Use of dual-energy computed tomography for the evaluation of calcinosis in patients with systemic sclerosis

We examined the usefulness of dual-energy computed tomography (DECT) in the evaluation of symptomatic systemic sclerosis (SSc)-related calcinosis of the hands. We performed DECT scan of the hands in 16 patients with symptomatic SSc-calcinosis to better characterize the calcinosis, their locations within the soft tissues, and exclude monosodium urate (MSU) crystal deposition. We also compared their computed tomography (CT) images to plain radiographs of one hand. Pertinent clinical information from this cohort was collected. Sixteen SSc patients underwent DECT and plain X-ray imaging of the hands. Five of the 16 SSc patients in our cohort had overlap disease, either rheumatoid arthritis (RA) and/or myopathy. Calcinosis symptoms included painful deposits (88 %), soft tissue swelling (66 %), and recurrent infections (44 %) from these deposits. On DECT, calcinosis deposits had the same color and density as the bone and no MSU was found. However, their CT images showed better details of the calcinosis locations in the soft tissues as well as the bone destruction, especially if there was overlying bulky deposits or flexion contractures. These deposits were most commonly found in the subcutaneous fat pads of the fingertips, along tendon and muscle groups, or within the carpal tunnel. DECT did not confirm MSU in our cohort with calcinosis. However, CT imaging was superior to plain radiographs in locating these deposits within the soft tissues and may be a useful tool to study SSc-calcinosis affecting the hands, particularly in the setting of progressive hand deformities.