Ultrasound quantitative assessment of ventral finger microvasculopathy in systemic sclerosis with Raynaud’s phenomena: a comparative study

OBJECTIVE: To assess the finger vascularity of systemic sclerosis patients with Raynaud’s phenomenon (RP-SSc) using various ultrasound techniques. METHODS: All fingers (except thumbs) of 18 RP-SSc patients and 18 controls were imaged at room temperature using four ultrasound vascular imaging techniques. The percent vascular area was quantified by counting blood flow pixels in a 25 mm(2) square centred at the nail fold for the dorsal side and in 25 mm(2) and 100 mm(2) square from the fingertip for the ventral side. The mean vascular intensity was calculated from the corresponding areas for dorsal and ventral sides. RESULTS: The percent vascular areas and mean vascular intensities in RP-SSc were significantly lower than those in controls for both dorsal and ventral sides (p<0.01). The mean vascular intensities showed slightly higher area under the curve (AUC) than the percent vascular areas (0.53–0.91 vs 0.53–0.90) regardless of imaging technique and assessment side. For each imaging technique, the ventral side vascularity showed a higher AUC (0.74–0.91) compared with the dorsal side (0.53–0.81). Moreover, ventral side abnormalities were associated with a history of digital ulcers. CONCLUSIONS: Ultrasound demonstrated potential to quantify finger vascularity of RP-SSc. The ventral side of the fingers showed a higher accuracy in detecting RP-SSc than the dorsal side.