JAMES M.GRICHNIKMD, PhDASHFAQ A.MARGHOOBMDALONSCOPEMD
Optical coherence tomography (OCT) is an emerging technology in dermatology. Translating the principles of ultrasound to use with light waves, OCT captures in vivo images allowing for 3-dimensional reconstruction and Doppler flow measurements. Compared with confocal microscopy, standard OCT has a greater depth of penetration but lower resolution. This places the technology between traditional ultrasound and confocal microscopy in the trade-off between depth penetration and surface resolution (Figure 1). Optical coherence tomography creates an image by splitting an infrared laser into a reference arm and a sample arm (Figure 2). The sample arm scans a designated region of skin, and an interferometer then compares the signal from the skin with a reference arm. Mathematical processing of the differences results in image creation. The depth of penetration and resolution of OCT is determined by the light wavelength and hardware and software processing capabilities. We used a 1310-nm laser system with a lateral resolution of 20 μm and a penetration depth of approximately 1.8 mm. Given the current improvements in handheld probes and software, OCT images can now be readily captured and viewed in the clinical setting. The photographs in Figures 3A, 4A, and 5A reveal the visible light surface features of a hemangioma, a telangiectasia, and a psoriatic lesion, respectively. With institutional review board approval and patient consent, we also obtained OCT images of these 3 lesions (Figures 3B, 4B, and 5B, respectively). Paired with vessel-rendering software, OCT may be useful in elucidating vessel angiogenesis and patterns in vascular lesions as shown in Figure 4B. Optical coherence tomography has Doppler capabilities, and it has superior sensitivity to ultrasound Doppler.1 Additionally, it can determine flow in a single vessel.2 The use of OCT in the clinical setting is increasing. Recent studies showed excellent correlation between the margins of basal cell carcinoma visualized by OCT and standard histopathologic analysis.3,4 Optical coherence tomography also successfully visualizes wound reepithelialization in studies.5,6 Furthermore, OCT appears useful for investigating the cutaneous penetration of light-scattering contrast agents.7 Optical coherence tomographic technology is likely to play a significant role in future bedside dermatologic diagnostics.
Thomas MW, Grichnik JM, Izatt JA. Three-Dimensional Images and Vessel Rendering Using Optical Coherence Tomography. Arch Dermatol. 2007;143(11):1468-1469. doi:10.1001/archderm.143.11.1468