X-ray studies in the diagnosis of pyloroduodenal ulcerative stenoses

Combined clinical and x-ray investigation of 100 patients operated on for pyloroduodenal ulcerative stenoses was conducted. Methods of polypositional and polyprojectional x-ray investigation including a double contrast study and a differentiated use of cholinolytic and cholinomimetic drugs were standardized. The x-ray classification of stenosis was improved on the basis of radiological and surgical correlations and quantitative analysis of indices characterizing a degree of stenosis compensation. Criteria for the determination of a degree of stenosis were worked out.     

Uncertainty quantification in cerebral circulation simulations focusing on the collateral flow: Surrogate model approach with machine learning

Collateral circulation in the circle of Willis (CoW), closely associated with disease mechanisms and treatment outcomes, can be effectively investigated using one-dimensional–zero-dimensional hemodynamic simulations. As the entire cardiovascular system is considered in the simulation, it captures the systemic effects of local arterial changes, thus reproducing collateral circulation that reflects biological phenomena. The simulation facilitates rapid assessment of clinically relevant hemodynamic quantities under patient-specific conditions by incorporating clinical data. During patient-specific simulations, the impact of clinical data uncertainty on the simulated quantities should be quantified to obtain reliable results. However, as uncertainty quantification (UQ) is time-consuming and computationally expensive, its implementation in time-sensitive clinical applications is considered impractical. Therefore, we constructed a surrogate model based on machine learning using simulation data. The model accurately predicts the flow rate and pressure in the CoW in a few milliseconds. This reduced computation time enables the UQ execution with 100 000 predictions in a few minutes on a single CPU core and in less than a minute on a GPU. We performed UQ to predict the risk of cerebral hyperperfusion (CH), a life-threatening condition that can occur after carotid artery stenosis surgery if collateral circulation fails to function appropriately. We predicted the statistics of the postoperative flow rate increase in the CoW, which is a measure of CH, considering the uncertainties of arterial diameters, stenosis parameters, and flow rates measured using the patients’ clinical data. A sensitivity analysis was performed to clarify the impact of each uncertain parameter on the flow rate increase. Results indicated that CH occurred when two conditions were satisfied simultaneously: severe stenosis and when arteries of small diameter serve as the collateral pathway to the cerebral artery on the stenosis side. These findings elucidate the biological aspects of cerebral circulation in terms of the relationship between collateral flow and CH.     

SUPRAVALVULAR PULMONARY STENOSIS IN LEVO TRANSPOSITION AND "SINGLE" VENTRICLE

A case of supravalvular and valvular pulmonary stenosis in an L-transposition of the great arteries and "single" or double inlet left ventricle is described. Supravalvular pulmonary stenosis has not heretofore been reported in transposition of the great arteries. The clinical, hemodynamic and angiographic features are described. Surgical correction has many problems.     

Assessment of boundary conditions for CFD simulation in human carotid artery

Computational fluid dynamics (CFD) is an increasingly used method for investigation of hemodynamic parameters and their alterations under pathological conditions, which are important indicators for diagnosis of cardiovascular disease. In hemodynamic simulation models, the employment of appropriate boundary conditions (BCs) determines the computational accuracy of the CFD simulation in comparison with pressure and velocity measurements. In this study, we have first assessed the influence of inlet boundary conditions on hemodynamic CFD simulations. We selected two typical patients suspected of carotid artery disease, with mild stenosis and severe stenosis. Both patients underwent digital subtraction angiography (DSA), magnetic resonance angiography, and the invasive pressure guide wire measured pressure profile. We have performed computational experiments to (1) study the hemodynamic simulation outcomes of distributions of wall shear stress, pressure, pressure gradient and (2) determine the differences in hemodynamic performances caused by inlet BCs derived from DSA and Womersley analytical solution. Our study has found that the difference is related to the severity of the stenosis; the greater the stenosis, the more the difference ensues. Further, in our study, the two typical subjects with invasively measured pressure profile and thirty subjects with ultrasound Doppler velocimeter (UDV) measurement served as the criteria to evaluate the hemodynamic outcomes of wall shear stress, pressure, pressure gradient and velocity due to different outlet BCs based on the Windkessel model, structured-tree model, and fully developed flow model. According to the pressure profiles, the fully developed model appeared to have more fluctuations compared with the other two models. The Windkessel model had more singularities before convergence. The three outlet BCs models also showed good correlation with the UDV measurement, while the Windkessel model appeared to be slightly better (\( R^{2} = 0.942 \)). The structured-tree model was seen to have the best performance in terms of available computational cost and accuracy. The results of our numerical simulation and the good correlation with the computed pressure and velocity with their measurements have highlighted the effectiveness of CFD simulation in patient-specific human carotid artery with suspected stenosis.     

Increased Inlet Blood Flow Velocity Predicts Low Wall Shear Stress in the Cephalic Arch of Patients with Brachiocephalic Fistula Access

BackgroundAn autogenous arteriovenous fistula is the optimal vascular access for hemodialysis. In the case of brachiocephalic fistula, cephalic arch stenosis commonly develops leading to access failure. We have hypothesized that a contribution to fistula failure is low wall shear stress resulting from post-fistula creation hemodynamic changes that occur in the cephalic arch.MethodsTwenty-two subjects with advanced renal failure had brachiocephalic fistulae placed. The following procedures were performed at mapping (pre-operative) and at fistula maturation (8–32 weeks post-operative): venogram, Doppler to measure venous blood flow velocity, and whole blood viscosity. Geometric and computational modeling was performed to determine wall shear stress and other geometric parameters. The relationship between hemodynamic parameters and clinical findings was examined using univariate analysis and linear regression.ResultsThe percent low wall shear stress was linearly related to the increase in blood flow velocity (p < 0.01). This relationship was more significant in non-diabetic patients (p < 0.01) than diabetic patients. The change in global measures of arch curvature and asymmetry also evolve with time to maturation (p < 0.05).ConclusionsThe curvature and hemodynamic changes during fistula maturation increase the percentage of low wall shear stress regions within the cephalic arch. Low wall shear stress may contribute to subsequent neointimal hyperplasia and resultant cephalic arch stenosis. If this hypothesis remains tenable with further studies, ways of protecting the arch through control of blood flow velocity may need to be developed.     

Congenital Aortic Stenosis: Some Observations on the Natural History and Clinical Assessment

Three hundred patients, 30 years of age or under, with the clinical diagnosis of aortic stenosis were reviewed to provide information on the accuracy of clinical assessment and the natural history of the condition when left untreated. Sudden death was uncommon and occurred only in patients with clinical evidence of severe obstruction. In infants, the early presentation and lethal nature of aortic stenosis appeared to result from the presence of additional cardiac lesions. Correlation of clinical assessment with hemodynamic data in 83 patients indicated that important stenosis was present if the systolic murmur was accompanied by a thrill and associated with an increased left ventricular impulse, decreased brachial artery pulse pressure, or left ventricular hypertrophy on the electrocardiogram. The site of obstruction could not be established with certainty by clinical examination, but an early systolic ejection click was strong evidence against subvalvular stenosis.     

Influence of hemodynamic conditions on fractional flow reserve: parametric analysis of underlying model

Pressure-based fractional flow reserve (FFR) is used clinically to evaluate the functional severity of a coronary stenosis, by predicting relative maximal coronary flow (Q(s)/Q(n)). It is considered to be independent of hemodynamic conditions, which seems unlikely because stenosis resistance is flow dependent. Using a resistive model of an epicardial stenosis (0-80% diameter reduction) in series with the coronary microcirculation at maximal vasodilation, we evaluated FFR for changes in coronary microvascular resistance (R(cor) = 0.2-0.6 mmHg. ml(-1). min), aortic pressure (P(a) = 70-130 mmHg), and coronary outflow pressure (P(b) = 0-15 mmHg). For a given stenosis, FFR increased with decreasing P(a) or increasing R(cor). The sensitivity of FFR to these hemodynamic changes was highest for stenoses of intermediate severity. For P(b) > 0, FFR progressively exceeded Q(s)/Q(n) with increasing stenosis severity unless P(b) was included in the calculation of FFR. Although the P(b)-corrected FFR equaled Q(s)/Q(n) for a given stenosis, both parameters remained equally dependent on hemodynamic conditions, through their direct relationship to both stenosis and coronary resistance.     

Computational simulation of flow-induced arterial remodeling of the pancreaticoduodenal arcade associated with celiac artery stenosis

Arterial remodeling of the pancreaticoduodenal arcade, which enables collateral flow to the liver, spleen, and stomach, is a well-recognized clinical sign of celiac artery (CA) stenosis. However, the hemodynamic changes due to remodeling are poorly understood, despite their importance in surgical procedures such as pancreaticoduodenectomy. In this study, a framework to simulate remodeling of the arterial network following pathological flow alterations was developed and applied to investigate the hemodynamic characteristics of patients with CA stenosis. A one-dimensional–zero-dimensional cardiovascular model was used for blood flow simulation. After introducing CA stenosis into the normal network, arterial remodeling was simulated by iteratively changing the diameter of each artery until time-averaged wall shear stress reached its value under normal conditions. A representative case was simulated to validate the present framework, followed by simulation cases to investigate the impact of stenosis severity on remodeling outcome. A markedly dilated arcade was observed whose diameter agreed well with the corresponding values measured in subjects with CA stenosis, confirming the ability of the framework to predict arterial remodeling. A series of simulations clarified how the geometry and hemodynamics after remodeling change with stenosis severity. In particular, the arterial remodeling and resulting blood flow redistribution were found to maintain adequate organ blood supply regardless of stenosis severity. Furthermore, it was suggested that flow conditions in patients with CA stenosis could be estimated from geometric factors, namely, stenosis severity and arcade diameter, which can be preoperatively and non-invasively measured using diagnostic medical images.     

Percutaneous balloon mitral valvuloplasty in patients with severe mitral stenosis and low transmitral diastolic pressure gradient

An elevated left atrial pressure and high diastolic pressure gradient (DPG) across the mitral valve are the major hemodynamic abnormalities in mitral stenosis (MS). However, a subgroup of patients with severe MS is characterized by low initial DPG. The authors reviewed the clinical, echocardiographic and hemodynamic data as well as procedural results in 180 patients who underwent percutaneous balloon mitral valvuloplasty (PBMV). An initial mean DPG > 10 mmHg was found in 144 patients (80%) (group A) and mean DPG < or = 10 mmHg in 36 patients (20%) (group B). Patients in group A had higher left ventricular ejection fraction (LVEF) than in group B (61 +/- 5% versus 42 +/- 6%, respectively) and higher cardiac index (2.8 +/- 0.4 versus 2.0 +/- 0.3 l/min/m(2) ). In group B 12 patients (33%) had normal LVEF, whereas 24/36 (67%) had reduced LVEF. All the latter had wall motion abnormalities on ventriculography. Unlike group A, intraprocedural echocardiography was essential for monitoring and evaluating immediate results of PBMV in group B. On follow-up of three years, 75% of group A patients and 55% in group B were in functional class I (p < 0.05). PBMV did not significantly improve symptoms in patients in group B who had preprocedure LVEF < or = 35%.     

Problems in distinguishing tuberculosis of bowel from Crohn's disease in Asians.

The cases of five immigrants with definite or almost certain intestinal tuberculosis are described. Because of the clinical, pathological, and radiological features all were thought as some time, often for long periods, to have Crohn''s disease. Recommendations are made for medical and surgical treatment.     

Non-Invasive Determination of Left Ventricular Workload in Patients with Aortic Stenosis Using Magnetic Resonance Imaging and Doppler Echocardiography

Early detection and accurate estimation of aortic stenosis (AS) severity are the most important predictors of successful long-term outcomes in patients. Current clinical parameters used for evaluation of the AS severity have several limitations including flow dependency. Estimation of AS severity is specifically challenging in patients with low-flow and low transvalvular pressure gradient conditions. A proper diagnosis in these patients needs a comprehensive evaluation of the left ventricle (LV) hemodynamic loads. This study has two objectives: (1) developing a lumped-parameter model to describe the ventricular-valvular-arterial interaction and to estimate the LV stroke work (SW); (2) introducing and validating a new index, the normalized stroke work (N-SW), to assess the global hemodynamic load imposed on the LV. N-SW represents the global hemodynamic load that the LV faces for each unit volume of blood ejected. The model uses a limited number of parameters which all can be measured non-invasively using current clinical imaging modalities. The model was first validated by comparing its calculated flow waveforms with the ones measured using Cardiovascular Magnetic Resonance (CMR) in 49 patients and 8 controls. A very good correlation and concordance were found throughout the cycle (median root mean square: 12.21 mL/s) and between the peak values (r = 0.98; SEE = 0.001, p<0.001). The model was then used to determine SW using the parameters measured with transthoracic Doppler-echocardiography (TTE) and CMR. N-SW showed very good correlations with a previously-validated index of global hemodynamic load, the valvular arterial impedance (), using data from both imaging modalities (TTE: r = 0.82, SEE = 0.01, p<0.001; CMR: r = 0.74, SEE = 0.01, p<0.001). Furthermore, unlike , N-SW was almost independent from variations in the flow rate. This study suggests that considering N-SW may provide incremental diagnostic and prognostic information, beyond what standard indices of stenosis severity and provide, particularly in patients with low LV outflow.     

Fluid–structure interaction (FSI) simulation for studying the impact of atherosclerosis on hemodynamics,arterial tissue remodeling,and initiation risk of intracranial aneurysms

The biomechanical and hemodynamic effects of atherosclerosis on the initiation of intracranial aneurysms (IA) are not yet clearly discovered. Also, studies for the observation of hemodynamic variation due to atherosclerotic stenosis and its impact on arterial remodeling and aneurysm genesis remain a controversial field of vascular engineering. The majority of studies performed are relevant to computational fluid dynamic (CFD) simulations. CFD studies are limited in consideration of blood and arterial tissue interactions. In this work, the interaction of the blood and vessel tissue because of atherosclerotic occlusions is studied by developing a fluid and structure interaction (FSI) analysis for the first time. The FSI presents a semi-realistic simulation environment to observe how the blood and vessels' structural interactions can increase the accuracy of the biomechanical study results. In the first step, many different intracranial vessels are modeled for an investigation of the biomechanical and hemodynamic effects of atherosclerosis in arterial tissue remodeling. Three physiological conditions of an intact artery, the artery with intracranial atherosclerosis (ICAS), and an atherosclerotic aneurysm (ACA) are employed in the models with required assumptions. Finally, the obtained outputs are studied with comparative and statistical analyses according to the intact model in a normal physiological condition. The results show that existing occlusions in the cross-sectional area of the arteries play a determinative role in changing the hemodynamic behavior of the arterial segments. The undesirable variations in blood velocity and pressure throughout the vessels increase the risk of arterial tissue remodeling and aneurysm formation.

     

Sequential venous anastomosis design to enhance patency of arterio-venous grafts for hemodialysis

Arterio-venous grafts (AVGs), the second best option as long-term vascular access for hemodialysis, face major issues of stenosis mainly due to development of intimal hyperplasia at the venous anastomosis which is linked to unfavorable hemodynamic conditions. We have investigated computationally the utility of a coupled sequential venous anastomotic design to replace conventional end-to-side (ETS) venous anastomosis, in order to improve the hemodynamic environment and consequently enhance the patency of AVGs. Two complete vascular access models with the conventional and the proposed venous anastomosis configurations were constructed. Three-dimensional, pulsatile blood flow through the models was simulated, and wall shear stress (WSS)-based hemodynamic parameters were calculated and compared between the two models. Simulation results demonstrated that the proposed anastomotic design provides: (i) a more uniform and smooth flow at the ETS anastomosis, without flow impingement and stagnation point on the artery bed and vortex formation in the heel region of the ETS anastomosis; (ii) more uniform distribution of WSS and substantially lower WSS gradients on the venous wall; and (iii) a spare route for the blood flow to the vein, to avoid re-operation in case of stenosis. The distinctive hemodynamic advantages observed in the proposed anastomotic design can enhance the patency of AVGs.     

The XXXXY Chromosome Anomaly: Report of Three New Cases and Review of 30 Cases from the Literature

The majority of abnormal sex chromosome complexes in the male have been considered to be variants of Klinefelter''s syndrome but an exception should probably be made in the case of the XXXXY individual who has distinctive phenotypic features. Clinical, radiological and cytological data on three new cases of XXXXY syndrome are presented and 30 cases from the literature are reviewed. In many cases the published clinical and radiological data were supplemented and re-evaluated. Mental retardation, usually severe, was present in all cases. Typical facies was observed in many; clinodactyly of the fifth finger was seen in nearly all.Radiological examination revealed abnormalities in the elbows and wrists in all the 19 personally evaluated cases, and other skeletal anomalies were very frequent. Cryptorchism is very common and absence of Leydig''s cells may differentiate the XXXXY chromosome anomaly from polysomic variants of Klinefelter''s syndrome. The relationship of this syndrome to Klinefelter''s syndrome and to Down''s syndrome is discussed.     

螺旋CT头颈部血管成像对急性脑梗死患者颈动脉狭窄的诊断价值

目的:探讨螺旋CT头颈部血管成像对急性脑梗死患者颈动脉狭窄的诊断价值。方法:选取2014年1月至2016年1月期间来我院就诊的60例急性脑梗死患者作为观察组,另选同期来我院就诊的非急性脑梗死患者60例作为对照组。两组患者均进行螺旋CT头颈部血管成像检查,比较两组患者的颈动脉狭窄程度及各段血管斑块分布情况,并根据检查结果评价螺旋CT头颈部血管成像对急性脑梗死患者颈动脉狭窄的诊断价值。结果:观察组轻度狭窄与中度狭窄检出率均显著高于对照组(P0.05),重度狭窄与闭塞检出率与对照组比较无统计学差异(P0.05),观察组总检出狭窄率高于对照组(P0.05)。观察组与对照组在颈动脉分叉处、颈总动脉、颈内动脉及颈外动脉均有斑块检出,观察组斑块总检出率为69.4%,显著高于对照组的41.2%(P0.05)。结论:临床上应用128层螺旋CT头颈部血管成像技术对急性脑梗死患者颈动脉狭窄情况可进行有效评估,该方法对患者轻、中度狭窄以及双侧颈动脉斑块检出率更高,在临床诊断及预后防治中具有应用推广价值。     

Ventriculo-atrial gradient due to first degree atrio-ventricular block: a case report

Background

Isolated, asymptomatic first degree AV block with narrow QRS has not prognostic significance and is not usually treated with pacemaker implantation. In some cases, yet, loss of AV synchrony because of a marked prolongation of the PR interval may cause important hemodynamic alterations, with subsequent symptoms of heart failure. Indeed, AV synchrony is crucial when atrial systole, the "atrial kick", contributes in a major way to left ventricular filling, as in case of reduced left ventricular compliance because of aging or concomitant structural heart disease.

Case presentation

We performed a trans-septal left atrium catheterization aimed at evaluating the entity of a mitral valve stenosis in a 72-year-old woman with a marked first-degree AV block, a known moderate aortic stenosis and NYHA class III symptoms of functional deterioration. We occurred in a deep alteration in cardiac hemodynamics consisting in an end-diastolic ventriculo-atrial gradient without any evidence of mitral stenosis. The patient had a substantial improvement in echocardiographic parameters and in her symptoms of heart failure after permanent pacemaker implantation with physiological AV delay.

Conclusion

We conclude that if a marked first degree AV block is associated to instrumental signs or symptoms of heart failure, the restoration of an optimal AV synchrony, achieved with dual-chamber pacing, may represent a reasonable therapeutic option leading to a consequent clinical improvement.     

Correlation between clinical findings and magnetic resonance imaging for the assessment of local response after standard treatment in cervical cancer

Background

The aim of our study is to evaluate the correlation between gynecological examination and magnetic resonance (MRI) findings for the assessment of local response in cervical cancer patients treated with radiotherapy/chemotherapy (RT/ChT).

Patients and methods

This study is a retrospective review of 75 consecutive cervical cancer patients from April 2004 to November 2009 treated with RT/ChT. Clinical and radiological data were subsequently analyzed. Patient''s median age was 51 with a FIGO stage from Ib to IVb. Individualized RT/ChT was administered with a median dose of 45 Gy. Sixty-three patients received a complementary brachytherapy. Seventy-one patients received chemotherapy on a weekly basis. Gynecological exam was performed 3 months and 6 months after treatment and these findings were compared to MRI results at the same time.

Statistic analysis

We used the Spearman''s Rho test to determine the correlation level between the clinical and radiological methods.

Results

A correlation of 0.68 (60%) was observed between the clinical and MRI findings at 3 months with a further increase of up to 0.86 (82.6%) at 6 months. In the few cases with a poor correlation, the subsequent assessment and the natural history of the disease showed a greater value of the clinical exam as compared with the MRI findings.

Conclusions

Physical exam remains an essential tool to evaluate the local response to RT/ChT for cervical cancer. The optimal clinical radiological correlation found at 6 months after treatment suggests that the combination of gynecological examination and MRI are probably adequate in patient monitoring.     

Coflex固定加椎板开窗减压在腰椎管狭窄症的疗效观察

目的:观察Coflex固定加椎板开窗减压在腰椎管狭窄症的疗效。方法:选择2009年8月至2012年8月在我院治疗,经CT诊断为腰椎椎管狭窄的患者82例,随机分为观察组和对照组,每组各41例。观察组行Conflex固定加椎板开窗减压治疗,对照组行常规手术治疗。观察和比较两者患者1年后的健康情况、术后满意程度、VAS评分及Barthel指数。结果:观察组术后满意度90.2%,对照组为65.9%,与对照组比较,观察组满意度更高,差异有统计学意义(X2=16.8,P0.001);两组患者健康情况的比较:观察组优良率(82.9%)较对照组(56.1%)高,两组健康情况相互比较差异有统计学意义(X2=17.1,P0.001);观察组随访VAS评分2.34±1.02,对照组VAS评分4.31±1.33,两组VAS评分比较差异均有统计学意义(t=7.43,P0.0 01);观察组Barthel指数(92.3±5.1)优于对照组(81.2±4.2),差异有统计学意义(t=5.31,P0.0 01)。结论:Conflex固定加椎板开窗减压对腰椎管狭窄症的疗效确切,不良反应少,值得在临床上推广。     

Prediction of peak pressure from clinical and radiological measurements in patients with diabetes

Background

Various structural and functional factors of foot function have been associated with high local plantar pressures. The therapist focuses on these features which are thought to be responsible for plantar ulceration in patients with diabetes. Risk assessment of the diabetic foot would be made easier if locally elevated plantar pressure could be indicated with a minimum set of clinical measures.

Methods

Ninety three patients were evaluated through vascular, orthopaedic, neurological and radiological assessment. A pressure platform was used to quantify the barefoot peak pressure for six forefoot regions: big toe (BT) and metatarsals one (MT-1) to five (MT-5). Stepwise regression modelling was performed to determine which set of the clinical and radiological measures explained most variability in local barefoot plantar peak pressure in each of the six forefoot regions. Comprehensive models were computed with independent variables from the clinical and radiological measurements. The difference between the actual plantar pressure and the predicted value was examined through Bland-Altman analysis.

Results

Forefoot pressures were significant higher in patients with neuropathy, compared to patients without neuropathy for the whole forefoot, the MT-1 region and the MT-5 region (respectively 138 kPa, 173 kPa and 88 kPa higher: mean difference). The clinical models explained up to 39 percent of the variance in local peak pressures. Callus formation and toe deformity were identified as relevant clinical predictors for all forefoot regions. Regression models with radiological variables explained about 26 percent of the variance in local peak pressures. For most regions the combination of clinical and radiological variables resulted in a higher explained variance. The Bland and Altman analysis showed a major discrepancy between the predicted and the actual peak pressure values.

Conclusion

At best, clinical and radiological measurements could only explain about 34 percent of the variance in local barefoot peak pressure in this population of diabetic patients. The prediction models constructed with linear regression are not useful in clinical practice because of considerable underestimation of high plantar pressure values. Identification of elevated plantar pressure without equipment for quantification of plantar pressure is inadequate. The use of quantitative plantar pressure measurement for diabetic foot screening is therefore advocated.     

Pulsatile flow through a constricted tube: effect of stenosis morphology on hemodynamic parameters

In this paper, we investigate pulsatile flow through a constricted tube with the aim of assessing the effect of stenosis morphology on hemodynamic parameters. The fluid-solid interaction of pulsatile flow through a compliant tube with elastic walls was simulated using an arbitrary Lagrangian-Eulerian (ALE) finite-element method. We consider blood flow through various mild stenoses of 25.8% severity in diameter with trapezoidal and bell-like morphologies at a fixed Womersley number of 7.75. The results show that the distribution of the time-averaged wall shear stress (TAWSS), which is the main factor affecting the hemodynamic parameters, strongly depends on the axial stretch of the stenosis; elongation of the stenotic region increases by 41.1% the maximum TAWSS for stenoses of trapezoidal morphology whereas the maximum TAWSS decreases by 14.8% for the corresponding stenoses of bell-like morphology. The present findings indicate that risk factors due to atherosclerosis may vary in a complicated manner as an atheromatous plaque gradually builds up and morphs with time.