The effect of wound dressings on diagnostic ultrasound imaging

A study was carried out to determine the effect of wound and fixation dressings on diagnostic ultrasound imaging. Each dressing was scanned with four ultrasound probes at two focal depth settings and the results were independently rated by five observers on a scale of 0-5. Data were analysed using the Chi-squared test and Pearson's correlation coefficient for inter-observer rating. The effect of the dressings was found to be independent of focal depth. Three probes produced similar results while the C7-4 curved array probe produced images affected by the dressings to a significantly greater extent. The total score for each dressing allows ranking according to lucency and demonstrates that hydrogel, thin film, and tulle gras dressings have the smallest effect on diagnostic ultrasound images, whereas dressings which are dense or contain air allow poor ultrasound penetration. It is suggested that, where diagnostic ultrasound is likely to be required in patients with wounds, traditional gauze-and-tape dressings should be avoided wherever possible as modern alternatives are available which meet the requirements of the wound while allowing the ultrasound system to produce a useful image.