In the setting of rotator cuff injuries, higher degrees of fatty infiltration into cuff muscles are positively correlated with higher repair failure rates and worse clinical outcomes. MRI continues to be the gold standard imaging modality for evaluating fatty infiltration of the rotator cuff, but ultrasound represents another viable modality for that assessment—at considerably lower cost. Such is the conclusion of Tenbrunsel et al. in a recent issue of JBJS Reviews.
The authors reviewed 32 studies that investigated imaging modalities used to assess fatty infiltration and fatty atrophy. They found that grading fatty infiltration using ultrasound correlated well with grading using MRI. However, the authors identified difficulties distinguishing severe from moderate fatty infiltration on ultrasound, but they added that discerning mild from moderate fatty infiltration is more important clinically. Tenbrunsel et al. also mention sonoelastography, which measures tissue elasticity and can also be used to help determine the severity of fatty atrophy of the rotator cuff.
Overall, the trade-off between MRI and ultrasound comes down to higher precision with the former and lower cost with the latter.
For more information about JBJS Reviews, watch this video featuring JBJS Editor-in-Chief Dr. Marc Swiontkowski.