Adhesive Capsulitis of the Shoulder MRI Findings
Introduction
The term “frozen shoulder” is used synonymously with adhesive capsulitis. Women in their 50s-70s are most commonly diagnosed with adhesive capsulitis (1). The pathophysiology of an adhesive capsulitis is inflammation of the synovial surface of the GH joint (3). There is also fibroblast proliferation in both the axillary recess and rotator cuff interval (5). Histologic samples have shown thickening of the capsule and synovium (3).
Patients with a frozen shoulder typically complain of shoulder pain and a decrease in their shoulder range of motion (1). Clinical exam can be difficult because patients can have concurrent calcific tendonitis, subacromial bursitis, and GH arthritis. As a result, MRI has been used to help aid in diagnosis.
Imaging Findings
The relevant anatomy when evaluating an MRI for adhesive capsulitis is the rotator interval, the coracohumeral ligament, and the axillary pouch (1).
Patients typically have painful inflammatory capsules of the joint capsule secondary to inflammation in the glenohumeral ligaments (2). Thickening of both the rotator interval and coracohumeral ligament have a high specificity for the diagnosis of adhesive capsulitis (1). The rotator interval is a triangular space that is bordered by the supraspinatus tendon, subscapularis tendon, coracoid process and long head of the biceps tendon (8). The coracohumeral ligament aids in restraining external rotation (4).
Image of the rotator interval (8)
Thickness of the rotator interval >3mm and coracohumeral ligament > 4mm are the thresholds used for diagnosis (1). On MRI, the rotator cuff interval appears hypointense in a patient with adhesive capsulitis.
Hypointensity of the rotator cuff interval in a patient with adhesive capsulitis (10)
Providers also need to look for capsular and synovial thickening (1). Thickness of the joint capsule can be measured on a T2-weighted fat suppression coronal oblique view (4). A thickness >4mm on a coronal oblique T2-weighted fat suppression image has a high specificity for adhesive capsulitis (1).
Thickening of the anterior capsule (2)
Signal change within the subcoracoid fat triangle is also diagnostic of adhesive capsulitis (2). The subcoracoid fat triangle can be visualized on a sagittal oblique image seen below (9).
Arrow shows obliteration of the subcoracoid fat pad (9)
Conclusion
A frozen shoulder can be a debilitating condition causing nighttime pain and restriction in shoulder range of motion. Diagnosis is difficult and can be aided with MRI. Typical MRI findings include thickening of the axillary joint capsule, subcoracoid fat signal change, coracohumeral ligament thickening, and rotator cuff interval thickening. Treatment options go beyond the scope of this review.
By Gregory Rubin, DO
rubinsportsmed.com
– Read More Shoulder Pain @ Sports Med Review: https://www.sportsmedreview.com/by-joint/shoulder/
– Read More @ Wiki Sports Medicine: https://wikism.org/Adhesive_Capsulitis
References
1) Fields, Brandon K. K., et al. “Adhesive Capsulitis: Review of Imaging Findings, Pathophysiology, Clinical Presentation, and Treatment Options.” Skeletal Radiology, vol. 48, no. 8, Aug. 2019, pp. 1171–84. PubMed, https://doi.org/10.1007/s00256-018-3139-6.
2) Park, Jina, et al. “Anterior Capsular Abnormality: Another Important MRI Finding for the Diagnosis of Adhesive Capsulitis of the Shoulder.” Skeletal Radiology, vol. 48, no. 4, Apr. 2019, pp. 543–52. PubMed, https://doi.org/10.1007/s00256-018-3064-8.
3) Manton, G. L., et al. “Utility of MR Arthrography in the Diagnosis of Adhesive Capsulitis.” Skeletal Radiology, vol. 30, no. 6, June 2001, pp. 326–30. PubMed, https://doi.org/10.1007/s002560100326.
4) Ahn, Kyung-Sik, et al. “Correlation between Magnetic Resonance Imaging and Clinical Impairment in Patients with Adhesive Capsulitis.” Skeletal Radiology, vol. 41, no. 10, Sept. 2012, pp. 1301–08. PubMed, https://doi.org/10.1007/s00256-012-1391-8.
5) Erber, Bernd, et al. “MR Imaging Detection of Adhesive Capsulitis of the Shoulder: Impact of Intravenous Contrast Administration and Reader’s Experience on Diagnostic Performance.” Skeletal Radiology, vol. 51, no. 9, Sept. 2022, pp. 1807–15. PubMed, https://doi.org/10.1007/s00256-022-03994-x.
6) Ramirez, Jason. “Adhesive Capsulitis: Diagnosis and Management.” American Family Physician, vol. 99, no. 5, Mar. 2019, pp. 297–300
7) Akkaya, Hüseyin, et al. “Evaluation of Magnetic Resonance Imaging Findings in Adhesive Capsulitis: Which Quantitative Findings Are Most Valuable?” Revista Da Associacao Medica Brasileira (1992), vol. 67, no. 11, Nov. 2021, pp. 1719–23. PubMed, https://doi.org/10.1590/1806-9282.20210808.
8) Lee, J. C., et al. “MRI of the Rotator Interval of the Shoulder.” Clinical Radiology, vol. 62, no. 5, May 2007, pp. 416–23. PubMed, https://doi.org/10.1016/j.crad.2006.11.017.\
9) Zhao, Wen, et al. “An MRI Study of Symptomatic Adhesive Capsulitis.” PLoS ONE, vol. 7, no. 10, Oct. 2012, p. e47277. PubMed Central, https://doi.org/10.1371/journal.pone.0047277.
10) Petchprapa, Catherine N., et al. “The Rotator Interval: A Review of Anatomy, Function, and Normal and Abnormal MRI Appearance.” AJR. American Journal of Roentgenology, vol. 195, no. 3, Sept. 2010, pp. 567–76. PubMed, https://doi.org/10.2214/AJR.10.4406.
