearm (DXA), Calcaneus (QUS), and Tiba (QCT and MRI). Pearson correlation coefficients was calculated between the bone parameters and age. The highest correlation coefficient between bone parameters and age was related to T1 (r = 0.766, p <0.01).

Saya Horiuchi¹, Taiki Nozaki¹, Shigekazu Funada¹, Atsushi Nozaki², Hiroyuki Kabasawa², Yasuyuki Kurihara¹, and Nobuto Kitamura^3
1Radiology Department, St. Luke's International Hospital, Tokyo, Japan, ²GE Healthcare, Japan, Tokyo, Japan, ³Orthopedic Department, St. Luke's International Hospital, Tokyo, Japan

Zero Echo Time (ZTE) MR imaging provides “CT-like” contrast for cortical bone of the knee. We compared sagittal images of CT and ZTE of 15 patients, and demonstrated inter-modality agreement between morphology of the cortical bone of the tibia from CT and ZTE images. Metallic screws were blurred on ZTE in patients who underwent Anterior cruciate ligament (ACL) reconstruction. ZTE may be used clinically instead of CT in some cases who can undergo ACL reconstruction.

Anmol Monga¹, Dimitri Martel¹, Stephen Honig², and Gregory Chang^1
1Radiology, NYU Langone Health, New York, NY, United States, ²Osteoporosis Center, NYU Langone Health, New York, NY, United States

In recent years, there is greater emphasis on detecting microstructural information in bones that may lead to improved diagnosis of osteoporosis in patients. Radiomics provides a tool to quantify the textural information of medical images and may serve as a marker of bone microstructure. We aim to analyze if the distribution of the textural features computed in the proximal femur  is significantly in subjects with previous fragility fractures compared to those without fracture.

Xiaodong Zhang^1,2, Hyungseok Jang², Yanjun Chen^1,2, Zhenyu Cai², Ya-Jun Ma², Wei Zhao², Yanqiu Feng³, and Jiang Du^2
1Department of Radiology, Third Affiliated Hospital of Southern Medical University, Guangzhou, China, ²Department of Radiology,University of California San Diego, San Diego, CA, United States, ³School of Biomedical Engineering, Southern Medical University, Guangzhou, China

After injection of gadolinium-based contrast agents (GBCAs) for enhanced magnetic resonance imaging (MRI), levels of gadolinium (Gd) in the brain are much lower than that measured in bone. The 3D ultrashort echo time Cones Quantitative susceptibility mapping (3D UTE-Cones-QSM) technique has been used to assess calcium in cortical bone. In this study, we investigated the feasibility of evaluating gadolinium deposition in cortical bone in vitro using 3D UTE-Cones-QSM on a 3T clinical scanner. Higher QSM values were observed with higher Gd concentrations, indicating that 3D UTE-Cones-QSM could be a new, non-invasive technique for evaluation of Gd deposition in bone.

Ryan E Breighner¹, Matthew F Koff¹, and Hollis G Potter^1
1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States

Zero Echo Time (ZTE) MRI yields positive contrast for bone visualization using MRI. The present study highlights cases in which ZTE provides additional diagnostic information in the context of orthopedic trauma. The presented cases are ones in which MRI was deemed necessary for the evaluation of ligament, tendon, or nerve integrity and ZTE was added to aid in the assessment of fractures. In conjunction with our prior work, this study demonstrates that ZTE MRI provides additional diagnostic information in musculoskeletal MRI, specifically in the context of joint trauma.

Francesco Caliva¹, Victoria Wong¹, Roland Krug¹, Drew Lansdown¹, and Valentina Pedoia^1
1University of California, San Francisco, San Francisco, CA, United States

We present a fully-automatic, 2D deep learning based strategy for extracting scapular shape from a high-resolution MRI scan and we quantify network’s segmentation uncertainty. Our method has the potential to greatly improve the diagnostic process for patients with shoulder instability, rotator cuff tears, and osteoarthritis by decreasing the need for multiple imaging scans and ionizing radiation while still providing clinically-useful information to clinicians.

Dongdong Wang¹, Huijia Yin¹, Wenling Liu¹, Zhong Li¹, Wenguang Dou¹, Dongming Han¹, and Kaiyu Wang^2
1The First Affiliated Hospital of Xinxiang Medical University, Weihui, China, ²GE Healthcare, MR Research China, Weihui, China

In this study, we compared and analyzed the active, inactive, and healthy control groups using T2 mapping and assessed the activity of AS using the changes in T2 values. The purposes of this study are to use T2 mapping to assess AS activity, to compare the quantitative assessment values of T2 mapping and DWI for subchondral bone marrow edema of the sacroiliac joint, and to provide potential imaging technical support for the clinical diagnosis of AS and efficacy evaluations of AS treatments.

Mengyue Wang¹, Wentao Wang², Lei Xu¹, Liang Qi¹, and Yuefen Zou^1
1Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China

  Effective diagnosis of ankylosing spondylitis (AS) activity plays an important role for clinical treatment and prognosis. In our study, we used intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to differentiate the active and chronic stage of AS. As a result, we found that D_slow, K^trans and V_e had a high diagnostic sensitivity and specificity.