Investig Magn Reson Imaging.  2016 Dec;20(4):224-230. 10.13104/imri.2016.20.4.224.

Fatty Degeneration and Atrophy of Rotator Cuffs: Comparison of Immediate Postoperative MRI with Preoperative MRI

• Shin SM
• Chai JW
• Kim SJ
• Park J
• You JY

• KMID: 2366404
• DOI: http://doi.org/10.13104/imri.2016.20.4.224

Abstract

PURPOSE
The purpose of this study was to compare the grade of fatty degeneration and atrophy of rotator cuffs on immediate postoperative MRI to those on preoperative MRI in patients with rotator cuff tears.
MATERIALS AND METHODS
Seventy patients were included in this study, who received arthroscopic rotator-cuff repair and underwent both preoperative magnetic resonance imaging (MRI) and immediate postoperative MRI in our institution. Fatty degeneration of rotator cuffs and the atrophy of supraspinatus muscles were evaluated with T1 oblique sagittal images in the Y-shaped view. Fatty degeneration was evaluated using a Goutallier classification system, and the atrophy of supraspinatus muscles was evaluated using a modified tangent sign and a visual occupation ratio.
RESULTS
From 70 patients, a total of 100 tendons were repaired: 18, 69, and 13 tendons were treated for subscapularis, supraspinatus, and infraspinatus, respectively. The Goutallier grades (P = 0.012), modified tangent signs (P = 0.000), and visual occupation ratios (P = 0.000) of supraspinatus muscles were significantly decreased in immediate postoperative MRIs when compared to preoperative MRIs. In immediate postoperative MRIs, the Goutallier grades of supraspinatus muscles were decreased by one grade in 18.8% (n = 13) of the patients, and the atrophy of supraspinatus muscles was improved by one grade in 26.1% (n = 18) for modified tangent signs and 21.7% (n = 15) for visual occupation ratios. However, fatty infiltration by the Goutallier grades of subscapularis (P = 1.000) and infraspinatus (P = 0.157) muscles were not significantly changed after arthroscopic surgery.
CONCLUSION
Immediate postoperative MRIs showed a significant improvement of fatty degeneration and muscle atrophy in supraspinatus muscles when compared to preoperative MRIs.

Keyword

Rotator cuffs; Surgery; Degeneration; Atrophy; Magnetic resonance imaging

MeSH Terms

Arthroscopy
Atrophy*
Classification
Humans
Magnetic Resonance Imaging*
Muscles
Muscular Atrophy
Occupations
Rotator Cuff*
Tears
Tendons

Figure

• 

  Fig. 1 Pre- and immediate postoperative MRIs of a 69-year-old female patient. The interval between the two MRIs was eight days. (a) The preoperative MRI shows atrophy of supraspinatus muscle; grade 2 (borderline) by the modified tangent (represented by a dashed line) sign and grade 3 (< 40%) by the visual occupation ratio. (b) The postoperative MRI shows atrophy of the supraspinatus muscle; grade 1 (negative) by the modified tangent sign and grade 2 (40-60%) by the visual occupation ratio. The occupation ratio of the cross-sectional area of the supraspinatus muscle to the supraspinatus fossa (represented by a dotted line) was assessed visually.

• 

  Fig. 2 The fatty infiltration grades of subscapularis, supraspinatus, and infraspinatus observed in pre- and postoperative MRIs are shown in a stacked bar graph. The Goutallier grades of subscapularis tendons were not changed after arthroscopic surgery. Note the decreased number of patients showing grade 3 and grade 4 fatty degeneration of the supraspinatus upon postoperative MRI.

• 

  Fig. 3 Grades of supraspinatus muscle atrophy, assessed by a modified tangent sign and visual occupation ratio in pre- and postoperative MRIs, are shown in a proportional stacked bar graph. Note the decrease of proportion of patients showing grade 2 and grade 3 atrophy assessed by a modified tangent sign and visual occupation ratio upon postoperative MRIs.

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