T2 Mapping of the Sacroiliac Joints With 3-T MRI: A Preliminary Study

OBJECTIVE. The objective of this study was to assess the feasibility of T2 relaxation time measurements of the sacroiliac joints. SUBJECTS AND METHODS. The sacroiliac joints of 40 patients were imaged by 3-T MRI using an oblique axial multislice multiecho spin-echo T2-weighted sequence. Manual plotting and automatic subdivision of ROIs allowed us to obtain T2 values for up to 48 different areas per patient (posterior and anterior parts, sacral, intermediate, and iliac parts). Intraand interobserver reproducibility of T2 values were calculated after independent assessment by two musculoskeletal radiologists. RESULTS. A total of 1656 measurement sites could be analyzed. Mean (+/- SD) T2 values were 40.6 +/- 6.7 ms and 41.2 +/- 6.3 ms for observer 1 and 39.9 +/- 6.6 ms for observer 2. The intraobserver intraclass correlation coefficient was 0.72 (95% CI, 0.70-0.74), and the interobserver intraclass correlation coefficient was 0.71 (95% CI, 0.68-0.72). CONCLUSION. Our study shows the feasibility of T2 relaxation time measurements at the sacroiliac joints.