Ultrasonographic imaging of systemic sclerosis digital ulcers: A systematic literature review and validation steps

Skin ulcers are a complex array of clinical manifestations of systemic sclerosis (SSc) and are often difficult to treat. However, the definition of SSc-skin ulcers has to date not been promising, demonstrating poor reliability and accuracy. There are emerging data that ultrasound has significant potential to evaluate SSc-skin ulcers.

To perform a systematic literature review (SLR) to understand the degree to which ultrasound of SSc skin ulcers has been validated according to OMERACT criteria.

In a SLR, we investigated the Cochrane Library, Web of Science and Pubmed databases for manuscripts from inception to 1st April 2020. Inclusion and exclusion criteria included manuscripts on SSc patients aged over 16 years, performing SSc-related skin ulcer evaluation with ultrasound machines. Papers on animal model, diseases other than SSc, venous ulcers were excluded. Data extraction used a uniform case report form which collected data on patient demographics, disease activity, description of the ultrasound machine and procedures and the degree to which domains of validity were fulfilled. Manuscript evaluation and extraction was performed by two independent assessors, with a third author being consulted in case of disagreement.

amongst 308 manuscripts that were identified, 6 published manuscripts/ posters fulfilled the inclusion/exclusion criteria and were extracted. Face validity was found. Three studies developed an US definition of SSc-ulcers across patients (content validity); one study evaluated the concordance between US image and clinical assessment. Criterion validity was shown by one study and ultrasound detected improvement (sensitivity to change) of SSc-skin ulcer in response to therapy. Feasibility was demonstrated by US use for skin ulcers in multiple settings (the 6 manuuscripts/posters).

This systematic literature review shows that ultrasound for skin ulcers in SSc has been partially validated. It has face, content, criterion validity, responsiveness and reasonable feasibility. Further validation for construct validity, reliability and discrimination is required.