A handheld scanner for analyzing the skin of psoriasis patients was shown to provide clinically relevant information, such as the structure of skin layers and blood vessels, without the need for contrast agents or radiation exposure. The device generates a weak laser pulse to excite the tissue, which then absorbs energy and heats up minimally. This causes momentary tissue expansion, which generates ultrasound waves. Scientists can measure the ultrasound signals and use this information to reconstruct a high resolution image of what lies beneath the skin. A newly developed tissue scanner allows scientists to look under the skin of psoriasis patients. Courtesy of Helmholtz Zentrum München. The device uses raster-scan optoacoustic mesoscopy (RSOM) implemented in ultra-broadband (10 to 180 MHz) detection mode to combine the depth capabilities of ultrasound with the resolution range and high contrast of optical methods. The team, comprising researchers from Helmholtz Zentrum München and the Technical University of Munich (TUM), showed how label-free biomarkers, detected by RSOM implemented in a handheld device, correlated with clinical scores. Tomographic reconstruction and frequency equalization were used to represent low and high spatial-frequency components for the imaging of skin morphology and vascular patterns in the dermis and sub-dermis of patients, enabling quantification of inflammation and other biomarkers of psoriasis, including skin thickness, capillary density, number of vessels, and total blood volume in the skin. The researchers used this information to compile a novel clinical index for assessing psoriasis severity, which takes into account characteristics below the skin surface. “This technology, which is easy to use and does not involve any radiation exposure or contrast agent, is allowing us to acquire the first new insights into the disease mechanisms. It also facilitates treatment decisions for the physicians,” said professor Vasilis Ntziachristos. Currently, physicians evaluate the severity of the disease based on visual assessment of features of the skin surface. “Unfortunately, these standards miss all parameters that lie below the surface of the skin, and may be subjective,” said researcher Juan Aguirre. “Knowing the structure of the skin and vessels before treatment can provide the physician with useful information.” Psoriasis treatment depends on the severity of the disease and possible organ involvement, which the novel imaging technique can help assess in a non-invasive way, obtaining information that before could only be retrieved through a biopsy. The method could be extended to assess a larger spectrum of dermatological conditions and diseases, including skin cancer and diabetes. The research was published in Nature Biomedical Engineering (doi:10.1038/s41551-017-0068).