The analysis of data from relevant domestic and foreign literature on the intraoperative determination of intestinal viability using modern diagnostic methods in various diseases of the abdominal cavity accompanied by impaired blood supply to the intestinal wall is presented in this work. The analysis is based on the concept of mesenteric ischemia and the methods of its intraoperative assessment, which are described in the literature. Methods: An analysis of the literature on intraoperative assessment of intestinal ischemia using online search engines, libraries, and various databases was conducted. Mesenteric blood supply disorders, often found in surgical practice, are the result of several causes (mesenteric thrombosis, acute adhesive intestinal obstruction, strangulated hernia, etc.), and they are a high-risk factor for death.Special attention is paid to the occlusive pathogenic mechanism of mesenteric ischemia, which leads to rapid development of irreversible morphological changes in tissues and pronounced disruption of the body's homeostatic system. The currently available intraoperative method for visual assessment of intestinal viability does not provide unambiguous results in determining the severity of ischemic changes in the intestinal wall. The algorithm for assessing intestinal viability includes evaluating the color of the intestinal wall, presence of peristaltic activity, pulsation, and blood flow in mesenteric vessels. These signs are assessed dynamically after administering a local anesthetic solution to the intestinal mesentery and warming the intestine with sodium chloride-soaked napkins. However, surgeons currently require a more comprehensive intraoperative evaluation of organ perfusion during surgery.Clinical recommendations for an objective assessment of intestinal blood supply: If technically feasible, it is recommended to utilize intraoperative ultrasound, laser Doppler flowmetry, and regional transillumination angiotensometry of the intravenous vessels of the small intestine to assess the blood supply. These methods are highly sensitive to changes in blood microcirculation. However, there is still ambiguity in the literature regarding the effectiveness of these methods for assessing regional hemomicrocirculatory disorders and intestinal viability. Therefore, further research is needed to study and evaluate the use and effectiveness of these techniques.

Although there is currently sufficient information on various parameters of capillary blood flow, including the average values of blood velocity, there is no data on the dynamics of velocity and the mechanisms of its modulation in various parts of the capillary. The main idea of this work is to develop a tool and image data processing to study the characteristics of the capillary blood flow dynamics. In this study, using the developed method of high-speed videocapillaroscopy, the red blood cells (RBC) velocities in the arterial and venous parts of the nailfold capillaries were compared and a time–frequency analysis of the dynamics of the velocity signals with the calculation of phase coherence was performed. We indicated that the velocity in the arterial part is twice as high and that the ratio of velocities in the arterial and venous parts is stable regardless of the local velocity. This study also empirically confirms the similarity between the oscillations of blood flow in different parts of the capillary and the synchronization of the velocity phases. We believe that the determination of the absolute velocity characteristics of blood flow, together with the mechanisms of its regulation and the ratio of velocities in the arterial and venous parts, can act as a diagnostic approach.

Objectives One of the widely used optical biopsy methods for monitoring cellular and tissue metabolism is time-resolved fluorescence. The use of this method in optical liver biopsy has a high potential for studying the shift in energy-type production from oxidative phosphorylation to glycolysis and changes in the antioxidant defense of malignant cells. On the other hand, machine learning methods have proven to be an excellent solution to classification problems in medical practice, including biomedical optics. We aim to combine time-resolved fluorescence measurements and machine learning to automate the division of liver parenchyma and tumors (primary malignant, metastases and benign tumors) into classes. Materials and Methods An optical biopsy was performed using a developed setup with a fine-needle optical probe in clinical conditions under ultrasound control. Fluorescence decays were recorded in a conditionally healthy liver and lesions during percutaneous needle biopsy. The labeled data set was created on the basis of the recorded fluorescence results and the histopathological classification of the biopsies obtained. Several machine learning methods were trained using different separation strategies of the training test set, and their respective accuracy was compared. Results Our results show that each of the tumor types had its own characteristic metabolic shifts recorded by the time-resolved fluorescence spectroscopy. The application of machine learning demonstrates a reliable separation of the liver and all tumor types into cancer and noncancer classes with sensitivity, specificity and corresponding accuracy greater than 0.91, 0.79 and 0.90, using the random forest method. We also show that our method is capable of giving a preliminary diagnosis of the type of liver tumor (primary malignant, metastases and benign tumors) with a sensitivity, specificity and accuracy of at least 0.80, 0.95 and 0.90. Conclusions These promising results highlight its potential as a key tool in the future development of diagnostic and therapeutic strategies for liver cancers.

The work presents the results of the use of the convolutional neural network ResNet-50 in digital diaphanoscopy for the diagnosis of maxillary sinus conditions. The analysis of registered diaphanograms of patients with sinusitis, cystic fluid and conditionally healthy volunteers was carried out. It is shown that applying the proposed classification model to diaphanograms recorded at a sensing wavelength of 850 nm and fixation threshold of 80% allows to reduce the false negative result. The results analysis made it possible to establish requirements for the registered diaphanograms. An approach to dividing the developed model into static and dynamic components is proposed.

The effects of the interaction of optical radiation and biological tissues underlie various optical diagnostics technologies, including laser Doppler flowmetry, diffuse reflection spectroscopy, fluorescent spectroscopy, photodynamic diagnostics (fluorescent cystoscopy), confocal microscopy, optical coherence tomography, etc. The efficiency of these technologies is the subject of study in various fields of medicine, such as dermatology and ophthalmology, anesthesiology and cardiac surgery, in the diagnosis of malignant tumors and others. In the first part of our review, the available data on the feasibility of using laser Doppler flowmetry and diffuse reflection spectroscopy as a diagnostic tool in urological practice are reviewed and systematized.