Optical coherence tomography for margin definition of basal cell carcinoma before micrographic surgery-recommendations regarding the marking and scanning technique.

BACKGROUND/PURPOSE: Mohs Micrographic Surgery (MMS) is the preferred therapeutic treatment for high-risk basal cell carcinoma (BCC). Optical Coherence Tomography (OCT) is a non-invasive imaging technique that enables the diagnosis of BCC. We thought to determine the margins of BCCs with OCT, prior to MMS, to reduce the number of surgical steps. METHODS: Different permanent markers were tested on the skin regarding line width, resistance against disinfection and brightness in the OCT image. The visible tumor margins of BCCs were defined by dermoscopy, adding a safety margin of 2 mm and labeled using the selected pen, causing a signal shadow in OCT. Scans of the center and of entire margin were performed. If parts of the BCC were visible outside the margin, another 2 mm were added and the scan was repeated until the tissue outside the labeling looked tumor free. RESULTS: Eight out of ten BCCs were totally excised in a single stage when margin delineation was done by OCT. Macroscopic margins were enlarged after OCT scanning in four patients, saving further stages of MMS. CONCLUSION: OCT may help to better define the microscopic dimensions of BCCs and therefore reduce the number of stages of MMS.

Validation of Dynamic optical coherence tomography for non-invasive, in vivo microcirculation imaging of the skin.

OBJECTIVES: Dynamic optical coherence tomography (D-OCT) is an angiographic variation of OCT that non-invasively provides images of the in vivo microvasculature of the skin by combining conventional OCT images with flow data. The objective of this study was to investigate and report on the D-OCT technique for imaging of the vascular networks in skin as well as to validate the method by comparing the results against already accepted blood flow measuring tools. METHODS: 35 healthy subjects were recruited for the multicentre study, consisting of three experiments set up to examine the vascular blood perfusion during different induced physiologic changes in the blood flow. In order to validate the D-OCT images against existing techniques for blood flow measuring we performed consecutive D-OCT, chromametry and laser speckle contrast imager (LSCI) measurements on identical skin sites in all of the experiments. Blinded observer evaluations were performed in order to evaluate the vascular morphology in the D-OCT images. RESULTS: The results showed a statistically significant positive correlation between the D-OCT measurements and the LCSI flux measurements (rs=0.494; 95% CI [0.357, 0.615]; p<0.001), and also the redness a* measurements were positively correlated with the D-OCT measurements (r=0.48; 95% CI [0.406, 0.55]). D-OCT was able to reliably image and identify morphologic changes in the vascular network consistent with the induced physiological changes of blood flow. CONCLUSION: This study has initiated validation of the use of D-OCT for imaging of skin blood flow. Our results showed that D-OCT was able to reliably image and identify changes in the skin vasculature consistent with the induced physiological blood flow changes. These basic findings support the use of D-OCT imaging for in vivo microcirculation imaging of the skin.