Measurement of depth of burns by laser Doppler perfusion imaging

Laser Doppler perfusion imaging (LDPI), is a further development in laser D oppler flowmetry (LDF). Its advantage is that it enables assessment of micr ovascular blood flow in a predefined skin area rather than. as for LDF, in one place. In many ways this method seems to be more promising than LDF in the assessment of burn wounds. However, several methodological issues that are inherent in the LDPI technique, and are relevant for the assessment of burn depth, must be clarified. These include the effect of scanning distanc e, curvature of the tissue, thickness of topical wound dressings, and patho physiological effects of skin colour, blisters, and wound fluids, Furthermo re, we soon realised that to examine the perfusion image generated by LDPI adequately the process of analysis was appreciably improved by the simultan eous use of digital photography. In the present investigation we used both in vitro and in vivo models and also examined burned patients, and found th at the listed factors all significantly affected the LDPI output signal. Ho wever, if these factors are known to the examiner, most of them can be adju sted for. If the technique is further improved by minimizing such effects a nd by reducing the practical difficulties of applying it to a burned patien t in the burns unit, the technique may find uses in everyday clinical decis ion-making. (C) 2001 Elsevier Science Ltd and ISBI. All rights reserved.