In vivo microvascular imaging of cutaneous actinic keratosis, Bowen's disease and squamous cell carcinoma using dynamic optical coherence tomography

Background: A clear distinction between actinic keratosis (AK), Bowen's disease (BD) and squamous cell carcinoma (SCC) cannot reliably be made by clinical and dermoscopic evaluation alone. Dynamic optical coherence tomography (D-OCT) is a novel angiographic variant of OCT that allows for non-invasive, in vivo evaluation of the cutaneous microvascular morphology. Objective: To investigate the microvascular structures of AK, BD and invasive SCC using D-OCT in order to gain insights into the microvascular morphology of lesions in the spectrum of keratinocyte skin cancers. Methods: Forty-seven patients with a total of 54 lesions (18 AK, 12 BD and 24 SCC) were included in the study. D-OCT still images of AK, BD and SCC at three predefined skin depths were prepared and randomized, creating a study set of 162 D-OCT images. Three observers performed blinded evaluations of the randomized study set assessing multiple parameters including the different types of vascular morphology. Non-blinded quantitative measurements of vascular diameter were also performed. Results: The blinded observer analysis suggests that D-OCT evaluation of the vascular morphology may aid in distinguishing AK, BD and SCC lesions. We identified two vascular shapes that presented significantly differently across the lesion types, namely ‘blobs’ and ‘curves’. A strong presence of blobs at 300 μm skin depth was characteristically seen in a third of BD cases, while not or only slightly present in AK and SCC lesions. Vascular curves were predominantly present in AK lesions. Conclusion: We identified various vascular D-OCT features that may aid in non-invasively differentiating subtypes within the keratinocyte skin cancer spectrum.