Effect of knee positioning during MRI scan on segmented cartilage volume and mean T2

Motivation: Differences in knee positioning between measurements can influence calculated cartilage volume and T2 values. Goal(s): To assess the repeatability of cartilage volume and mean T2 values of 9 femoral segments when volunteers knees were measured in different positions. Approach: 8 volunteers underwent test-retest scan using 3D DESS sequence in 5 knee positions. Knee rotation angles were measured in axial view and correlated to cartilage volume and mean T2 values in the femoral region. Results: Knee positioning during measurement has minimal impact on femoral cartilage volume and T2, however volume of posterior cartilage and T2 of lateral cartilage could be affected. Impact: This study highlights the repeatability of femoral cartilage volume and T2 values in relation to patient positioning. Given the weak correlations between position, volume, and T2 in certain cartilage regions, to conduct a test-retest prior to longitudinal studies is advisable.