Location Of Stenosis Research Articles

Numerical simulation of hemodynamics in patient-specific pulmonary artery stenosis.

The incidence rate of pulmonary artery stenosis is increasing year by year and its numerical simulation has become a key project of biomedical engineering. The purpose of this work is to study the changes of hemodynamic parameters in patient-specific pulmonary artery stenosis. A pulmonary artery stenosis model is established based on patient-specific computed tomography (CT) images. According to the actual anatomy of patient-specific pulmonary artery stenosis, the stenosis area is simulated using a porous medium to study its hemodynamic changes. The computational fluid dynamics (CFD) method is used to simulate the hemodynamic changes of pulmonary artery stenosis, and to explore the mechanical characteristics between blood flow and vessel wall. The results suggest that the blood pressures of arterial branches increase and the pressure drop at both ends of the stenosis is higher. There is a high flow rate and wall shear stress at the stenosis. This study shows that the hemodynamic model of pulmonary artery stenosis can be accurately reconstructed by achieving numerical simulation of the local stenosis through CT images, and this work has important implications for improving the confidence of clinical diagnosis and treatment of pulmonary artery diseases.

Flow Rate Augmentation of Valveless Pumping via a Time-Dependent Stenosis: A Novel Device

A novel device of flow rate augmentation is proposed and experimentally examined in a horizontal valveless closed loop pump using a time-dependent stenosis (convergent–divergent channel) in contrast with the commonly used taper tubes of constant opening as flow rectifiers. The stenosis, being a part of the flexible tube of the pump, is formed by a semi-cylindrical surface attached to a compression spring of adjustable pretension compressing the tube against a flat plate. Located at either side of the pump pincher, the shape of the stenosis changes in time, without any external power source, as a function of the fluid pressure and the pretension of the spring. The spring pretension is adjusted by a trial-and-error procedure aiming for net flow rate maximization for each pinching frequency. For the examined pitching frequencies (5 Hz to 11 Hz, for which net flow rate is maximized) and for compression ratios 38% to 75%, the maximum net flow rate was found to be 720% of the non-stenosis case. Important parameters for flow enhancement were found to be the stenosis location along the loop, its opening, the compression ratio at the pincher area and the pinching frequency.

Airway management during unusual tracheal stenosis: A clinical feasibility trial.

Prolonged intubation is a known risk factor of LTS. LTS related to COVID-19 may result in a different phenotype: pronation affects the location of stenosis and COVID-19 pneumonia can decline lung mechanics. Therefore, airway management in these patients may carry unique challenges for both anesthesiologists and surgeons.This prospective observational feasibility trial aims to evaluate the use of a novel thin, cuffed, endotracheal tube (Tritube) in combination with flow-controlled ventilation (FCV) in the management of patients with COVID-19-related LTS undergoing laryngeal surgery. 20 patients suffering from COVID-19-related LTS, as diagnosed by CT, requiring endolaryngeal surgery, with or without CO2 laser, were included. Ultrathin endotracheal tube Tritube, together with FCV was used for airway management and ventilation. Feasibility, ventilation efficiency, and surgical exposure were evaluated. Median duration of mechanical ventilation during their ICU stay was 17 days, (range, 7-27), and all patients had been pronated. In 18/20 patients, endoscopic diagnosis confirmed the initial CT diagnosis: posterior subglottic stenosis. Surgeons' satisfaction on the view was rated 9 out of 10 (range 7-10), where 0 was the worst view and 10 was the best view. Hemodynamic and respiratory variables were within the normal clinical range during the surgical procedure. One patient that had a SpO2 of 90% before induction of anesthesia, a temporal drop to 89%, caused meeting the predefined requirement of "respiratory complication." This study demonstrates the feasibility of using Tritube with FCV in patients with relatively unusual subglottic posterior location tracheal stenosis, undergoing laryngotracheal surgery. Tritube provides a good surgical field and FCV provides highly adequate ventilation especially in patients with compromised lung mechanics. IV, non-comparitive prospective clinical trial with 20 patients.

Lumbar Spinal Stenosis Analysis with Deep Learning Based Decision Support Systems

Lumbar spinal stenosis (LSS) is a condition that affects the quality of life of the 3 vertebrae, the disc and the canal in the lower back. In this region, the nerves in the canal may be subjected to pressure for various reasons, and disease occurs. Surgical intervention is required to treat canal stenosis, and the exact location and size of the spinal stenosis is critical to the surgery. The UNet model, which is an example of this network, can be further deepened with various deep learning networks. In this study, it will be the basis for creating a system that helps in the diagnosis of spinal stenosis by using a deeper network. The ResUNET model using ResNet as the backbone achieved an average IoU of 0.987. This study demonstrated that expert decision support systems using MR images can be used in the diagnosis of LSS.

Differentiation Between the Low and High Trans-Stenotic Pressure Gradient in Patients With Idiopathic Intracranial Hypertension Using 4D Flow MRI-Derived Hemodynamic Parameters.

Trans-stenotic pressure gradient (TPG) measurement is essential for idiopathic intracranial hypertension (IIH) patients with transverse sinus (TS) stenosis. Four-D flow MRI may provide a noninvasive imaging method for differentiation of IIH patients with different TPG. To investigate the associations between 4D flow parameters and TPG, and to evaluate the diagnostic performance of 4D flow parameters in differentiating patients with high TPG (GroupHP) from low TPG (GroupLP). Prospective. 31 IIH patients with TS stenosis (age, 38 ± 12 years; 23 females) and 5 healthy volunteers (age, 25 ± 1 years; 2 females). 3T, 3D phase contrast MR venography, and gradient recalled echo 4D flow sequences. Scan-rescan reproducibility of 4D flow parameters were performed. The correlation between TPG and flow parameters was analyzed. The netflow and velocity difference between inflow plane, outflow plane, and the stenosis plane were calculated and compared between GroupHP and GroupLP. Pearson's correlation or Spearman's rank correlation coefficient, Independent samples t-test or Wilcoxon rank-sum test, Intra-class correlation coefficient (ICC), Bland-Altman analyses, Receiver operating characteristic curves. A P value <0.05 was considered significant. Significant correlations were found between TPG and netflow parameters including Favg,out-s, Favg,in-s, Fmax,out-s, and Fmax,in-s (r = 0.525-0.565). Significant differences were found in Favg,out-s, Fmax,out-s, Favg,in-s, and Fmax,in-s between GroupHP and GroupLP. Using the cut-off value of 2.19 mL/sec, the Favg,out-s showed good estimate performance in distinguishing GroupHP from GroupLP (AUC = 0.856). The ICC (ranged 0.905-0.948) and Bland-Altman plots indicated good scan-rescan reproducibility. 4D flow MRI derived flow parameters showed good correlations with TPG in IIH patients with TS stenosis. Netflow difference between outflow and stenosis location at TS shows the good performance in differentiating GroupHP and GroupLP cases. 2 TECHNICAL EFFICACY: Stage 2.

Rehabilitation Outcome Measures in Patients with Spinal Stenosis: A Literary Review

Background: Lumbar spinal stenosis causes considerable disability in everyday life; its incidence is increasing due to aging in the world population. First-line treatment is generally conservative, but rehabilitation outcome is still unclear; the aim of this systematic review was to define which domains need to be evaluated for the lumbar stenosis physiotherapy approach, further specifying if the literature suggests patient-centred or objective measures. Methods: A systematic review of the literature according to the PRISMA statement was carried out; the PICO model was used to draw research questions. RCTs about the rehabilitation of lumbar spinal stenosis conducted in the last five years were considered includible, with no difference in terms of stenosis location. The following databases were screened through specific search strings: PubMed, EBSCO, PEDro, Cochrane Database, Scopus, and Google Scholar; two independent researchers assessed results and a third opinion was requested to solve conflicts. Critical appraisal of the included studies was conducted through Pedro Jadad scores. The following data were extracted: author and year, country, sample, intervention, outcome domains, and tools. Results: From 10,069 records, three RCTs were included in the final review stage; they all showed high methodological quality. It is recommended for physiotherapists dealing with lumbar spinal stenosis to assess five main domains: disability, pain, clinical tests, mental wellbeing and kynesiophobia, and quality of life. Domains were mainly assessed through self-reported questionnaires/scales, while objective tests evaluate general lower limb movements, the active range of motion, or the muscles’ endurance. Conclusion: This five-domain evaluation model is reliable and can be practised in each rehabilitation setting (home, outpatient, and hospital); sustainability is guaranteed by the prevalent employment of self-reported tools. Future studies should evaluate the best questionnaire/scale for each domain, especially the definition of a gold standard for pain assessment in patients with lumbar stenosis as this is a challenge for the future.

Degenerative lumbar spondylolisthesis: review of current classifications and proposal of a novel classification system

PurposeTo review existing classification systems for degenerative spondylolisthesis (DS), propose a novel classification designed to better address clinically relevant radiographic and clinical features of disease, and determine the inter- and intraobserver reliability of this new system for classifying DS.MethodsThe proposed classification system includes four components: 1) segmental dynamic instability, 2) location of spinal stenosis, 3) sagittal alignment, and 4) primary clinical presentation. To establish the reliability of this system, 12 observers graded 10 premarked test cases twice each. Kappa values were calculated to assess the inter- and intraobserver reliability for each of the four components separately.ResultsInterobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation was 0.94, 0.80, 0.87, and 1.00, respectively. Intraobserver reliability for dynamic instability, location of stenosis, sagittal alignment, and clinical presentation were 0.91, 0.88, 0.87, and 0.97, respectively.ConclusionThe UCSF DS classification system provides a novel framework for assessing DS based on radiographic and clinical parameters with established implications for surgical treatment. The almost perfect interobserver and intraobserver reliability observed for all components of this system demonstrates that it is simple and easy to use. In clinical practice, this classification may allow subclassification of similar patients into groups that may benefit from distinct treatment strategies, leading to the development of algorithms to help guide selection of an optimal surgical approach. Future work will focus on the clinical validation of this system, with the goal of providing for more evidence-based, standardized approaches to treatment and improved outcomes for patients with DS.

Applied coronary physiology for planning and guidance of percutaneous coronary interventions. A clinical consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the European Society of Cardiology.

The clinical value of fractional flow reserve and non-hyperaemic pressure ratios are well established in determining an indication for percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD). In addition, over the last 5 years we have witnessed a shift towards the use of physiology to enhance procedural planning, assess post-PCI functional results, and guide PCI optimisation. In this regard, clinical studies have reported compelling data supporting the use of longitudinal vessel analysis, obtained with pressure guidewire pullbacks, to better understand how obstructive CAD contributes to myocardial ischaemia, to establish the likelihood of functionally successful PCI, to identify the presence and location of residual flow-limiting stenoses and to predict long-term outcomes. The introduction of new functional coronary angiography tools, which merge angiographic information with fluid dynamic equations to deliver information equivalent to intracoronary pressure measurements, are now available and potentially also applicable to these endeavours. Furthermore, the ability of longitudinal vessel analysis to predict the functional results of stenting has played an integral role in the evolving field of simulated PCI. Nevertheless, it is important to have an awareness of the value and challenges of physiology-guided PCI in specific clinical and anatomical contexts. The main aim of this European Association of Percutaneous Cardiovascular Interventions clinical consensus statement is to offer up-to-date evidence and expert opinion on the use of applied coronary physiology for procedural PCI planning, disease pattern recognition and post-PCI optimisation.

Performance of deep learning-based autodetection of arterial stenosis on head and neck CT angiography: an independent external validation study.

To externally validate the performance of automated stenosis detection on head and neck CT angiography (CTA) and investigate the impact factors using an independent bi-center dataset with digital subtraction angiography (DSA) as the ground truth. Patients who underwent head and neck CTA and DSA between January 2019 and December 2021 were retrospectively included. The degree of stenosis was automatically evaluated using CerebralDoc based on CTA. The performance of CerebralDoc across levels (per-patient, per-region, per-vessel, and per-segment) and thresholds (≥ 50%, ≥ 70%, and = 100%) was evaluated. Logistic regression was performed to identify independent factors associated with false negative results. 296 patients were analyzed. Specificity across levels and thresholds was high, exceeding 92%. The area under the curve ranged from poor (0.615, 95% CI: 0.544, 0.686; at the region-based analysis for stenosis ≥ 70%) to excellent (0.945, 95% CI: 0.905, 0.985; at the patient-based analysis for stenosis ≥ 50%). Sensitivity ranged from 0.714 (95% CI: 0.675, 0.750) at the segment-based analysis for stenosis ≥ 70% to 0.895 (95% CI: 0.849, 0.919) at the patient-based analysis for stenosis ≥ 50%. The multiple logistic regression analysis revealed that false negative results were primarily more likely to specific stenosis locations (particularly the M2 segment and skull base segment of the internal carotid artery) and occlusion. CerebralDoc has the potential to automated stenosis detection on head and neck CTA, but further efforts are needed to optimize its performance.

Numerical investigation of the effect of carotid bifurcation stenosis degree on pulsatility characteristics.

Arterial bifurcations are regions that are susceptible to hemodynamic effects and thrombus formation. In the current study, the hemodynamic effects of a simplified 3D model of an arterial bifurcation were simulated using the commercial computational fluid dynamics software FLUENT. The non-Newtonian properties of blood were modeled using the Carreau model, and the pulsation dynamics and heat transfer characteristics of blood at different degrees of stenosis in the arterial bifurcation were analyzed. The results indicate that arterial stenosis caused by a thrombus when the pulsation velocity reaches its peak has an essential impact on blood transport. The stenosis of the bifurcation increases the peak pulsatile flow pressure drop, and each 0.5mm stenosis of the arterial bifurcation increases the mean wall shear stress of the bifurcated segment by approximately 0.25Pa. From the heat transfer perspective, arterial stenosis has little effect on the heat transfer coefficient. The heat transfer coefficient measured inside the bifurcation is much larger than that measured outside the bifurcation. The stenosis of the arterial bifurcation causes an increase in the mean velocity of the arterial cross-section, and the volume-averaged absolute vorticity is introduced to quantify the secondary flow effect during the pulsation cycle, where the arterial stenosis causes an increase in the mean absolute vorticity at pulsation velocity and accelerates the decay of the vorticity at uniform velocity. In this paper, the hemodynamics of carotid bifurcation pulsation is analyzed in conjunction with flow field properties to reveal the flow field dynamics factors and heat transfer characteristics of local stenosis of the carotid bifurcation and to conduct an exploratory study for the diagnosis and treatment of carotid bifurcation thrombosis.

Endoscopic balloon dilation of a stenosed artery stenting via cfd tool open-foam: Physiology of angioplasty and stent placement

The blood flow analysis inside an arterial segment of the left main coronary artery having stenosis is mathematically modeled. Numerical simulations are provided for the very first time for two considered cases that cover the thorough process of angioplasty and stent placement inside a coronary artery having symmetric stenosis. Firstly, the numerical simulations are disclosed for the section of a stenosed artery having a catheter placed inside it with a balloon plus stent over it. The second case covers the numerical simulations of blood flow inside the artery after a stent is placed that keeps the artery wide open and minimizes the effect of stenosis. Thus, the prime novelty of this work entertains the thorough mathematical modeling and FVM based numerical simulations for angioplasty of a coronary artery having a symmetric shape of stenosis. The current research work is modeled for the non-Newtonian Casson fluid to consider a more realistic approach of blood flow. This computational fluid dynamics (CFD) analysis is interpreted through the free source CFD C++ toolbox Open-FOAM. Numerical solutions are provided by using Open-FOAM that works on the principle of finite volume method. The detailed graphical results are disclosed for the process of angioplasty in addition to the simulation work obtained after completion of angioplasty and stent placement. The work provided is beneficial for surgical interpretations, detecting location of stenosis, place the balloon and stent at exact location via catheter, minimizing the effect of stenosis by placing a stent inside the artery, reducing the experimental cost by using simulations data. The catheter and balloon is removed after angioplasty, and the stent keeps the artery wide open to normalize the blood flow. Eventually, the coronary artery disease (CAD) is cured through this angioplasty and the risk of a heart attack is eliminated. A more developed and easily passing blood flow is revealed after the placement of stent.

Evaluation of left ventricular systolic function by tissue motion annular displacement of the mitral valve derived by speckle-tracking echocardiography in patients with coronary artery disease

ABSTRACT Objectives: Evaluation of the left ventricular systolic function using tissue motion annular displacement of mitral valve derived by speckle - tracking echocardiography and the correlation between mitral valve annular displacement and echocardiographic parameters for left ventricular systolic function in patients with coronary artery disease. Methods: Descriptive cross - sectional study on 106 patients with coronary artery disease and 106 controls, at Hue University of Medicine and Pharmacy Hospital, from 3/2019 - 10/2021. The study population meet all inclusion criteria according to research objectives. Mitral valve annular displacement derived by speckle - tracking echocardiography was acquired and analyzed offline with QLAB 13. Results: Median age was 66.09 ± 13.25 years and 66.7% was woman. Mitral valve annular displacement derived by speckle - tracking echocardiography in patients with coronary artery disease decreased statistically significant when comparing to control group (p &lt; 0.01). This index which was strongly correlated not only with left ventricular ejection fraction on 2D (r = 0.706) but also with peak mitral annular systolic velocity (S’ velocity) by tissue Doppler (r = 0.882). It was a favorable correlation with maximum mitral annular systolic displacement on M - mode (r = 0.419), but was not correlated with the location, degree, and number of coronary stenosis. Conclusions: Tissue motion annular displacement of the mitral valve derived by speckle - tracking echocardiography is a simple, rapid and endothelium - independent parameter that supports the left ventricular ejection fraction parameter in the evaluation of left ventricular systolic function when poor endocardial visualization.

Effects of Anastomotic Angles and Distances of the Bypass Graft to the Stenosis on Blood Flow Hydrodynamics in a Bypass Grafting Coronary Artery

It is believed that the proper distance between the grafting location and the stenosis location and the appropriate angle of graft or transplantation in the blocked artery of the heart are two important factors in the removal or decrease of reappearance and re-development of intimal hyperplasia (IH), blood clotting, and re-blockage of the surgical artery. In the present study, a 3-D geometry of the host coronary artery as non-elastic with 75% symmetric axial cross-sectional area reduction is considered. The main assumptions were incompressible, laminar, steady-state, Newtonian, and non-Newtonian (with Herschel Bulkley model) blood flow. The 3-D Navier-Stokes equations coupled with the non-Newtonian constitutive model were solved numerically using a finite volume method with the procedure of the SIMPLE program. Shear stress distribution was obtained on the areas of potential re-obstruction and the occurrence of IH such as the Toe, Heel, arterial bed, suture location, and graft artery walls. Based on the results, the distribution of wall shear stress near the Heel, Toe location, and the intersection of the host and graft arteries suddenly increased dramatically. Wall shear stress (WSS) distribution was obtained in the areas of hyperplasticity re-incidence for some important anastomosis angles of grafted arteries, i.e. α=35°,45°,65°,75°. In addition, the increase in the angle of the graft artery caused a sharp increase in the shear stress on the area after the graft and the arterial bed in front of the branching region, and the shear stress decreases in the pre-graft region. Therefore, the excessive angle of the graft artery can cause damage to the arterial endothelial cells in the surrounding suture region.

Location of Venous Infrainguinal Bypass Stenosis Is Associated with Reverse/nonreverse Orientation and Responds Differently to Endovascular vs Open Revision

Location of Venous Infrainguinal Bypass Stenosis Is Associated with Reverse/nonreverse Orientation and Responds Differently to Endovascular vs Open Revision

Multiphase Flow Hemodynamic Evaluation of Vertebral Artery Stenosis Lesions and Plaque Stability.

Atherosclerosis is one of the main causes of vertebral artery stenosis, which reduces blood supply to the posterior circulation, resulting in cerebral infarction or death. To investigate stenosis rates and locations on the development of vertebral artery plaques. Stenosis models with varying degrees and positions of stenosis were established. The stenosis area was comprehensively analyzed using multiphase flow numerical simulation. Wall shear stress (WSS), blood flow velocity, and red blood cell (RBC) volume fraction were calculated. Blood flow velocity in 30-70% stenosis of each segment tended to increase significantly higher than normal. Downstream of 50% stenosis exhibited turbulent flow; downstream of 70% displayed reflux. Severe stenosis increases the WSS and distribution area. The mixed area of high and low WSS appeared downstream of the stenosis. The RBC volume fraction at the stenosis increased (maximum value: 0.487 at 70% stenosis in the V4), which was 1.08 times the normal volume fraction. Turbulent and backflow regions exhibited complex RBC volume fraction distributions. Flow velocity, WSS, and RBC volume fraction at the stenosis increase with stenosis severity, increasing plaque shedding. Narrow downstream spoiler and reflux areas possess low WSS and high erythrocyte volume fractions, accelerating plaque growth.

Association of bone turnover biomarkers with severe intracranial and extracranial artery stenosis in type 2 diabetes mellitus patients

Intracranial and extracranial artery stenosis is associated with cerebral infarction. Vascular calcification and atherosclerosis are the main causes of stenosis and major risk factors for cardiovascular and cerebrovascular events in patients with type 2 diabetes mellitus (T2DM). Bone turnover biomarkers (BTMs) are associated with vascular calcification, atherosclerosis, glucose, and lipid metabolism. To investigate the association of circulating BTM levels with severe intracranial and extracranial artery stenosis in patients with T2DM. For this cross-sectional study including 257 T2DM patients, levels of the BTMs serum osteocalcin (OC), C-terminal cross-linked telopeptide of type I collagen (CTX), and procollagen type I N-peptide were measured by electrical chemiluminescent immunoassay, and artery stenosis was assessed by color Doppler and transcranial Doppler. Patients were grouped according to the existence and location (intracranial vs. extracranial) of artery stenosis. Correlations between BTM levels, previous stroke, stenosis location, and glucose and lipid metabolism were analyzed. T2DM patients with severe artery stenosis had a higher frequency of previous stroke and levels of all three tested BTMs (all P < 0.05) than patients without. Some differences in OC and CTX levels were observed according to the location of artery stenosis. Significant associations were also observed between BTM levels and some glucose and lipid homeostasis parameters. On multivariate logistic regression analysis, all BTMs were significant predictors of artery stenosis in T2DM patients with and without adjustment for confounding factors (all P < 0.001), and receiver operating characteristic curve analysis demonstrated the ability of BTM levels to predict artery stenosis in T2DM patients. BTM levels were found to be independent risk factors for severe intracranial and extracranial artery stenosis and were differentially associated with glucose and lipid metabolism in patients with T2DM. Therefore, BTMs may be promising biomarkers and potential therapeutic targets for artery stenosis.

Association between the degree of vertebrobasilar stenosis, location, infarction pattern, and QMRA flow state.

We aimed to investigate the relationship between the degree and location of vertebrobasilar stenosis and quantitative magnetic resonance angiography (QMRA) distal flow. We retrospectively reviewed patients who presented with acute ischemic stroke with ≥50% stenosis of the extracranial or intracranial vertebral or basilar arteries, and QMRA performed within 1year of stroke. Standardized techniques were used to measure stenosis and to dichotomize vertebrobasilar distal flow status. Patients were grouped based on the involved artery and the severity of disease. All p-values were calculated using chi-squared analysis and Fisher exact test with statistical significance defined as p<.05. Sixty-nine patients met study inclusion, consisting of 31 with low distal flow and 38 with normal distal flow. The presence of severe stenosis or occlusion was 100% sensitive, but only 47% predictive and 26% specific of a low distal flow state. Bilateral vertebral disease was only 55% sensitive but was 71% predictive and 82% specific of a low-flow state and was five times and nearly three times more likely to result in a low-flow state compared to unilateral vertebral disease (14%) and isolated basilar disease (28%), respectively. Severe stenosis of ≥70% may mark the minimal threshold required to cause hemodynamic insufficiency in the posterior circulation, but nearly half of these patients may remain hemodynamically sufficient. Bilateral vertebral stenosis resulted in a fivefold increase in QMRA low distal flow status compared to unilateral vertebral disease. These results may have implications in the design of future treatment trials of intracranial atherosclerotic disease.

Identification of coronary artery stenosis based on hybrid segmentation and feature fusion

Coronary artery disease has been the utmost mutual heart disease in the past decades. Various research is going on to prevent this disease. Obstructive CAD occurs when one or more of the coronary arteries which supply blood to myocardium are narrowed owing to plaque build-up on the arteries’ inner walls, causing stenosis. The fundamental task required for the interpretation of coronary angiography is identification and quantification of severity of stenosis within the coronary circulation. Medical experts use X-ray coronary angiography to identify blood vessel/artery stenosis. Due to the artefact, the image has less clarity and it will be challenging for the medical expert to find the stenosis in the coronary artery. The solution to the problem a computational framework is proposed to segment the artery and spot the location of stenosis in the artery. Here the author presented an automatic method to detect stenosis from the X-ray angiogram image. A unified Computational method of Jerman, Level-set, fine-tuning the artery structure, is developed to extract the segmented artery features and detect the artery’s stenosis. The current experimental outcomes illustrate that this computational method achieves average specificity, sensitivity, Accuracy, precision and F-scores of 95%, 97.5%, 98%, 97.5% and 97.5%, respectively.

Airway Management in Tracheal Resection and Anastomosis – Challenges and Novel Solutions!

Airway management in tracheal resection and anastomosis is very challenging. The technique of securing the airway depends on the degree and location of stenosis. Multidisciplinary planning and good communication are the keys to the successful management of these cases. The technique used to maintain the airway and ventilation may vary and needs to be chosen on a case-to-case basis.

Ultrasound and magnetic resonance of extrinsic stenosis and hypoplasia of internal jugular veins

Highlights. Ultrasound and MR venography of internal jugular veins in case of unilateral cerebellar hypoplasia or extrinsic stenosis enables noninvasively and without contrast agents differentiation of these conditions due to local and region-specific indicators, including the area and velocity of blood flow, arterial-venous balance, visualization of low blood flow, compression factor, and the overall clinical picture of venous network of the neck remodeling and the development of collateral circulation.Aim. To compare the visual and hemodynamic characteristics of ultrasound and magnetic resonance venography of extrinsic stenosis and hypoplasia of internal jugular veins (IJV).Methods. Ultrasound and magnetic resonance (MR) venography were performed in 47 patients with extrinsic stenosis and 23 patients with hypoplasia of one of internal jugular veins, and in the control group (30 patients).Results. In case of obvious vein compression and deformation and local stenosis (65% on average), there is a decrease in the vein cross-sectional area by 2 times compared with the contralateral vein, the blood flow velocity in the stenotic vein in acute cases increases (on average, up to 45 cm/s), and in chronic cases it significantly (p = 0.00001) decreases (to 13 cm/s on average). The criteria for hypoplasia are the small caliber of the vein (on average 0.22 cm², within the range of 0.13–0.46 cm²) throughout its entire length - with the cross-sectional area not exceeding that of the common carotid artery, and the vein being 4 times smaller than IJV on contralateral side, as well as a significant (p = 0.0006) velocity increase on the contralateral side (on average 40.9±12.52 cm/s) with normal velocity in the hypoplastic vein. Ultrasound assessment of the arterial-venous balance (AVB) makes it possible to evaluate the contribution of each IJV to the outflow of venous blood from the brain separately. From the hypoplastic side it was only 11.01±6.72%, and from the stenotic side it was 18.22±17 42% on average, which is significantly (p = 0.000001) below the norm, but does not allow us to differentiate these conditions. The total AVB for IJVs on both sides was within normal values (65–85%), and the absence of a pronounced expansion of the vertebral veins during MR venography confirms their insignificant role in the compensatory mechanisms of ensuring adequate outflow of venous blood from the brain in cases of unilateral hypoplasia and extrinsic stenosis of IJV.Conclusion. Ultrasound and MR venography of internal jugular veins in cases of unilateral hypoplasia or extrinsic stenosis enable noninvasively and without contrast agents differentiation of these conditions due to local and region-specific indicators, including the area and velocity of blood flow, arterial-venous balance, visualization of low blood flow, compression factor, and the overall clinical picture of venous network of the neck remodeling and the development of collateral circulation.