OCT of healthy skin, actinic skin and NMSC lesions

Abstract Objective Optical coherence tomography (OCT) is able to produce two-dimensional images of living skin in situ . We evaluated a frequency-domain OCT system (SR-OCT Imaging System, Thorlabs) with regard to its clinical impact. Material and methods Seven healthy volunteers and 10 patients were recruited who had been referred for local photodynamic therapy (PDT) of suspicious dermal lesions (actinic lesions with different degrees of dysplasia (AK), Bowen's disease (BD) and basal cell carcinoma (BCC)). In a first step, OCT images were obtained from the healthy skin of the forearms and foreheads of all 17 subjects to compare interindividual differences. OCT images from the suspicious skin lesions (AK, BD, and BCC) were then taken for the 10 patients and compared with OCT images of corresponding healthy skin. Additionally, the OCT images of pathological sites were compared to histopathological preparations. Results In healthy skin a good correlation was found between the images of standard histological samples and the two-dimensional OCT images with regard to the discrimination of epithelial layer with its different zones and borders and adjacent dermal structures. The thickness of skin layers in the forehead and the forearm varied between the subjects (of different ages), but showed similar patterns of ‘lucidity’ in the OCT images. In diseased skin, the typical histological features of epithelial dysplasia and changes in dermal layers could be recognized in the equivalent OCT images. Conclusion OCT may be used as investigative tool in the clinical evaluation of actinic keratosis and NMSC lesions. The comparison of images revealed a strong correlation with histological cross-section images for the dermis.