Color Doppler Ultrasound Measurements Research Articles

Sensitivity and Specificity of Color Doppler Ultrasound Measurement in the Evaluation of Renal Artery Stenosis

Renal artery stenosis typically results from plaque development. Mostly frequent cause of severe hypertension is RAS, which affects 1% to 5% of all patients with hypertension. Objective: To assess the sensitivity and specificity of Doppler ultrasound in RAS. Methods: Data from several search engines were retrieved for this literature view. Research was evaluated for both its quality and its usefulness. Data extraction from the whole journal articles was done. Results: Only 20 articles were used for extraction of data related to Sensitivity and Specificity of color Doppler ultrasound measurement in evaluation of RAS. The current study looked at the assessment of RAS. Conclusions: From assessing stenosis of renal artery diameter to analyzing the enhanced velocity field at the obstruction site, identifying new measures to describe plaque susceptibility in the renal artery has become more significant.

#4626 EFFECTS OF HEMODYNAMIC PARAMETERS OF THE BRACHIAL ARTERY ON AVF FLOW

Abstract Background and Aims Arteriovenous fistula (AVF) remains the preferred form of vascular access for hemodialysis, although dealing with the high rate of maturation failure. Many factors are found to be influencing the AVF outcome, however the diameter of the blood vessels, both arteries and veins, is recognized as the most important predictor. Aim of this study was to evaluate hemodynamic parameters of the brachial artery (Ab) on the change of volume flow (VF) during AVF maturation. Method This single-centre observational study included patients in whom AVF was created between September 2021 and December 2022. All patients underwent pre-operative physical and Color Doppler Ultrasound (CDU) measurements of the radial artery (Ar), brachial artery and cephalic vein (Vc). AVF maturation was evaluated by CDU consecutively 1, 14 and 28 days after AVF creation. As the hemodynamic parameters of the arteries, peak systolic volume (PSV), end-diastolic volume (EDV) and resistance index (RI) were measured. Results Study included 33 patients (81.8% male, mean age 64±10). VF was 346.55±126.86, 491.26±183.51, and 608.28±275.10 at day 1, 14 and 28, respectively (p = 0,000). Univariate regression analysis showed PSV (Beta = 0,456; p = 0,008) and EDV (Beta = 0,551; p = 0,001), both measured on Ab at day 1 post-AVF creation, are statistically significant predictors of flow change during 28 days of maturation. In the linear regression model EDV measured on Ab at day 1 post-AVF creation (Beta = 0,683; p = 0,003) and diameter of Ab (Beta = 0,441; p = 0,004) remained significant (Fig. 1 and 2). The vast majority of the study population undergone the first AVF puncture between 15-30th day post-creation (48.5%), while 12 (36.4%) and 5 (15.1%) experienced AVF puncture after more than 30 days and at the 14th day, respectively Conclusion Hemodynamic parametres of the brachial artery, precisely peak systolic volume and end-diastolic volume at the first day post-AVF creation, play a significant role in AVF maturation. CDU measurements of those hemodynamic parameters at day 1 may be useful for an early identification of AVF maturation outcomes.

Quantification of paravalvular leaks associated with TAVI implants using 4D MRI in an aortic root phantom made possible by the use of 3D printing.

Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical replacement of the aortic valve elderly patients. However, TAVI patients may suffer from paravalvular leaks (PVL). Detecting and grading is usually done by echocardiography, but is limited by resolution, 2D visualization and operator dependency. 4D flow magnetic resonance imaging (MRI) is a promising alternative, which did not reach clinical application in TAVI patients. The aim of this study was applying 3D printing technologies in order to evaluate flow patterns and hemodynamics of PVLs following TAVI, exploiting 4D flow MRI and standard ultrasound. An MR-compatible, anatomically left ventricle, aortic root, and ascending aorta model was fabricated by combining 3D-printed parts and various soft silicone materials to match physiological characteristics. An Abbott Portico™ valve was used in continuous antegrade flow (12-22 l/min), retrograde flow with varying transvalvular pressures (60-110 mmHg), and physiological pulsatile hemodynamics (aortic pressure: 120/80 mmHg, cardiac output: 5 l/min) Time-resolved MR measurements were performed above and below the TAVI stent and compared with color Doppler ultrasound measurements in exactly the same setup. The continuous antegrade flow measurements from MRI largely agreed with the flowmeter measurements, and a maximum error of only 7% was observed. In the retrograde configuration, visualization of the paravalvular leaks was possible from the MR measurements, but flow was overestimated by up to 33%. The 4D MRI measurement in the pulsatile setup revealed a single main PVL, which was also confirmed by the color Doppler measurements, and velocities were similar (2.0 m/s vs. 1.7 m/s). 4D MRI techniques were used to qualitatively assess flow in a patient-specific, MR-compatible and flexible model, which only became possible through the use of 3D printing techniques. Flow patterns in the ascending aorta, identification and quantification of PVLs was possible and the location and extent of PVLs were confirmed by ultrasound measurements. The 4D MRI flow technique allowed evaluation of flow patterns in the ascending aorta and the left ventricle below the TAVI stent with good results in identifying PVLs, demonstrating its capabilities over ultrasound by providing the ability to visualize the paravalvular jets in three dimensions at however, additional expenditure of time and money.

Application of contrast-enhanced ultrasound-assisted superficial inferior epigastric artery perforator flap to repair oral and maxillofacial defects

To investigate the application value of contrast-enhanced ultrasound (CEUS) technique to assist the repair of oral and maxillofacial defects by superficial inferior epigastric artery perforator flap. Sixteen oral cancer patients, 10 males and 6 females, who were to undergo superficial inferior epigastric artery perforator flap repair between June 2018 and February 2020, were selected, with an average age of 55.8 years (range, 24-77 years). There were 13 cases of squamous cell carcinoma, 2 cases of adenoid cystic carcinoma, and 1 case of mucinous epidermis-like carcinoma. The color Doppler ultrasound (CDUS) and CEUS were used to screen the superficial inferior epigastric artery, assisted in the design of the flap, and compared it with the actual intraoperative exploration. The sensitivity, specificity, positive predictive value, and negative predictive value of CEUS and CDUS examinations were analyzed. Fourteen of 16 patients were repaired with superficial inferior epigastric artery perforator flap, and 2 patients were repaired with superficial iliac artery flap because the source artery was not found. After surgery, regular follow-up was performed to check for disease recurrence and metastasis and to evaluate the appearance of the patien's donor area, the recovery of transoral feeding function, and the presence of complications. Comparison of preoperative CDUS and CEUS findings and intraoperative exploration showed that CEUS had 100% sensitivity, specificity, positive predictive value, and negative predictive value for vascular exploration of the superficial inferior epigastric artery perforator flap, compared with 57%, 100%, 100%, and 25% for CDUS. The preoperative CDUS identified 25 penetrating vessels in 14 cases repaired with superficial inferior epigastric artery flaps. All vessel signals were enhanced by CEUS enhancement, and an additional 11 penetrating vessels were identified confirmed intraoperatively. The preoperative CEUS measurements of the initial diameter of superficial arteries in the abdominal wall were significantly higher than both CDUS and intraoperative measurements ( P<0.05); the difference in peak systolic velocity between CEUS and CDUS measurements was significant ( t=3.708, P=0.003). One case of superficial epigastric artery perforator flap developed venous embolism crisis at 48 hours after operation, the wound healing delayed. The other incisions in donor sites healed by first intention. All the patients were followed up 3-12 months, with an average of 8 months. No recurrence or metastasis appeared during the follow-up. There was no serious complications such as abdominal wall hernia, the location of abdominal scarring was hidden, and transoral feeding was resumed. The superficial inferior epigastric artery perforator flap with small injury in supply area and hidden scar location is a better choice for repairing oral and maxillofacial defects. The use of CEUS technique to assist the preoperative design of the superficial inferior epigastric artery perforator flap has good feasibility and high accuracy.

Comparison of Color Doppler Ultrasound and Ankle-Brachial Pressure Index Measurement in Peripheral Vascular Diseases

Peripheral vascular diseases (PVD) are a group of common degenerative (organic) and vasospastic (functional) disease processes that result in significant morbidity and are strong predictors of subsequent mortality. It is diagnosed by definitive history of intermittent claudication or if one or more of peripheral pulses are absent in one or both lower limbs. A variety of non-invasive techniques, viz., ankle-brachial pressure index (ABPI) test and color Doppler imaging, are available to diagnose the presence of PVD as well as to localize areas of stenosis, assess severity of disease, and follow patients for disease progression or response to therapy. Therefore, the focus of this study is to compare color Doppler ultrasound and ABPI individually and in combination in diagnosing cases of peripheral vascular diseases, considering CT angiography the gold standard investigation. Patients were assessed on the basis of history; clinical examination and relevant investigations done were noted in the data sheet according to the proforma including the Edinburgh Claudication Questionnaire. Comparison of color Doppler ultrasound and ankle-brachial pressure index measurement in peripheral vascular diseases was determined using relevant statistical tests. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for comparison of ABPI and color Doppler imaging with CT angiography. Color Doppler ultrasound proved to be a better modality as compared to the ankle-brachial pressure index for diagnosis of peripheral vascular disease, considering CT angiography the gold standard investigation.

Thermography and colour Doppler ultrasound: a potential complementary diagnostic tool in evaluation of rheumatoid arthritis in the knee region.

The aim and objectives of this study were as follows: (i) to perform automated segmentation of knee thermal image using the regional isotherm-based segmentation (RIBS) algorithm and segmentation of ultrasound image using the image J software; (ii) to implement the RIBS algorithm using computer-aided diagnostic (CAD) tools for classification of rheumatoid arthritis (RA) patients and normal subjects based on feature extraction values; and (iii) to correlate the extracted thermal imaging features and colour Doppler ultrasound (CDUS) features in the knee region with the biochemical parameters in RA patients. Thermal image analysis based on skin temperature measurement and thermal image segmentation was performed using the RIBS algorithm in the knee region of RA patients and controls. There was an increase in the average skin temperature of 5.94% observed in RA patients compared to normal. CDUS parameters such as perfusion, effusion and colour fraction for the RA patients were found to be 1.2 ± 0.5, 1.8 ± 0.2 and 0.052 ± 0.002, respectively. CDUS measurements were performed and analysed using the image J software. Biochemical parameters such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) showed significant positive correlation with the thermal imaging parameters. The CDUS parameters such as effusion, perfusion and colour fraction correlated significantly with the clinical and functional assessment score. According to the results of this study, both infrared (IR) thermal imaging and CDUS offer better diagnostic potential in detecting early-stage RA. Therefore, the developed CAD model using thermal imaging could be used as a pre-screening tool to diagnose RA in the knee region.

Dynamic, patient-specific mitral valve modelling for planning transcatheter repairs.

Transcatheter, beating heart repair techniques for mitral valve regurgitation is a very active area of development. However, it is difficult to both simulate and predict the clinical outcomes of mitral repairs, owing to the complexity of mitral valve geometry and the influence of hemodynamics. We aim to produce a workflow for manufacturing dynamic patient-specific models to simulate the mitral valve for transcatheter repair applications. In this paper, we present technology and associated workflow, for using transesophageal echocardiography to generate dynamic physical replicas of patient valves. We validate our workflow using six patient datasets representing patients with unique or particularly challenging pathologies as selected by a cardiologist. The dynamic component of the models and their resultant potential as procedure planning tools is due to a dynamic pulse duplicator that permits the evaluation of the valve models experiencing realistic hemodynamics. Early results indicate the workflow has excellent anatomical accuracy and the ability to replicate regurgitation pathologies, as shown by colour Doppler ultrasound and anatomical measurements comparing patients and models. Analysis of all measurements successfully resulted in t critical two-tail > t stat and p values > 0.05, thus demonstrating no statistical difference between the patients and models, owing to high fidelity morphological replication. Due to the combination of a dynamic environment and patient-specific modelling, this workflow demonstrates a promising technology for simulating the complete morphology of mitral valves undergoing transcatheter repairs.

Does the measurement of the difference of resistive indexes in spleen and kidney might be used for characterization of intrarenal tardus parvus phenomenon in chronic kidney disease?

Doppler sonography is used as a routine test for detection of renal artery stenosis (RAS). Although increased peak systolic velocity at the site of the narrowing is a widely accepted method for assessing main renal artery stenosis, tardus parvus phenomenon detected on the downstream blood flow has been used as an alternative to direct insonation of the main artery. However, the uncertainty about the best Doppler parameter to be used for characterization of tardus parvus has yielded a variety of studies. Recently, the difference between the resistive index of the spleen and kidney (RISK) has been proposed as a potential marker of kidney damage and Doppler criterion for RAS in hypertensive patients without chronic kidney disease (CKD). The hypothesis of this study was to speculate further and propose the RISK as valuable new Doppler diagnostic criteria for the tardus parvus in CKD too. Data from 183 control patients and 135 chronic kidney disease patients (CKD) were included in the study to test the feasibility of the method and plausibility of the hypothesis. Criteria inclusion was a color Doppler ultrasound measurement of the renal (RRI) and spleen resistive index (SRI). Serum creatinine (0.83 ± 0.20 vs 3.27 ± 1.74), RRI (0.60 ± 0.06 vs 0.69 ± 0.09), SRI (0.55 ± 0.06 vs 0.58 ± 0.09), RISK (0.06 ± 0.04 vs 0.11 ± 0.08), and spleen size (94.1 ± 13.2 vs 100.8 ± 16.5) were higher in CKD patients (p < 0.05). RRI correlated with SRI in both groups; however, the coefficient of determination was different (Z = 2.29, p = 0.022). In the CKD group, RISK correlated inversely with age (r = −0.276; p = 0.001) and positively with creatinine (r = 0.509; p < 0.001). In the multivariate analysis, creatinine remained an independent predictor of the high RISK (Wald = 13.07; p < 0.001; odds ratio = 1.87; 95% confidence interval 1.33–2.62). Since extraneous factors similarly influence RRI and SRI, the SRI can be considered the correction factor that can estimate the cardiovascular burden on the RRI. Consequently, according to the suggested hypothesis, RISK helps to distinguish the tardus parvus related to RAS from tardus parvus related to systemic influences on Doppler morphology. The identification of the underlying mechanisms of tardus parvus, would help a more accurate characterization of the phenomenon and improve screening and diagnostic test for RAS in CKD patients.

The effect of downstream resistance on flow diverter treatment of a cerebral aneurysm at a bifurcation: A joint computational-experimental study

Intracranial aneurysm can lead to hemorrhagic stroke upon rupture. Deployment of flow diverters can restrict the blood flow into aneurysm and mitigate the rupture risk. Computational fluid dynamics (CFD) and ultrasonography with pulse-wave and color Doppler ultrasound measurements were employed jointly to investigate the complex flow pattern in cerebral aneurysms, both before and after the deployment of flow diverters. Patient-specific configurations of both bifurcation and side-wall aneurysms were selected. The effect of downstream flow resistance was investigated by adjusting the volume flow rate and pressure at the outlet vessels computationally and experimentally. Velocity profiles in the aneurysm measured from ultrasonography showed good agreement with those from computer simulations. The discrepancy in velocity between the computational and experimental sets of data is less than 10%. The downstream resistance can alter the volume flux into a bifurcation aneurysm with a flow diverter deployed by 236%, while the corresponding value of a side-wall aneurysm is negligible. The vorticity of the aneurysmal flow was reduced by more than 80% in both cases after stenting. This study demonstrated that careful investigation of downstream flow resistance of a bifurcation aneurysm is essential to provide an accurate assessment of the aneurysmal flow dynamics after flow diverter deployment.

Administration routes affect thrombolytic effect of catheter-directed thrombolysis with pro-urokinase in treating deep vein thrombosis.

Deep venous thrombosis (DVT) is a common disorder with a significant mortality rate. Catheter-directed thrombolysis (CDT) is a preferred treatment for DVT patients. The aim of this study is to evaluate the thrombolytic effect of CDT with pro-urokinase (pro-UK) in different administration routes. An inferior vena cava (IVC) model was induced in 36 New Zealand white rabbits by catheter injury and placement of IVC filter. The animals were divided into 6 groups with 6 rabbits in each group: group A: systemic thrombolysis with intravenous injection; group B: CDT with pump infusion; group C: CDT with pulse injection; group D: CDT with combination of pump infusion and pulse injection; group E: catheter-directed aspiration thrombectomy; group F: mechanical thrombectomy. The thrombolytic effects were evaluated by color Doppler ultrasound and blood measurement of D-dimer and fibrinogen. The minimum effective concentration of pro-UK solution was identified. Two groups (group A and B) did not achieve successful thrombolysis. Among all catheter-directed administration groups, the rabbit groups that received pro-UK therapy through catheter-directed thrombolytic pump infusion combined with pulse injection (group D) showed the best thrombolysis effect. In contrast, catheter-directed aspiration thrombectomy (group E) is effective but not safe. CDT with combination of pump infusion and pulse injection of pro-UK safely and significantly improves thrombolysis procedure in rabbits, suggesting potential benefits from the use of CDT in proximal DVT.

Carotid Atherosclerotic Plaque Features in Patients with Acute Ischemic Stroke.

To investigate the carotid atherosclerotic plaque features in patients with acute ischemic stroke. A total of 288 patients meeting the included criteria were enrolled and divided into an ulcerated plaque group (n= 139) and a nonulcerated plaque group (n=149). Patients in the ulcerated plaque group were further subdivided into <50% and ≥50% stenosis groups. Carotid plaque component characteristics including luminal stenosis, carotid plaque volume, hypoechoic plaque volume, and hyperechoic plaque volume were analyzed by color Doppler ultrasound measurement. Associations between ulcerated plaque and carotid plaque features were also evaluated. The relationships among the levels of MMP-9, hs-CRP, and carotid stenosis rate were detected by enzyme-linked immunosorbent assay. The plaque volume, hypoechoic plaque volume, and luminal stenosis in the ulcerated plaque group were higher than that of the nonulcerated plaque group (P<0.05). Ulcerated plaque was positively associated with luminal stenosis, plaque volume, and hypoechoic plaque volume after adjusting for sex and age. The result remained similar after adjusting for age, sex, and carotid luminal stenosis. The levels of MMP-9 and hs-CRP in the ulcerated plaque group were significantly higher than those of the nonulcerated plaque group (P < 0.01). For the ulcerated plaque group, the higher the carotid stenosis rate, the higher the level of MMP-9 and hs-CRP. Higher carotid atherosclerosis plaque volume, hypoechoic plaque volume, and luminal carotid stenosis may be symptoms of ulcerated plaque. Increased MMP-9 and hs-CRP levels could be used as adjunctive therapies of carotid stenosis at the molecular level.

Color Doppler ultrasound characteristics after subinguinal microscopic varicocelectomy.

The present study evaluated the effect of differences in the peak systolic velocity (PSV) and resistive index (RI) inthe testicular artery (TA), capsular artery (CA), and intratesticular artery (ITA) after microscopic subinguinal varicocelectomy(MSV) on postoperative pain and semen parameters. Scrotal color Doppler ultrasound (CDUS) measurementswere made in 33 patients (age 18-31 years) prior to MSV and 3 and 6 months after MSV. Pain was recorded using avisual analog scale and sperm concentration was determined to analyze the predictive value of the CDUS parameters regardingsurgical outcome. A significant decrease in pain scores was observed in most patients at both follow-ups. The firstpostoperative CDUS revealed a significant increase in the TA-PSV (p<0.001) and a decrease in the TA-RI (p=0.002) and CARI(p=0.006). The second postoperative CDUS also revealed a significant increase in the TA-PSV and a decrease in the TA-RI,and the PSV in the ITA and CA and RI in the ITA and CA were significantly different from the values obtained pre-operativelyand at the first follow-up. A negative correlation was found between the pain level and TA-PSV (r=-0.433, p=0.012), whereassperm concentration positively correlated with both the TA-PSV and CA-PSV (r=0.534, p=0.001 and r=0.455, p=0.008, respectively). The PSV and RI are useful parameters for detecting changes in testicular microhemodynamics afterMSV. In addition, the TA-PSV and CA-PSV can be used to predict improvements in pain and sperm concentration.

Color Doppler Ultrasound Evaluation of Ureteral Jet Angle to Detect Vesicoureteral Reflux in Children

Vesicoureteral reflux is the most common urinary tract abnormality in children. Although voiding cystourethrography is the gold standard for diagnosing reflux, this approach is invasive. We evaluated color Doppler ultrasound measurement of ureteral jet angle as a noninvasive screening tool for detecting reflux. We retrospectively evaluated 125 children (250 renal units) who presented with urinary tract infections or hydronephrosis. All patients underwent color Doppler ultrasonography and voiding cystourethrography. Ureteral jet angle was measured as angle between the direction of the ureteral jet and interureteral ridge. Reflux was diagnosed in 80 patients (117 renal units). Mean ± SD ureteral jet angle was significantly greater in refluxing units (67.9 ± 18.7 degrees) than in nonrefluxing units (47.8 ± 17.3 degrees, p <0.0001). Angle value in each reflux grade became significantly greater according to grade (p <0.0001). Overall ability of ureteral jet angle to detect grade III to V and grade IV/V reflux, as given by the area under the receiver operating characteristic curve, was 0.81 and 0.88, respectively. A cutoff angle of 55 degrees or greater detected grade III to V and grade IV/V reflux with a sensitivity of 85.5% and 94.7%, respectively. A cutoff angle of 70 degrees or greater diagnosed grade IV/V reflux with a sensitivity of 81.6% and a specificity of 82.7%. Color Doppler ultrasound measurement of ureteral jet angle represents a simple and noninvasive method that is applicable as a screening tool to detect high grade vesicoureteral reflux in children.

Comparison of colour Doppler ultrasound and ankle-brachial pressure index measurements in peripheral vascular disease in type 2 diabetic patients with foot infection

Background: Peripheral vascular disease is diagnosed by definitive history of intermittent claudication or if one or more of peripheral pulses are absent in one or both lower limbs. Diagnostic testing for peripheral vascular disease must be accurate, inexpensive, widely accessible, easy to perform and preferably non-invasive. A variety of non-invasive techniques are available to detect the presence of peripheral vascular disease as well as to localize areas of stenosis, assess severity of disease and follow patients for disease progression or response to therapy. In this study we compare the specificity and sensitivity of ankle brachial pressure index with colour Doppler ultrasound for diagnosis of peripheral vascular disease in type 2 diabetes. Methods: This prospective study was carried out in the department of General surgery, GMCH, Udaipur, Rajasthan, India, from September 2014 to February 2016 after taking the permission from institutional ethical committee. A total of 50 patients were selected. The selected patients were evaluated by detailed clinical history, physical examination, local examination, ankle brachial pressure index (ABPI), colour doppler study and other relevant investigations. The ABPI ratio was calculated in every patient and an ABPI less than 0.9 in either foot was defined to have PVD. Colour duplex ultrasound was done in all selected patients. Imaging of peripheral arteries of the lower limbs was done using high resolution colour duplex ultrasound. PVD was diagnosed if the stenosis in the artery was greater than 50% or presence of occlusion. Results: Total 50 patients having type 2 diabetes mellitus with foot infection were included and most of the patients were between 40-60 years of age (68%) with males preponderance. In our study 12 (24%) patients had normal ABPI of 1.0 to 1.29 and 22 (44%) patients were in the range of mild to moderate PVD with ABPI between 0.41 to 0.90. Colour doppler was used as a standard diagnostic test for PVD & out of 50 patients, 36 (72%) showed involvement of arteries and among them both anterior and posterior tibial arteries were involved in 12 (24%) patients. In our study colour doppler ultrasound was used as standard diagnostic method for PVD. The sensitivity, specificity, positive predictive value and negative predictive value of ABPI against colour duplex ultrasound were calculated. Conclusions: In our study it’s concluded that ABPI is a good initial screening tool for peripheral vascular disease, but some patients with significant stenosis or in whom collaterals have developed in lower extremity would be missed, if ABPI measurement alone is used for diagnosis of peripheral vascular disease.

Carotid intima-media thickness and uric acid level and the research of the prognosis of patients with coronary heart disease

Objective To explore the carotid intima-media thickness and the value of uric acid in predicting the prognosis of coronary heart disease patients. Methods Using the random number table method,182 patients diagnosed with coronary heart disease were divided into two groups: group A was 92 cases of acute coronary syndrome (ACS),groups B was 90 cases of chronic stable angina,healthy check-up 90 cases as control group(group C), fasting blood test blood uric acid(UA),application of color Doppler ultrasound measurement carotid intima-media thick ness(IMT). Results Acute coronary syndrome(ACS)set of uric acid,IMT,plaque index were(428.5±70.3) mmol/L,(1.58±0.92)mm,(3.24±1.81)and those in stable angina group were(356.4±68.2)mmol/L,(1.32±0.86)mm,(3.08±1.62)and those of the control group were(251.2±65.4)mmol/L,(0.92±0.41)mm, (2.80±1.18)to compare the difference was statistically significant(group A compared with group B(t= 4.47,3.26,5.21,all P<0.05),group A compared with group C(t=8.23,9.36,7.48,all P<0.01);group SAP compared with control group the difference was statistically significant(t=6.34,5.26,7.12,all P<0.05);Linear correlation analysis showed that uric acid and carotid intima-media thickness were positively correlated,r value was 0.67.The ACS group soft carotid atherosclerosis plaque detection rate was 60.9%,SAP group was 26.7%and the control group was 8.9%, the difference was statistically significant(χ2=21.60,P<0.05;χ2= 69.11,P<0.01),group SAP compared with the control group,the difference was statistically significant(χ2= 39.84,P<0.01). Conclusion Uric acid levels and carotid artery atherosclerosis and coronary artery disease are closely related, which can provide theoretical basis for the risk assessment and prognosis of coronary heart disease. Early intervention can prevent the occurrence of serious cardiovascular events. Key words: Coronary heart disease; Carotid intima-media thickness; Uric acid

Comparative study of healthy vertebral artery blood flow from plain and plateau region

Objective To conduct comparative study of healthy vertebral artery (VA) blood flow of subjects from plain and plateau region using color Doppler ultrasound (CDUS) measurement,and to investigate the influence of plateau on blood flow of VA.Methods One hundred and thirty-five subjects from plain region and eighty from high altitude region were recruited.Time averaged maximum velocity and inradium (D) of VA were measured with CDUS technology.Unilateral VA blood flow and total blood flow were calculated.Peripheral blood viscosity measurement was carried out by testing low cut,mid cut,high cut,plasma viscosity and red blood cell count (RBC),hemoglobin concentration (HGB),hematocrit (HCT).Results VA diameter,blood viscosity,RBC,HGB,and HCT of plateau group are all higher than that of the plain group (P＜0.05),while the total blood flow was lower than that of plain group and the value of male was higher than that of female (P＜0.05).The inradiums of right side VA were larger than that of the left side (P＜0.05) in plain group,while no difference was observed in plateau group (P＞0.05).Conclusions Long term (＞10 years) living in plateau hypoxia (altitude＞3 000 m) environment can reduce the average flow velocity and the blood flow of VA. Key words: Color Doppler ultrasound; Plain; Plateau; Vertebral artery; Blood flow

Role of endometrial and subendometrial blood flow index assessment in predicting pregnancy outcome of freezing embryo transfer cycles

Objective To evaluate the role of transvaginal color Doppler ultrasound measurements of endometrial thickness,endometrium and subendometrial blood distribution patterns and flow index in predicting endometrial receptivity and pregnancy outcome of freezing embryo transfer(FET).Methods 468 cycles FET were analysed retrospectively.Endometrial thickness,endometrium and subendometrial blood distribution patterns,pulsatility index (PI),resistance index (RI),systolic /diastolic ratio (S/D) of endometrial and subendometrial blood flows with transvaginal ultrasonography were measured on the day of progesterone initiation.Based on the clinical pregnancy or not,patients were divided into two groups.The comparison of these indicators were carried out between pregnant group and non pregnant group.Results The endometrium and subendometrial blood distribution patterns had statistical difference between the two groups(P ＜0.05),the clinical pregnancy rate of Ⅰ,Ⅱ,Ⅲ blood distribution patterns were 31.0％,62.5％,79.0％ respectively.In the pregnancy group,the S/D,PI,and RI of endometrium were significantly lower than those in the nonpregnant group (P ＜ 0.05),and there was no significant difference between the pregnant group and nonpregnant group in endometrial thickness(P ＞0.05).Conclusions Endometrium and subendometrial blood distribution patterns and flow index measured with transvaginal color Doppler ultrasound could assess endometrial receptivity and guide the time selecting of FET transplantation. Key words: Ultrasonography, Doppler, color; Endometrium; Hemodynamics; Embryo transfer; Pregnancy outcome

Hemodynamic Effects of Spiral ePTFE Prosthesis Compared with Standard Arteriovenous Graft in a Carotid to Jugular Vein Porcine Model

The primary patency rate of arteriovenous (AV) grafts is limited by distal venous anastomosis stenosis or occlusion due to intimal hyperplasia associated with distal graft turbulence. The normal blood flow in native arteries is spiral laminar flow. Standard vascular grafts do not produce spiral laminar flow at the distal anastomosis. Vascular grafts which induce a spiral laminar flow distally result in lower turbulence, particularly near the vessel wall. This initial study compares the hemodynamic effects of a spiral flow-inducing graft and a standard graft in a new AV carotid to jugular vein crossover graft porcine model. Four spiral flow grafts and 4 control grafts were implanted from the carotid artery to the contralateral jugular vein in 4 pigs. Two animals were terminated after 48 hours and 2 at 14 days. Graft patency was assessed by selective catheter digital angiography, and the flow pattern was assessed by intraoperative flow probe and color Doppler ultrasound (CDU) measurements. The spiral grafts were also assessed at enhanced flow rates using an external roller pump to simulate increased flow rates that may occur during dialysis using a standard dialysis needle cannulation. The method increased the flow rate through the graft by 660 ml/min. The graft distal anastomotic appearances were evaluated by explant histopathology. All grafts were patent at explantation with no complications. All anastomoses were found to be wide open and showed no significant angiographic stenosis at the distal anastomosis in both spiral and control grafts. CDU examinations showed a spiral flow pattern in the spiral graft and double helix pattern in the control graft. No gross histopathological effects were seen in either spiral or control grafts. This porcine model is robust and allows hemodynamic flow assessment up to 14 days postimplantation. The spiral flow-inducing grafts produced and maintained spiral flow at baseline and enhanced flow rates during dialysis needle cannulation, whereas control grafts did not produce spiral flow through the distal anastomosis. There was no deleterious effect of the spiral flow-inducing graft on macroscopic and histological examination. The reducing effect of spiral flow on intima hyperplasia formation will be the subject of further study using the same AV graft model at a longer period of implantation.

Direct numerical simulation of transitional flow in a stenosed carotid bifurcation

The blood flow dynamics of a stenosed, subject-specific, carotid bifurcation were numerically simulated using the spectral element method. Pulsatile inlet conditions were based on in vivo color Doppler ultrasound measurements of blood velocity. The results demonstrated the transitional or weakly turbulent state of the blood flow, which featured rapid velocity and pressure fluctuations in the post-stenotic region of the internal carotid artery (ICA) during systole and laminar flow during diastole. High-frequency vortex shedding was greatest downstream of the stenosis during the deceleration phase of systole. Velocity fluctuations had a frequency within the audible range of 100–300 Hz. Instantaneous wall shear stress (WSS) within the stenosis was relatively high during systole (∼25–45 Pa) compared to that in a healthy carotid. In addition, high spatial gradients of WSS were present due to flow separation on the inner wall. Oscillatory flow reversal and low pressure were observed distal to the stenosis in the ICA. This study predicts the complex flow field, the turbulence levels and the distribution of the biomechanical stresses present in vivo within a stenosed carotid artery.

Changes of testicular blood flow after vasectomy: Assessment by color Doppler ultrasound resistive index measurement

Objective: The objectives of this study were to evaluate the testicular blood flow in patients after vasectomy by use of color Doppler ultrasound resistive index measurement.