Vadim Malis¹, Usha Sinha², Edward Smitaman¹, Jed Keenan Obra³, Henning T Langer³, Agata A Mossakowski³, Keith Baar³, and Shantanu Sinha^1
1Radiology, UC San Diego, San Diego, CA, United States, ²Physics, San Diego State University, San Diego, CA, United States, ³Physiology and Membrane Biology, UC Davis, Davis, CA, United States

Diffusion modeling (RPBM) of the time dependence of the skeletal muscle diffusion eigenvalues was applied to probe tissue changes with age.  λ₂ (TM=30 ms) was significantly lower in seniors; permeability and the residence time from RPBM were significantly positively correlated with grip size and 200 m walk. Significant negative correlations of λ₁ and λ₂ to age and to physical λ₂ / λ₃ to collagen matrix angle and to systolic/diastolic blood pressure were seen. λ₂ and λ₃ were significantly positively correlated to the projection of the strain on the diffusion eigenvector corresponding to the secondary eigenvalue.

Alecio F. Lombardi^1,2, Zhao Wei¹, Dina Moazamian¹, Saeed Jerban¹, Hyungseok Jang¹, Nicole Le¹, Jiang Du¹, Christine B. Chung^1,2, Eric Y. Chang^1,2, and Ya-Jun Ma^1
1Department of Radiology, University of California, San Diego, CA, United States, ²Radiology Service, Veterans Affairs, San Diego Healthcare System, San Diego, CA, United States

MRI-based compositional imaging of cartilage has higher sensitivity to detect early changes in osteoarthritis. The osteochondral junction (OCJ) is of particular interest since it has been associated with early changes and progression of cartilage degeneration. However, conventional MRI sequences cannot differentiate with high contrast the OCJ region for quantification. Here we present quantification of T1, T1rho, T2*, and macromolecular fraction (MMF) of deep and superficial layers knee cartilage using 3D ultrashort echo time (UTE) MRI cones sequences and correlate the values from the OCJ with the degree of cartilage degeneration according to the MRI Osteoarthritis Knee Cartilage Score (MOAKS).

Brandon Cunnane¹, Vadim Malis², Usha Sinha¹, Ryan Hernandez¹, John Hodgson³, and Shantanu Sinha^2
1Physics, San Diego State University, San Diego, CA, United States, ²Radiology, UC San Diego, San Diego, CA, United States, ³Inteegrative Biology and Physiology, UC Los Angeles, Los Angles, CA, United States

Feasibility is shown of  studying aging muscles using rapid, compressed sensing VE-PC technique at relatively high isometric forces to calculate projections of 3D strain and strain rate tensor along fiber eigenvectors calculated from DTI.

Abdul Wahed Kajabi^1,2, Stefan Zbyn^1,2, Marc A. Tompkins³, Bradley J. Nelson³, Kevin G. Shea⁴, Cathy S. Carlson⁵, and Jutta M. Ellermann^1,2
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, ²Department of Radiology, University of Minnesota, Minneapolis, MN, United States, ³Department of Orthopedic Surgery, University of Minnesota, Minneapolis, MN, United States, ⁴Stanford Children's Hospital, Stanford University, Palo Alto, CA, United States, ⁵Department of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States

This study examined seven clinically asymptomatic siblings of patients with Osteochondritis Dissecans (OCD) utilizing 3T MRI, including quantitative apparent diffusion coefficient (ADC) mapping to evaluate morphological integrity of the epiphyseal cartilage, integrity of secondary physis and trabecular bone quality in the distal femoral condyles of bilateral knees. A high prevalence (86%) of morphological MRI abnormalities that can be seen in early OCD and increased diffusivity (high quantitative ADC values) in trabecular bone were detected. The high prevalence of early signs of OCD in clinically asymptomatic siblings of OCD patients supports evidence of a genetic predisposition for the disease.

Brandon Cunnane¹, Usha Sinha¹, Vadim Malis², Ryan Hernandez¹, John Hodgson³, and Shantanu Sinha^2
1Physics, San Diego State University, San Diego, CA, United States, ²Radiology, UC San Diego, San Diego, CA, United States, ³Inteegrative Biology and Physiology, UC Los Angeles, Los Angles, CA, United States

Study of muscle fiber strains at different foot positions can reveal the dependence of muscle force on muscle architecture. Prior studies of isometric contraction in calf muscle using dynamic MRI revealed in the medial gastrocnemius (MG), strain heterogeneity along and across fibers, constant in-plane areas, and gear ratios decreasing with unloading. This study examines correlation of fiber strains in the MG at three-foot positions and two sub-maximal isometric contractions with fiber directions extracted from DTI. The plantarflexed foot position had the highest normalized fiber strain (to force and to torque) while the dorsiflexed position had the lowest normalized fiber strains.

Mohammad Zarenia¹, Samantha R. Schwartz², Joshua M. Leonardis², Alyssa J. Schnorenberg², Volkan E. Arpinar¹, Brooke A. Slavens², and Kevin M. Koch^1
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, ²Department of Rehabilitation Sciences & Technology, University of Wisconsin-Milwaukee, Milwaukee, WI, United States

4D MRI and external motion capture systems were utilized to track unconstrained movement of wrist carpal bones. Using slab-to-volume registration of dynamic MRI to static MRI reference images, wrist kinematic profiles for 19 healthy subjects were computed and compared to gold-standard motion analysis metrics during ulnar/radial deviation and flexion/extension motions. The agreement of kinematic measures derived using the intrinsic (i.e. carpal bone volume) MRI-based approach and external (sensor-based) motion capture methods provided validation of the deployed MRI-based kinematic profiling methodology.

Alecio F. Lombardi^1,2, Saeed Jerban¹, Ya-Jun Ma¹, Micah Blais³, Robert K. Eastlack³, Gregory M. Mundis Jr.³, Jiang M. Du¹, Eric Y. Chang^1,2, and Bahar K. Shahidi^4
1Department of Radiology, University of California, San Diego, CA, United States, ²Radiology Service, Veterans Affairs, San Diego Healthcare System, San Diego, CA, United States, ³Department of Orthopedic Surgery, Scripps Clinic, San Diego, CA, United States, ⁴Department of Orthopedic Surgery, University of California, San Diego, CA, United States

This study aimed to quantify T1, T1rho, T2*, and MMF values of the human interspinous ligament using 3D ultrashort echo time (UTE) cones MRI and correlate them with biomechanical properties. We found a significant negative correlation between T1 and elastic modulus; significant moderate to strong negative correlations between T1rho and both tensile stress and maximum load; and significant moderate to strong positive correlations between MMF and both tensile stress and maximum load. There was an overall trend towards negative correlation between T2* and biomechanical properties.

zhiyuan zhang^1,2,3, Jeehun Kim^2,3,4, Richard Lartey^2,3, Carl S. Winalski^2,3,5, and Xiaojuan Li^2,3,5
1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, ²Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States, ³Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States, ⁴Department of Electrical, Computer, and Systems Engineering, Case Western Reserve University, Cleveland, OH, United States, ⁵Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH, United States

MR T1ρ and T2 have been suggested as promising imaging markers for detecting early cartilage degeneration in osteoarthritis¹. However, one hurdle of applying such quantitative MRI to large clinical trials and clinical practice is the lack of standardization of data acquisition and processing. In this study, we evaluated multiple factors that affect cartilage T1ρ and T2 quantification including maximum TE, number of echoes, SNR, and fitting methods for single and multi-channel situations with simulations, phantoms and human data. Such evaluations will help to provide useful guidance in standardizing data acquisition and processing for cartilage T1ρ and T2 imaging.

Jason Matakas¹, Steven Shamah¹, Esther Rong¹, Jenna Le¹, Karen Sperling¹, Can Wu², and Qi Peng^1
1Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, United States, ²Memorial Sloan Kettering Cancer Center, New York, NY, United States

Osteoarthritis (OA) is a leading cause of disability characterized by proteoglycan loss and collagen matrix disruption in the cartilage. Quantitative T1ρ and T2 mapping obtained in a static setting have been proposed to detect the biochemical changes associated with OA, which however lack the functional information of the cartilage. We here present a novel dynamic approach to elucidate biochemical recovery of knee cartilage after stair-climbing exercise with high-spatiotemporal-resolution simultaneous 3D T1ρ and T2 mapping. It could serve as an innovative, clinically feasible imaging biomarker to evaluate both biochemical and functional properties of cartilage for early OA diagnosis and prognosis.

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

Detecting microstructural information in bones leads to improved diagnosis, monitoring, and understanding of osteoporosis in patients. Recent advances allow for comprehensive and automated mining of quantitative image features to capture disease characteristics. Among these, graph and network analysis permit to characterize and assess network as the trabecular one and been previously applied in the wrist. In this study, we aim to apply the graph and network analysis method to the femoral trabecular bone network of osteoporosis subjects with and without previous fragility fracture history and assess features associated with fracture. 

Saeed Jerban¹, Michael Song², Amir M Afsahi¹, Dina Moazamian¹, Michael Carl², Yajun Ma¹, Alecio Lombardi¹, Christine B Chung¹, Eric Y Chang^1,3, and Jiang Du^1
1Department of Radiology, University of California, San Diego, San Diego, CA, United States, ²General Electric Healthcare, San Diego, CA, United States, ³Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

High susceptibility levels at the marrow/bone interface may significantly reduce T2* of marrow, leading to trabecular bone volume overestimation when imaged using conventional MRI sequences. The presence of fat in bone marrow further complicates trabecular bone imaging due to chemical shift artifacts. In this study, an ultrashort echo time MRI (UTE-MRI) technique focused on the fat peak frequency was investigated to image trabecular bone ex vivo and in vivo. This technique was shown to improve trabecular bone imaging by minimizing chemical shift artifacts as well as susceptibility related short T2* effects, thereby providing more accurate estimation of trabecular bone structure.

Dimitri Martel¹, Benjamin Leporq², Anmol Monga¹, Stephen Honig³, and Gregory Chang^1
1Radiology, NYU Langone Health, New York, NY, United States, ²Université de Lyon; CREATIS CNRS UMR 5220, Inserm U1206, INSA-Lyon, Villeurbanne, France, ³Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Health, New York, NY, United States

Osteoporosis (OP) is associated with low bone mass and deterioration of bone tissue microarchitecture leading to increased bone fragility and fracture risk. There are increasing pieces of evidence that bone marrow adipose tissues (BMAT) play a significant role in the pathophysiology of osteoporosis. Our aim was to assess the proximal femur BMAT composition in OP without (OP) and with history of fragility fracture (OP-Fx) and compare it to naive controls using Chemical Shift Encoded MRI. 

Dimitri Martel¹, Amit Saxena², H. Michael Belmont², Stephen Honig³, Anmol Monga¹, and Gregory Chang^1
1Department of Radiology, NYU Langone Health, New York, NY, United States, ²Department of Rheumatology, NYU Langone Health, New York, NY, United States, ³Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Health, New York, NY, United States

Systemic Lupus Erythematosus (SLE) is a chronic, inflammatory, multisystem disease predominantly affecting young women. Patients with SLE have a significantly worse health-related quality of life compared to healthy subjects or patients with other chronic diseases. MSK manifestations in SLE patients are common, including reductions in bone quality. Studies using magnetic magnetic resonance spectroscopy (MRS) have shown that change in bone marrow fat amount and composition is associated with decreased bone quality. The aim of our study was to use MRS to assess differences of BMAT in SLE without treatment (n=28), SLE treated (n=15) and controls (n=21).

Daniele Mattioli¹, Vincenzo Vinicola², Marco Montuori³, Umberto Tarantino⁴, and Silvia Capuani^5
1Physics Dpt., Sapienza University of Rome, Rome, Italy, ²Center for Prevention, Diagnosis and Treatment of Osteoporosis, IRCCS Santa Lucia Foundation, Rome, Italy, ³Institute for Complex Systems, National Research Council CNR-ISC, Rome, Italy, ⁴Department of Orthopaedics and Traumatology, Tor Vergata University of Rome, Rome, Italy, ⁵Institute for Complex Systems, National Research Council CNR-ISC, Roma, Italy

Changes occurring in the bone-marrow fatty-acids (BMFA) could be precursors of the bone mineral loss due to the development of osteoporosis. In this view, early biomarkers of osteoporosis among BMFA could be highlighted by quantifying fatty-acids with 1H-MRS in young, premenopausal, postmenopausal women with normal t-score and in osteoporotic women. In this study, L13, L09, fUFA, and fPUFA together with TL quantification obtained in women calcanei  could be early osteoporosis markers. The present work confirms the potential of MRS to investigate BMFA metabolic variations due to postmenopause and to the development of osteoporosis. 

Po-hung Wu¹, Kaipin Xu², Gabby Joseph¹, Yan Li¹, Xiaojuan Li², Thomas Link¹, and Galateia Kazakia^1
1Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, United States, ²Biomedical Engineering, Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States

Patients with type II diabetes (T2D) have increased fracture risk. Increased bone marrow fat is associated with increased fracture risk. We hypothesized that T2D patients will have altered bone marrow fat (BMF) and marrow composition biomarkers. In this study, we performed magnetic resonance spectroscopy (MRS) to quantify BMF and composition biomarkers at the spine in 37 T2D patients and 36 controls, and at the distal tibia in 30 T2D patients 32 controls. The results suggest that T2D may change vertebral marrow composition, particularly in men, which may be a factor in the development of increased bone fragility related to T2D.