Flow reversal in the carotid bifurcation. Detection using color-coded Doppler sonography

Pulsatile blood flow within the normal carotid sinus involves at least two distinct components. Beside the laminar antegrade flow, there is a boundary layer separation zone in the posterolateral aspect with transient flow reversal. This flow reversal is well known from in vitro studies. It is now possible to document these flow velocity components using color-coded Doppler sonography. It is hypothesized that if flow separation is detected, this is indicative of a normal condition of the carotid bifurcation. When atherosclerosis develops, it involves preferentially the posterolateral bulb region, obliterating the normal configuration of the sinus with consequent loss of the flow separation. Therefore, loss of flow reversal should be indicative of atherosclerosis. We have studied this flow pattern retrospectively in 156 patients (312 arteries). In 4 patients no flow reversal could be detected although no atheromatous lesions could be found at the bifurcation, but in these cases there was no bulb formation in the common carotid artery or in the internal carotid artery. On the other hand, flow reversal was demonstrable in several pathological conditions within the carotid bifurcation. These included plaque formation after the bifurcation in 7 patients, internal carotid artery occlusion at the origin in 12, common carotid artery occlusion despite a patent bifurcation in 4, and marked dilatation of the lumen forming a pseudobulb following disocclusion of the carotid artery in 11 patients.     

Doppler sonography in basilar artery occlusion

Summary We have investigated 6,972 patients with directional continuous-wave Doppler sonography within the last three and a half years, and have derived criteria for the sonographic diagnosis of basilar artery occlusion or tight stenosis in conjunction with 1,071 retrograde brachial angiograms. By sonographic patterns, we have suspected obstruction of the basilar artery or of both distal vertebral arteries in nine cases. Either bilateral sonographic silence or the absence of a diastolic flow component of the vertebral arteries served as criteria in the sonographic evaluation. Angiography of the vertebro-basilar system, performed in eight cases, showed near or complete occlusion in the distal vertebrals or in the proximal basilar artery. Degrees of stenosis less than an 80 percent reduction in lumen diameter could not be detected sonographically. Two further basilar artery occlusions were detected by means of angiography despite negative Doppler sonography: one of these patients showed an extensive collateral circulation between the posterior inferior and the superior cerebellar arteries, and one patient had an occlusion only of the middle and rostral thirds of the basilar artery, the proximal third and the anterior inferior cerebellar arteries being widely patent. Thus, we believe that directional CW Doppler sonography is very useful in the diagnosis of near or complete occlusion of both distal vertebral arteries or of the proximal basilar artery.     

Color-coded Doppler sonography of the carotid artery

A total of 844 patients were evaluated to compare the value of ultrasonography and color-flow Doppler and to demonstrate the advantage presented by the latter method. In 89%, 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. Non-stenotic plaques were seen more often (43%) in the wide carotid bulb; stenotic plaques and occlusion were found more often (66% and 82%) in the internal carotid artery. Color-flow Doppler allows the sonomorphological (plaques, stenoses, occlusion) and functional parameters (turbulences, flow enhancement) to be studied at the same time.     

Doppler sonography of the deep lingual artery

Purpose: To clarify the Doppler sonographic features of the lingual artery in normal subjects and to evaluate those of patients with cancer of the tongue.Material and Methods: Sixty-seven volunteers and 12 patients with cancer and/or leukoplakia of the tongue were examined with an intraoral sonographic probe. The visibility of the deep lingual artery was determined on transverse and anteroposterior images. On the transverse images, the vascular index, which was defined as the number of colored pixels, was measured on bilateral lingual arteries. Thereafter, the degree of symmetry was evaluated for normal subjects and patients.Results: In normal subjects, between younger and older volunteers, there were no significant differences in visibility of the trunk but differences were found between the two groups for the dorsal branches. The vascular indices of the right and left sides were not different. The characteristic Doppler sonographic feature was vasculature in and around the tumors in the patients with cancer of the tongue. The symmetry indices of the cancer patients were significantly different from those of normal subjects.Conclusion: Doppler sonography should be an important procedure for evaluation of tongue neoplasms.     

Duplex and color Doppler flow sonography of occlusion and near occlusion of the carotid artery.

PURPOSETo determine whether color Doppler flow imaging with the use of slow-flow sensitivity improves sensitivity and specificity in the differentiation of occlusion and near occlusion of the internal carotid artery.METHODSColor Doppler and duplex sonography were performed in symptomatic patients who had angiographically confirmed occlusion and/or near occlusion of the internal carotid artery. The study consisted of two phases: in the first, we assessed the usefulness of color Doppler flow imaging by retrospectively reviewing the records of 35 patients with 36 angiographically confirmed occlusions or near occlusions of the internal carotid artery who were examined with color Doppler flow imaging at our institution during a period of 4 years; in the second phase, we incorporated color Doppler sonography into the routine scanning protocols of 39 patients with 41 occluded or nearly occluded internal carotid arteries seen over a period of 2 1/2 years.RESULTSOverall, color Doppler imaging correctly showed all 34 of the near occlusions (sensitivity, 100%) and 36 of the 43 occlusions (specificity, 84%). Seven patients with angiographically confirmed occlusion had sonographic findings that suggested near occlusion. In the first phase, eight near occlusions were misinterpreted as occlusions with conventional duplex sonography, but were correctly shown with color Doppler flow imaging. In the second phase, sensitivity increased from 50% to 100% (18 or 18) because of better detection of the nearly occluded lumen. This was at the expense of a decrease in specificity (from 100% to 78%). owing to identification of apparent flow in the internal carotid artery on color Doppler flow images in five of 23 occlusions.CONCLUSIONBecause of its ability to depict slow flow, color Doppler imaging with slow-flow sensitivity is superior to conventional duplex sonography for the noninvasive discrimination of occlusion from near occlusion of the internal carotid artery.     

Color flow Doppler sonography of the abdomen

This paper reviews recent developments in color flow Doppler sonography of the abdomen reported from October 1989 to September 1990. Areas of focus include instrumentation and technical considerations, and current clinical applications.     

双功彩色多普勒超声检测糖尿病患者眼动脉血流量

目的：探讨双功彩色多普勒超声(CDUS)定量评价糖尿病患者眼动脉血流量的可行性。方法：糖尿病组33例66条眼动脉，正常对照30例60条眼动脉。检测指标包括眼动脉彩色血流束宽度以代表其内径(D)和平均血流速度(Vmean)，并计算每条眼动脉的血流量。结果：糖尿病组眼动脉平均内径及平均血流速度均低于正常组，进而导致其眼动脉血流量低于正常组。结论：双功CDUS是检测糖尿病患者眼动脉血流量可行且实用的技术。     

输卵管妊娠血液动力学改变的彩色多普勒超声研究

目的对比分析输卵管妊娠（tubal pregnancy，TP）时双侧输卵管动脉血流，探讨彩色多普勒血流显像（color Doppler flow imaging，CDFI）诊断输卵管妊娠的价值。方法临床拟诊宫外孕患者40例，于术前行经阴道超声（transvaginal scanning，TVS）检查，CDFI显示双侧子宫动脉输卵管支血流，用脉冲多普勒检测收缩期最大流速（peak systolic velocity，PSV）、舒张末期流速（end diastolic velocity，EDV）、平均流速（time averge mature，TAMAX）、搏动指数（pulsatility index，PI）及阻力指数（resistivity index，RI），并进行统计学处理。结果40例均确诊为TP，其中33例黄体位于患侧，输卵管动脉血流信号较健侧丰富，色泽明亮鲜艳，血流频谱呈单向高舒张期、低阻特征，EDV、TAMAX明显高于健侧，PI、RI则明显低于健侧（P〈0．05），PSV双侧差异无统计学意义（P〉0．05）；5例黄体位于健侧者，所有参数差异无统计学意义（P〉0．05）。2例TP破裂出血者，患侧EDV、TAMAX均低于健侧，且PI、RI高于健侧。结论经阴道CDFI监测输卵管动脉血流有助于TP的早期定性和定位诊断。     

Three-dimensional color Doppler sonography in carotid artery stenosis

BACKGROUND AND PURPOSE: Color Doppler sonography (CDS) suffers from such disadvantages as high interobserver variability and problems with data presentation and storage. We therefore performed a prospective trial to assess the role of three-dimensional CDS (3D-CDS) in the evaluation of internal carotid artery stenosis (ICAS). METHODS: We included 32 consecutive patients with sonographically verified ICAS (30-99%) and 16 asymptomatic volunteers. All underwent CDS and 3D-CDS, and 23 patients also underwent intraarterial angiography. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of high-grade ICAS were analyzed by three blinded readers, who also graded the percentage of ICAS. RESULTS: CDS revealed 14 patients with mild to moderate ICAS and 18 patients with high-grade ICAS. Mean sensitivity of 3D-CDS was 81.5%, mean specificity was 98.9%, mean positive predictive value was 97.9%, and mean negative predictive value was 89.9%. 3D-CDS correlated significantly with CDS (mean r=0.85; P<.001) and angiography (mean r=0.57; P=.01). CONCLUSION: 3D-CDS findings correlate with those obtained by CDS and angiography; 3D-CDS also offers excellent interobserver correlation, positive predictive value, and specificity, approaching 100% for the detection of high-grade ICAS.     

Carotid artery disease assessed by color Doppler flow imaging: correlation with standard Doppler sonography and angiography

Carotid artery disease was assessed in 180 patients by means of color Doppler flow imaging. Color Doppler findings in 360 carotid arteries were compared with the results of standard Doppler sonography, and color Doppler findings in 60 bifurcations were compared with the results of intraarterial angiography. The sensitivity of color Doppler for the detection of carotid disease was 100% when compared with angiography. The accuracy of color Doppler in classifying minor (40-60%), moderate (61-80%), and severe (81-90%) stenosis ranged from 91.3% to 97.8% vs standard Doppler sonography, and from 91.7% to 95.8% vs angiography. Whereas all occlusions were identified correctly by both color Doppler and angiography, four pseudoocclusions of the carotid artery were misdiagnosed as occluded. Characteristic features providing reliable criteria of the degree of stenosis are (1) intensity, extent, and duration of color fading; (2) postprocessed systolic peak frequency; (3) plaque extent on serial sonograms; and (4) poststenotic flow patterns. Display of hemodynamic disturbances induced by less pronounced plaques showed highly variable patterns that could not be anticipated from the plaque morphology alone. Thus, color Doppler preserves the advantages of standard Doppler and duplex sonography but provides additional information about otherwise anechoic necrotic and thrombotic material that often causes cerebral embolisms. With atherogenesis, repair mechanisms may be sustained or progression be stopped by reducing the risk factors and instituting medical treatment; thus, the application of this noninvasive technique is important.     

Carotid artery disease assessed by color Doppler flow imaging: correlation with standard Doppler sonography and angiography

Carotid artery disease was assessed in 180 patients by means of color Doppler flow imaging. Color Doppler findings in 360 carotid arteries were compared with the results of standard Doppler sonography, and color Doppler findings in 60 bifurcations were compared with the results of intraarterial angiography. The sensitivity of color Doppler for the detection of carotid disease was 100% when compared with angiography. The accuracy of color Doppler in classifying minor (40-60%), moderate (61-80%), and severe (81-90%) stenosis ranged from 91.3% to 97.8% vs standard Doppler sonography, and from 91.7% to 95.8% vs angiography. Whereas all occlusions were identified correctly by both color Doppler and angiography, four pseudoocclusions of the carotid artery were misdiagnosed as occluded. Characteristic features providing reliable criteria of the degree of stenosis are (1) intensity, extent, and duration of color fading; (2) postprocessed systolic peak frequency; (3) plaque extent on serial sonograms; and (4) poststenotic flow patterns. Display of hemodynamic disturbances induced by less pronounced plaques showed highly variable patterns that could not be anticipated from the plaque morphology alone. Thus, color Doppler preserves the advantages of standard Doppler and duplex sonography but provides additional information about otherwise anechoic necrotic and thrombotic material that often causes cerebral embolisms. With atherogenesis, repair mechanisms may be sustained or progression be stopped by reducing the risk factors and instituting medical treatment; thus, the application of this noninvasive technique is important.     

Duplex Doppler sonography of the carotid artery: false-positive results in an artery contralateral to an artery with marked stenosis

Anecdotal reports have described a false-positive "jet effect" or velocity increase in the carotid artery contralateral to an artery with significant stenosis or occlusion when using duplex Doppler sonography. In this study, the frequency, significance, and possible reasons for this finding were evaluated by a retrospective comparison of duplex sonography and angiography. Twenty-three patients with unilateral 81-100% carotid artery stenosis who underwent both duplex sonography (16 Acuson, seven Quantum) and angiography were evaluated. In 14 patients, there was an accurate or slight underestimate (less than 20%) of stenosis present in the internal carotid artery contralateral to an artery with tight stenosis/occlusion. In nine, a velocity increase in the internal carotid artery resulted in overestimation (10-80%) of the actual degree of stenosis. In one of these nine patients, real-time images were sufficient to explain the velocity increase on the basis of vessel tortuosity. In one, falsely elevated velocity resulted from inaccurate assignment of the Doppler angle of incidence in a patient in whom real-time visualization of a distal internal carotid lesion was poor. In four of the nine patients, cross filling via the circle of Willis toward the side of greater stenosis occurred. However, seven of 14 patients in whom there was duplex sonography/angiography agreement or slight duplex sonography underestimation also had cross filling. Vertebral artery patency did not correlate well with the presence of a "jet effect." These findings suggest that an increase in blood flow velocity with duplex Doppler sonography in the internal carotid artery on the side opposite an artery with a tight stenosis is a common source of error and is not readily explained by angiographic evidence of collateral flow.     

Duplex Doppler sonography of the carotid artery: false-positive results in an artery contralateral to an artery with marked stenosis

Anecdotal reports have described a false-positive "jet effect" or velocity increase in the carotid artery contralateral to an artery with significant stenosis or occlusion when using duplex Doppler sonography. In this study, the frequency, significance, and possible reasons for this finding were evaluated by a retrospective comparison of duplex sonography and angiography. Twenty-three patients with unilateral 81-100% carotid artery stenosis who underwent both duplex sonography (16 Acuson, seven Quantum) and angiography were evaluated. In 14 patients, there was an accurate or slight underestimate (less than 20%) of stenosis present in the internal carotid artery contralateral to an artery with tight stenosis/occlusion. In nine, a velocity increase in the internal carotid artery resulted in overestimation (10-80%) of the actual degree of stenosis. In one of these nine patients, real-time images were sufficient to explain the velocity increase on the basis of vessel tortuosity. In one, falsely elevated velocity resulted from inaccurate assignment of the Doppler angle of incidence in a patient in whom real-time visualization of a distal internal carotid lesion was poor. In four of the nine patients, cross filling via the circle of Willis toward the side of greater stenosis occurred. However, seven of 14 patients in whom there was duplex sonography/angiography agreement or slight duplex sonography underestimation also had cross filling. Vertebral artery patency did not correlate well with the presence of a "jet effect."(ABSTRACT TRUNCATED AT 250 WORDS)     

Using Doppler sonography to reveal renal artery stenosis: an evaluation of optimal imaging parameters.

OBJECTIVE: The aim of this study was to determine the accuracy of direct and indirect parameters for the diagnosis of renal artery stenosis and to determine the most useful thresholds for these parameters. SUBJECTS AND METHODS: One hundred twenty-five arteries in 63 patients were examined with renal Doppler sonography and angiography for the presence or absence of renal artery stenosis. Arteries were considered stenosed on angiography if there was a diameter reduction of greater than 60%. Renal Doppler sonographic measures of peak systolic velocity, renal aortic ratio, acceleration time, and acceleration were recorded and compared with the angiographically determined presence or absence of disease. RESULTS: Doppler examination was technically successful in 87% of kidneys and 76% of patients. Receiver operating characteristic analysis showed the optimal peak systolic velocity threshold to be 180 cm/sec and the optimal renal aortic ratio threshold to be 3.0. An acceleration time greater than 70 msec and an acceleration less than 300 cm/sec2 yielded sensitivities of 41% and 56%, respectively, and specificities of 85% and 62%, respectively. Combining a renal aortic ratio of greater than 3.0 or peak systolic velocity greater than 180 cm/sec provided the best combination of parameters with a sensitivity and sensitivity at 85% and 76%, respectively. CONCLUSION: The most accurate use of parameters was found to be a combination of either peak systolic velocity greater than 180 cm/sec or renal aortic ratio greater than 3.0. Indirect parameters were not found to be useful in predicting the presence or absence of renal artery stenosis.     

Color Doppler sonography of the hepatic artery and portal venous system

Color Doppler sonography is an important noninvasive diagnostic tool for detecting abnormalities of the hepatic vasculature in patients with diffuse liver disease. To study its usefulness in these cases, we retrospectively reviewed the findings in 147 patients with abnormal portal venous color Doppler sonograms. This group comprised all patients with abnormal portal venous color Doppler sonograms studied from February 1987 to July 1989. Correlative imaging was not available in all cases. The sonographic diagnoses included (1) portal venous thrombosis (50 patients, 93 vessels); (2) portal-systemic or portal-portal collaterals (80 patients, 95 collaterals); (3) reversed, bidirectional, or other abnormal portal venous flow patterns (36 patients); and (4) abnormal hepatic arterial flow (20 patients). Since the results reported derive from a retrospective review without consistent correlation with other imaging studies, no appraisal of the sensitivity or accuracy of portal color Doppler sonography could be made from our data. The ability of color Doppler sonography to visualize flow without altering hemodynamics has led to several novel observations in these patients. These include increased arterial flow in states of low portal blood flow, reversal of portal flow direction postprandially, coincident reversed and hepatopetal flow in different branches of a single portal vein, and normal helical portal venous flow. These and other findings show that color Doppler sonography has enhanced our ability to detect abnormalities of the hepatic and portal venous system.     

Common hepatic artery aneurysm: diagnosis with duplex sonography and color Doppler.

Hepatic artery aneurysms are uncommon lesions, often with a nonspecific clinical presentation and difficult to diagnose before rupture. The authors report a case which was correctly diagnosed with non-invasive procedures (duplex sonography and color Doppler).     

Transgluteal sonography. A new approach to the posterior pelvic compartment

Ten patients with presacral tumors proved by histologic and computed-tomographic investigations underwent ultrasound scanning. The sound beam was directed through the ischial foramen along longitudinal, transverse, and oblique planes. Nine of 10 tumors localized in the sacral fossa were identified sonographically. In six of 10 instances, tumor demarcation was possible. Sonographic evaluation was impaired because of distance between the transducer and the target due to a patient's large volume and by the cranial location of the tumor. The transgluteal approach is suggested for sonographically guided percutaneous biopsy.