Associating Knee Osteoarthritis Progression with Temporal‐Regional Graph Convolutional Network Analysis on MR Images

Background Artificial intelligence shows promise in assessing knee osteoarthritis (OA) progression on MR images, but faces challenges in accuracy and interpretability. Purpose To introduce a temporal‐regional graph convolutional network (TRGCN) on MR images to study the association between knee OA progression status and network outcome. Study Type Retrospective. Population 194 OA progressors (mean age, 62 ± 9 years) and 406 controls (mean age, 61 ± 9 years) from the OA Initiative were randomly divided into training (80%) and testing (20%) cohorts. Field Strength/Sequence Sagittal 2D IW‐TSE‐FS (IW) and 3D‐DESS‐WE (DESS) at 3T. Assessment Anatomical subregions of cartilage, subchondral bone, meniscus, and the infrapatellar fat pad at baseline, 12‐month, and 24‐month were automatically segmented and served as inputs to form compartment‐based graphs for a TRGCN model, which containing both regional and temporal information. The performance of models based on (i) clinical variables alone, (ii) radiologist score alone, (iii) combined features (containing i and ii), (iv) composite TRGCN (combining TRGCN, i and ii), (v) radiomics features, (vi) convolutional neural network based on Densenet‐169 were compared. Statistical Tests DeLong test was performed to compare the areas under the ROC curve (AUC) of all models. Additionally, interpretability analysis was done to evaluate the contributions of individual regions. A P value <0.05 was considered significant. Results The composite TRGCN outperformed all other models with AUCs of 0.841 (DESS) and 0.856 (IW) in the testing cohort (all P < 0.05). Interpretability analysis highlighted cartilage's importance over other structures (42%–45%), tibiofemoral joint's (TFJ) dominance over patellofemoral joint (PFJ) (58%–67% vs. 12%–37%), and importance scores changes in compartments over time (TFJ vs. PFJ: baseline: 44% vs. 43%, 12‐month: 52% vs. 39%, 24‐month: 31% vs. 48%). Data Conclusion The composite TRGCN, capturing temporal and regional information, demonstrated superior discriminative ability compared with other methods, providing interpretable insights for identifying knee OA progression. Level of Evidence 4. Technical Efficacy Stage 2.