Is T2 mapping reliable in evaluation of native and repair cartilage tissue of the knee?

Abstract Purpose To evaluate the effect of imaging plane and experience of observers on the reliability of T2 mapping of native and repair cartilage tissue of the knee. Methods Fifteen consecutive patients from two randomised controlled trials (RCTs) were included in this cross‐sectional study. Patients with an isolated knee cartilage lesion were randomised to receive either debridement or microfracture (RCT 1) or debridement or autologous chondrocyte implantation (RCT 2). T2 mapping was performed in coronal and sagittal planes two years postoperatively. A musculoskeletal radiologist, a resident of radiology and two orthopaedic surgeons measured the T2 values independently. Intraclass Correlation Coefficient (ICC) with 95% Confidence Intervals was used to calculate the inter‐ and intraobserver agreement. Results Mean age for the patients was 36.8 ± 11 years, 8 (53%) were men. The overall interobserver agreement varied from poor to good with ICCs in the range of 0.27– 0.76 for native cartilage and 0.00 – 0.90 for repair tissue. The lowest agreement was achieved for evaluations of repair cartilage tissue. The estimated ICCs suggested higher inter‐ and intraobserver agreement for radiologists. On medial femoral condyles, T2 values were higher for native cartilage on coronal images (p