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 âblobsâ and âcurvesâ. 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

Optical Coherence Tomography

Optical coherence tomography (OCT) is a non-invasive imaging technology that offers a view into the superficial layers of the skin in vivo in real-time. An infrared broadband light source allows the visualization of micro structural morphology of tissues and changes up to a depth of 1–2 mm with a resolution between 3 and 15 μm, depending on the system used. The combination of the classical cross-sectional OCT images (vertical) and en-face view (horizontal) is now established routine and adds additional value to the diagnostic capability of the technique. Moreover, technological developments have led to an increased resolution, a larger field of view as well as an increased scanning speed in current systems. OCT enables evaluation of non-melanoma skin cancers, melanocytic lesions and inflammatory diseases, assessment of wound, investigation of hair and nail disorders, quantification of skin changes and therapy monitoring. Dynamic OCT (D-OCT) allows the in vivo evaluation of blood vessels and their distribution within specific lesions, providing additional functional information and consequently greater density of data. D-OCT is applicable in skin cancers including melanoma, as well as in a variety of inflammatory skin diseases, chronic wounds and other areas of dermatological research. This chapter will give an overview of this technology and its indications

Diagnostic accuracy of optical coherence tomography in actinic keratosis and basal cell carcinoma

Early diagnosis of non-melanoma skin cancer (NMSC) is potentially possible using optical coherence tomography (OCT) which provides non-invasive, real-time images of skin with micrometre resolution and an imaging depth of up to 2mm. OCT technology for skin imaging has undergone significant developments, improving image quality substantially. The diagnostic accuracy of any method is influenced by continuous technological development making it necessary to regularly re-evaluate methods