Rotator Cuff Fatty Infiltration Are Coronal Images More Helpful for Characterization than Sagittal Images?

To assess for a difference in the characteriza - tion of rotator cuff (RC) muscle fatty infiltration (FI) between the sagittal and coronal planes in the setting of a large or massive RC tear.

Retrospective review of pa - tients with MRIs demonstrating large or massive RC tears (study group-SG) and no tearing (control group-CG) was conducted. Sagittal T1W and coronal PD images of the supraspinatus and infraspinatus muscles from each patient were selected, separated, and placed in random order. Three MSK readers reviewed the images blindly and independently and qualified the FI based on the Goutallier classification.

The SG included 15 men and 15 women (mean age: 65; range: 45 to 87 years); CG included 10 men and 10 women (mean age: 60; range 45 to 76 years). Statistically significant (SS) discrepancies in the assessment of the FI between the sagittal and coronal images occurred 62% in SG and 33% in CG, (p < 0.001). In SG, each reader demon - strated a SS tendency (p < 0.04) to assign a higher value to each muscle when grading the sagittal images compared to coronal images. In SG, 33% of the time (37% supraspinatus, 29% infraspinatus), there was a grade greater than or equal to 3 assigned on the sagittal images but less than 3 grade on corresponding coronal images.

There was a statistically significant differ - ence in the characterization of RC FI between the sagittal and coronal planes in the setting of a large or massive tear, likely related to incomplete visualization of the musculature on sagittal imaging secondary to muscle and tendon retrac - tion and more complete visualization on coronal imaging. Awareness of this difference may allow for a more accurate characterization of the degree of fatty infiltration.