Duplex carotid sonography. Peak systolic velocity in quantifying internal carotid artery stenosis

Duplex ultrasonography combining high-resolution imaging and Doppler spectrum analysis was performed in 92 consecutive patients (total, 180 vessels) and compared with the findings of conventional arteriography. All duplex studies were categorized into four groups based upon the maximum internal carotid artery (ICA) velocity: group 1: less than 125 cm/sec; group 2: 125 to 224 cm/sec; group 3: greater than 225 cm/sec; and group 4: no flow. Sensitivities and specificities were highest when peak ICA velocity was used as one of several criteria in quantifying the degree of ICA stenosis. These additional criteria were: (1) the presence of extensive sonographically visible plaque within the ICA; (2) an abnormal spectral waveform with elevated diastolic velocity (greater than 100 cm/sec); (3) resistive pattern ("externalization") of the common carotid artery (CCA) waveform; and (4) the ratio of the right CCA peak velocity to the left of less than 0.7 or greater than 1.3. The overall accuracy for the combined groups using all criteria was 94%.     

Duplex Doppler sonography of transplant renal artery stenosis

PURPOSE: The aim of this study was to evaluate the accuracy of duplex Doppler sonography in diagnosing transplant renal artery stenosis (TRAS) and to determine which parameter is the most reliable for making that diagnosis. METHODS: Over a 3-year period, we sonographically evaluated patients who were referred for investigation of possible TRAS. We investigated the following parameters: peak systolic velocity (PSV) in the external iliac and renal arteries, acceleration time and acceleration in the intrarenal arteries, acceleration time in the renal artery, resistance index, and the ratio of the PSVs in the renal and external iliac arteries. We also used MR angiography and digital subtraction arteriography to verify the degree of stenosis. After the evaluations, the patients were classified into 2 groups, 1 with and the other without significant stenosis (> 50% narrowing of the lumen) on digital subtraction arteriography. We also included a control group of patients who had undergone renal transplantation at least 6 months before, had had a good course after transplantation, had a diastolic blood pressure of 90 mm Hg or less, and were taking a maximum of 1 antihypertensive drug. RESULTS: Our study population consisted of 22 patients suspected to have TRAS (10 without and 12 with confirmed significant stenosis) and 19 control patients. We found statistically significant differences between the mean values of these 3 groups except for the PSV in the iliac artery and the resistance index in the intrarenal arteries. The most accurate parameters to use in diagnosing TRAS were an acceleration time of 0.1 second or higher in the renal and intrarenal arteries, a PSV of greater than 200 cm/second in the renal artery, and a ratio of PSVs in the renal and external iliac arteries of greater than 1.8. CONCLUSIONS: Duplex Doppler sonography is an excellent method for screening patients suspected to have TRAS and can help select which of those patients should undergo digital subtraction arteriography.     

Evaluation of renal artery stenosis with velocity parameters of Doppler sonography.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of velocity parameters for the diagnosis of renal artery stenosis (RAS) with color Doppler sonography and to determine the optimal threshold values for these parameters. METHODS: The study group was composed of 187 renal arteries, which were examined by color Doppler sonography and angiography. Four Doppler parameters, including the peak systolic velocities (PSVs) in the renal and interlobar arteries, the renal-aortic ratio, and the renal-interlobar ratio (RIR), were measured. Receiver operating characteristic curve analysis was performed to determine the optimal parameter. The sensitivity, specificity, and negative and positive predictive values at various threshold values were calculated. RESULTS: Doppler sonographic examination was technically successful in 96% of renal arteries (180/187). The RIR was determined to be the best parameter. With threshold values of RIR greater than 5, PSV greater than 150 cm/s in the renal artery, renal-aortic ratio greater than 2, and PSV less than 25 cm/s in the interlobar artery, the sensitivity values were 88%, 81%, 70%, and 74%, respectively. An RIR greater than 5 and PSV less than 15 cm/s in the interlobar artery provided the optimal combination of parameters, with sensitivity and specificity of 91% and 87%, respectively. CONCLUSIONS: The RIR is the best velocity parameter in the detection of RAS (> or =50%), and its best cutoff is 5. Valuing influencing factors of PSV in the renal artery will help reduce misdiagnosis. The combination of RIR greater than 5 and PSV less than 15 cm/s in the interlobar artery provides the best diagnostic efficiency of RAS.     

Spectral analysis of Doppler velocity patterns in normals and patients with carotid artery stenosis

Summary. A computerized pattern recognition program was utilized to assess the predictive ability of various parameters obtained from the spectra of ultrasonic pulsed Doppler signals from the carotid arteries. The most accurate features selected by linear regression analysis were the natural log (In) of the ratio of the mean velocity in the internal carotid artery compared to that in the common carotid artery, and the In of the maximum velocity, the In of the maximum frequency, and the square of the fractional broadening term, all of which were measured at peak systole in the internal carotid artery. Using the combination of the velocity ratio and the fractional broadening term, the average difference in the estimated percentage stenosis, as compared to that obtained by arteriography, was 12-8%.     

Diagnosing carotid stenosis by Doppler sonography: state of the art.

OBJECTIVE: The goal of this review article is to present the state of the art in the clinical applications and technical performance and interpretation of carotid sonographic examinations. METHODS: Relevant publications regarding color and duplex Doppler sonography (CDDS) of the carotid arteries extracted from a computerized database (MEDLINE) and from references cited in these articles not appearing on the Internet were reviewed. RESULTS: The ability to quickly and efficiently identify stenosis in the carotid artery is an important goal for clinicians and vascular surgeons. Identification of potentially treatable carotid stenosis enables selection of appropriate candidates for endarterectomy or stent implantation. Advances in performance and interpretation of carotid sonographic studies over the last 20 years have been driven by technological improvements in gray scale and CDDS examinations and have made carotid sonography an important means to reach this goal. On the basis of CDDS, intima-media thickness measurements and plaque location and characterization on gray scale imaging, flow disturbance and areas of stenosis on color Doppler sonography, and flow velocities on spectral Doppler sonography are obtained. The degree of the diameter of a stenosis of the internal carotid artery is the main parameter used for therapeutic approaches. Advantages and limitations of the method are included. CONCLUSIONS: Carotid sonography is a unique imaging method for the investigation of carotid abnormalities. Noninvasive, accurate, and cost-effective, it provides morphologic and functional information. It is increasingly becoming the first and often the sole imaging study before endarterectomy, whereas costly and invasive procedures are reserved for special cases.     

Evaluation of severe transplant renal artery stenosis with Doppler sonography

PURPOSE: To evaluate and determine Doppler criteria for predicting a severe transplant renal artery stenosis (80%-99% diameter reduction) and to compare the Doppler findings in patients with end-to-end and end-to-side anastomosis. METHODS: We performed Doppler sonography on 16 consecutive patients with transplant renal artery stenosis (TRAS) confirmed by digital subtraction arteriography (DSA). Fourteen patients had end-to-end anastomosis, and 2 had end-to-side anastomosis. Eleven patients were re-evaluated with color Doppler sonography within 4 days after intervention. Seven Doppler parameters, including the peak systolic velocity (PSV) in the renal, iliac and interlobar artery, Pre-PSV ratio (the ratio of the PSV in the renal artery to that in the iliac artery), Post-PSV ratio (the ratio of the PSV in the renal artery to that in the interlobar arteries, acceleration time and resistance index, were measured. In the patients with severe TRAS the measurements of these parameters were compared before and after successful intervention. RESULTS: In the 16 patients with a single transplanted kidney, arteriography demonstrated 14 main renal arteries with severe stenosis, and 3 renal arteries with moderate stenosis. When using the cutoff values of Post-PSV ratio >13, renal artery PSV >4 m/sec, acceleration time >0.06 second, and resistance index <0.5 for the detection of all 14 severe stenoses, the sensitivities were 100%, 71%, 93%, and 50%, respectively. For assessing all 14 severe stenoses and 12 severe stenoses of end-to-end anastomosis, the cutoff value of Pre-PSV ratio >5 had sensitivities of 86% and 100%, respectively. Pre-PSV ratios in severe stenoses of end-to-end anastomosis (range, 5.1-11.5) were significantly greater than those recorded in severe stenoses of end-to-side anastomosis (range, 2.8-3.1). Statistically significant differences before and after successful intervention were found for all 7 Doppler parameters in the 7 patients with severe stenosis. CONCLUSIONS: An 80%-99% diameter reduction of the renal artery can be diagnosed based on a Post-PSV ratio >13 for patients with either end-to-end or end-to-side anastomosis. A Pre-PSV ratio >5 for patients with end-to-end anastomosis and acceleration time >0.06 second are helpful in the diagnosis of severe TRAS.     

Color-coded Doppler sonography in the diagnosis of carotid artery diseases

Color-flow Doppler is a new development of duplex sonography of the peripheral vessels. In this study 844 consecutive patients were evaluated (a) to assess the comparative value of these two methods, (b) to see if there is a correlation between the degree of stenosis and the incidence of neurological symptoms and (c) to find a possible relationship between the plaque structure and the incidence of neurological deficits. (a) In 89%, the color-flow assessment was in complete agreement with the duplex assessment. In the remaining 11%, important additional results were discovered in the color flow examination. (b) Non-stenotic plaques were seen more often (43%) in the wide carotic bulb, stenotic plaques and occlusion were found more often (66 and 82%) in the internal carotic artery. Vessel occlusion was found most often in patients with cerebral ischemia. Color-flow Doppler demonstrated a higher incidence of hemodynamic stenosis in patients with peripheral vascular disease, hypertension and bruits. (c) Patients with heterogeneous plaques demonstrated a significantly higher risk of neurological deficits than those with homogeneous plaques. The great advantage of color-flow Doppler is that it enables sonomorphological (plaques, stenoses, occlusion) and functional parameters (turbulences, flow enhancement) to be studied during the same procedure.     

Duplex Doppler sonography of celiac trunk and superior mesenteric artery: comparison with intra-arterial angiography

DDS was compared to intra-arterial angiography for the diagnosis of significant (> 50%) stenoses of the celiac trunk and the SMA in 38 consecutive patients referred for angiographic evaluation of peripheral arterial occlusive disease. Celiac trunk occlusion was correctly identified by DDS in three of three patients. In patients with significant celiac trunk stenoses, mean peak systolic velocity was 246 (+/- 154) cm/sec and differed significantly (P < 0.05) from the peak systolic velocity (101 +/- 22 cm/sec) of 22 patients with no angiographic evidence of significant stenosis. Five false-negative DDS examinations in patients with > 50% celiac trunk stenoses were noted. Using a peak systolic velocity of > 160 cm/sec (mean value in normal vessels plus 3 standard deviations) to diagnose > 50% celiac trunk stenosis, sensitivity of DDS was 57% and specificity was 100%. However, considering celiac trunk stenoses and occlusions as a single group, the sensitivity rate of DDS in diagnosing significant stenosis and occlusion of celiac trunk was 70%.     

Three-dimensional power Doppler sonography in screening for carotid artery disease

PURPOSE: Color Doppler sonography has gained considerable recognition as a noninvasive method to detect carotid artery disease and to assess the degree of carotid artery stenosis. However, results are highly operator-dependent and cannot be presented as survey images. The purpose of this study was to evaluate real-time 3-dimensional (3D) power Doppler sonography as a method for screening for atherosclerosis in the carotid arteries. METHODS: We prospectively screened 75 patients for carotid artery disease using both conventional color Doppler sonography and 3D power Doppler sonography, and the results from the 2 modalities were compared. A total of 150 common carotid arteries, 150 internal carotid arteries, and 150 external carotid arteries were examined utilizing a 7.5-MHz linear-array transducer combined with tissue harmonic imaging. RESULTS: Color Doppler sonography detected 297 normal or atherosclerotic arteries without stenosis, 57 arteries with mild (1-49%) stenosis, 41 with moderate (50-69%) stenosis, 32 with severe (70-99%) stenosis, and 9 with occlusions. The degree of stenosis determined by color Doppler sonography correlated with that determined by 3D power Doppler sonography (r = 0.982-0.998). Moreover, there was a good correlation between the measurements for both the length of the lesion and its distance from the bulb as determined by the 3D volume surveys and by color Doppler sonography (r = 0.986). The interobserver variability rate was 3.7% +/- 0.5%. Generally, the acquisition and reconstruction of the 3D data took less than 5 minutes. CONCLUSIONS: 3D power Doppler sonography is easy to perform and is an accurate method in screening for atherosclerotic lesions of the carotid arteries. Moreover, it provides excellent 3D volume surveys that may be helpful in the planning of surgical treatment.     

直接超声参数在肾动脉狭窄诊断中的应用研究

目的 探讨内径狭窄≥50%肾动脉狭窄（RAS）的直接超声参数特点及其诊断价值.方法 经彩色多普勒血流成像（CDFI）检查后并接受肾动脉造影的89例患者共177条肾动脉构成研究组,测量了肾动脉峰值流速（RPSV）、肾动脉与腹主动脉峰值流速比值（RAR）、肾动脉与肾动脉峰值流速比值（RRR）、肾动脉与段动脉峰值流速比值（RSR）和肾动脉与叶间动脉峰值流速比值（RIR）.肾动脉造影显示肾动脉内径狭窄≥50%者确定为RAS.使用ROC曲线分析确定最佳诊断指标.计算这些流速指标不同阈值的敏感性、特异性、阳性预测值、阴性预测值和准确率.结果 在肾动脉造影显示的177条肾动脉中,80条狭窄程度为50%～99%,7条闭塞.在狭窄程度50%～99%的80条肾动脉中,动脉粥样硬化性RAS 46条,大动脉炎RAS 20条,纤维肌性发育不良性RAS 12条,其他病因2条.肾动脉CDFI检查成功率为98.9%（175/177）.RPSV、RAR、RRR、RSR、RIR最佳阈值分别为170 cm/s、2.3、2.0、3.8、5.5.RPSV、RSR和RIR均获得较好的诊断效果（准确率均大于87%）,RAR和RRR的诊断敏感性较差（分别为79%和80%）.结论 对于狭窄≥50%的RAS,RPSV、RIR和RSR均是较好的诊断指标,RAR和RRR的诊断敏感性较差.影响肾动脉和腹主动脉PSV的因素都可导致RAR的诊断准确性下降,而PSV后比参数受腹主动脉PSV的影响较小,且各种原因所致肾动脉主干、肾内动脉PSV等成比例改变对PSV后比参数的影响也较小,其能明显弥补RAR的一些不足.     

Duplex Doppler sonography of renal transplants. Correlation with histopathology

The correlation of histopathologic findings with duplex Doppler sonography (DDS) in 24 biopsies in 21 patients was studied. The resistive indices (RI) of the acute rejection group were statistically different (p = .04) from those that were negative for rejection or clinical controls. Although the number of cases of moderate to severe interstitial and/or vascular rejection was relatively small compared to the mild group, patients with the more severe forms of rejection (moderate to severe interstitial with or without vascular rejection) tended to have higher RIs (.89 +/- .04) than those with the milder forms of rejection (.75 +/- .05).     

Duplex carotid sonography: correlation with digital subtraction angiography and conventional angiography

Duplex sonography is a relatively new technique for noninvasive evaluation of the extracranial carotid arteries. In a prospective, double-blind study of 453 vessels (229 patients) over a one-year period, an excellent correlation was found with intravenous digital subtraction angiography (DSA) in 66.3 per cent of vessels, good correlation in an additional 28.4 per cent of vessels, and poor correlation in only 5.3 per cent. Duplex was compared with conventional biplane angiography in 86 vessels (45 patients); there was excellent correlation in 71 per cent, good correlation in 20 per cent, and poor agreement in 9 per cent of vessels. Duplex sonography is a highly accurate method of evaluating the cervical carotid system and it has a complementary role with DSA.     

彩色多普勒超声在脑梗死患者颈动脉病变中的应用价值

目的:应用彩色多普勒超声检查初步探讨脑梗死与颈动脉粥样硬化病变的关系及特点。方法:对52例脑梗死患者和49例非脑梗死患者进行颈动脉彩色多普勒超声检查。结果:52例脑梗死患者有颈动脉粥样硬化斑块形成者35例,检出率67.3%。颈动脉粥样硬化斑块好发于颈动脉分叉处。软斑、溃疡斑是脑梗死患者的主要栓子来源。结论:颈动脉粥样硬化斑块与脑梗死有密切相关性。彩色多普勒超声检测脑梗死患者颈动脉粥样硬化斑块形成有重要临床价值。     

Features of carotid artery flow velocity in healthy subjects and consequences for evaluating stenosis in the internal carotid artery

C-W-Doppler analysis of flow velocity in the carotid arteries was performed in 98 healthy volunteers, age 16-74 years, 49 of each sex, and in 23 subjects with carotid disease. Maximum frequency shift (MFS) and total band-width in the healthy proximal internal carotid artery were negatively correlated to age in both sexes (p less than 0.001). MFS was lower in the normal proximal internal carotid artery than in the common carotid artery in both sexes. Minimum frequency shifts were more often, and more negative in the proximal than in the distal part of the internal carotid artery (p less than 0.001 in men and less than 0.01 in women) and still more so in the proximal part of the pathological internal carotids as compared with the normal ones (p less than 0.001). The computer-fitted regression between MFS and the degree of angiographic stenosis in the subjects with carotid artery disease was nearly identical with the mathematically calculated relationship for an ellipsoid stenosis. There is reason to believe that the degree of area stenosis calculated from frequency shift and predicted normal values gives a more true interpretation of functional stenosis than angiography, while the latter might be superior for evaluating vascular patho-anatomy, giving information also about intrathoracic and intracranial vessels, which also is important for evaluating patients with TIA and related symptoms.     

评估颈内动脉病变狭窄程度的多普勒血流参数选择

目的评估不同颈内动脉超声血流动力学参数的选择及其取值对诊断狭窄程度的准确性.方法检测91例脑血管病患者的140支颈内动脉狭窄段收缩期峰值流速(PSVICA)、舒张期末流速(EDVICA)、颈总动脉远段收缩期峰值流速(PSVCCA)、颈总动脉远段舒张期末流速(EDVCCA)、狭窄远段收缩期峰值流速(PSVDIS)、狭窄远段舒张期末流速(EDVDIS),计算PSVICA/EDVIC、PSVICA/PSVDISEDVIC/EDVDIS、PSVICA/PSVCCA、EDVICA/EDVCCA、PSVICA×EDVICA.采用ROC曲线下面积计算PSVICA/PSVCCA、EDVICA/EDVCCA、PSVICA/EDVCCA、PSVICA×EDVICA,并计算上述参数不同取值的敏感性和特异性.结果诊断颈内动脉狭窄程度较准确的参数依次为PSVICA/PSVDIS、PSVICA、PSVICA×EDVICA、EDVICA/EDVDIS、EDVICA.结论 PSVICA/PSVDIS、PSVICA、PSVICA×EDVICA、EDVICA/EDVDIS、EDVICA是评估颈内动脉狭窄程度较准确的多普勒血流参数,不同参数取值的确定应根据临床需要而确定.     

Duplex ultrasonography is an efficient diagnostic tool for the detection of moderate to severe internal carotid artery stenosis

BACKGROUND: The aim of this prospective national multicentre study with 10 participating university and county hospitals was to establish the diagnostic accuracy of carotid duplex sonography in the identification of >or=70% internal carotid artery (ICA) stenosis defined according to European Carotid Surgery Trial (ECST) criteria. METHODS: In 134 patients, aged 69 +/- 9 years, ICA stenoses were identified by routine carotid duplex ultrasonography, confirmed angiographically within 2 months, and graded according to ESCT criteria. The accuracy of carotid duplex to detect ICA stenosis >or=70% was assessed using receiver operating characteristic (ROC) analysis with carotid angiography as a reference. RESULTS: Measurement of peak systolic velocity in ICA (PSV(ICA)) identified ICA stenosis >or=70% with high diagnostic accuracy that was Doppler angle dependent resulting in different optimal PSV(ICA) cut points within the angle range 0 degrees -49 degrees (1 x 7 m s(-1)) and 50 degrees -62 degrees (2 x 3 m s(-1)). The diagnostic discrimination was significantly better when narrow Doppler angles (0 degrees -49 degrees ) were used (P<0 x 01) providing the sensitivity of 98 +/- 2% and specificity of 94 +/- 4%. DISCUSSION: Ultrasound duplex technique identifies moderate to severe (>or=70%) ICA stenoses (ECST criteria) with high degree of accuracy that can be further improved by the use of Doppler angle specific optimal PSV(ICA) cut points.