Prevalence of carotid artery stenosis in Taiwanese patients with one ischemic stroke

PURPOSE: Ethnic differences in the distribution of atherosclerosis in the brain-supplying vessels are well described. However, only scarce data exist on the prevalence of extracranial carotid artery stenosis in Taiwanese patients who have had a single ischemic stroke. METHODS: Color-coded duplex sonography was used to evaluate the carotid arteries in a hospital-based study on 276 consecutive first-time Taiwanese stroke patients. Significant atherosclerotic lesions of the internal carotid arteries (ICA) were defined as a stenosis of more than 50% or an occlusion. RESULTS: The prevalence of significant carotid lesions was 6% (35/552) in the entire cohort and 8% (17/224) in patients with hemispheric strokes. Among patients with large-artery atheroscleroses, according to criteria of the Trial of Org 10172 in Acute Stroke Treatment, only 27% had significant extracranial ICA disease whereas 69% had intracranial vessel stenoses. Older patients tended to have more severe ICA lesions, while other risk factors were not correlated with carotid stenosis. CONCLUSION: The prevalence of more than 50% ICA stenosis was low in Taiwanese patients with first hemispheric ischemic strokes, indicating that it is not a major cause of ischemic stroke in this population.     

Duplex sonographic predictors of restenosis,vascular and neurological events after carotid endarterectomy

BACKGROUND: Although excellent short- and long-term results have been achieved with surgery in extracranial internal carotid artery stenosis, recurrent stenosis continues to play an important role in post-endarterectomy. Therefore, a close follow-up of patients is warranted. The value of postoperative duplex sonographic evaluations in postoperative follow-up is highly disputed. The study evaluates duplex sonographic parameters as predictors of carotid restenosis, general vascular events and ipsilateral neurological symptoms, in order to assess the role of duplex sonography in follow-up after carotid endarterectomy. METHODS: A retrospective cohort study with a follow-up period ranging from 7 months to 7.5 years was performed in 150 patients who underwent carotid endarterectomy. Pre- and postoperative duplex sonographic and clinical data were analyzed by life-table analysis and multivariate Cox regression with respect to carotid restenosis, vascular and ipsilateral neurological events. MAIN FINDINGS: Duplex sonographic predictors of carotid restenosis include the postoperative degree of stenosis (residual stenosis > or = 30% or more: relative risk (RR) = 1.56; 1.05-2.32), pre- to postoperative reduction of stenosis (higher than 50%: RR = 0.61; 0.45-0.83), and residual plaques in the operated carotid artery (RR = 1.96; 1.31-2.93). Some of these morphological parameters such as reduction of stenosis are also predictive of vascular events (RR = 1.25; 1.01-1.56) and ipsilateral neurological events (RR = 1.52; 1.05-2.19). In 12 cases restenosis was discovered by duplex sonography and in 3 cases by evaluation of clinical symptoms. In 5 cases restenosis was treated by repeat surgery. Contralaterally, progressive or newly developed carotid stenoses were observed in 17 cases, and only 5 were discovered on the basis of clinical symptoms. Fourteen contralateral stenoses required surgery. Overall, 12 patients underwent treatment for stroke prevention on the basis of duplex follow-up findings (8% of the study population). CONCLUSIONS: Postoperative duplex sonography allows for the identification of patients at risk for carotid restenosis as well as those at risk for other vascular events. As expected, regular examinations permit early detection of restenosis requiring surgical treatment. However, a large number of contralateral stenoses requiring surgical treatment were detected by routine duplex sonographic examinations. The timing of follow-up intervals may be oriented towards the perioperative outcome of duplex sonography.     

The validation of duplex scanning and continuous wave doppler imaging: A comparison with conventional angiography

Colour-coded continuous wave (CW) Doppler imaging and duplex scanning have been assessed prospectively in comparison with biplanar angiography for their accuracy in detecting significant arterial disease in the extracranial circulation. Of 96 comparisons with biplanar angiography, the sensitivity of Doppler imaging was 90% and specificity 98% in the detection of >50% internal carotid stenosis and 86 and 100%, respectively, in the diagnosis of internal carotid occlusion. Of 85 comparisons with biplanar angiography, the sensitivity of duplex scanning was 93% and specificity 98% in the detection of >50% internal carotid stenosis and 92 and 100%, respectively, in the diagnosis of internal carotid occlusion. The value of the peak systolic Doppler shift frequency of the internal carotid artery signal has proved to be the most reliable indicator of >50% stenosis and is utilised in conjunction with a periorbital examination. It is concluded that both Doppler imaging and duplex scanning are effective screening techniques for the presence of significant (>50%) internal carotid artery disease.     

Transcranial Doppler evaluation of middle cerebral artery stenosis

Symptomatic stenoses of the middle cerebral artery (MCA) are not uncommon, although Corston observed the occurrence of stroke in 24% of patients with MCA stenoses during a 6-year follow-up study. We tried to use transcranial Doppler (TCD) sonography for the detection and evaluation of MCA stenoses. Intra-arterial angiography demonstrated 16 MCA stenoses of more than 30% diameter reduction in 15 patients (14 atheromatous stenoses, 2 dysplasias). Severe associated lesions were present in 2 cases (more than 75% internal carotid artery stenosis). These 15 patients with MCA stenosis were examined with TCD in a blind study. A Doppler signal from the MCA was obtained through the temporal bone and was recognized on the result of common carotid artery compression test. We ascertained MCA stenosis when TCD demonstrated 1) segmental flow acceleration with peak systolic frequency of more than 3 KHz with or without high energy low frequency direct or reverse components; or 2) segmental increase in systolic peak frequency of more than 20%. Using these criteria, we confirmed through TCD the presence of MCA stenosis in nine out of 12 cases with diameter reduction of at least 50%, and one among four cases with less than 50% diameter reduction. Although our results are consistent with Aaslid and von Reutern's figures, methodological problems and diagnostic criteria have to be improved. Nevertheless, TCD seems to be a useful tool for the detection of stenosis with at least 50% diameter reduction, where it proved to offer a 75% sensitivity. Further studies are necessary to improve sensitivity and specificity.     

Noninvasive evaluation of vertebrobasilar insufficiency

The diagnosis of vertebrobasilar insufficiency (VBI) is a clinical challenge because its manifestations are subjective and difficult to quantify. We evaluate 61 patients with the clinical diagnosis of VBI and 30 control patients with other medical problems. We used duplex scanning to study the extracranial carotid, vertebral, and subclavian arteries, and a 2-MHz transcranial Doppler (TCD) to examine the intracranial vertebral and basilar arteries. Extracranial lesions were more common in VBI patients than among controls, including stenosis of the subclavian artery with and without subclavian-vertebral steal and stenosis of the vertebral artery. Intracranial abnormalities identified in the vertebrobasilar circulation included stenosis and occlusion of the intracranial vertebral artery and basilar artery steal. Overall, significant lesions were detected in 32.8% of VBI patients and 3.0% of controls (P less than 0.05). Systolic artery velocity (cm/sec) in the extracranial vertebral artery was higher in controls (65.9 +/- 23.3) than in VBI patients who had no evidence of vertebrobasilar steal (43.0 +/- 17.4, P less than 0.05). Patients with a steal mechanism had an intracranial vertebral artery systolic velocity of 90.0 +/- 38.9, compared with 53.0 +/- 15.0 in controls (2P less than 0.050). Intracranial vertebral artery systolic velocity was higher among VBI patients with significant carotid artery disease (greater than 50%, 76.7 +/- 28.8) than in those with less severe disease (less than 50%, 47.3 +/- 13.8, P less than 0.05). Evaluation and quantitation of the vertebrobasilar circulation using both intra- and extracranial noninvasive studies may afford further insight as to the pathophysiology of vertebrobasilar insufficiency and provide a readily available, direct, and simple method of initial and serial assessment of VBI patients.     

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.     

Doppler examination of the periorbital arteries adds valuable hemodynamic information in carotid artery disease

The periorbital flow direction and internal carotid artery (ICA) angiogram were compared to the ICA pressure gradient across the stenosis and the distal ICA pressure in 51 patients subjected to carotid endarterectomy. All 17 patients with inverted periorbital flow had stenoses exceeding 50%. The remaining 16 patients with the same degree of stenosis had antegrade flow, which was also observed in all patients with less than 50% stenosis. In 16 of 17 patients with inverted periorbital flow, the mean pressure gradient exceeded 10 mmHg, whereas 33 of 34 patients with antegrade flow had gradients of 12 mmHg or less. For diagnostic purpose, the periorbital Doppler test is inferior to direct Doppler examination or angiography. However, as an adjunct to direct techniques, patients can be classified into 3 groups: Patients with less than 50% stenosis, Patients with 50% stenosis or more and good collaterals and, Patients with 50% stenosis or more and insufficient collaterals.     

Determination of the hemodynamic factors which influence the carotid Doppler spectral broadening

In the diagnosis of extracranial carotid arterial disease, quantitative measurements from the continuous wave (CW) Doppler spectrum have the potential for detecting stenoses and occlusions. The measurement of maximum peak Doppler frequency at the site of stenosis has been shown to detect severe, but not minor or moderate, stenoses. Diagnosis of minor or moderate stenoses may be possible by assessing the degree of flow disturbance beyond the stenosis. Such flow disturbances cause the Doppler spectrum at peak systole to be broadened, and it has been suggested that the measurement of spectral broadening may be of diagnostic value. This paper describes the results of an in vitro study aimed at determining the hemodynamic factors that influence the severity of the Doppler spectral broadening. The spectral broadening index (SBI) at peak systole, defined as SBI = 1 - Fmean/Fmax, was used to quantify the instantaneous spectrum. In a pulsatile flow in vitro model that produced spectral waveforms virtually identical to those recorded in the human carotid, we observed a direct linear relationship between SBI and the severity of stenosis, at least for those stenoses having greater than 40% cross-sectional area (R = 0.82 to 0.93). The SBI was found to be maximum when recorded immediately beyond the stenosis and returned to normal 4-5 cm downstream from the stenosis. The SBI was higher for nonsymmetrically shaped stenoses than for symmetrical stenoses for lesions greater than 60%, but not for stenoses less than 60%. In this model, the SBI recorded from both normal or abnormal waveforms was not affected by the flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Capabilities and limitations of pulsed Doppler sonography in carotid imaging

Pulsed Doppler ultrasonic imaging of the extracranial carotid arteries was performed in 118 patients (226 arteries) in whom selective contrast arteriograms were available for comparison to ultrasonic images. Specificity for the detection of normal and stenosis less than 50% was 84%, whereas sensitivity for detecting stenosis greater than 50% and occlusion of the internal carotid arteries was 89%. Overall accuracy was 85%. Capabilities and limitations in the use of the technique are presented in selected case reports.     

Detection of stenoses in the anterior circulation using frequency-based transcranial color-coded sonography

Atherosclerotic stenoses of the intracranial vessels are less frequent than those of the extracranial vessels, but they are associated with a considerable annual stroke rate. The aim of the present study was to investigate the usefulness of frequency-based transcranial color-coded sonography (TCCS), transcranial Doppler sonography (TCD) and digital subtraction angiography (DSA) in patients with middle cerebral artery (MCA) and intracranial internal carotid artery (ICA) stenosis. Forty patients presenting with 48 intracranial stenoses of the anterior circulation were involved in the study. The stenoses were detected in the neurovascular laboratory during routine TCD examinations. All patients underwent an additional frequency-based TCCS examination. Both the axial and coronal planes were obtained to allow the exact localization of MCA stenosis and differentiation from intracranial ICA stenosis. Angle-corrected flow velocity measurements were performed if straight vessel compartments were 20 mm or more in length. A total of 18 stenoses (44%) were investigated additionally with DSA. According to the investigation with TCD, 20 (42%) stenoses were low-grade, 12 (25%) were moderate, and the remaining 16 (33%) were severe. Angle-corrected flow velocity measurements obtained with the integrated pulse-wave Doppler device of the TCCS machine were highly correlated (0.912, p < 0.001) with those obtained with TCD. TCCS achieved a reliable differentiation of MCA main stem stenosis vs. intracranial ICA stenosis in 7 patients and vs. MCA branch stenosis in 4 patients, but TCD failed in these two subgroups. The agreement between DSA and TCCS to evaluate semiquantitatively 18 intracranial stenoses resulted in a weighted-kappa value of 0.764. The major clinically relevant advantages of TCCS over TCD in MCA stenosis are its ability to differentiate MCA trunk stenosis from terminal ICA or MCA branch stenosis reliably and to perform angle-corrected flow velocity measurements.     

The clinical use of objective quantification of flow disturbance in carotid artery disease: correlation between spectral broadening index and arteriography

In order to assess the accuracy of objective quantification of carotid flow disturbance, 147 carotid arteries were examined with continuous wave (CW) Doppler technique. The systolic spectral broadening index (SBI), determined as (maximum-mean)/maximum frequency, was calculated from the power spectrum and together with the peak frequency related to the angiographic degree of stenosis. Receiver operating characteristics curves were calculated and the SBI predicted disease with a specificity of 94%. On the other hand, the ability of the SBI to discriminate minor disease was not satisfactory. Both the SBI and the peak frequency were accurate in discriminating between greater or less than 50% stenosis. The study concludes that using CW Doppler the SBI can reliably predict carotid artery stenoses. For exclusion of minor lesions an additional test should be performed, e.g., pulsed Doppler spectral analysis.     

评价颅外颈动脉狭窄的影像学比较研究

目的评价不同影像学检查技术对颅外段颈动脉狭窄的评估价值。方法对23例临床怀疑颈动脉狭窄的患者行彩色多普勒超声(US)、对比增强磁共振(CEMRA)及DSA检查,以颈总动脉法(CC法)计算狭窄率。结果以DSA检查结果为金标准,超声诊断颈动脉狭窄的敏感性为93.75%,特异性64.29%;CEMRA诊断的敏感性96.88%,特异性71.43%。结论超声检查的敏感性较高、无创伤,适用于人群初选检查。CEMRA检查的敏感性、特异性均高于超声,一次检查可显示颈动脉全程。DSA检查仍为评价颈动脉狭窄的金标准,须有机结合超声、CEMRA和DSA检查,以全方位了解狭窄的颈动脉,制定合理的治疗方法。     

Duplex Doppler sonography of the carotid artery: velocity measurements in an artery with contralateral stenosis

To determine if a significant contralateral stenosis affects interpretation tables of the ipsilateral internal carotid artery's degree of stenosis in duplex Doppler ultrasound, the records of 307 patients with carotid duplex ultrasound studies with an angiogram performed within 3 months without intervening intervention were retrospectively reviewed for peak systolic velocity, end-diastolic velocity, internal carotid artery-common carotid artery ratio, and angiographic degree of stenosis. Data were grouped into categories of degree of contralateral stenosis, and Pearson r correlation was used to determine significance of ipsilateral Doppler parameters to angiographic data.As the degree of contralateral stenosis increases, the correlation of ultrasound parameters becomes less significant. At a contralateral stenosis of less than 40%, the P value for peak systolic velocity was 0.0006; at a contralateral stenosis between 40% and 59%, the P value was 0.133; at a contralateral stenosis between 60% and 79%, the P value was 0.241; and at a contralateral stenosis between 80% and 99%, the P value was 0.439. Therefore, correlations are no longer significant at levels above 40% contralateral stenosis. The Doppler parameters were scattered in patients with greater than 40%contralateral stenosis, and "corrected" correlation tables could not be derived. As stenosis increases in the contralateral internal carotid artery, Doppler values become inaccurate in determining the degree of stenosis in the ipsilateral internal carotid artery, with the occurrence of both the overestimation and underestimation of the degree of stenosis.     

Evaluation of the peak frequency ratio (PFR) measurement in the detection of internal carotid artery stenosis

The peak frequency ratio (PFR) between the internal carotid and common carotid artery Fast Fourier Transform Spectral Analysis patterns has been used to identify patients with internal carotid artery stenosis. To evaluate further the accuracy of the PFR, we applied it to the spectral analysis data from 396 vessels whose sound signals were obtained with a Duplex scanner (pulsed Doppler) and 246 arteries whose audible flow data were generated by a continuous-wave Doppler. The pulse Doppler with spectral analysis (PD/SA) correctly identified 221/254 (87%) of the vessels with less than 50% angiographic stenosis, 81/100 (81%) of the arteries with 50–99% stenosis, and 35/42 (83%) of the totally occluded internal carotid vessels for an overall accuracy of 85%. The continuous-wave Doppler with spectral analysis (CW/SA) did well in two categories but had an unacceptably high 47% false-negative rate for arteries with 50–99% stenosis. The PFR when applied to PD/SA test results is a useful parameter in screening patients with suspected internal carotid artery stenosis.     

Carotid artery disease: A prospective evaluation of pulsed doppler imaging

Ultrasonic imaging of the carotid artery bifurcation using a 30 channel pulsed Doppler system has been studied in a prospective trial. The results were compared to X-ray contrast angiography. Ninety per cent of the lesions of less than 50% were detected, as were all total occlusions of the internal carotid artery. The overall sensitivity was 93% and specificity 100%. Lateral ultrasonic scans were important in detecting lesions of less than 50% stenosis providing the diagnostic information in 48% of these vessels.

The ability to identify both low and high grade stenoses with this system provides a basis for routine screening of patients with suspected carotid disease.     

Detection of vertebrobasilar intracranial stenoses: transcranial Doppler sonography versus angiography

Vertebrobasilar intracranial stenoses seem to carry a higher risk of brain stem ischemia than proximal vertebral artery stenoses. Our aim was to assess the value of transcranial Doppler sonography versus angiography in detecting and quantifying these intracranial stenoses. All consecutive patients who underwent transcranial Doppler sonography prior to angiography from 1989 to 1994 and whose sonograms showed a stenosis of greater than 50% of one vertebral artery (21 cases) or of the basilar artery (eight cases) were included in the study. These patients were compared with 60 other consecutive stroke patients studied via transcranial Doppler sonography prior to normal vertebrobasilar angiography The transcranial Doppler sonographic criteria for stenosis were a peak systolic frequency shift greater than 2 KHz. A tight stenosis was identified by this pattern combined with direct and reverse low frequencies of high spectrum energy. The sensitivity of transcranial Doppler sonography using a peak systolic frequency shift in diagnosing stenoses reached 80% and its specificity was 97% if only atheromatous stenoses were considered. The main diagnostic failures concerned bilateral stenoses or contralateral occlusion, tandem lesions, and upper basilar artery stenosis. Transcranial Doppler sonography underestimated the degree of stenosis compared to angiography in 55% of the cases. We conclude that transcranial Doppler sonography is accurate in recognizing a stenosed vessel in the intracranial vertebrobasilar circulation, but if this finding will alter therapy, the examination must be complemented by magnetic resonance angiography.     

Doppler-ophthalmomanometry in patients with obstruction of the carotid arteries

A novel noninvasive method to determine simultaneously ophthalmic artery pressure (OAP) and flow direction based on Doppler ultrasound principles is presented: ophthalmomanometry-Doppler (OMD). Studies performed on 25 angiographically proven normal subjects with direct recording of the internal carotid artery pressure (ICP) and indirect determination of the brachial artery pressure (BAP) demonstrated that OAP values assessed by the OMD device are highly correlated with simultaneous ipsilateral intraarterial systolic ICP measurements (r = 0.95, n = 10) and with simultaneous recordings of the BAP (r = 0.88, n = 15). In 50 patients presenting angiographically occlusions and 52 patients presenting angiographically stenoses (greater than 60%) of the carotid artery the measured Doppler ophthalmic pressure index (OPI = ratio of the ophthalmic to systemic blood pressure) was lower ipsilateral to an occlusion (0.46 +/- 0.08) than ipsilateral to a stenosis (0.54 +/- 0.08; p less than 0.001) of the carotid artery. In both it was clearly diminished compared to normal values (0.68 +/- 0.04; p less than 0.001). In carotid artery occlusions, the ipsilateral OPI was 0.46 +/- 0.06 for antegrade (n = 17) and 0.46 +/- 0.09 for retrograde (n = 28) ophthalmic artery flow. In carotid artery stenoses, the ipsilateral OPI was 0.55 +/- 0.07 for antegrade (n = 41) and 0.48 +/- 0.06 for retrograde (n = 9) ophthalmic artery flow (p less than 0.01). It is concluded that in carotid occlusions presenting a longer disease history extra-intracranial collateralisation via the ophthalmic artery are as efficient as a functional circle of Willis.     

Reflections from a decade of carotid reconstructive surgery

Carotid artery reconstructive surgery for atherosclerotic lesions of the extracranial cerebral circulation has become the most common operation in peripheral vascular surgery. A better understanding of the indications for operative intervention, enhanced monitoring during surgery, and more precise management of intraoperative anesthesia have all helped decrease the risks associated with internal carotid endarterectomy. To evaluate the safety and efficacy of extracranial carotid reconstructive surgery, we reviewed 2,857 operations done on 2,087 patients from 1976 to 1985. Operation was recommended because of hemispheric symptoms in 58%, and because of asymptomatic, significant stenosis in 14%. Postoperative hemiparesis occurred in 24 patients and was associated with thrombosis at the operative site in 18 patients. Antiplatelet drugs used during the last three years were found to be effective in preventing thrombosis at the operative site. Operative mortality during the study period was 1.5%. Follow-up has ranged from one month to 104 months, with 84% of the patients alive and 79% symptom free.     

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.     

Ultrasonic features of extracranial carotid dissections: 47 cases studied by angiography.

The purpose of this prospective study was to assess the value of continuous wave Doppler velocimetry, standard duplex scanning and color Doppler flow imaging in the diagnosis of carotid dissections. From 1975 to 1993, 42 patients (mean age, 44 +/- 14 years) were admitted to the University Hospital of Angers for a carotid dissection studied first by ultrasonography, then defined by angiography. Five cases were bilateral. Continuous wave Doppler examination revealed signs of severe obstruction of the carotid arteries in 96% of the cases (occlusion, extensive submandibular tight stenoses, significant slowdowns in the carotid and ophthalmic vessels, retrograde ophthalmic blood flow). Standard duplex scanning suggested dissection in 72% of the cases (tapering stenoses or occlusion, segmental ectasis, tubular vessel, peripheral residual channel, or rare irregular "membrane"). Color Doppler flow imaging suggested a dissection in 82% of the cases. This method has the advantage of underlining the peripheral channel, the double lumen, and the dissecting hematoma, which often is hypoechoic. The ultrasonic methods (continuous wave Doppler combined with color Doppler flow imaging) failed only when they are performed late and when moderate or segmental intrapetrosal dissections were present. These ultrasonic investigations would thus appear to be useful for early diagnosis of carotid dissections.