Looking into the skin with optical coherence tomography

Linked Article:   Wan et al. Br J Dermatol 2021; 184 :1014–1022. Most skin problems are diagnosed by their naked eye appearance. Recently, hand‐held magnifiers (dermatoscopes) have been introduced to aid diagnosis. More accurate diagnosis often requires taking a skin sample and looking at it under a microscope. A number of modern, non‐invasive optical imaging techniques are being developed to potentially facilitate diagnosis. One of these is optical coherence tomography (OCT). This review article on applications of OCT in dermatology is by authors from several centres in London, UK. They discuss the scientific principles of the technology and its potential as a diagnostic tool. Using infrared wavelengths, OCT can generate a picture of the skin both parallel to the skin surface, and vertically downwards to a depth of 2 mm. It is particularly effective for showing the arrangement of the blood vessels near the surface of the skin (angiographic OCT). So far, OCT has been shown to assist diagnosis of the commonest skin cancer, basal cell carcinoma, and to assess the response to treatment of some conditions such as psoriasis. Currently the potential of OCT is limited by its depth of penetration and cost. Applying artificial intelligence to OCT may offer a way of improving its clinical applications in the future.