Jennifer Anne Cummings¹, Kenneth Gao¹, Vincent Chen², Alejandro Morales Martinez², Sharmila Majumdar¹, and Valentina Pedoia^1
1University of California, San Francisco, San Francsico, CA, United States, ²University of California, San Francisco, San Francisco, CA, United States

The trajectories of femur cartilage thickness and T2 relaxation time over an 8 year period were analyzed for 787 subjects from the Osteoarthritis Initiative dataset. Biomarkers were automatically extracted and used to generate time series for 27 regions of interest within the cartilage map to create a connectivity matrix (connectome). Statistically significant differences in thickness and T2 trajectories were found to correlate with demographic and clinical factors such as sex, BMI, Radiographic OA and presence of knee pain.

Valentina Mazzoli^1,2, Scott Uhlrich^2,3, Feliks Kogan¹, Amy Silder^2,4, Andrea Finlay⁵, Scott Delp ^3,4, Gary Beaupre^4,6, Julie Kolesar^4,6, and Garry Gold^1
1Radiology, Stanford University, Stanford, CA, United States, ²Musculoskeletal Research Laboratory, VA Palo Alto Healthcare System, Palo Alto, CA, United States, ³Mechanical Engineering, Stanford University, Stanford, CA, United States, ⁴Bioengineering, Stanford University, Stanford, CA, United States, ⁵Center for Innovation and Implementation, VA Palo Alto Healtcare System, Palo Alto, CA, United States, ⁶Musculoskeletal Research Laboratory, VA Palo Alto Healtcare System, Palo Alto, CA, United States

We performed a single-blind randomized clinical trial in subjects with medial knee OA to evaluate the effect of a gait modification. Primary outcomes were pain and KAM (surrogate measure of medial knee loading). We also utilized cartilage T₂ and T_1ρ to assess (micro)structural changes induced by the treatment. In the Intervention group, we observed a greater reduction in pain and KAM (reduced loading), and less increase in T_1ρ in the medial femoral compartment, potentially indicating slowed cartilage degeneration. Our study shows that quantitative cartilage MRI is a promising outcome measure in clinical trial assessing non-surgical treatment for knee OA.

Jose G Raya¹, Alejandra Duarte², Richard Kijowski¹, Svetlana Krasnokutsky-Samuels¹, Jenny T Bencardino³, and Jonathan Samuels^1
1NYU Langone Medical Center, New York, NY, United States, ²Fundacion Santa Fe de Bogota, Bogota, Colombia, ³Penn Medicine, Philadelphia, PA, United States

The goal of this study is to validate DTI of articular cartilage at 3T as a biomarker for OA progression in a population at early stages of the disease and high likelihood of short-term progression. The goal of this study is to validate DTI of articular cartilage at 3T as a biomarker for OA progression in a population at early stages of the disease and high likelihood of short-term progression. We show that DTI has potential for prognosis of 3-year radiographic changes in a population with early stages of disease. 

Michelle W. Tong^1,2, Aniket A. Tolpadi^1,2, Alex Beltran^1,2, Sharmila Majumdar², and Valentina Pedoia ^2
1Department of Bioengineering, University of California Berkeley, Berkeley, CA, United States, ²Department of Radiology and Biomedical Imaging, University of California San Francsico, San Francisco, CA, United States

This study explores the use a deep learning network to generate T₁rho maps from T₂ maps for knee MRI. T₁rho maps have clinical value in the diagnosis of osteoarthritis in addition to T₂ maps while T₂ maps are more widely adopted and available in clinical datasets. This study found synthetic T₁rho maps images maintain excellent fidelity for data collected in a research setting while performance is reduced for data collected in a clinical setting. This work elucidates the promise of deep learning in accelerating imaging protocols through domain adaptation as opposed to more common reconstruction approaches.

Frida Johansson^1,2, Zainab Sirat¹, Hanna Hebelka^1,3, Helena Brisby^1,4, Fredrik Nordström^1,2, and Kerstin Lagerstrand^1,2
1Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden, ²Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden, ³Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden, ⁴Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden

In vivo evaluation of the intervertebral disc (IVD) during spinal loading may yield greater insight into the biomechanical properties of the IVD. This study aimed to investigate how the lumbar IVD deforms during loading, quantified with a novel non-invasive method utilizing MRI and image registration. Findings showed that the intradiscal deformation depends not only on disc degeneration but also on the lumbar spine level. This highlights the need for tools that can evaluate the mechanical properties of the disc in vivo. The proposed method offers a possibility to depict and track biomechanical changes non-invasively while characterizing disc structures in detail. 

Ashley A Williams^1,2, Yongxian Qian^3,4, 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, ³Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States, ⁴Center for Biomedical Imaging, NYU Langone Health, New York, NY, United States

This work evaluates mono- and bi-exponential UTE-T2* relaxation in 6 tread mark regions of knee cartilage of 18 participants with ACL-injury prior to reconstruction surgery and in 15/18 participants 2 years after surgery. Bi-exponential T2*_short had a smaller fractional contribution than T2*_long in all regions examined. However, T2*_short accounted for a higher fraction of total signal in deep cartilage layers compared to superficial. While both mono- and bi-exponential UTE-T2* analyses showed significant longitudinal changes, bi-exponential analyses did not exceed the sensitivity of mono-exponential UTE-T2* for detection of knee cartilage compositional changes over the first two years following ACL reconstruction.

Woowon Lee¹, Emily Y Miller², Callan M Luetkemeyer¹, and Corey P Neu^1,2
1Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States, ²Biomedical Engineering Program, University of Colorado, Boulder, CO, United States

Osteoarthritis (OA) is a degenerative process in cartilage mainly occurring in knee. OA affects the structure and function of cartilage thus, measuring the mechanical properties of cartilage is crucial. We use spiral DENSE MRI to quantify the mechanics of intact and defected bovine articular cartilage. The samples underwent cyclic compressive load and 27 frames are captured while the joint was compressed. Displacement and strain gradually increased over time and the defected cartilage showed higher strain in the tibiofemoral contact areas. We also found creep response in the defected cartilage which may be a potential biomarker for OA detection.

Amelia Kruse¹, Austin Carcia¹, Adam Bradshaw¹, Charles Ho¹, Johnny Huard¹, Scott Tashman¹, and Lauren Watkins^1
1Steadman Philippon Research Institute, Vail, CO, United States

In this exploratory study, we examine relationships between joint function and cartilage composition in individuals with knee osteoarthritis (OA). MRI T2 relaxation times were used to assess articular cartilage and joint kinematics were recorded over walking gait cycles using video-motion analysis. There were significant correlations between cartilage T2 relaxation times and knee flexion, extension, and swing-stance ratio in both affected and contralateral legs. MRI measures of cartilage quality and joint function provide complimentary information that may be useful in measuring disease progression and intervention effectiveness using MRI.