Diagnostic performance and reliability of ultrasonography for fatty degeneration of the rotator cuff muscles.
In patients suffering complaints resulting from rotator cuff tears, the extent to which fatty degeneration (FD) is present provides valuable information to guide options for intervention. Since ultrasonography has various practical advantages above MRI, this study sought to determine the methodological characteristics of ultrasonography in detecting and grading FD using MRI – currently accepted as the gold standard – as a reference.
Eighty patients who were suspected to have pathology of rotator cuff tendons were included in the study. In both examinations a standardized protocol was followed. The amount of FD in the MRI findings was graded according to the five-point Goutallier scale. To be able to compare this with the ultrasound findings, in which a three-point scale was applied, the Goutallier scale was collapsed to a three-point scale. Both examination modalities were also collapsed to a dichotomous scale (FD present or absent).
Ultrasonography had, based on the dichotomous scales, excellent agreement with MRI for the identifying FD in the supraspinatus and infraspinatus and moderate agreement for the teres minor. Using the three-point scales to determine the progression of FD, the agreement was substantial for the supraspinatus and infraspinatus and again moderate for the teres minor. Overall percentages of agreement were 92.5% for the supraspinatus and infraspinatus and 87.5% for the teres minor. Moreover, the interobserver reliability of both methods was comparable. > From: Wall et al., J Bone Joint Surg Am 94 (2012) e83(1-9). All rights reserved to The Journal of Bone and Joint Surgery, Inc.
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(Image by: Bianchi 2007.)