Purpose To evaluate in vivo T2 mapping as quantitative, imaging-based biomarker for meniscal degeneration in humans, by
studying the correlation between T2 relaxation time and degree of histological degeneration as reference standard.
Methods In this prospective validation study, 13 menisci from seven patients with radiographic knee osteoarthritis (median age
67 years, three males) were included. Menisci were obtained during total knee replacement surgery. All patients underwent preoperative magnetic resonance imaging using a 3-T MR scanner which included a T2 mapping pulse sequence with multiple echoes.
Histological analysis of the collected menisci was performed using the Pauli score, involving surface integrity, cellularity, matrix
organization, and staining intensity. Mean T2 relaxation times were calculated in meniscal regions of interest corresponding with the
areas scored histologically, using a multi-slice multi-echo postprocessing algorithm. Correlation between T2 mapping and histology
was assessed using a generalized least squares model fit by maximum likelihood.
Results The mean T2 relaxation time was 22.4 ± 2.7 ms (range 18.5–27). The median histological score was 10, IQR 7–11 (range
4–13). A strong correlation between T2 relaxation time and histological score was found (rs = 0.84, CI 95% 0.64–0.93).
Conclusion In vivo T2 mapping of the human meniscus correlates strongly with histological degeneration, suggesting that T2
mapping enables the detection and quantification of early compositional changes of the meniscus in knee OA