Exploring the application of ultrasound technology in pressure ulcer prevention – an international multidisciplinary team study

Introduction: High frequency ultrasound (HFUS) can create real-time two-dimensional images of internal structures to examine the first few centimetres depth of sub-dermal soft tissue, thus may have the potential to detect tissue changes in pressure ulcer prevention. However, there is no evidence on the repeatability of HFUS. This study aimed to investigate the inter- and intra-rater repeatability of HFUS scanning.Methods: In a laboratory based study, 24 healthy subjects (21 females, 3 males;32.0812.25 years; BMI 24.945.57) participated on two occasions, one day apart. Consenting subjects had points marked (day 1 only) on both heels (lateral,posterior and medial aspects) and seating interface (coccyx, and left and right ischial tuberosities) and scanned by a researcher, then repeated by a second researcher using a HFUS scanner. Both researchers were blinded to each other’s scanning. HFUS images were quantitatively and qualitatively analysed blindly by two assessors.Results: Qualitative visual analysis showed almost perfect agreement between two assessors (0.88 kappa co-efficient). Intraclass correlation coefficients (ICCs) conducted on pixel intensity summation quantitative results showed low inter and intra-rater repeatability (25% moderate or high ICCs; ICC Z0.6). Conclusions: Although quantitative analysis showed low inter- and intra-rater repeatability, qualitative analysis showed better agreement. In practice, clinicians qualitatively read the images, and visual analysis appears to be the gold standard in HFUS interpretation. Quantitative methods of analysing HFUS images require further exploration by industry, scientists and clinicians