COMPARISON OF THERMAL INFRARED AND LASER DOPPLER IMAGING IN THE ASSESSMENT OF CUTANEOUS TISSUE PERFUSION IN SCLERODERMA PATIENTS AND HEALTHY CONTROLS

In this study we propose a non-invasive method to calculate blood flow by means of thermal infrared imaging and bio-heat transfer modeling. The method is able to provide high time-resolution series of cutaneous blood flow images with the same spatial resolution of the thermal images. The method was tested against a standard laser Doppler imaging system, which to date is considered the gold standard for non-invasive assessment of cutaneous blood flow, on both healthy subjects and patients suffering from systemic sclerosis (SSc; a pathological condition with microvessel endothelium injury). Twenty healthy subjects and twenty SSc patients simultaneously underwent laser Doppler and thermal imaging of the dorsum of the hand. A linear correlation between perfusion values obtained with the two methods was found for the healthy control group (R = 0.85, Pearson Product Moment Correlation). A significant correlation was not observed for the SSc patient group. The results of this study suggest that combined laser Doppler, thermal imaging and bio-heat transfer modeling could effectively discriminate between healthy vs. impaired conditions of the cutaneous tissue thermal properties and cutaneous vasculature. Such method, in addition to providing a potential effective imaging-based tool for a variety of biomedical and clinical applications ranging from diagnostics to treatment follow-up, may help the understanding of the morphological and functional impairment secondary to the disease. The thermal imaging-based method provided faster and better time-resolved imaging of cutaneous perfusion than standard laser Doppler techniques as the thermal cameras can provide up to 100 complete 524x524 pixel images per second, thus allowing real time monitoring of tissue perfusion rates.