Vessel Depth Research Articles

NIR-I Activated Orthogonal NIR-IIb/c Emissions in a Lanthanide-Doped Nanoparticle for Fluorescence Imaging and Information Encryption.

Applying the orthogonal principle for distinguishable second near-infrared (NIR-II) emissions has brought new dimensions for ratio fluorescence imaging (RFI) detection and information encryption, deepening the tissue detection depth and improving signal-to-noise ratio and information security. However, the orthogonal NIR-II emissions underlying these advanced optical applications have been reported only in heterogeneous structures and mixtures, limiting their practicality and potential impact. Herein, NIR-I-activated orthogonal NIR-IIb/c (1530/1825nm) emissions nanoparticles (ONNPs) are developed by spatially separated doping of Tm3+ and Er3+ emitter upon switching 808 and 980nm excitations. RFI techniques and orthogonal NIR-II emission ONNPs are used to demonstrate vessel depth detection based on wavelength-dependent optical attenuation properties in tissue. The superiority of the optical coding and encoding process in a 4×1 binary matrix is demonstrated for anticounterfeiting and decryption imaging of quick-response (QR) code for information storage. The research progress of this NIR-II orthogonal emissions probe will drive the development of biomedical sensing, imaging safety, and future biophotonics technologies.

Ultrasonographic Anatomical Changes in the Nasal Vasculature after Rhinoplasty: Analysis of a Series of Cases

It is known that surgical procedures can change the vascularization of the face, and these changes can be related in the course and depth of vessels, increasing the risk for complications with injectable products. The goal of this work is to objectively demonstrate the course and variation of these vascular structures through Doppler ultra-sonographic monitoring. In this research 9 patients were studied, of which 7 completed the study. The presurgical ultrasound study detected anatomical variations like agenesy of the angular artery and dorsal nasal artery in 11.12% of tha patients. The post surgical evaluation detected 85.71% of vascular changes mainly in the nasal arteries. This findings confirm the importance of practicing ultrasonographis evaluation in patients with rhinoplasty, previous to practicing new filler injections in the face.

Right subclavian vein sonoanatomy from the supraclavicular fossa approach in children

Introduction: Although the subclavian vein offers significant advantages over other approaches for ultrasound-guided central venous access, it is not the first choice in the pediatric population, mainly due to its proximity to the pleura and the subclavian artery. Objective: To assess the sonoanatomical characteristics of the subclavian vein and adjacent structures using the supraclavicular approach in a pediatric population. Materials and Methods: Observational, intraoperative, cross-sectional study, between June 2021 and March 2022. The population consisted of ASA I, II and III children taken to non-emergent surgical procedures under general anesthesia. Images were acquired with the patients under general anesthesia, using a high-frequency linear probe to identify the subclavian vein and measure the anatomical landmarks. Results: A total of 67 children were recruited; mean age was 6 years (IQR: 2-12 years), with male sex predominance (61%). Median weight was 22 kg (IQR: 12.2-34 Kg) and median height was 115 cm (IQR: 88-142 cm). Measurements in relation to the vessel showed a mean distance from the skin of 0.70 cm (SD: 0.18 cm), while mean distance from the skin to the pleura was 1.31 cm (SD: 0.28 cm). Mean vein diameter was 0.49 cm (IQR: 0.40-0.63 cm). The mean hypothetical approach angle to the vessel was 22.09 degrees (SD: 4.37 degrees), while the approach angle to the pleura was 39 degrees (SD: 5.31 degrees). No concurrent visualization of the vein and artery was documented in any of the recorded sonoanatomy windows. The tests pointed to an average difference of 0.61 cm in vessel depth in relation to the pleura, and the angle of approach to the vessel was 16.91 degrees smaller when compared with the angle of approach to the pleura (p < 0.001). Conclusions: Using this technique, the supraclavicular approach to the subclavian vein in children is safe and feasible, with an average skin-to-vessel distance of 0.70 cm, minimizing the risk of pleural puncture. Additional studies are required to optimize this technique in the pediatric population.

Method for measuring blood flow and depth of blood vessel based on laser speckle contrast imaging using 3D convolutional neural network: A preliminary study

Laser speckle contrast imaging (LSCI) is a technology that can acquire real-time two-dimensional perfusion images non-invasively. However, measuring perfusion velocity under a tissue is difficult due to its optical properties. Dynamic scattered light occurs by perfusion is diffused by the surrounding tissue and it depends on the depth of tissue. We aimed to develop a three-dimensional convolutional neural network (3D-CNN) model based on laser speckle contrast images to measure the flow velocity and the depth of tissue using a flow phantom. The training data was selected as a region containing both static speckles and dynamic speckles, and the model was trained on the laser speckle contrast image data. The trained model showed a measurement accuracy of more than 90 % for velocity and 99 % for depth measurement. This study has the potential of a deep-learning model based on LSCI to analyze the blood flow and depth of blood vessels in bio-applications.

Superficial Intramuscular Gluteal Lipograft by Doppler Ultrasound: A Report of 24 Patients.

Gluteal fat grafting is a common procedure in liposculpture. This study proposes a Doppler ultrasound-guided intramuscular and subcutaneous gluteal lipotransfer technique that allows for visualization of the location of the gluteal vessels, avoiding approaching them during lipotransfer by having the cannula localized during fat infiltration. This new technique was applied to 24 women after obtaining informed consent and providing them with a clear explanation of potential risks and complications. Doppler ultrasound was used to locate the site and depth of blood vessels, and for quadrant scanning of vessels and superficial intramuscular visualization of the cannula's location. Intramuscular lipotransfer was performed with a volume of 400 mL per gluteus (or less), and 12 patients underwent magnetic resonance imaging before and 3 months after surgery. This technique allowed for visualizing the location of the gluteal vessels, and infiltration could be easily performed in patients. In the 24 glutei reviewed postsurgery, from 12 patients who underwent pre- and postsurgery magnetic resonance imaging, intramuscular fat was found; however, there was no migration outside the gluteus maximus muscle. No local or systemic complications were observed. The results of our report show that fat filtration did not migrate outside the gluteus maximus muscle. This finding seeks to promote new research to create theoretical/practical precedents for the intervention of plastic surgeons and, from there, promote the standardization of a new and safe technique.

Non-Invasive Hemoglobin Assessment with NIR Imaging of Blood Vessels in Transmittance Geometry: Monte Carlo and Experimental Evaluation

Non-invasive methods for determining blood hemoglobin (Hb) concentration are urgently needed to avoid the painful and time-consuming process of invasive venous blood sampling. Many such methods rely on assessing the average attenuation of light over a tissue area where hemoglobin is the dominant chromophore, without separating those areas corresponding to vessels and bloodless tissue. In this study, we investigate whether it is possible to determine hemoglobin levels in the blood by assessing the changes in light intensity when passing through large vessels in comparison to adjacent tissues, using this as a Hb level predictor. Using Monte Carlo light transport modeling, we evaluate the accuracy of determining hemoglobin levels via light intensity contrast and vessel widths estimated in the transmittance illumination geometry and estimate the influence of physiologically significant parameters such as vessel depth, dermis vascularization, and melanin content in the epidermis on the blood Hb prediction error. The results show that physiological variations in tissue parameters limit the mean absolute error of this method to ~15 g/L for blood Hb levels varying in the 60–160 g/L range, which finding is also supported by experimental data obtained for volunteers with different total blood Hb levels that have been determined invasively. We believe the application of new approaches to the non-invasive assessment of Hb levels will lead to the creation of reliable and accurate devices that are applicable in point-of-care and clinical practice.

Staging corneal neovascularization to guide treatment

To describe the diagnostic technique to assess corneal neovascular (CoNV) complexes and identify feeder vessels in ocular surface pathologies. To illustrate the role of corneal angiography in clinical assessment and surgical treatment of patients with complex corneal neovascularization. To compare corneal angiography with non‐invasive diagnostic tests such as OCT angiography and slit lamp camera. A case series of patients with CoNV is presented whose management was guided by indocyanine green (ICG) and fluorescein corneal angiography. Corneal angiography is a useful diagnostic tool to guide medical and surgical management of CoNV by enabling the localization of vessel depth and topography.

Effect of Assistant Gas Pressure on Cutting Performance when 80mmt Stainless Steel Laser Cutting in Pressurized Underwater Environment

Various studies are being conducted on underwater cutting using lasers for nuclear power plant dismantling environment. The depth of pressure vessels for most reactors is more than 10 m. When cutting a structure contained in a reactor with 10 m or more depth, pressure is applied, and the shape of the cut due to the cutting gas in this environment needs to be identified. Though several studies exist on laser cutting of stainless steel underwater, laser cutting research in pressurized underwater environment is insufficient. This study investigated the relationship between the cutting kerf width and the assistant gas flow at a depth of 10 m or more in underwater environments. Laser cutting was performed on 80 mm<sup>t</sup> stainless steel in a pressurized underwater environment. The conditions for obtaining sound cut surface quality were derived by analyzing the kerf shape and roughness of the test piece according to the assistant gas pressure. Additionally, the relationship between the kerf width and the assistant gas flow was established by visualizing the flow of gas through Schlieren analysis and by analyzing the shape of the drag line according to the kerf width and assistant gas flow.

Diameter and depth of femoral vessels by duplex ultrasound

Background: The anatomy of the femoral artery and vein plays an integral role in vascular access. Both technical feasibility and complication rates are associated with femoral vessel diameter and depth. The goal of this study is to establish normative values for common femoral artery (CFA) and vein (CFV) depth and diameter using a large, diverse patient population. Methods: A retrospective review of all patients undergoing lower extremity venous duplex imaging over a 1 year period were reviewed. Patients with inadequate imaging or with evidence of deep vein thrombosis were excluded. The index image of all studies was a non-compressed view of the common femoral vein at the saphenous-femoral junction. All measurements were taken from this still. Vessel diameters were measured from intima to intima. Depth was measured from skin to intima. BMI and BSA were calculated using standard formulas. Chi square was used for univariate analysis. Linear regression was used to establish correlation. Results: Over the 1 year period, 983 patients met criteria for inclusion. The majority were male (53%) with a mean age of 55. The patients were 47% white and 44% black. The majority had hypertension (53%). The mean BMI and BSA were 29 and 2, respectively. Mean CFA depth was 1.7 cm, while mean CFV depth was 1.8 cm. The mean CFA and CFV diameters were 0.9 and 1.1 cm, respectively. Amongst height, weight, BMI, and BSA, weight correlated best with CFA ( R = 0.548) and CFV ( R = 0.552) depth, while BSA correlated best for diameter for both CFA ( R = 0.390) and CFV ( R = 0.440). Conclusions: This study establishes mean diameters and depths for the common femoral artery and vein using a large, diverse patient group. BSA was most closely associated with vessel diameter, while weight was correlated with depth. This study provides normative diameter and depth values for the common femoral vasculature, which may assist in vascular access planning for providers.

Connect Brain, a Mobile App for Studying Depth Perception in Angiography Visualization: Gamification Study

Background One of the bottlenecks of visualization research is the lack of volunteers for studies that evaluate new methods and paradigms. The increased availability of web-based marketplaces, combined with the possibility of implementing volume rendering, a computationally expensive method, on mobile devices, has opened the door for using gamification in the context of medical image visualization studies. Objective We aimed to describe a gamified study that we conducted with the goal of comparing several cerebrovascular visualization techniques and to evaluate whether gamification is a valid paradigm for conducting user studies in the domain of medical imaging. Methods The study was implemented in the form of a mobile game, Connect Brain, which was developed and distributed on both Android (Google LLC) and iOS (Apple Inc) platforms. Connect Brain features 2 minigames: one asks the player to make decisions about the depth of different vessels, and the other asks the player to determine whether 2 vessels are connected. Results The gamification paradigm, which allowed us to collect many data samples (5267 and 1810 for the depth comparison and vessel connectivity tasks, respectively) from many participants (N=111), yielded similar results regarding the effectiveness of visualization techniques to those of smaller in-laboratory studies. Conclusions The results of our study suggest that the gamification paradigm not only is a viable alternative to traditional in-laboratory user studies but could also present some advantages.

Ultrasound assessment of the nose vasculature: A review of the common method of non-surgical filler-based rhinoplasty.

With the increasing use of dermal injectable fillers in aesthetic medicine, the popularity of non-surgical filler-based rhinoplasty (NSR) is also growing. While performing this procedure might result in certain vascular complications, injecting deep into the midline of the nose is commonly considered the safest method for blind primary NSR. In this study, we challenged the common NSR method with a Doppler ultrasound study of the nose. The vascular pattern of the common zones of the NSR procedure(radix and nasal tip) of 21 Iranian women were investigated by using a 14 MHz Doppler handheld ultrasound device (Silarious L14PS). Participants had never undergone any procedure on their nose. We focused on the depth of midline vessels in the radix and nasal tip. The radix was studied sagittally and horizontally, and the nasal tip was examined axially by ultrasound. In the radix of eight cases (38%), at least one vessel was observed at midline, and all were superficial. In the nose tip of 18 cases (86%), at least one vessel was observed at midline, and 9 out of these 18 vessels (50%) were deep. As a result, conducting NSR by the common method in our study population was relatively safe in the radix, but there was an increased likelihood of vascular events in the tip. Our research results show that while the common method of the NSR may carry a high risk of vascular events, the safety of this procedure could be enhanced by using ultrasound for planning and conducting a tailored treatment.

Mapping the human parafoveal vascular network to understand flow variability in capillaries.

Capillary flow is known to be non-homogenous between vessels and variable over time, for reasons that are poorly understood. The local properties of individual vessels have been shown to have limited explanatory power in this regard. This exploratory study investigates the association of network-level properties such as vessel depth, branch order, and distance from the feeding arteriole with capillary flow. Detailed network connectivity analysis was undertaken in 3 healthy young subjects using flood-illuminated adaptive optics retinal imaging, with axial depth of vessels determined via optical coherence tomography angiography. Forty-one out of 70 vessels studied were of terminal capillary type, i.e. fed from an arterial junction and drained by a venous junction. Approximately half of vessel junctions were amenable to fitting with a model of relative branch diameters, with only a few adhering to Murray's Law. A key parameter of the model (the junction exponent) was found to be inversely related to the average velocity (r = -0.59, p = 0.015) and trough velocity (r = -0.67, p = 0.004) in downstream vessels. Aspects of cellular flow, such as the minimum velocity, were also moderately correlated (r = 0.46, p = 0.009) with distance to the upstream feeding arteriole. Overall, this study shows that capillary network topology contributes significantly to the flow variability in retinal capillaries in human eyes. Understanding the heterogeneity in capillary flow is an important first step before pathological flow states can be properly understood. These results show that flow within capillary vessels is not affected by vessel depths but significantly influenced by the upstream feeder distance as well as the downstream vessel junction exponents, but there remains much to be uncovered regarding healthy capillary flow.

Rapid and non-invasive detection of high-thickness glucose solution concentrations using quantum cascade laser-based transmission infrared spectroscopy

Most existing spectroscopic methods measure the concentration of blood glucose using attenuated total reflection. However, the short penetration depth (in the range of 2–15 μm) is a severe limitation. In practice, this approach is difficult to use because the depth of blood vessels in the skin exceeds 0.2 mm. As a solution, this work introduces a transmission spectroscopic method to measure the concentration of glucose. A fast infrared spectroscopic glucose concentration measurement method using a mid-infrared wavelength-swept pulsed quantum cascade laser (QCL) is adopted. This method employs a transmission optics system that does not require complicated adjustments or maintenance, together with an asynchronous signal method developed to shorten the measurement time. The combination of the high power of the QCL with the proposed algorithm enables measurements of glucose solution samples with an optical path length of 0.2 mm, which is sufficient for obtaining absorbance spectra and calculating the concentration of glucose in these samples. A linear regression of the average absorbance of the different glucose concentrations yields R2 values as high as 0.999. Moreover, using the asynchronous signal–based method reduces the single measurement time to 20 ms, and a 30 × integration required only 0.6 s. The proposed transmission method not only enables detection on the skin but also exhibits potential for measuring tear film on the eyeball in the tangential direction. This has potential applications in the diagnosis and management of diabetes.

Optoacoustic quantitative in vitro detection of diabetes mellitus involving the comprehensive impacts based on improved quantum particle swarm optimized wavelet neural network

The high accurate detection of blood glucose level (BGL) is very important for non-invasive monitoring of diabetes mellitus. In this work, the optoacoustic (OA) quantitative in vitro detection of diabetes mellitus involving the comprehensive impacts of multiple factors (irradiation energy, concentration, temperature, flow rate and vessel depth) was firstly studied. To achieve this aim, a set of OA in vitro detection system of blood glucose with the comprehensive influence of five factors was constructed. The real-time OA signals of 625 rabbit whole blood were obtained at the characteristic wavelength of 750 nm, as well as peak-to-peak values (PPVs). Results show that the accurate detection of BGL was very difficult due to the complicated OA signals. To accurately predict the BGL under the comprehensive impacts of five factors, wavelet neural network (WNN) was employed to train BGL of 500 training set blood. The mean square error (MSE) of BGL for 125 testing set blood was 6.5782 mmol/L. To decrease the MSE, WNN optimized by quantum particle swarm optimization (QPSO), i.e., QPSO-WNN algorithm was utilized. The MSE of BGL based on QPSO-WNN was 0.37485 mmol/L, which was superior to 0.48005 mmol/L of PSO-WNN. Particularly, to further decrease MSE, a novel nonlinear dynamic shrinkage coefficient (DSC) strategy was proposed, and compared with other four kinds of DSC strategies and the fixed one. With the optimal parameters, the MSE of BGL was decreased to 0.3088 mmol/L. Comparison results of seven algorithms and research works demonstrate that OA technology combined with QPSO-WNN algorithm and the novel nonlinear DSC strategy has excellent performance in the quantitative detection of diabetes mellitus involving in the comprehensive impacts.

Usefulness of 33 MHz Linear Probe in Lymphatic Ultrasound for Lymphedema Patients.

Background: Lymphatic ultrasound has recently been reported useful in the treatment of lymphedema. However, no conclusions have been reached regarding the best probe for lymphatic ultrasound. Methods: This was a retrospective study. Fifteen limbs of 13 patients with lymphedema in whom we could not find dilated lymphatic vessels on lymphatic ultrasound with an 18 MHz probe but later could find them with 33 MHz probe were included. All patients were women, and the mean age was 59.5 years. We performed lymphatic ultrasound in four areas per limb by applying an index of D-CUPS, as we previously reported. We measured the depth and diameter of the lumen of the lymphatic vessels. We also diagnosed the degree of lymphatic degeneration based on the normal, ectasis, contraction, and sclerosis type (NECST) classification. Results: We found lymphatic vessels in 22/24 (91.7%) areas in the upper limbs and 26/36 (72.2%) areas in the lower limbs. The mean depth and diameter of the lymphatic vessels were 5.2 ± 0.28 mm and 0.33 ± 0.029 mm, respectively. Based on the NECST classification, 68.2% of the upper limbs and 56.0% of the lower limbs were of the ectasis type. We found functional lymphatic vessels in 6/6 (100%) of the upper limbs and 5/7 (71.4%) of the lower limbs, which indicated lymphaticovenous anastomosis (LVA) in these 11 patients. Conclusion: Using 33 MHz probe, we could detect functional lymphatic vessels in most patients. Even if lymphatic vessels were not found with the 18 MHz probe, LVA could be performed using a higher frequency probe.

The Algorithm for the Study of Deep Femoral Vessels Using Ultrasound Duplex Angioscanning

The deep femoral vessels are the main branches/donor vessels of the femoral vessels. Their branches penetrate the entire array of muscles of the posteromedial group and descend almost to the popliteal region, so they are able to both largely compensate for blood flow disorders in obliterating atherosclerosis of the arteries of the lower extremities, and in the presence of an anastomosis with the popliteal vein, influence the course of acute and chronic vein diseases. The modern standard for studying the vascular system of the lower extremities is duplex scan, but it allows deep femoral vessels to be examined only in the ostium segment up to 5–6 cm.AIM OF STUDY To determine the patency and state of blood flow in the deep femoral vessels throughout the entire length using ultrasound duplex angioscanning.MATERIAL AND METHODS The analysis of the results of 30 computed tomograms and 100 ultrasound scans of patients (aged 20 to 85 years) who underwent routine examination of the vascular system of the lower extremities in a polyclinic setting was carried out. The study was performed according to the original method (Patent for invention No. 2751819).RESULTS In the upper third of the thigh, the deep femoral vessels are located most superficially, 2.3±0.15 cm from the skin surface and 0.5±0.08 cm from the posterior wall of the femoral artery. In the middle third of the thigh, the depth of the deep femoral vessels is 3.5±0.9 cm from the skin surface and 4.3±0.24 cm from the posterior wall of the femoral artery. The deep femoral vessels are located between the vastus medialis and adductor longus muscles closer to the femur. In the lower third of the thigh, deep femoral vessels are located at a distance of 4.3±0.4 cm from the skin surface and 1.8±0.5 cm from the posterior wall of the femoral artery. Therefore, for ultrasound examination, a linear probe is first used, which is placed along the projection line of the femoral vessels in the upper third of the thigh, and then the orifice of the deep femoral vessels is visualized. Next, a convex probe is used, and in the middle and lower third of the thigh, it is drawn along a line located 2 cm medially to the projection line of the femoral vessels, while the probe itself deviates posteriorly by ~ 15°.CONCLUSION The research algorithm helps increase the length of the areas of the deep femoral artery and vein available for research and help the physician choose the optimal method of treating the patient.

Ultrasonography-Guided Cannula Method for PMMA Injection in Aesthetic Gluteal Augmentation: A Technical Note

Purpose: Revolumization with deep injections has become increasingly common, even in high-risk areas for intravascular infusion or nerve injury. This study aimed to assess the usefulness of the ultrasonography-guided cannula method for preventing side effects during the injection of polymethylmethacrylate (PMMA) fillers. Real-time ultrasonography was used to monitor the injection of PMMA as a filler in the gluteus for aesthetic purposes. This way, adjacent anatomical structures such as arteries, veins, and nerves could be seen during the whole procedure. Materials and Methods: This study describes the technique used for ultrasound-guided injections of PMMA in the gluteal region of two patients. Patients 1 and 2 were injected with 300 mL and 220 mL of the filler, respectively. Injections were administered intramuscularly and subcutaneously into sites that had been marked before the procedure. While one professional performed the injections, another guided them with real-time ultrasound imaging, using the same equipment for both patients. The location and depth of blood vessels and nerves were determined before the procedure, and the insertion of the cannula was accompanied by ultrasound imaging. Results: The PMMA filler, as well as the cannula, blood vessels, and nerves, was visualized using ultrasound. Some differences were observed between the cases. In the first patient, a small amount of PMMA from a previous procedure could be found (hyperechoic images), while the second one had had no filler injection before. Conclusion: Based on these cases, ultrasonography can be seen as a complementary tool to monitor tissue filler injections, especially in the gluteal region, thus, avoiding possible vascular and nervous injuries. Real-time ultrasound makes the procedure safer, protecting regional structures from lesions. The ultrasonography-guided method succeeded in localizing the cannula, blood vessels, and the sciatic nerve, allowing for safe injection of PPMA filler into a deep gluteal region.

Combined Monte Carlo and k-Wave Simulations for Reconstruction of Blood Oxygen Saturation in Optoacoustics: A Pilot Study

Optoacoustic (OA) imaging of biological tissues is a modern technique allowing for three-dimensional blood oxygen saturation mapping based on OA spectroscopy data. Since biological tissues are optically inhomogeneous and the spatial distribution of optical parameters within a biological tissue is a priori unknown, Monte Carlo simulation technique is traditionally used to estimate the distribution of probing illumination within tissues in quantitative OA reconstruction. Currently, machine learning techniques are actively employed for reconstructing 3D distribution of blood oxygen saturation or estimating optical properties of biological tissues based on training datasets. In this paper, systemic calculations of synthetic OA images of a medium with embedded vessel-like structures were performed to create a training dataset for machine learning employing combined application of the Monte Carlo technique for direct solution of optical problem and difference-space pseudo-spectral approach implemented through k-Wave Toolbox calculations for the acoustical part. The calculations were performed for probing wavelengths of 532 nm, 658 nm and 1064 nm, which are commonly employed in spectral OA imaging. Simulated OA data for different orientation, diameter and embedding depth of blood vessels allows analyzing the effect of these parameters on the formation of OA image and the reconstruction of blood oxygen saturation. The ratio of OA signals corresponding to probing wavelengths of 658 nm and 1064 nm was employed for simple reconstruction of blood oxygen saturation in silico for different vessel geometries with the precision of < 3–15% for the most of blood vessels diameters and embedding depths and the range of blood oxygen saturation values ≥ 0.8. The obtained set of synthetic OA data has high potential as a training set for employment in machine learning techniques aiming at mapping blood oxygenation based on spectral OA data.

Region-based SVD processing of high-frequency ultrafast ultrasound to visualize cutaneous vascular networks

Observing alterations in cutaneous vasculature in response to any disease or pathology is considered as a potential diagnostic marker in the progression and cure of a disease. To observe skin morphologies and tissue conditions, high-frequency ultrasound (HFUS) has been used in dermatology, although its ability to selectively visualize micro-vessels is limited due to insufficient Doppler sensitivity to peripheral slow-speed blood flow. In recent studies, this issue has been improved by increasing the sensitivity of Doppler imaging to slow flow, leveraging advanced cutter filtering approaches based on singular value decomposition (SVD) techniques that aid to effectively extract flow signals overlapped with tissue echo signals. Nevertheless, in skin imaging, variations in flow speed, diameter, and depth of the blood vessels at different skin layers can make clutter filtering challenging because these variations are problematic in selecting the optimal cut-off value for the SVD filtering. In this study, we aimed to devise a novel region-based SVD filtering approach for ultrafast HFUS data to visualize cutaneous vascular networks. The proposed method divides the acquired high-framerate data into two regions based on B-mode cutaneous morphological identification (dermis layer and subcutaneous tissue). Singular value decomposition processing was performed on each region to effectively extract the desired flow signal, and the processed regions were merged to generate a single power Doppler image, thereby highlighting the appearance of a complete cutaneous vascular network. Finally, top-hat transform was applied to the power Doppler image to further suppress the background noises and enhances the visibility of the micro-vessels. Experimental observations of the human cutaneous circulation showed that the image quality (contrast-to-noise ratio) through the region-based SVD filtering was measured to be 4.1 dB (before top-hat filtering) and 5.2 dB (after top-hat filtering), which were improved from 3.4 dB and 4.0 dB obtained using the global SVD approach with and without top-hat filtering, respectively. We envisioned that this approach would provide diverse applications in the diagnosis of cutaneous disorders.

THE COMPLEX STUDY OF GINGIVAL MICROVESSELS IN YOUNG PEOPLE

Morphological and functional features of tissue blood flow are genetically determined, the identification of individual characteristics of microcirculation in the oral mucosa in the gum area can help determine the specifics of periodontal tissue damage in various patients. The aim of the study was to study tissue blood flow and microvessels in different areas of the oral mucosa in young people. In 40 healthy young people, biomicroscopy and laser Doppler flowmetry were used to record blood microcirculation indicators in various parts of the gums in the upper and lower jaws. On cadaveric material, the depth of blood vessels in different parts of the gum was studied. As a result of the study, it was found that the density of microvessels and the intensity of blood flow decrease with distance from the transitional fold to the edge of the gum. In the same areas of the mucous membrane in the upper and lower jaws, the microcirculation indicators do not differ. The most common (in 35 out of 40 subjects) in the vessels of the oral mucosa was the mesoemic type of blood microcirculation, in which the tissue blood flow was of medium intensity and the mechanisms of its regulation were balanced. In other cases, very low (hypoemic type) or high (hyperemic type) indicators of tissue blood flow with weak activity of vasomotor mechanisms of regulation of the state of microvessels of the oral mucosa were recorded. Thus, the use of a set of methods for studying the microvasculature of the oral mucosa in the gingival region allows us to quantitatively characterize the state of microvessels, as well as the intensity of tissue blood flow in different parts of the gingiva of the upper and lower jaws in young people. The richest microvascular network is observed in the region of the transitional gingival fold. As the distance from the transitional fold to the marginal part of the gums, the density of capillaries and the intensity of blood flow in them decrease, the gingival mucosa near the neck of the tooth has the lowest microcirculation rates.