Cross-Polarization Optical Coherence Tomography for Clinical Evaluation of Dermal Lesion Degrees in Vulvar Lichen Sclerosus

Abstract

The aim of the study was to identify different degrees of dermal lesions in vulvar lichen sclerosus (VLS) using cross-polarization optical coherence tomography (CP OCT) based on attenuation coefficient to detect disease early manifestations and to monitor the effectiveness of treatment.Materials and Methods. The study included 10 patients without pathology and 39 patients with VLS diagnosed histologically. CP OCT was performed in vivo on the inner surface of the labia minora, in the main lesion area. From each scanning point, a 3.4×3.4×1.25-mm 3 3D data array was obtained in 26 s. CP OCT examination results were compared with histological examination of specimens stained with Van Gieson's picrofuchsin.Quantitative analysis of OCT images was performed by measuring the attenuation coefficient in co-polarization and cross-polarization. For visual analysis, color-coded charts were developed based on OCT attenuation coefficients.Results. According to histological examination, all patients with VLS were divided into 4 groups as per dermal lesion degree: initial (8 patients); mild (7 patients); moderate (9 patients); severe (15 patients). Typical features of different degrees were interfibrillary edema up to 250 μm deep for initial degree, thickened collagen bundles without edema up to 350 μm deep for mild degree, dermis homogenization up to 700 μm deep for moderate degree, dermis homogenization and total edema up to 1200 μm deep for severe degree.Pathological processes in dermis during VLS like interfibrillary edema and collagen bundles homogenization were visualized using CP OCT method based on values of attenuation coefficient in co-and cross-polarization channels. However, CP OCT method appeared to be less sensitive to changes of collagen bundles thickness not allowing to distinguish thickened collagen bundles from normal ones with enough statistical significance. The CP OCT method was able to differentiate all degrees of dermal lesions among themselves. OCT attenuation coefficients differed from normal condition with statistical significance for all degrees of lesions, except for mild. Conclusion.For the first time, quantitative parameters for each degrees of dermis lesion in VLS, including initial degree, were determined by CP OCT method allowing to detect the disease at an early stage and to monitor the applied clinical treatment effectiveness.

Multimodal OCT Control for Early Histological Signs of Vulvar Lichen Sclerosus Recurrence after Systemic PDT: Pilot Study

“…OCT data are a 3D stack of 512 B-scans, which allows studying the dermis both integrally to the entire visualization depth up to 1200 µm and layer by layer at different depths (in the en face projection). In severe VLS, the dermis in most cases is affected to the depth of up to 1200 µm [ 36 ], which occupies the entire available scanning depth for OCT. However, changes in the dermis during the early stages of VLS develop directly under the epidermis at the depth of up to 350 µm from the basement membrane [ 2 ].…”

“…Before PDT, the vulvar skin has characteristic OCT signs of severe VLS [ 36 ]. On structural OCT images (in the B-scan projection), two layers are visualized, which are not identified throughout the entire length of the images.…”

“…Unlike RCM, OCT allows one to effectively visualize the structure of the dermis to the depth of 800 µm, as well as to visualize and quantify the structure of blood and lymphatic vessels. A decrease in the number of blood and lymphatic vessels is an important marker of dermal involvement in VLS and is associated with its severity [ 36 ]. Therefore, we tend to believe that multimodal OCT is a more promising method for examining the skin in VLS, as well as other pathological skin processes accompanied by damage to the dermis.…”

Depth-Resolved Attenuation Mapping of the Vaginal Wall under Prolapse and after Laser Treatment Using Cross-Polarization Optical Coherence Tomography: A Pilot Study

“…In this paper, for the first time, we calculated the attenuation coefficient from CP OCT images of human vaginal wall tissue in different states: age norm, stage I-II prolapse and stage I-II prolapse after Nd:YAG laser treatment. Attenuation coefficient calculation from OCT data allowed us to achieve improved biological structure visualization and objectively differentiate between tissues of different morphology [41][42][43][44]. In the present study, the depth-resolved method for attenuation coefficient was used for the first time to evaluate connective tissue changes in the vaginal wall.…”

“…The attenuation coefficient of the OCT signal is commonly used to quantify the CP OCT data. It helps to improve the assessment of the collagen state, for example, in non-tumorous and tumorous tissues [41], in the identification of an early stage of vulvar lichen sclerosus [42], and in the detection of areas of inflammation vs. norm and necrosis [43]. More recently, it became possible to build depth-resolved attenuation maps in the B-scan projection for the earlier detection of ovarian and fallopian tube malignancy [44].…”