Dystrophic diseases of the vulva represent a large group of dermatoses. The clinical picture of these lesions is often nonspecific, and non-invasive diagnosis is ineffective. The in vivo diagnosis of dystrophic diseases is difficult due to the lack of informative imaging methods for examining the vulvar mucosa. The new method of multimodal optical coherence tomography (OCT) is a non-invasive approach for biological tissues visualization with high spatial resolution, which does not require contrasting agents. Here we report the application of multimodal OCT to in vivo study the vulvar mucosa structure and its lymphatic and blood microcirculation. Multimodal OCT showed that normally the mucous membrane of the vulva has a good blood supply and a well-developed lymphatic vessels network. The difference in the diameter of the vessels in depth is clearly traced. In the subepithelial zone, only blood capillary loops are visualized. Lymphatic capillaries are visualized starting from submucosa.
The purpose of the study was in vivo assessment of the vulvar blood and lymphatic vessels characteristics in norm and lichen sclerosus by multimodal optical coherence tomography (OCT). The study was performed using a multimodal OCT setup developed at the Institute of Applied Physics RAS (Russia). OCT angiography and OCT lymphangiography are based on the analysis of speckle structure. Visualization of blood and lymph vessels does not require the use of exogenous contrast agents. A histological study of vulvar biopsy samples from two points was carried out for 10 patients without vulvar pathology and 12 patients with lichen sclerosus. 3D OCT data was obtained from six vulvar points in each patient. OCT images were verified by histological examination. It was shown that normally the vulvar mucosa has good blood supply and a well-developed network of lymphatic vessels. In the case of lichen sclerosus, the density of blood vessels in the area of hyalinosis significantly reduced and amounted to 2.5 ± 0.79% versus 3.9 ± 0.23% in norm (p = 0.0003). OCT lymphangiographic images also show a significant decrease in the number of lymphatic vessels, their density was 1.7 ± 0.75% versus 3.7 ± 0.54% in norm (p = 0.02). A direct relationship between the state of the blood and lymph vessels from the condition of the connective tissue of the vulva was shown. The number of blood and lymph vessels is sharply reduced in the area of hyalinosis and sclerosis of collagen fibers.
Lichen Sclerosus is a chronic recurrent inflammatory dermatosis of unknown etiology, which affects both the skin and also the mucous membrane and is usually localized at the genital area. OCT angiography is a promising tool for microcirculation mapping in 3D with ~micrometer resolution. During the study, we developed and implemented a robust real time OCT angiography realization for routine clinical practice. This allows clinicians to combine structural OCT imaging with angiograms during routine clinical practice. Normal vulvar mucosa and dystrophic vulvar mucosa were analyzed by multimodal OCT. In the structural OCT scans of connective tissue, lymphatic vessels were visualized as contrast, low-signal regions. The angiographic images of the normal mucosa show dense, uniform network, mostly consisting of relatively thin vessels. Lymphatic vessel network presented by rare, very thick vessels. Further realization of OCT lymphangiography in real-time in parallel with OCT blood-vessel angiography can improve diagnostic capabilities of the multifunctional OCT in real clinical practice.
We present an optical coherence tomography (OCT) lymphangiography visualization approach based on analysis of speckle statistics. For in-vivo experimentation, normal and tumor tissues are examined in mouse dorsal skin window chamber model. In order to evaluate the speckle statistics, OCT datasets are acquired in 3 spatial and 1 temporal dimensions to be divided then into smaller volumes of interests. In temporal dimension, repeated same-location scanning is performed for simultaneous blood vessel detection through speckle variance processing. Speckle statistics in each volume of interest are tested for similarity to known distributions corresponding either to noise or to tissue. We show that lymphatic vessels could be detected using a specific parameter range of speckle statistics as a filter, to separate the surrounding tissues and blood vessels. The proposed approach does not require numerous post-processing steps that are often used in lymphatic detection methods that are based on low signal amplitude regions (e.g., OCT signal attenuation compensation, inversion, amplitude thresholding etc.). Instead, we use a fast 2-step filtering procedure to reveal lymphatic vessels in imaged tissues.
Collageneus tissues manifest strongly pronounced viscoelastic behavior. Namely, viscosity leads to time-dependence of
the deformation processes. This concerns both compression (loading) and unloading of the tissue. Both processes can be
characterized by a relaxation time - the time during which the strain changes e-times. We demonstrate the applicability
of the OCT-based 2D relaxography to characterize local relaxation time of collageneous tissues. The developed
technique can be used for further investigation of the viscoelastic properties of healthy and pathological collageneous
OCT-based local strain relaxation/creep evaluation is an emerging tool for tissue viscoelasticity characterization. We present a tool for 2D visualization of local strain relaxation and creep time/rate inside the tissue.