PracticeUpdate: Dermatology & Rheumatology

AAD 2016 9

Dr Jane Grant discusses new and emerging technologies in dermatology

SYM S035 – New and emerging technologies in dermatology. Jane Grant-Kels This session reviewed current and evolving technologies available to help us differentiate benign from malignant lesions without performing a biopsy. Reflectance confocal microscopy In vivo reflectance confocal microscopy (RCM) is a noninvasive optical imaging technique that provides a high-resolution image of the skin to a depth of 200 to 300 μm (0.2–0.3 mm). RCM relies on a low-power laser that emits near infrared light projected through a lens system. To obtain an image of skin, RCM uses the different reflection indices of various structures to produce a horizontally sectioned (ie, sections parallel to the skin surface) black-and-white image. The resulting images are comparable to histopathology images but are obtained in vivo, without performing a biopsy. I reviewed clinical applications of the VivaScope 1500, or the wideprode traditional RCM that has recently been awarded CPT codes and can be used to evaluate 8 mm x 8 mm areas on the skin. Dr Harold Rabinovitz from the University of Miami reported on the handheld VivaScope 3000, which provides stacks of images through the skin that are only 1 mm x 1 mm in size. The handheld adaptor is most applicable to evaluate tumours on the eyes, periorbital skin, mucosal surfaces, and curved surfaces of the face, which are difficult to capture with the larger head of the VivaScope 1500. Both I and Dr Rabinovitz gave many examples of how this technology can spare our patients unnecessary biopsies and improve our malignant to benign biopsy ratio. Electrical impedance spectroscopy Dr Peter Mohr from Buxtehude, Germany, reviewed his data on the use of electrical impedance spectroscopy (EIS) to differentiate benign from malignant lesions of the skin without biopsy. EIS measures the overall resistance within tissue at alternating currents of various frequencies. The resulting different measurements detect changes in cellular structure, cellular orientation, cell sizes, and cell types. The ultimate score is calculated by the computer and reflects the degree of atypia, helping to establish the difference between a benign nevus and melanoma with a sensitivity of 97% and specificity of 35% and without a painful procedure. Of interest is that the sensitivity for dermatopathology was 85% and the sensitivity for dermoscopy was 71% on the same lesions. Dr Mohr suggested that this new technology would be particularly helpful in those melanomas that defy clinical and dermatoscopic diagnosis. The use of EIS in dermatology clinics in Europe has been shown to reduce excisions by 40% to 50%. Raman spectroscopy and photoacoustic tomography Dr Eric Tkaczyk from Vanderbilt University reviewed the exciting future roles for Raman spectroscopy and photoacoustic tomography. Raman spectroscopy is a technique that measures inelastic scattering of monochromatic light. The light interacts with molecular vibrations that

Jane Grant-Kels MD, is Director of Dermatopathology and Chair of the Melanoma Signature Program at the University of Connecticut Health Center, and an Advisory Board Member of PracticeUpdate Dermatology .

result in a “fingerprint” of the biochemical compo- sition of the tissue. Clinical applications include imaging of topical drug delivery. Photoacoustic tomography allows deep detection of melanin, hae- moglobin, and oxygenation. Three-dimensional im- aging of tissue results from light that is absorbed by biological tissue and converted to transient heating, which is then converted into ultrasonic waves. De- tection of the ultrasonic waves yields a tomographic image based on the photoacoustic effect. Dr Tkaczyk demonstrated how photoacoustic microscopy could identify melanoma metastases in lymph nodes in lieu of sentinel lymph node biopsies! This new and exciting technology is still only in the research lab but someday will be applied in the clinic to reduce procedures and enhance accuracy in early diagnosis.

© 2016 AMERICAN ACADEMY OF DERMATOLOGY

DECEMBER 2016