MAVIS - A NONINVASIVE INSTRUMENT TO MEASURE AREA AND VOLUME OF WOUNDS

Accurate measurement of the physical size of wounds is vital for asses sment of the progress of healing. An instrument has been developed to measure area and volume of skin wounds, ulcers, and pressure sores. MA VIS-Measurement of Area and Volume Instrument System-is based on the p rinciple of colour coded structured light. A set of parallel stripes o f alternating colours is projected onto the wound area at an angle of approximately 45 degrees and is recorded by a CCD camera. From the kno wn position of the focal points of projector and camera, and from the observed intersection points of the stripes of light with the wound su rface, a computer calculates a three-dimensional map of the observed w ound. The volume of the wound is defined as the volume of the region s andwiched between the observed surface and the original healthy skin s urface which is simulated by cubic spline interpolation. This paper co mpares the performance of the instrument with three traditional wound measurement techniques using results obtained from a clinical trial in volving 50 patients. Traditional area measurement techniques such as t ransparency tracings produce results with standard deviations between 4% (large wounds) and up to 20% (small wounds) of the measured mean va lue. MAVIS measurements reduce these standard deviations by 3-5%. Meas uring the wound volume by alginate casts produces errors in volume fig ures between 5% and 40%. Standard deviations of MAVIS results are 5% s maller on average. The results demonstrate that MAVIS yields more repr oducible results with a minimum of inter-observer error. The instrumen t does not make contact with the wound, provided visual records and me asurements are made in less then 5 min. It is not suitable for undermi ned, very deep or very large wounds. (C) 1998 IPEM. Published by Elsev ier Science Ltd. All rights reserved.