A preliminary study of the clinical applicability of quantitative T1 and T2 mapping of the knee cartilage: An experimental approach

Abstract

Objectives: To explore the value of T2 and T1 mapping in the early detection of degenerating articular cartilage. Materials and Methods: Twenty-six New Zealand rabbits were randomly divided into three groups. Groups A and B (n = 10 each) had the right knee joint injected with either collagenase type II or papain. The equivalent dilution was injected into the left knee joint as control. In addition, six rabbits served as blank group. Both knees were scanned using MRI, and T2 and T1 values of the cartilage were measured. The femurs were examined microscopically and immunohistologically. T2 and T1 values were compared within and between groups. Results: In group A, immunohistochemistry found that collagen type II decreased in the treated knees. T2 and T1 values were higher in the treated knees than the controls (P < 0.001). In group B, Alcian blue staining showed reduced proteoglycan in the treated knees. The T1 values in the treated knees were higher than the controls (P < 0.001). Conclusion: T2 and T1 mapping may be useful in the early diagnosis of cartilage degeneration. The changes in collagen content of the cartilage were related to T2 relaxation time; whereas, T1 relaxation time was affected by both collagen and proteoglycan.