Fig. 5

a Sagittal fat-suppressed proton density-weighted shows preserved signal intensity of the cartilage covering the medial femoral articular cartilage with uniform cartilage thickness (blue arrow). b and c Corresponding T2 map shows normal cartilage T2 relaxation time (ROI). b: 0 ms ≤ T2 ≤ 39 ms; c: T2 ≤ 40 ms)