Exploratory analysis of infrapatellar fat pad MRI-based radiomics for detection of knee structure abnormalities in collegiate basketball players and swimmers

Magnetic resonance imaging (MRI) based radiomic evaluation of the infrapatellar fat pad (IPFP) has been shown to predict knee osteoarthritis. As IPFP abnormalities can arise from sport-related injuries, this study evaluated whether qualitatively identified knee structure abnormalities in young athletes can be detected by IPFP MRI-based radiomics. Bilateral knee MRIs using Dixon fat-water decomposition techniques were obtained from 46 NCAA Division 1 collegiate 46 basketball players (26 male, 20 female) and 21 swimmers (10 male, 11 female). Board-certified musculoskeletal radiologists evaluated anatomic features and patellar height using the modified Noyes score and Caton-Deschamps index.. IPFP volumes were segmented, and fat fraction was computed. Radiomic features were calculated within 2D overlapping patches extracted from the IPFP in the fat and water images separately. Cross-validated logistic regression models were developed using IPFP radiomic features as predictors of an athlete’s sport and the occurrence of cartilage lesions, tendinopathy, or bone abnormalities as observed on MRI. Mann-Whitney U tests evaluated differences in fat fraction between sports and knee structure abnormalities. The area under the receiver operating characteristic (ROC) curve (AUC; maximum 0.79) indicated that IPFP radiomics from fat-only images can differentiate between basketball and swimming athletes. Tendinopathy was identified (AUC = 0.68 ± 0.05) at larger patch sizes. Qualitative radiological assessments of cartilage lesions and bone abnormalities were not distinguished (AUC < 0.57). Fat fraction did not differ across sports or knee structure abnormality (p > 0.49, mean difference < 0.5%). In the absence of inflammatory arthropathy, IPFP radiomics discriminated between sports but not cartilage lesions, tendinopathy, or bone abnormalities, suggesting structural adaptation to sport-specific loading. Abnormal IPFP signal intensity may not present in young athletes without traumatic injury or knee arthroscopy.