gms | German Medical Science

Objective: Pathophysiology of adhesive capsulitis is not well known and controversial. We compared findings of indirect magnetic resonance arthrography (iMRA) and 18F-FDG PET (PET) in patients with adhesive capsulitis and other shoulder disorders to investigate if inflammatory process contributes to pathophysiology of adhesive capsulitis.

Material/Methods: Among patients who visited outpatient clinic for shoulder pain, 28 shoulders had taken PET for medical screening. Patients were classified as typical adhesive capsulitis, early adhesive capsulitis and other shoulder pain which includes rotator cuff disorder, acute calcific tendintis, and chronic calcific tendinitis group (Table 1 [Tab. 1], Table 2 [Tab. 2]). Thickness of joint capsule in the axillary recess, area of hyposignal intensity around coracohumeral ligament, enhancement of axillary recess and rotator interval was measured in iMRA (Figure 1 [Fig. 1], Figure 2 [Fig. 2]). Location, degree, and distribution of FDG uptake were identified, and maximum standardized uptake values (SUVmax) were acquired in PET. Differences of iMRA and PET findings between groups and correlation between clinical data, PET (Table 3 [Tab. 3]), and iMRA were measured (Table 4 [Tab. 4]).

Results: Sixteen shoulders were classified as typical adhesive capsulitis, four shoulders were classified as the early adhesive capsulitis (Figure 3 [Fig. 3]) and 8 were classified as other shoulder pain group. In iMRA findings, there were significant differences between adhesive capsulitis group (typical and early) and other shoulder pain group in most of parameters. And there were no differences between typical and early adhesive capsulitis group. In PET findings, there were significant differences between adhesive capsulitis and other shoulder pain group in SUVmax of AR and RI. And there were no differences between typical and early adhesive capsulitis group. SUVmax were increased until 5th month from onset of pain, and then started to decrease.

Conclusion: This study confirms that the pathophysiology of adhesive capsulitis is the inflammation of rotator interval and axillary recess and the inflammation naturally tend to decline. In addition, PET may offer an alternative diagnostic tool for early adhesive capsulitis, and have an advantage for the quantitative measurement of inflammation.