The Utility of Modified Dixon Turbo Spin Echo Shoulder Magnetic Resonance Arthrography in Assessing Rotator Cuff Disorder and Evaluating the Rotator Cuff Muscles

Rationale and Objectives: To compare the diagnostic ability of modified Dixon (mDixon) turbo spin echo (TSE) T1-weighted (T1W) shoulder magnetic resonance arthrography (MRA) with that of conventional shoulder MRA, and evaluate the feasibility of mDixon TSE in-phase (IP) images in measuring the fat fraction and size of rotator cuff muscles. Materials and Methods: This retrospective study included 57 patients who underwent 3T shoulder MRA examinations with conventional and mDixon TSE T1W images (mean age: 56.7 years; range: 20–78 years). Two musculoskeletal radiologists independently evaluated the rotator cuff tendons with fat saturated T1W images and mDixon TSE T1W water images. Occupation ratios measured on T1W and mDixon TSE T1W IP images were compared. The fat fraction of the supraspinatus from the mDixon TSE T1W images was calculated and correlated with fatty infiltration of the supraspinatus on T1W images. Results: For tendon pathology, the kappa value for inter-sequence and inter-reader agreement was 0.957 (95% confidence interval [CI]: 0.923–0.990) and 0.839 (95% CI: 0.778–0.899), respectively. For retear, the kappa value for inter-sequence and inter-reader agreement was 0.913 (95% CI: 0.796–1.000) and 0.779 (95% CI: 0.594–0.963), respectively. The intraclass correlation coefficient for both occupation ratios was 0.986 (95% CI: 0.973–0.993). Comparison of mDixon TSE T1W fat fraction with Goutallier grade showed a strong positive linear correlation (r = 0.929). Conclusions: The mDixon TSE T1W sequence is a good alternative to conventional sequences in shoulder MRA for evaluating rotator cuff pathology. Furthermore, this sequence provides information on the size and fat infiltration of rotator cuff muscles.