[Possibilities of multiphoton microscopy for the diagnosis of the vulvar lichen sclerosus]. / Vozmozhnosti mul'tifotonnoi mikroskopii dlya diagnostiki skleroticheskogo likhena vul'vy.

BACKGROUND: Vulvar lichen sclerosus (VLS) is a chronic and recurrent dermatosis of an inflammatory nature with severe focal atrophy of the skin. Connective tissue changes are polymorphic and are still not taken into account in histological diagnostics due to the difficulty of interpreting routine histological methods. In this work, we use multiphoton microscopy (MPM) as a new imaging technique that provides detailed information about the organization of collagen fibers in the dermis based on a non-linear second harmonic generation (SHG) process. OBJECTIVE: To determine the degree of connective tissue damage in lichen sclerosus using standard histological techniques and to reveal the diagnostic capabilities of multiphoton microscopy. MATERIAL AND METHODS: We studied 42 biopsies with a histopathological diagnosis of VLS and 10 biopsies of normal vulvar skin. Histological, histochemical and immunohistochemical evaluation was used in comparison with MPM data. Quantitative analysis included the determination of the thickness, length of collagen fibers and the average intensity of the SHG signal. RESULTS: A comprehensive study of the skin showed 4 groups of changes that can be regarded as the degree of the dermis damage: initial, mild, moderate, severe. The affected area at the initial and mild degree has subtle changes, however, it is reliably identified by quantitative analysis of the SHG signal. So, the initial degree is characterized by thin (1.3-1.8 µm) long (56-69 µm) collagen fibers, with a moderate degree, the fibers are thickened (3.4-4.3 µm) and fragmented (22-37 µm). The affected area in moderate and severe cases undergoes homogenization, which is associated with the deposition of extremely thin (0.6-0.9 µm) short (16-28 µm) collagen fibers and the expression of type V collagen. CONCLUSION: Multiphoton microscopy in the second harmonic generation mode is a reliable method for identifying collagen fibers in tissues. The study made it possible to identify 4 degrees of the dermis damage in vulvar lichen sclerosus.

[The value of optical coherence tomography and morphometry in evaluating the peripancreatic adipose tissue in infected pancreatic necrosis]. / Znachenie opticheskoi kogerentnoi tomografii i morfometrii dlia otsenki sostoianiia parapankreaticheskoi zhirovoi kletchatki pri infitsirovannom pankreonekroze.

OBJECTIVE: To investigate the morphometric and optical coherence tomography (OCT) characteristics of the microstructure of retroperitoneal peripancreatic adipose tissue during passive drainage and active perfusion-aspiration drainage for infected pancreatic necrosis. MATERIAL AND METHODS: The authors analyzed 74 samples of peripancreatic adipose tissue obtained from 37 patients with passive (Group 1) and active perfusion-aspiration drainage (Group 2) of a focus of peripancreatitis. The tissues were examined with OCT, then fixed in a formalin solution and underwent histological examination, including morphometric one. RESULTS: The examined groups showed qualitative and quantitative differences in the tissue microstructure. In Group 1 samples, the proportion (median (upper quartile; lower quartile)) of interlobular connective tissue was 5.6 (3.9; 6.1)%; and that of adipocytes was 44.6 (41.2; 51.6)%. Necrotic tissue occupied 46.2 (35.6; 56.1)% of the area of specimens. The OCT images of necrotic tissue displayed a preponderance of unstructured regions with a high signal level while the parenchymal areas showed a cellular structured pattern. In Group 2 samples, the proportion of interlobular connective tissue was 16.2 (11.4; 19.7)%, and that of adipocytes was 68.5 (59.7; 71.2)%. At the same time, Group 2 exhibited necrosis - 14.4 (11.5; 19.2%) that was 3.2 times less than in Group 1. The OCT images of Group 2 samples showed a preponderance of cellular structured regions characteristic of the parenchyma, with pronounced stromal elements, which corresponded to the histological pattern. CONCLUSION: Active perfusion-aspiration drainage of peripancreatic adipose tissue versus passive drainage is associated with a smaller proportion of necrotic tissue (14.4% versus 46.2%; p≤0.05) and a larger proportion of a stromal vascular component (16.2% vs. 5.6%; p≤0.05). OCT could qualitatively distinguish viable fat tissue parenchyma from necrotic areas, without specially preparing the samples, which was confirmed by histomorphometric results.

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

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-mm3 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 Optical Coherence Tomography for Intraoperative Evaluation of Tumor Margins and Surgical Margins in Breast-Conserving Surgery.

The aim of the study: We compare the effectiveness of multimodal optical coherence tomography (MM OCT) in the traditional structural OCT mode and the OCT elastography (OCE) mode in addressing two clinically important tasks: (1) detecting groups of tumor cells at surgical margins during breast-сonserving surgery (BСS) in breast cancer (BC) and (2) identifying breast tumor margins. The obtained results were correlated with corresponding histological sections. Materials and Methods: The study was performed on 100 surgical margin samples (top, bottom, medial, and lateral - four samples from each patient in total) obtained from 25 patients with BC who underwent BCS (lumpectomy), and on 25 postoperative tumor samples (to determine tumor margins). With MM OCT method, we visually and numerically assessed the scattering (level and depth of OCT signal penetration) and elastic (stiffness values, or Young's modulus (kPa)) properties of the tumor and non-tumor breast tissue and the obtained values were compared with the results of postoperative histological examination. Results: In 4 surgical margin samples (out of 100), with the OCE method we identified groups of histologically confirmed tumor cells ("positive" resection margins) at the distance of about 5 mm from the visible tumor margin. The identified zones were larger than 0.5 mm with stiffness of more than 400 kPa in all these cases. However, the structural OCT could not identify these groups of tumors and they were not distinguishable from the surrounding fibrous tissue.In the areas of tumor into non-tumor tissue transition, structural OCT images detected tumor margins only if they were adjacent to adipose tissue and did not detect them if there were adjacent to non-tumor fibrous tissue. OCE images with high stiffness values (more than 400 kPa) and high contrast showed a clear tumor margin with both adipose and fibrous tissue. Conclusion: The study demonstarets the potential of MM OCT, particularly its OCE mode, as a real-time method for intraoperative tumor margin and surgical margin assessment in BCS. OCE images compared to structural OCT images visualize higher contrast between different types of breast tissue (adipose tissue, fibrous stroma, hyalinized stroma, tumor cell clusters), as well as more accurate identification of the tumor border and detection of small groups of tumor cells at surgical margins. An algorithm for intraoperative MM OCT examination of the state of the resection margin is proposed in accordance with standard clinical guidelines for achieving clean surgical margins in breast cancer patients.

Effect of Surgical Technique on the Microstructure and Microcirculation of the Small Intestine Stump during Delayed Anastomosis: Multimodal OCT Data.

The aim of the study was to use multimodal optical coherence tomography (MM OCT) to evaluate microstructure and microcirculation in the proximal and distal sections of the intestine relative to the resected area in acute mesenteric ischemia. MATERIALS AND METHODS: The study was carried out using three groups of male Wistar rats weighing 270-435 g (n=18). Acute occlusive arterial ischemia of the small intestine was initiated in all animals. After 80-90 min, the ischemic non-viable part of the intestine was resected, and the operation was completed by stoma exteriorization (group 1, n=6), by applying purse-string sutures (group 2, obstructive resection, n=6), or by internal drainage of the proximal and distal ends of the small intestine (group 3, bypass, n=6). Relaparotomy and anastomosis formation were performed 2 days later.With the help of MM OCT at each stage of the surgical intervention, images were obtained from the serous membrane side: the intestinal wall microstructure (layers) was viewed using cross-polarization OCT (CP OCT) and the intramural circulation - using optical coherent angiography (OCA). The MM OCT images obtained from the terminal intestine sections immediately after resection and 2 days later (before the anastomosis formation) were compared between the experimental groups, as well as with the pre-ischemic data (norm). All resected sections of the intestine were then histologically examined. The MM OCT data were compared with the histological and intravital macroscopy data. RESULTS: As a result of studying the intestinal wall microstructure by in vivo CP OCT, it was found that during ostomy (group 1) and obstructive resection (group 2), the images showed signs of tissue edema and destructive changes in the mucous membrane that were confirmed histologically, while with bypass surgery (group 3), there were minimal changes as compared with the norm.According to the OCA data, on day 2 of ostomy in the proximal and distal segments of the intestine, there was a noticeable disappearance of small and medium blood vessels; mainly large arteries and veins could be visualized. Following obstructive resection (purse-string suturing) or bypass surgery, the most noticeable changes (a decrease in the number of visualized blood vessels) were observed in the distal part of the intestine. The L index calculated from OCA images and characterizing the total length of the intramural perfused vasculature, showed a statistically significant decrease during ostomy: 12.18 [10.40; 14.20] µm - in the proximal and 10.67 [7.98; 13.05] µm - in the distal section; for comparison, the L index before ischemia was 18.90 [17.98; 19.73] µm and 18.74 [17.46; 19.90] µm, respectively (p=0.0001). In obstructive resection (group 2), statistically significant differences in the L parameter were found only for the distal bowel section: 16.39 [12.37; 18.10] µm compared with 18.74 [17.46; 19.90] µm before ischemia (p=0.041). After bypass surgery (group 3), there were no significant deviations in the L index. CONCLUSION: By using MM OCT, we found that in treating the remaining sections of the intestine after its emergency resection for acute mesenteric ischemia, the type of surgical technique determines the tissue structure in the period before the delayed anastomosis is applied.The least pronounced and most balanced changes occur in the proximal and distal segments of the intestine when operated using the bypass technique. However, to recommend this type of surgery, the development of reliable, safe, and effective bypass instruments is needed.

Trans-Serosal Multimodal Optical Coherence Tomography for Visualization of Microstructure and Blood Circulation of the Small Intestine Wall.

The aim of the study was to evaluate the performance of trans-serosal multimodal OCT (MM OCT) in in vivo detecting of changes in microstructure and blood circulation of the small intestine wall caused by arteriovenous ischemia resulted from intestine strangulation. MATERIALS AND METHODS: In experiments on Wistar rats (n=22), we examined the small intestine wall in vivo using MM OCT; the access to the intestine was reached through laparotomy. The microvasculature and microstructure of the wall were studied before and after acute arteriovenous ischemia created by ligation of a small bowel segment. The results were then added with data obtained from histological and intravital microscopic examination. RESULTS: Trans-serous MM OCT allowed us to visualize the bowel wall to its entire thickness, distinguish between the serous-muscular and mucous-submucosal layers, and detect the villi and functioning blood vessels. The structures were best seen after a fat emulsion had been administered into the bowel lumen. In OCT images made in the optical coherent angiography (OCA) mode, large paired vessels (arteries and veins) and micro-vessels with a diameter of >15 µm could be seen. Most of the blood vessels were imaged in the depth range of 80-300 µm from the surface. Capillaries with a diameter of 7-10 µm were not seen, but they produced an overall bright background. In the OCA images reconstructed from a volume of 2.4×2.4×1.8 mm, the total length of the vascular bed before ischemia was 18.3 [16.6; 19.8] mm.Strangulation of the intestinal loop was associated with changes in the CP OCT picture: the villi-associated vertical pattern and shadows of blood vessels disappeared and the depth of tissue visualization in the cross-channel decreased. The optical equivalents of the serous-muscular layer were preserved; after 180±12 min of ischemia, their proportion in the intestinal wall thickness increased from 25 [18; 32] to 42 [31; 55]% (p=0.031). At that time-point, OCA images of the strangulated bowel loop looked all similar: a uniform dark background with isolated fragmentary large vessels and no signs of blood flow in the microvascular network. CONCLUSION: Trans-serous MM OCT provides for in vivo visualization of microstructures critical for surgical gastroenterology: the intestinal wall layers including villi and blood vessels of each layer, as confirmed by histological analysis. Destructive processes in the intestinal wall resulting from bowel ligation bring about optical changes, which can be detected using real-time MM OCT.

[Use of optical coherence tomography for prognosis of the severity of oral mucositis].

The results of oral mucosa monitoring by optical coherence tomography (OCT) in the course of radiochemotherapy of 18 cases of oropharyngeal cancer are discussed. Damage to the mucosa was mainly assessed using contrast characteristics deterioration and reduction of epithelial layer thickness. Significant variation in OCT image characteristics was identified vs. mucositis grade and prognostic criteria for individual mucosal radiosensitivity worked out intact contrast on day 1 of mucositis should be interpreted as a sign of relatively mild complication. Blurred contrast would indicate mucositis stage III-IV development. Numerical analysis of OCT image patterns confirmed the contribution of the endothelial blood vessels and connecting tissue to radiation-induced damage to the mucosa.

Accurate early prediction of tumour response to PDT using optical coherence angiography.

Prediction of tumour treatment response may play a crucial role in therapy selection and optimization of its delivery parameters. Here we use optical coherence angiography (OCA) as a minimally-invasive, label-free, real-time bioimaging method to visualize normal and pathological perfused vessels and monitor treatment response following vascular-targeted photodynamic therapy (PDT). Preclinical results are reported in a convenient experimental model (CT-26 colon tumour inoculated in murine ear), enabling controlled PDT and post-treatment OCA monitoring. To accurately predict long-term treatment outcome, a robust and simple microvascular metric is proposed. It is based on perfused vessels density (PVD) at t = 24 hours post PDT, calculated for both tumour and peri-tumour regions. Histological validation in the examined experimental cohort (n = 31 animals) enabled further insight into the excellent predictive power of the derived early-response OCA microvascular metric. The results underscore the key role of peri-tumour microvasculature in determining the long-term PDT response.

Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study.

Microvascular networks of human basal cell carcinomas (BCC) and surrounding skin were assessed with optical coherence angiography (OCA) in conjunction with photodynamic therapy (PDT). OCA images were collected and analyzed in 31 lesions pre-treatment, and immediately/24 hours/3-12 months post-treatment. Pre-treatment OCA enabled differentiation between prevalent subtypes of BCC (nodular and superficial) and nodular-with-necrotic-core BCC subtypes with a diagnostic accuracy of 78%; this can facilitate more accurate biopsy reducing sampling error and better therapy regimen selection. Post-treatment OCA images at 24 hours were 98% predictive of eventual outcome. Additional findings highlight the importance of pre-treatment necrotic core, vascular metrics associated with hypertrophic scar formation, and early microvascular changes necessary in both tumorous and peri-tumorous regions to ensure treatment success.

[Optical coherence tomography in surgical treatment of esophageal cancer].

The authors present an analysis of possibilities of optical coherence tomography in preoperative determination of the proximal interface of the tumor. Under investigation there were 24 patients (14 of them with squamous cell carcinoma and 10 with adenocarcinoma), with localization of the process not more than 5 cm the from z-line.

Photodynamic therapy monitoring with optical coherence angiography.

Photodynamic therapy (PDT) is a promising modern approach for cancer therapy with low normal tissue toxicity. This study was focused on a vascular-targeting Chlorine E6 mediated PDT. A new angiographic imaging approach known as M-mode-like optical coherence angiography (MML-OCA) was able to sensitively detect PDT-induced microvascular alterations in the mouse ear tumour model CT26. Histological analysis showed that the main mechanisms of vascular PDT was thrombosis of blood vessels and hemorrhage, which agrees with angiographic imaging by MML-OCA. Relationship between MML-OCA-detected early microvascular damage post PDT (within 24 hours) and tumour regression/regrowth was confirmed by histology. The advantages of MML-OCA such as direct image acquisition, fast processing, robust and affordable system opto-electronics, and label-free high contrast 3D visualization of the microvasculature suggest attractive possibilities of this method in practical clinical monitoring of cancer therapies with microvascular involvement.

In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography.

Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT). A spectral domain OCT system with a specially-designed oral imaging probe was used. Microvasculature visualization was based on temporal speckle variations of the full complex signal evaluated by high-pass filtering of 3D data along the slow scan axis. Angiographic image quantification demonstrated an increase of the vascular density and total length of capillary-like-vessels before visual signs or clinical symptoms of mucositis occur. Especially significant microvascular changes compared to their initial levels occurred when grade two and three mucositis developed. Further, microvascular reaction was seen to be dose-level dependent. OCT monitoring in radiotherapy offers a non-invasive, convenient, label-free quantifiable structural and functional volumetric imaging method suitable for longitudinal human patient studies, furnishing fundamental radiobiological insights and potentially providing useful feedback data to enable adaptive radiotherapy (ART).

[Potential of optical coherence tomography for diagnosing mucositis in cancer of the nasal cavity and throat in the course of radio- and chemoradiotherapy].

The monitoring data on mucosa of the nasal cavity and throat using optical coherence tomography imaging in 14 cases during radiochemotherapy are presented. Typical alterations such as reduction in contrast distinctions between tissue layers to an extent that it blurs down completely at the peak of radiation-related response are discussed. Due to use of the technique valuable information on individual response was obtained.

In vivo optical coherence tomography imaging of human skin: norm and pathology.

BACKGROUND/AIMS: Since the majority of skin diseases are known to be accompanied by structural alterations, research efforts are focused on the development of various novel diagnostic techniques capable of providing in vivo information on the skin structure. An essential parameter here is spatial resolution. In this paper we demonstrate the capabilities of optical coherence tomography (OCT) in detecting in vivo specific features of thin and thick skin. A particular focus is made on the identification of OCT patterns typical of certain pathological processes in skin, by performing parallel histological and tomographical studies. METHODS: To obtain images of the skin, we used a compact fiber OCT system developed at the Institute of Applied Physics of the Russian Academy of Sciences. A low coherence source (superluminescent diode) operated at a wavelength of 1280 nm; the output power was 0.5-2 mW. This power is low enough to conform to the ANSI safety standards for light exposure. The in-depth resolution limited by the spectral bandwidth (40-50 nm) of the probing light was approximately 20 &mgr;m. The lateral resolution determined by the probe light focusing ranged from 15 to 30 &mgr;m. In this series of experiments the maximum depth of imaging did not extend beyond 1.5 mm. Obtaining images of skin regions 2-6 mm long took 2-4 s. OCT capabilities for imaging normal skin of different localization and some skin diseases were studied in 12 healthy volunteers and 24 patients. RESULTS: OCT imaging of the skin can detect in vivo such general pathological reactions of the human body as active inflammation and necrosis. OCT is useful for in vivo diagnosis of some specific processes in the skin, including hyperkeratosis, parakeratosis and formation of intradermal cavities. OCT imaging is noninvasive and therefore allows frequent multifocal examination of skin without any adverse effects. OCT can perform monitoring of disease progress and recovery in the course of therapy. Morphometric studies, measurements of the depth and extension of skin pathology within the human body can be easily performed by OCT. CONCLUSIONS: OCT allows imaging of subsurface soft tissues with the spatial resolution of 15-20 &mgr;m, a resolution one order of magnitude higher than that provided by other clinically available noninvasive diagnostic techniques. An imaging depth of up to 1.5-2 mm, given by current OCT technology, is sufficient to examine the skin. Real time OCT imaging can provide information not only on the structure, but also on some specific features in the functional state, of tissues. OCT imaging is a noninvasive technique, i.e., OCT does not cause trauma and has no side effects since it utilizes radiation in the near infrared wavelength range at a power as low as 1 mW.

[The HLA system and Coxsackie B viral myocarditis in adults]. / Sistema HLA i virusnyi Koksaki B miokardit u vzroslykh.

The distribution of HLA antigens A, B and C was studied in 152 normal donors, 53 patients with Coxsackie B virus myocarditis, 35 patients with myocarditis of unknown origin, 16 coronary patients and 14 rheumatic patients with high titres of anti-Coxsackie virus antibodies. Coxsackie virus myocarditis was associated with increased occurrence of HLA antigens A3, B40, Cw2 and A28, the increase being significant (with an adjustment to the number of the tested antigens) for A3 in severe and medium myocarditis, and B40 in patients who had developed myocarditis before age 30. Antigen Cw2 was more common in myocarditis patients with high titres of anti-Coxsackie virus B4 antibodies. The distribution of HLA antigens in coronary patients was similar to that of the controls. Rheumatic patients showed increased incidence of antigen Cw2. It is suggested that carriers of histocompatibility antigen A3 may be predisposed genetically to severe or medium Coxsackie B virus myocarditis.

[The choice of the method for intravascular laser therapy in rheumatoid arthritis]. / Vybor metodiki vnutrisosudistoi lazernoi terapii pri revmatoidnom artrite.

A randomized placebo-controlled study was made of the clinical efficacy of four different methods of intravascular laser blood irradiation (ILBI) with helium-neon laser in 150 patients suffering from rheumatoid arthritis (RA). As to ILBI methods used, the most remarkable clinical effect was produced by daily procedures. The positive effect of ILBI was of liminal character bearing in mind the power range examined whereas the negative effect of irradiation was dose-dependent. ILBI may cause an exacerbation of the inflammatory process in RA whatever the single dose and frequency of procedures. The best clinical effect with daily ILBI was attained in women, individuals with the presence of rheumatoid factor but with low titers thereof, and in patients with initial stages of RA and minimum inflammation activity. The efficacy of ILBI may be predicted on the basis of the patient's clinical findings.

[Optic coherent tomography in evaluation of the buccal mucosa status. Communication 1. Normal mucosa]. / Opticheskaia kogerentnaia tomografiia v otsenke sostoianiia slizistoi obolochki polosti rta. Soobshchenie 1. Normal'naia slizistaia obolochka.

The potentialities of optic coherent tomography (OCT) in the diagnosis of the buccal mucosa status were studied and the results are presented in two communications. Communication 1 demonstrates the tomograms of various parts of normal buccal mucosa and methods of their identification as exemplified by analysis of 1180 in vivo and 43 ex vivo OCT images. Using parallel histo-tomographic comparison, the authors distinguished the main signs of optic images, depending on the type of epithelium and characteristic features of the connective tissue stroma in various parts of the buccal mucosa. These signs are essential for understanding the optic images of the mucosa in disease, which will be shown in communication 2.

[Optical coherence tomography in the evaluation of the oral cavity mucosa. Part II. Benign and malignant diseases]. / Opticheskaia kogerentnaia tomografiia v otsenke sostoianiia slizistoi obolochki polosti rta. Soobshchenie II. Dobrokachestvennye i zlokachestvennye zabolevaniia.

This paper is the last one in the series of publications on the investigation of the capability of Optical Coherence Tomography (OCT) in diagnostic of state of oral cavity mucosa. Part II demonstrates the diversity of optical images, different forms specific to leukoplakia, lichen planus and squamous cell carcinoma on the basis of the investigation of 56 pathologic lesions of 43 patients with precancer and cancer of oral cavity. The OCT sensitivity in malignancy detection in oral cavity is high - 83%, specificity is 98%, and accuracy is 81%. The kappa coefficient of interobserver agreement is 0.76.