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International audience; AimTo demonstrate that ultrasound screening of diabetic patients presenting with no cerebrovascular symptoms for evaluation of atheroma of the cervical arteries can be limited to the carotid arteries. Methods We retrospectively analyzed the results of cervical artery ultrasound imaging of diabetic patients with no cerebrovascular symptoms. This diabetic population was divided into two subpopulations according to whether or not the vertebral and subclavian artery findings were normal or abnormal. Results Of the 760 patients who fulfilled the criteria for study inclusion, the ultrasound imaging findings of the vertebral and subclavian arteries were normal in 712 cases. Review of the files of the 48 remaining patients showed that findings for either the vertebral or subclavian arteries did not lead to any changes in patient management because of associated risk factors, carotid atheroma or peripheral arterial disease. Conclusion A vascular risk evaluation in diabetic patients could include ultrasound imaging assessment for cervical artery atheroma and our data suggest that such an evaluation could be focused solely on the carotid arteries.

Thrombi within the carotid artery usually occur in vessels with severe atherosclerotic lesions and may embolize to cause TIAs and ischemic brain infarctions. The risk factors and potential causes for carotid artery thrombus formation in the absence of atherosclerosis are currently only speculative (e.g., embolic occlusion from a cardiac source).1 Furthermore, a focal adherent thrombus involving the CCA is even more exceptional because of the rarity of severe atherosclerotic disease in this large and nonturbulent vessel.1,2 A thrombus lodged in the CCA has been reported in only a very few cases in the literature.2 We present two patients with a focal adherent thrombus in the CCA diagnosed by ultrasonography and confirmed by neuroimaging. The aim of this work is to investigate the ultrasonographic features of this very uncommon finding in young stroke patients.

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 sono-grams 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.

The relationship between intracranial pressure or cerebral perfusion pressure (CPP), cerebral blood flow, and brain energy failure is unpredictable throughout the development of acute intracranial hypertension. The purpose of the present study was to correlate intracranial pressure with cerebral blood flow velocities and brain energy metabolism in adult rabbits. The acute intracranial hypertension was achieved by pressure transmission. Transcranial Doppler wave-forms were obtained from the basilar artery for monitoring cerebral blood flow velocities. 31P-Magnetic resonance spectroscopy was used to assess brain energy metabolism. The diastolic blood flow velocity began to decrease significantly (34.5%) when the intracranial pressure was equal to half the diastolic arterial pressure for a CPP of 36 +/- 18 mmHg. Circulatory cerebral resistances increased significantly (55%) for the same value of CPP. Diastolic frequency was near zero when intracranial pressure approached diastolic arterial pressure (51 +/- 12 mmHg), corresponding to a CPP of 30 +/- 15 mmHg. At the same time, only a tendency for brain energy metabolism to decrease was observed. Consequently, transcranial Doppler sonography could be proposed for the follow-up of intracranial hypertension. Magnetic resonance spectroscopy could help to monitor these patients and could be especially proposed in case of high intracranial pressure (near diastolic arterial pressure). The joint use of these two methods would help in making appropriate therapeutic decision in humans.

The effect of an intravenous injection of thiopental on middle cerebral artery blood velocities was assessed by transcranial pulsed Doppler monitoring in 20 children: ten head-injured patients and ten control subjects. Thiopental induced a moderate but immediate decrease of middle cerebral artery blood velocities in both groups; this variation was significant (P

OBJECTIVES—To compare the diagnosis and prognosis of extracranial versus intracranial vertebral artery dissections without intracerebral haemorrhage. METHODS—Twenty two vertebral artery dissections were defined by intra-arterial angiography and classified in two groups: group 1,nine extracranial dissections (seven patients) and group 2, 13intracranial dissections (nine patients), involving the basilar artery in five cases. Bilateral dissections were found in 38% of the population. Before angiography, all the patients had been investigated by continuous wave Doppler, colour coded Doppler, and transcranial Doppler. Mean follow up was 44months. RESULTS—The two most important symptoms of both dissections (81% of patients) were unbearable pain preceding stroke and progressive onset of stroke within a few hours. Severe ultrasonic abnormalities were present in 94% of the patients whereas specific ultrasonic signs (segmental dilation with eccentric channel) were rare (19%) in both groups. Major strokes and brainstem strokes represented respectively 67% and 78% in intracranial versus 43% and 29% in extracranial dissections. Severe sequelae (permanent disabling motor or cerebellar deficit) were more often associated with intracranial (44%) than with extracranial dissections (14%). No recurrence of dissection and no cerebral haemorrhage were found under heparin. Significant factors of poor outcome (P< 0.05) were the initial severity of the stroke and the bilateral location of dissections. CONCLUSION—The combination of a pain and a progressive onset of the stroke, corroborated by ultrasonic findings, could have helped to recognise most of these types of dissections. Intracranial dissections have a poorer prognosis than extracranial dissections.

We undertook a prospective double-blind study of 128 carotid artery bifurcations using colour Doppler and duplex sonography and angiography. Sixty-four patients with cerebrovascular events were admitted for angiography. All underwent sonography within 24 h of angiography. Standard duplex sonography and colour Doppler imaging without spectral analysis were performed, on the same device, by two sonographers, using defined morphological and haemodynamic criteria. Digital radiological data on vessel diameter were interpreted independently by two radiologists. The two sonographic methods gave similar grading of stenosis, compared to angiography, with an accuracy ranging from 96% in severe to 83% in minor stenoses. Colour Doppler studies gave better area measurements than standard duplex sonography, except for major stenoses. Discrepancies between ultrasonography and angiography were due mainly to minor stenoses and large plaques of calcification on the vessel walls, which masked very segmental 70% stenoses in 2 cases. Angiography is limited by its own resolution, does not show uncalcified vessel walls and does not give cross-sectional data. It would therefore be inappropriate for showing small plaques, the full extent of ectasia or for defining the carotid bulb accurately. The advantages of colour methods were in investigating sinuous or deep vessels and hypoechoic plaques. Analysis of the residual lumen of a stenosis and its extent could be determined more rapidly. Haemodynamic quantification of stenoses by standard duplex sonography may be difficult because of limited sample volume and error in estimation of angle, whereas colour Doppler allows semiquantitative estimation of haemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)

A numerical model based on Navier-Stokes equations was used in conjunction with an experimental model in rabbits to study the effects of acute intracranial hypertension on basilar artery blood flow velocity. The hypertension was induced by pressure transmission via an epidural pressure sensor inserted into a parietal intracranial opening. A critical value of half of the diastolic arterial pressure for the intracranial cerebral pressure was determined by both numerical and experimental models. At this intracranial cerebral pressure level, the total input resistance and total input compliance, determined by the numerical model, exhibited an increase of 27% and 10%, respectively, and the tissular compliance a decrease of 25% from their physiologic baseline values. When the intracranial cerebral pressure reaches the level of the diastolic arterial pressure, a zero diastolic flow is observed into the cerebral vascular system. This study validates the theoretical model, which could be used in assessing intracranial cerebral pressure noninvasively in humans when O2 pressure can be stabilized.

Fifty-five patients with a permanent or intermittent subclavian steal syndrome demonstrated by continuous wave Doppler were included in a prospective study: 25 patients without vertebro-basilar symptoms, 8 symptomatic patients with defined vertebro-basilar symptoms and 22 with hemodynamic vertebro-basilar occurrences. The basilar artery velocity was recorded by Transcranial Doppler Sonography in baseline conditions, and after a hyperaemia test to the upper limb. A spontaneous, incomplete basilar steal was diagnosed in seven patients, and a complete basilar steal in one patient, (14.5% of the cases). After hyperaemia test, 18 other incomplete basilar steal were observed. The occurrence of a basilar steal was higher in the vertebro-basilar group (57% of the cases) especially in 7 of the 8 cases with defined vertebro-basilar symptoms; it was lower in the patients without vertebro-basilar occurrences (36% of the cases). This basilar steal was also seen in five of the six symptomatic patients with opposite vertebral artery stenosis above a 50% diameter. Transcranial Doppler Sonography could help to define a subgroup of subclavian steal syndrome with a high risk of strokes.

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.

The purpose of this study was to compare transcranial Doppler sonography (TCD) and 99Tcm-HMPAO cerebral scintigraphy in detecting the effects of acute intracranial hypertension by pressure transmission using a previously validated model. In 20 New Zealand rabbits, cerebral blood flow velocities of basilar artery and carotid siphon were simultaneously monitored in baseline conditions and during acute intracranial hypertension by pressure transmission. This hypertension was induced by progressive steps of 5 mmHg, for a 5 min duration by elevating a saline infusion bottle connected to the subdural space. In baseline conditions, significant correlations were found between basilar artery resistive index and 99Tcm-HMPAO uptake in brain stem, r = 0.5 (p0.05) and posterior cerebral areas, r = 0.78 (p0.001). Severe intracranial hypertension equal to the diastolic arterial pressure with a cerebral perfusion pressure of 22.8 +/- 12.7 mmHg significantly decreased the basilar artery blood flow velocities and global 99Tcm-HMPAO cerebral uptake. At this level of intracranial pressure, few correlations between the two methods were observed. TCD detected relatively high blood-flow velocities in the carotid siphon appearing to result from proximal cerebral artery vasospasm. Transcranial pulsed Doppler provides data about haemodynamic changes such as hypoperfusion, vascular resistance increase in the basilar artery territory and vasospasm of the carotid siphon. 99Tcm-HMPAO scintigraphy, which has not yet been studied during intracranial hypertension, gave immediate information on local cerebral perfusion. Cerebral scintigraphy demonstrated a significant diffuse and heterogeneous decrease in cerebral blood flow, without dissociation between supratentorial and infratentorial territories, and tissue perfusion deficit owing to arterial vasospasm. TCD provides emergency investigation in patients with severe head injuries or hydrocephalus. 99Tcm-HMPAO complements TCD in cases of vasospasm and in determining an area of perfusion tissue deficit.

Noninvasive diagnosis of vertebral artery disease is difficult, but the combined use of Doppler ultrasonography and dynamic radionuclide studies, with measurement of the carotid-basilar delay (CBD), increases the sensitivity and can indicate the level (cervical or distal) of the lesion. Forty patients with cerebrovascular disease were studied by continuous wave Doppler and CBD and the results were compared with vertebral angiograms. The mean normal CBD value was determined for a control group of 18 patients. Sensitivity and specificity were 87.5 per cent and 75 per cent, respectively, for Doppler alone, and 100 per cent and 60 per cent for combined Doppler and CBD.

Resume Les fistules arterio-veineuses spontanees de l'artere vertebrale sont rares (41 cas decrits dans la litterature). Un souffle cervical continu est constamment retrouve a l'auscultation. Il est une decouverte d'examen systematique dans 30 p. 100 des cas; sinon, ces fistules se revelent par des acouphenes pulsatiles unilateraux (30 p. 100) ou par des accidents ischemiques transitoires vertebro-basilaires (20 p. 100). Les principales complications de ces fistules sont les accidents ischemiques dans le territoire vertebro-basilaire et l'insuffisance cardiaque essentiellement chez l'enfant. Elles se rencontrent dans 40 p. 100 des cas. L'âge de revelation de ces malformations apparait conditionner le pronostic: 6 complications cardiaques sur 7 se produisent avant 10 ans: seules 2 complications sont observees au-dela de 50 ans; en revanche, l'anciennete de ces fistules et leur complexite ne semblent pas intervenir. L'exploration doppler cervico-cephalique guidee par la clinique conforte le diagnostic, et renseigne sur un eventuel hemodetournement. L'arteriographie par voie arterielle, indispensable en pre-operatoire, constitue souvent un premier temps therapeutique (embolisation, voire dans 4 observations, obliteration spontanee de la fistule au cours de cette investigation). La surveillance des formes asymptomatiques, dont l'embolisation et la chirurgie ont ete differees, peut maintenant etre assuree par les ultrasons.

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.