Dermal thickness and echogenicity using DermaScan C high frequency ultrasound: Methodology and reliability testing in people with and without primary lymphoedema

Background: DermaScan C high frequency ultrasound was investigated for image capture and analysis of dermal measures in people with and without primary lymphoedema. Method: Three repeated images were taken at six sites in people without lymphoedema (NLO). Intra-rater reliability was assessed by taking three sets of measures on images from 10 people and inter-session reliability by capturing three images, lifting the probe from the skin in between. Methods were adjusted, and repeated images from four sites were taken in people with primary lymphoedema (PLO) and reliability re-assessed. Results: Intra-rater reliability in NLO and PLO for echogenicity measures were excellent (NLO ICC_(3,1):.989; PLO.997) across all sites and specific to each site (calf: ICC_(3,1):.989; and foot: ICC_(3,1):.999, respectively). Inter-session reliability was moderate for NLO (ICC_(3,1):.727), improving after method modifications for PLO (ICC_(3,1):.916). When investigated by site, inter-session reliability was good in the foot (ICC_(3,1):.811) and moderate in the calf (ICC_(3,1):.616). Mean thickness analysed by site resulted in good inter-session reliability only in the foot (ICC_(3,1).838). Conclusion: Intra-rater reliability was excellent using the DermaScan C for dermal measures in people with primary lymphoedema. Inter-session reliability required particular attention to method and gain settings.