Optical imaging and automated melanoma detection: questions and answers

Early detection and prompt excision of cutaneous melanoma is of paramount importance to improve patient survival, and the clinician should be aware of the clinical features that suggest the presence of a malignant lesion. The clinical diagnosis is mainly based on observation of the colour and shape of a given skin lesion. Unfortunately, evaluation of a pigmented lesion is to a large extent subjective and is closely related to the experience of the clinician. To overcome this problem, optical imaging techniques using different instrumentation (i.e. colour video camera, epiluminescence microscopy, reflectance spectrophotometry) and computer image analysis have been proposed in an attempt to provide quantitative measurements in an objective and reproducible fashion. The different procedures employed to perform the diagnosis automatically all have a common denominator: mimicking the eye and the brain of the clinician by image processing and computerized analysis programs, respectively. Sensitivity and specificity data reported in the literature suggest that the computer-based diagnosis of melanoma does not greatly differ from the diagnostic capability of an expert clinician, and is independent of the optical acquisition method employed to analyse the lesions. Most of the computer-processed morphometric variables useful in automated diagnosis are not recognizable nor can be objectively evaluated by the human eye, except that of lesion dimension. However, several questions should be answered before assessing the actual usefulness, including the potential and limitations, of computer-based diagnostic procedures. The purpose of this study was to briefly review the different kinds of instrumentation being used to diagnose melanoma, and to raise questions and whenever possible provide answers in an attempt to establish whether there will be a future for these computerized systems.