Vessel Structure Research Articles

Super-Resolution Ultrasound Imaging Using the Erythrocytes-Part I: Density Images.

A new approach for vascular super-resolution (SR) imaging using the erythrocytes as targets (SUper-Resolution ultrasound imaging of Erythrocytes (SURE) imaging) is described and investigated. SURE imaging does not require fragile contrast agent bubbles, making it possible to use the maximum allowable mechanical index (MI) for ultrasound scanning for an increased penetration depth. A synthetic aperture (SA) ultrasound sequence was employed with 12 virtual sources (VSs) using a 10-MHz GE L8-18i-D linear array hockey stick probe. The axial resolution was [Formula: see text]m) and the lateral resolution was [Formula: see text]m). Field IIpro simulations were conducted on 12.5- μ m radius vessel pairs with varying separations. A vessel pair with a separation of 70 μ m could be resolved, indicating a SURE image resolution below half a wavelength. A Verasonics research scanner was used for the in vivo experiments to scan the kidneys of Sprague-Dawley rats for up to 46 s to visualize their microvasculature by processing from 0.1 up to 45 s of data for SURE imaging and for 46.8 s for SR imaging with a SonoVue contrast agent. Afterward, the renal vasculature was filled with the ex vivo micro-computed tomography (CT) contrast agent Microfil, excised, and scanned in a micro-CT scanner at both a 22.6- μ m voxel size for 11 h and for 20 h in a 5- μ m voxel size for validating the SURE images. Comparing the SURE and micro-CT images revealed that vessels with a diameter of 28 μ m, five times smaller than the ultrasound wavelength, could be detected, and the dense grid of microvessels in the full kidney was shown for scan times between 1 and 10 s. The vessel structure in the cortex was also similar to the SURE and SR images. Fourier ring correlation (FRC) indicated a resolution capability of 29 μ m. SURE images are acquired in seconds rather than minutes without any patient preparation or contrast injection, making the method translatable to clinical use.

Layup design and mechanical properties of an optimal dome profile

AbstractThe development of lightweight and high‐performance composite pressure vessels have become a popular research objective. The purpose of this study is to the layup design and improve the mechanical properties of pressure vessel structure with optimal dome profile under an internal pressure of 70 MPa. First, the prediction equations of fiber thickness for the cylindrical and dome sections are provided. Second, the influence laws of linear parameters on fiber layer thickness distribution are analyzed. Third, the optimal dome profile is used as the pressure vessel structure for the layup design, and the variable polar hole process is applied to solve the fiber thickness accumulation problem near the polar holes. Finally, the composite pressure vessel is modeled using Abaqus finite element software, and the stress and strain distributions of the liner and the composite layer under different internal pressure loads are analyzed under self‐tightening pressure. Results show that the variable polar hole process reduces the maximum thickness value by nearly 50.16% at the maximum fiber thickness of the dome. Under working pressure, the maximum stress of the liner is reduced by 43.41% after applying self‐tightening pressure. In addition, the variable polar hole process can effectively realize the lightweighting of composite pressure vessels while self‐tightening pressure can effectively improve the mechanical properties of the liner. This research provides a valuable reference for the design of composite pressure vessels.Highlights Fiber accumulation occurs in two bandwidth regions near the polar hole. The variable polar hole process can solve the fiber accumulation problem. The optimum dome profile geometric parameters are m = 0.8 and rc = 0.4R. The self‐tightening pressure improves liner loading capacity.

Analysis of damage characteristics of the rectangular steel container under near-earth explosion loading

In this study, the dynamic response of a semi-buried steel vessel under a near-surface explosion shock load was investigated through full-scale model tests. A three-dimensional precise numerical simulation model of the semi-buried steel vessel structure was established, and the dynamic response and damage consequences under different load conditions were analyzed. The influence of the thickness of corrugated steel on the dynamic damage and antiknock properties of the structure was studied. The results show that the weak part of the rectangular steel vessel structure is mainly located at the connection between the blast-facing panel and the beam column under near-surface explosion conditions. The peak stress and displacement of the blasting surface decrease with the increase in the horizontal angle of the incident wave, whilst/while increase with the height of the explosion. Under the same explosive yield, the main failure mode of the structure is the tearing of the plate and beam under plastic deformation. Increasing the thickness of the corrugated steel can significantly restrain the plastic deformation and acceleration of the plate. When the thickness is increased from 2 mm to 6 mm, the antiknock performance is significantly improved. However, when the thickness is increased from 6 mm to 8 mm, the improvement in antiknock performance slows down. Increasing the height of the enclosing soil can also effectively improve the explosion-proof performance of the structure, with full burial providing the best effect. The research results provide a theoretical basis for the application of rectangular steel vessel structures in the field of protection engineering.

Convective heat transfer with Hall current using magnetized non-Newtonian Carreau fluid model on the cilia-attenuated flow

PurposeCilia serves numerous biological functions in the human body. Malfunctioning of nonmotile or motile cilia will have different kinds of consequences for human health. More specifically, the directed and rhythmic beat of motile cilia facilitates the unidirectional flow of fluids that are crucial in both homeostasis and the development of ciliated tissues. In cilia-dependent hydrodynamic flows, tapering geometries look a lot like the structure of biological pathways and vessels, like airways and lymphatic vessels. In this paper, the Carreau fluid model through the cilia-assisted tapered channel (asymmetric) under the influence of induced magnetic field and convective heat transfer is investigated.Design/methodology/approachLubrication theory is a key player in the mathematical formulation of momentum, magnetic field and energy equations. The formulated nonlinear and coupled differential equations are solved with the aid of the homotopy perturbation method (HPM). The graphical results are illustrated with the help of the computational software “Mathematica.”FindingsThe impact of diverse emerging physical parameters on velocity, induced magnetic field, pressure rise, current density and temperature profiles is presented graphically. It is observed that the cilia length parameter supported the velocity and current density profiles, while the Hartman number and Weissenberg number were opposed. A promising effect of emerging parameters on streamlines is also perceived.Originality/valueThe study provides novel aspects of cilia-driven induced magnetohydrodynamics flow of Carreau fluid under the influence of induced magnetic field and convective heat transfer through the asymmetric tapered channel.

A reconstruction method of stress fields, bending moments and wave parameters for floating nuclear power plants through regular wave identification

Floating nuclear power plants (FNPPs) have the potential to supply abundant electricity, hot water, and freshwater resources for offshore islands and offshore oil and gas extraction platforms. However, the consequences of a nuclear reactor accident can be extremely serious. In addition, there may be many uncertain factors in the actual operation of FNPPs. These factors lead to higher structural safety requirements. So， developing more scientific structural monitoring methods is an effective way to enhance the structural safety of FNPP. Traditional hull monitoring schemes can only track bending and torsional forces on specific cross-sections, failing to identify the overall stress field of the entire vessel structure. The paper proposes a reconstruction method for the stress field, bending moment distribution, and wave parameters of FNPP using regular wave identification. Initially, irregular waves are decomposed into a linear combination of multiple regular waves with different amplitudes and frequencies. Subsequently, the strains induced by these regular waves on the FNPP are utilized as basic functions to establish a mathematical model for reconstructing the stress field. The stress field, bending moment distribution, and wave parameters of the FNPP can be reconstructed by identifying the combination coefficients of the regular wave loads. The ill-posedness of the mathematical model for stress field reconstruction has the potential to significantly impact the accuracy of the stress field reconstruction, which was addressed by optimizing the sensor installation position in this study. Meanwhile, the optimization of the sensor installation position greatly reduces the dimensionality of mathematical models. Finally, a numerical study, i.e. FNPP being designed by China, was used to validate the accuracy of the proposed stress field reconstruction algorithm. The reconstructed stress field of the FNPP closely matched the original stress distribution under various irregular wave conditions.

Exploring developmental MeHg impact on extraembryonic and cardiac vessels and its effect on cardiomyocyte contractility.

The toxicity of methylmercury (MeHg) during embryonic development is a relevant issue that remains unclear and deserves investigation. In this sense, there is evidence that links the intake of contaminated food with cardiovascular pathologies in human adults and children. Thus, this study aimed to verify the impact of MeHg on the structure and integrity of extraembryonic and cardiac blood vessels and the contractile function of cardiomyocytes, also evaluating embryonic weight and the cardiosomatic index (CSI). Thus, chicken embryos, used as an experimental model, were exposed to a single dose of 0.1μg MeHg/50 μl saline at E1.5 and analyzed at E10. After exposure, an increase in the number of extraembryonic blood vessels and the veins of the cardiac tissue was observed. These increases were accompanied by a reduction in the content of VEGF and VCAM proteins related to vessel growth and adhesiveness. Together, these results were related to reduced nitrite (NOx) levels. Furthermore, MeHg reduces the number of sarcomeres and increases the content of cardiac troponin I (cTnI), a protein that regulates contraction. In general, exposure to MeHg affected the integrity of extraembryonic and cardiac vessels and the contractile function of cardiomyocytes, which had a systemic impact evidenced by the reduction in embryonic weight gain and CSI.

Molecular pathophysiology of secondary lymphedema.

Lymphedema occurs as a result of lymphatic vessel damage or obstruction, leading to the lymphatic fluid stasis, which triggers inflammation, tissue fibrosis, and adipose tissue deposition with adipocyte hypertrophy. The treatment of lymphedema is divided into conservative and surgical approaches. Among surgical treatments, methods like lymphaticovenular anastomosis and vascularized lymph node transfer are gaining attention as they focus on restoring lymphatic flow, constituting a physiologic treatment approach. Lymphatic endothelial cells form the structure of lymphatic vessels. These cells possess button-like junctions that facilitate the influx of fluid and leukocytes. Approximately 10% of interstitial fluid is connected to venous return through lymphatic capillaries. Damage to lymphatic vessels leads to lymphatic fluid stasis, resulting in the clinical condition of lymphedema through three mechanisms: Inflammation involving CD4+ T cells as the principal contributing factor, along with the effects of immune cells on the VEGF-C/VEGFR axis, consequently resulting in abnormal lymphangiogenesis; adipocyte hypertrophy and adipose tissue deposition regulated by the interaction of CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor-γ; and tissue fibrosis initiated by the overactivity of Th2 cells, leading to the secretion of profibrotic cytokines such as IL-4, IL-13, and the growth factor TGF-β1. Surgical treatments aimed at reconstructing the lymphatic system help facilitate lymphatic fluid drainage, but their effectiveness in treating already damaged lymphatic vessels is limited. Therefore, reviewing the pathophysiology and molecular mechanisms of lymphedema is crucial to complement surgical treatments and explore novel therapeutic approaches.

Mapping the blood vasculature in an intact human kidney using hierarchical phase-contrast tomography.

The architecture of the kidney vasculature is essential for its function. Although structural profiling of the intact rodent kidney vasculature has been performed, it is challenging to map vascular architecture of larger human organs. We hypothesised that hierarchical phase-contrast tomography (HiP-CT) would enable quantitative analysis of the entire human kidney vasculature. Combining label-free HiP-CT imaging of an intact kidney from a 63-year-old male with topology network analysis, we quantitated vasculature architecture in the human kidney down to the scale of arterioles. Although human and rat kidney vascular topologies are comparable, vascular radius decreases at a significantly faster rate in humans as vessels branch from artery towards the cortex. At branching points of large vessels, radii are theoretically optimised to minimise flow resistance, an observation not found for smaller arterioles. Structural differences in the vasculature were found in different spatial zones of the kidney reflecting their unique functional roles. Overall, this represents the first time the entire arterial vasculature of a human kidney has been mapped providing essential inputs for computational models of kidney vascular flow and synthetic vascular architectures, with implications for understanding how the structure of individual blood vessels collectively scales to facilitate organ function.

Distributed fiber optic strain sensing for structural health monitoring of 70 MPa hydrogen vessels

We report on the development and testing of 70 MPa hydrogen pressure vessels with integrated fiber optic sensing fibers for the automotive use. The paper deals with the condition monitoring of such composite pressure vessels using the optical backscatter reflectometry (OBR) which was applied for a distributed fiber optic strain sensing along fully integrated polyimide-coated single-mode glass optical fiber (SM-GOF). The sensing fibers were embedded into the vessel structure by wrapping them over the inside polymer liner during the manufacturing process of the outside carbon fiber reinforced polymer (CFRP). Detecting local strain events by the integrated fiber optic sensors might be an opportunity for monitoring the material degradation. Regarding the investigation of the ageing behavior, both ambient hydraulic cycling tests and slow burst tests were conducted on 70 MPa pressure vessels with embedded fiber optic sensors. The achieved results contribute to the knowledge about material fatigue to guarantee the safe usage during the entire lifetime of the composite hydrogen storage vessels. The presented work stands in context of the European Horizon 2020 research project SH2APED focused on the development of an innovative hydrogen storage system composed of an assembly of nine 70 MPa tubular pressure vessels used as an automotive battery pack.

Retinal Blood Vessels Segmentation With Improved SE‐UNet Model

ABSTRACTAccurate segmentation of retinal vessels is crucial for the early diagnosis and treatment of eye diseases, for example, diabetic retinopathy, glaucoma, and macular degeneration. Due to the intricate structure of retinal vessels, it is essential to extract their features with precision for the semantic segmentation of medical images. In this study, an improved deep learning neural network was developed with a focus on feature extraction based on the U‐Net structure. The enhanced U‐Net combines the architecture of convolutional neural networks (CNNs) with SE blocks (squeeze‐and‐excitation blocks) to adaptively extract image features after each U‐Net encoder's convolution. This approach aids in suppressing nonvascular regions and highlighting features for specific segmentation tasks. The proposed method was trained and tested on the DRIVECHASE_DB1 and STARE datasets. As a result, the proposed model had an algorithmic accuracy, sensitivity, specificity, Dice coefficient (Dc), and Matthews correlation coefficient (MCC) of 95.62/0.9853/0.9652, 0.7751/0.7976/0.7773, 0.9832/0.8567/0.9865, 82.53/87.23/83.42, and 0.7823/0.7987/0.8345, respectively, outperforming previous methods, including UNet++, attention U‐Net, and ResUNet. The experimental results demonstrated that the proposed method improved the retinal vessel segmentation performance.

First Detection of Podocytes in the Circulatory System of Enigmatic Echiurids (Annelida: Thalassematidae).

The fine structure of echiurid blood vessels in the proboscis is known in detail, but the circulatory system of the trunk is still understood mainly at the level of general anatomy. The trunk circulatory system was studied in Bonellia viridis females, and specialized podocytes were found to form the walls of the ring vessel and the anterior part of the ventral vessel. Podocytes were for the first time described in the echiurid circulatory system. Podocytes of B. viridis displayed a typical cell architecture, which is known for other bilaterians. A podocyte consists of a cell body; primary processes; and pedicels, which extend from the primary processes and are interconnected via specialized slit diaphragms. The presence of podocytes indicates that the ventral and ring vessels act as ultrafiltration sites, where the plasma is filtered through the basal lamina into the body cavity.

Vascular remodelling in cardiovascular diseases: hypertension, oxidation, and inflammation.

Optimal vascular structure and function are essential for maintaining the physiological functions of the cardiovascular system. Vascular remodelling involves changes in vessel structure, including its size, shape, cellular and molecular composition. These changes result from multiple risk factors and may be compensatory adaptations to sustain blood vessel function. They occur in diverse cardiovascular pathologies, from hypertension to heart failure and atherosclerosis. Dynamic changes in the endothelium, fibroblasts, smooth muscle cells, pericytes or other vascular wall cells underlie remodelling. In addition, immune cells, including macrophages and lymphocytes, may infiltrate vessels and initiate inflammatory signalling. They contribute to a dynamic interplay between cell proliferation, apoptosis, migration, inflammation, and extracellular matrix reorganisation, all critical mechanisms of vascular remodelling. Molecular pathways underlying these processes include growth factors (e.g., vascular endothelial growth factor and platelet-derived growth factor), inflammatory cytokines (e.g., interleukin-1β and tumour necrosis factor-α), reactive oxygen species, and signalling pathways, such as Rho/ROCK, MAPK, and TGF-β/Smad, related to nitric oxide and superoxide biology. MicroRNAs and long noncoding RNAs are crucial epigenetic regulators of gene expression in vascular remodelling. We evaluate these pathways for potential therapeutic targeting from a clinical translational perspective. In summary, vascular remodelling, a coordinated modification of vascular structure and function, is crucial in cardiovascular disease pathology.

A Microvascular Segmentation Network Based on Pyramidal Attention Mechanism.

The precise segmentation of retinal vasculature is crucial for the early screening of various eye diseases, such as diabetic retinopathy and hypertensive retinopathy. Given the complex and variable overall structure of retinal vessels and their delicate, minute local features, the accurate extraction of fine vessels and edge pixels remains a technical challenge in the current research. To enhance the ability to extract thin vessels, this paper incorporates a pyramid channel attention module into a U-shaped network. This allows for more effective capture of information at different levels and increased attention to vessel-related channels, thereby improving model performance. Simultaneously, to prevent overfitting, this paper optimizes the standard convolutional block in the U-Net with the pre-activated residual discard convolution block, thus improving the model's generalization ability. The model is evaluated on three benchmark retinal datasets: DRIVE, CHASE_DB1, and STARE. Experimental results demonstrate that, compared to the baseline model, the proposed model achieves improvements in sensitivity (Sen) scores of 7.12%, 9.65%, and 5.36% on these three datasets, respectively, proving its strong ability to extract fine vessels.

Enhancing flame retardant wood’s versatility and adjustable properties through multi-scale micro-coating strategy

Wood, a naturally renewable material with a porous structure and breathability, rendering it a green construction material that can absorb sound, isolate heat and regulate moisture. Efforts to enhance wood’s resistance to combustion while maintaining its porous nature are hindered by the potential impact of physical and chemical treatments on its porous structure, posing a challenge in achieving flame-retardant wood that retains its breathability. Inspired by the multi-layer coating decoration method used on walls of various rooms in frame structure buildings, the study applies multi-scale micro-coating strategy to the multi-scale microstructure of wood. This strategy applied polyamino polyether methylene phosphonate (PAP), metal ions (Al3+/ Mg2+/ Ca2+), and alkali solutions to create a persistent multifunctional protective coating for the multi-scale wood structure. This coating effectively preserved the wood’s vessel, ray tissue, cell cavity, and pit structure, protecting its permeability. The modified wood demonstrated an increased limited oxygen value from 19.7 % to 38.4 % and a 55.9 % decrease in the total smoke release compared to natural wood, obtaining high fire safety. Furthermore, the modified wood exhibited adjustable antibacterial, photoaging-resistant and corrosion resistance properties depends on the type of metal. This strategy demonstrated proven reliability, versatility, and durability in the treatment of various metal ions, enabling the production of functional wood with tailored properties.

Compact fusion blanket using plasma facing liquid Li-LiH walls and Pb pebbles

Liquid plasma facing walls allow for increased neutron-wall loading expanding the design space of fusion power-plants and experimental devices towards compact high-field reactors. This study presents the design of a compact radial build blanket for fusion devices composed of variable quantities of Lead (Pb) and Lithium-Lithium Hydride (Li-LiH). A tank-like cylindrical neutronic model of the early design of the stellarator reactor proposed by Renaissance Fusion is implemented in OpenMC (neutron transport and dose rate analyses). The reactor's radial build composition and blanket layer thicknesses are varied to fulfill the requirements on tritium breeding ratio (TBR), nuclear heat extraction, radiation shielding (for the coils, internal structures and external environment) for a stellarator-based power-plant. The analyses suggest that a radial build lower than a meter thick between the plasma and coils would be sufficient to allow for a TBR ∼ 1.60, an energy multiplication factor of ∼ 1.07, to capture ≥ 90% of the nuclear heat, limit the neutron fluence at the coils below 1019 n/cm2, and limit the structural damage on the liquid metal vessel and magnet structure. In particular, a blanket composed of 32 cm of Pb and Li-LiH, 54 cm of a heavy metal hydride such as vanadium hydride (VH2), along with a 1.3 m of concrete bioshield, would minimize the radial build of the stellarator reactor while fulfilling tritium breeding, shielding and heat extraction requirements.

A retinal vessel segmentation network approach based on rough sets and attention fusion module

The morphological changes of retinal vessels are of significant diagnostic value for early ophthalmic diseases and can aid in distinguishing other conditions such as diabetes and cardiovascular diseases. However, precise segmentation poses a challenge due to the complex structure of retinal vessels. To address these issues, we propose a Rough Attention Fusion Module (RAFM). This module employs max-pooling and average-pooling to define the upper and lower bounds of feature significance, introducing upper and lower weight matrices to obtain more reasonable attention coefficients. This enables the model to more accurately focus on important features in retinal images. Additionally, we integrate the RAFM into the GTS U-Net model, a simplified version of the GT U-Net model, which enhances the segmentation accuracy while reducing computational complexity. Ultimately, we construct a retinal vessel segmentation network based on the RAFM along with Group Transformer. Finally, the network structure is tested on the public DRIVE color fundus image dataset, achieving an Accuracy, F1 score, and AUC of 0.9641, 0.8506, and 0.9820, respectively. In contrast to prevalent retinal vessel segmentation networks in the mainstream, our proposed network demonstrates certain strengths.

Influence of age, body mass index and gender on sonographic indicators of the liver in patients with metabolic dysfunction-associated steatotic liver disease

Background. The incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing along with the increasing prevalence of obesity. There are close relationships between these two pathologies due to the functioning of adipose tissue as an endocrine organ with a complex influence on various metabolic processes. It is known that premenopausal women are less prone to fatty liver disease than men. The aim was to study the influence of gender, body mass index (BMI) and age on sonographic indicators and the degree of liver steatosis in patients with metabolic dysfunction-associated steatotic liver disease. Materials and methods. Ninety-two patients with MASLD were included in the study, 48 women and 44 men. Inclusion criterion was metabolic dysfunction-associated steatotic liver disease, exclusion criteria were any non-metabolic factors of chronic diffuse liver disease. Patients were divided into groups by gender and age. Women were divided by age according to the presence and absence of menopause, men were divided into groups below and above 45 years — the conventional age of the beginning of the decline in gonadotropic function. The analysis of structural changes of the liver, namely the assessment of the size, contours, structure, echogenicity, and visualization of blood vessels in the B-mode was carried out with the help of ultrasound examination on Toshiba Xario 660 (Japan). The degree of steatosis was assessed by the controlled attenuation parameter. Results. In men, the right, left and caudate liver lobes were significantly larger (p < 0.05) than in women, which is due to the higher weight of men in the absence of a difference in the BMI. There was no significant difference between men and women in degree of steatosis (p > 0.05). A moderate positive correlation (r = 0.63) was found between BMI and the controlled attenuation parameter; in women, there was no connection between these indicators. Analysis of correlations in women of different ages, divided by the presence of menopause, found that before menopause, there was no dependence of steatosis indicators on BMI, while with the onset of menopause, the coefficient of correlation between these indicators was 0.39 (р < 0.02). Conclusions. No significant difference was found between the frequency of various degrees of steatosis in MASLD according to the controlled attenuation parameter in men and women. There was a dependence of the severity of liver steatosis on the BMI in men, the dependence of steatosis on the body mass index in women was manifested starting from the menopause period, which suggests the protective role of female sex hormones.

Precise diagnosis of cardiac‐cerebral vascular diseases with magnetic resonance imaging‐based nanoprobes

AbstractCardiac‐cerebral vascular diseases (CCVDs) are acknowledged as a major threat to public health, leading to more than one‐third of all deaths worldwide. The complex anatomical structure and immune features of blood vessels significantly affect the development of CCVDs, and magnetic resonance angiography (MRA) is one of the main diagnostic approaches for the accurate diagnosis and prognosis of CCVDs. However, MRA suffers from intrinsic problems derived from its blood flow‐dependency, and the clinical Gd‐chelating contrast agents are limited by their rapid vascular extravasation. Over the past decade, spurred on by nanoscience and nanotechnology, numerous contrast agents based on magnetic nanomaterials have been developed to enhance the contrast of MRA, with these including iron oxide nanoparticles, rare earth‐doped nanoparticles, and metal‐organic coordination polymers. The molecular MR imaging of vasculopathy using specific nanoprobes has been explored to obtain a better understanding of the molecular aspects of CCVDs. In this review, the state of the art in MRA nanoprobes is introduced, and recent achievements in the diagnosis of CCVDs using MR imaging are summarized. Additionally, the future prospects and limitations of MRA based on nanoprobes are discussed. The current review provides methodological designs and ideas for subsequent MRA nanoprobes.

IMPROVEMENT OF CAPILLAROSCOPY METHOD FOR STUDYING HUMAN MICROCIRCULATION

The human circulatory system has historically captivated researchers in the field of medicine. Modern medicine, however, has moved beyond identifying a single crucial element, such as the heart or venous system, for maintaining blood flow. Instead, it emphasizes a more analytical approach, focusing on the interconnected functioning of all components within the system. The aim of this work is to analyze the existing methods of studying blood microcirculation and to improve the technology of capillaroscopy, technical means of raster microphotography to determine the physiological state and disorders of capillary circulation. To achieve this objective, we address the following tasks: analyzing existing non-invasive methods for studying the human vascular system; enhancing the optical capillaroscopy method through the utilization of modern high-resolution digital cameras, computer, and multimedia equipment, along with appropriate software for analyzing electronic images; developing a technological scheme and equipment design for digital microphotography of capillaries in the periungual region of the upper extremities; providing software solutions for registering and analyzing digital microphotographic images obtained through capillaroscopy; conducting experimental studies to explore the structure and properties of capillaries utilizing the developed technologies and equipment. Magnetic resonance imaging (MRI) enables the comprehensive evaluation of both anatomical and functional aspects of blood flow. Magnetic resonance angiography (MRA) capitalizes on the distinction between the signal emitted by moving tissue (blood) and that of surrounding stationary tissue, facilitating the acquisition of vascular images without the need for radiopaque contrast agents. Ultrasonography integrates Doppler and conventional ultrasound techniques, providing physicians with insights into blood vessel structure and blood flow dynamics. Traditional ultrasound employs sound waves that are imperceptible to the human ear and bounce off blood vessels, while Doppler ultrasound measures the velocity of sound wave reflection from moving elements. Ophthalmoscopy constitutes a fundamental component of standard ophthalmological examinations, serving as a pivotal tool for diagnosing eye conditions and evaluating the condition of blood vessels. Additionally, ophthalmoscopy aids in diagnosing autoimmune disorders. Capillaroscopy enables comprehensive assessments of both systemic and regional microcirculation disorders, facilitating the characterization of tissue metabolism. Dysfunction in capillary function contributes to circulatory impairments, leading to blood stasis, metabolic irregularities, and compromised immunity, thereby exacerbating existing conditions and predisposing individuals to new diseases. Optical computerized capillaroscopy offers a non-invasive means of visualizing, examining, and archiving capillary images, enabling clinicians to make informed assessments regarding blood microcirculation. Experimental validation of the optimized hardware and software capillaroscopy system was conducted using nail bed capillaries of a patient with type II diabetes mellitus undergoing insulin therapy for 10 years. This study underscores the importance of refining and enhancing optical capillaroscopy methodologies by leveraging high-resolution camera sensors and modern computational tools for image processing.

Prediction of pedicled flap survival preoperatively by operating indocyanine green angiography at 1,450 nm wavelength: an animal model study.

Predicting flap viability benefits patients by reducing complications and guides flap design by reducing donor areas. Due to varying anatomy, obtaining individual vascular information preoperatively is fundamental for designing safe flaps. Although indocyanine green angiography (ICGA) is a conventional tool in intraoperative assessment and postoperative monitoring, it is rare in preoperative prediction. ICGA was performed on 20 male BALB/c mice under five wavelengths (900/1,000/1,100, /1,250/1,450 nm) to assess vascular resolution after ICG perfusion. A "mirrored-L" flap model with three angiosomes was established on another 20 male BALB/c mice, randomly divided into two equal groups. In Group A, a midline between angiosomes II and III was used as a border. In Group B, the points of the minimized choke vessel caliber marked according to the ICG signal at 1,450 nm wavelength (ICG1450) were connected. Necrotic area calculations, pathohistological testing, and statistical analysis were performed. The vascular structure was clearly observed at 1,450 nm wavelength, while the 900 to 1,100 nm failed to depict vessel morphology. Necrosis was beyond the borderline in 60% of Group A. Conversely, 100% of Group B had necrosis distal to the borderline. The number of choke vessels between angiosomes II and III was positively correlated with the necrotic area (%). The pathohistological findings supported the gross observation and analysis. ICG1450 can delineate the vessel structure in vivo and predict the viability of pedicled skin flaps using the choke vessel as the border between angiosomes.