Is laser speckle contrast analysis (LASCA) the new kid on the block in systemic sclerosis? A systematic literature review and pilot study to evaluate reliability of LASCA to measure peripheral blood perfusion in scleroderma patients.

Objectives:A reliable tool to evaluateflow is paramount in systemic sclerosis (SSc). We describe herein on theone hand a systematic literature review on the reliability of laser speckle contrast analysis (LASCA) to measurethe peripheral blood perfusion (PBP) in SSc and perform an additional pilot study, investigating the intra- andinter-rater reliability of LASCA.Methods:A systematic search was performed in 3 electronic databases, according to the Preferred ReportingItems for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In the pilot study, 30 SSc patients and 30healthy subjects (HS) underwent LASCA assessment. Intra-rater reliability was assessed by having afirst anchorrater performing the measurements at 2 time-points and inter-rater reliability by having the anchor rater and ateam of second raters performing the measurements in 15 SSc and 30 HS. The measurements were repeated witha second anchor rater in the other 15 SSc patients, as external validation.Results:Only 1 of the 14 records of interest identified through the systematic search was included in thefinalanalysis. In the additional pilot study: intra-class correlation coefficient (ICC) for intra-rater reliability of thefirstanchor rater was 0.95 in SSc and 0.93 in HS, the ICC for inter-rater reliability was 0.97 in SSc and 0.93 in HS.Intra- and inter-rater reliability of the second anchor rater was 0.78 and 0.87.Conclusions:The identified literature regarding the reliability of LASCA measurements reports good to excellentinter-rater agreement. This very pilot study could confirm the reliability of LASCA measurements with good toexcellent inter-rater agreement and found additionally good to excellent intra-rater reliability. Furthermore,similar results were found in the external validation