To investigate the ability of ultrasound (US) compared to radiographs to detect calcinosis in hands/wrists of patients with systemic sclerosis (SSc), and to assess US markers of pathologic perfusion.
Patients with SSc were evaluated for calcinosis in the hands/wrists by radiograph and US. The presence or absence of calcinosis was recorded by patient, hand, and anatomic zone; sensitivity and specificity for calcinosis detection by US versus radiographs was determined. Bilateral US vascular measurements of ulnar artery occlusion (UAO) and finger pulp blood flow (FPBF) were obtained. For each hand, associations between markers of pathologic blood flow (UAO, FPBF, and a composite severity score of UAO and FPBF) and the presence of calcinosis were assessed using generalized estimating equations.
Of 43 patients with SSc (19 diffuse, 24 limited), 39.5% had calcinosis on radiographs compared to 30.2% on US. Sensitivity and specificity for US, respectively, were 61% and 95% by zone, 78% and 98% by hand, and 76% and 100% by patient. UAO was seen in 30% and 28% of left and right hands, respectively; FPBF was absent in ≥1 digit of the left and right hands in 49% and 44%, respectively. UAO was associated with radiograph-identified calcinosis by hand (odds ratio [OR] 8.08 [95% confidence interval (95% CI) 2.45-26.60], P < 0.001), whereas FPBF and the composite severity score were not significant. UAO was associated with calcinosis even in the absence of digital ulcers (OR 33.00 [95% CI 3.39-321.09], P = 0.003).
US was sensitive and highly specific in detecting calcinosis in SSc. UAO was strongly associated with radiograph-identified calcinosis.