Extratendinous migration of calcific tendinitis of the rotator cuff: imaging findings and clinical characteristics with temporal changes

PURPOSE: The aim of this study was to analyze the imaging findings and clinical characteristics of extratendinous migration of calcific tendinitis of the shoulder with temporal changes. METHODS: Seventy-six patients with extratendinous calcific tendinitis of the shoulder diagnosed by ultrasonography (US) or magnetic resonance imaging (MRI) were enrolled in this retrospective study. Clinical symptoms and imaging findings (on radiography, US, and MRI) of extratendinous calcific tendinitis during an acute painful attack were analyzed. Temporal changes were analyzed in 28 patients before an acute attack and 40 patients after an acute attack. For comparison, 65 patients with intratendinous calcific tendinitis were included. RESULTS: Patients with extratendinous calcific tendinitis had a significantly higher average visual analogue scale (VAS) score (8.8±1.6) than the intratendinous group (6.4±2.2) (P<0.001). The fragmented type (80.5%) was the most common shape on US; sonographic black hole appearance (14.6%) and echogenic fluid (9.8%) were characteristic findings of intrabursal calcifications. In 28 patients with previous radiographs, radiographic type III (78.6%) was dominant and the location of calcific deposits changed (82.1%) during the acute painful attack, which was also perceivable in 12 patients with previous US or MRI. In follow-up radiographs of 40 patients, calcifications shrunk by more than 50% or became invisible in 82.5% of patients, with symptom improvement (VAS score, 8.9±1.5 to 1.9±1.2). Follow-up US and MRI of 16 patients also showed decreased size (56.3%) or disappearance (43.7%) of calcific deposits. CONCLUSION: Extratendinous calcific tendinitis has distinctive imaging features, the temporal changes of which correlate well with clinical symptoms.