Association of Patient Self-Reported Shoulder Scores to Quantitative and Semiquantitative MRI Measures of Rotator Cuff Intramuscular Fatty Infiltration: A Pilot Study

Abstract

OBJECTIVE. The purpose of this study was to determine the relationship of supraspinatus fat fraction and Goutallier grade to the American Shoulder and Elbow Surgeons (ASES) score in cohorts of older adults with painful full-thickness supraspinatus tendon (SST) tear and control subjects. SUBJECTS AND METHODS. Seventeen control subjects and 15 study participants with painful full-thickness SST tear were prospectively recruited (mean age ± SD, 63.0 ± 10.1 years and 62.6 ± 9.0 years, respectively). Study participants received shoulder MRI and completed ASES questionnaires at one time. Goutallier grade was assessed on T1-weighted MRI. Fat fraction was measured on 6-point Dixon MRI. Body mass index (BMI) was determined. Descriptive, correlation, reliability, and regression analyses were performed. RESULTS. The control and painful full-thickness SST tear cohorts differed in mean supraspinatus fat fraction (3.3% ± 1.4% and 7.3 ± 5.9%, respectively; p = 0.024) and Goutallier grade (0.4 ± 0.5 and 0.9 ± 0.7, respectively; p = 0.022). Fat fraction (p = 0.014) and Goutallier grade (p = 0.017) showed a significant inverse association with ASES score only in the SST tear cohort. The association of BMI to ASES score was significant only in the control group (p = 0.036). The correlation between BMI and fat fraction were different for the two groups (control cohort, r = 0.676 and p = 0.003; SST tear cohort, r = 0.124 and p = 0.687). Fat fraction showed strong interobserver reliability (intraclass correlation coefficient, 0.903); Goutallier grade showed poor interobserver reliability (κ = 0.178). CONCLUSION. The association of ASES score and supraspinatus fat fraction or Goutallier grade differs between patients with painful full-thickness SST tear and control subjects without symptoms. Although fat fraction shows strong reliability, Goutallier grade should be regarded cautiously because of suboptimal reproducibility. Our results also suggest that painful full-thickness SST tear alters the correlation between supraspinatus fat fraction and BMI as compared with control subjects.

Keywords: MRI; intramuscular fatty infiltration; quantitative; rotator cuff; shoulder.

Fig. 1 –

Shoulder MR image examples of study participants in each cohort. A, Oblique coronal STIR MR image from a study participant in the painful full-thickness supraspinatus tendon (SST) tear (long arrow) cohort. B, Oblique coronal STIR MR image demonstrating no full-thickness SST tear (short arrow) in a study participant from the control cohort.

Fig. 2–

Example shoulder MR images from study participants with differing amounts of supraspinatus intramuscular fatty infiltration. A and B. Example 1. Oblique sagittal T1-weighted MRI Y-shaped view for Goutallier grade (A) and oblique sagittal Dixon fat fraction map image (B), corresponding to the oblique sagittal T1-weighted MRI Y-shaped view . The gold outline about the supraspinatus muscle denotes the region of interest placed by manual segmentation for measurement of fat fraction. C and D. Example 2. Oblique sagittal T1-weighted MRI Y-shaped view (C) and corresponding oblique sagittal Dixon fat fraction map image (D).

Fig. 3—

Relationship of the American Shoulder and Elbow Surgeons (ASES) score with supraspinatus fat fraction. Fat fraction is expressed as a percentage. A, Scatterplot for the control cohort. B, Scatterplot for the painful full-thickness supraspinatus tendon tear cohort.

Fig. 4—

Correlation between supraspinatus fat fraction and body mass index. Fat fraction is expressed as a percentage. A, Scatterplot for the control cohort. B, Scatterplot for the painful full-thickness supraspinatus tendon tear cohort.