Video-mosaicking of human skin in vivo using handheld line-field confocal optical coherence tomography

Line-field confocal optical coherence tomography (LC-OCT) is an imaging method based on dynamically-focused line-field time domain OCT to generate cellular resolution images of biological tissues, either in vertical sections (cross-sectional) or in horizontal sections (en face), with field of views of 1.2 x 0.5 mm(2) (horizontal) and 1.2 x 0.4 mm(2) (vertical). A handheld LC-OCT probe has recently been developed to facilitate the use of this imaging technique in dermatology for non invasive detection of skin cancers. We present here a video mosaicking method to reconstruct LC-OCT images with extended fields of view from a sequence of images obtained by a free displacement by the user of the LC-OCT probe on the skin surface. The lateral field of view is extended in both vertical and horizontal section images to similar to 5 mm, while maintaining an isotropic spatial resolution of similar to 1 pm. LC-OCT imaging with video-mosaicking is demonstrated for following the edges of large skin structure, as a proof-of-principle of in vivo tumor margin delineation, and for extending the lateral field of vertical section images, in order to approach the field of view of histology in this direction.