Visual MRI Grading System to Evaluate Atrophy of the Supraspinatus Muscle

다국어 초록 (Multilingual Abstract)

Objective: To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI).
Materials and Methods: Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30–59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear.
Results: The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70–0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026).
Conclusion: The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.

참고문헌 (Reference)

1 Landis JR, "The measurement of observer agreement for categorical data" 33 : 159-174, 1977

2 Sugaya H, "Repair integrity and functional outcome after arthroscopic double-row rotator cuff repair. A prospective outcome study" 89 : 953-960, 2007

3 Zanetti M, "Quantitative assessment of the muscles of the rotator cuff with magnetic resonance imaging" 33 : 163-170, 1998

4 Melis B, "Natural history of fatty infiltration and atrophy of the supraspinatus muscle in rotator cuff tears" 468 : 1498-1505, 2010

5 Liem D, "Magnetic resonance imaging of arthroscopic supraspinatus tendon repair" 89 : 1770-1776, 2007

6 Tingart MJ, "Magnetic resonance imaging in quantitative analysis of rotator cuff muscle volume" (415) : 104-110, 2003

7 Resnick D, "Internal derangements of joints: Emphasis on MR imaging" W.B. Saunders Company 165-309, 1997

8 Goutallier D, "Influence of cuff muscle fatty degeneration on anatomic and functional outcomes after simple suture of full-thickness tears" 12 : 550-554, 2003

9 Goutallier D, "Impact of fatty degeneration of the suparspinatus and infraspinatus msucles on the prognosis of surgical repair of the rotator cuff" 85 : 668-676, 1999

10 Goutallier D, "Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan" (304) : 78-83, 1994

11 Gladstone JN, "Fatty infiltration and atrophy of the rotator cuff do not improve after rotator cuff repair and correlate with poor functional outcome" 35 : 719-728, 2007

12 Fuchs B, "Fatty degeneration of the muscles of the rotator cuff: assessment by computed tomography versus magnetic resonance imaging" 8 : 599-605, 1999

13 Strobel K, "Fatty atrophy of supraspinatus and infraspinatus muscles: accuracy of US" 237 : 584-589, 2005

14 Trudel G, "Extra- and intramuscular fat accumulation early after rabbit supraspinatus tendon division: depiction with CT" 255 : 434-441, 2010

15 Thomazeau H, "Atrophy of the supraspinatus belly. Assessment by MRI in 55 patients with rotator cuff pathology" 67 : 264-268, 1996

16 Khoury V, "Atrophy and fatty infiltration of the supraspinatus muscle: sonography versus MRI" 190 : 1105-1111, 2008

17 Pfirrmann CW, "Assessment of fat content in supraspinatus muscle with proton MR spectroscopy in asymptomatic volunteers and patients with supraspinatus tendon lesions" 232 : 709-715, 2004

18 Sher JS, "Abnormal findings on magnetic resonance images of asymptomatic shoulders" 77 : 10-15, 1995