Transcranial Color Doppler Sonography Research Articles

Cognitive decline and cerebral vasoreactivity in asymptomatic patients with severe internal carotid artery stenosis

The aim of the study was to correlate cognitive decline and cerebral vasoreactivity in 150 asymptomatic right-handed patients with severe ≥70% unilateral internal carotid artery (ICA) stenosis and to evaluate the role of intracranial collateral circulation during cognitive testing. Cognitive assessment was performed by means of Montreal Cognitive Assessment (MoCA) and Mini Mental State Exam (MMSE) scales. Cerebrovascular reactivity (CVR) and intracranial collateral circulation were evaluated by means of breath holding index (BHI) and transcranial color Doppler (TCD) sonography. The results were compared with 150 right-handed controls matched for demographic variables and vascular risk factors. Patients with severe unilateral ICA stenosis had MMSE scores within a normal range, but MoCA scores were lower than normal. By examining the side of the observed stenosis, it has been noted that patients with left-sided ICA stenosis had lower MoCA scores in categories of language and episodic memory performance, while patients with right-sided ICA stenosis had lower MoCA scores in a category of visual-spatial skills. All patients had BHI values lower than normal. Subjects with a single intracranial collateral artery recruited had slightly better cognitive results than the patients with two or more collateral arteries activated. Results of the study showed that altered cerebrovascular reactivity and cerebral hypoperfusion might be responsible for the reduction of specific cognitive functions ipsilateral to the ICA stenosis, therefore BHI and MoCA might be useful tools when screening for cognitive decline in asymptomatic patients with severe ICA stenosis.

Abstract 9344: Tobacco Smoke Exposure is Associated with Alterations of Cerebrovascular Flow Velocities and Regulation in Children

Background: Passive smoking (PS) is associated with increased risk for cerebrovascular and cardiovascular events, however, there has been little focus on cerebrovascular function. The purpose of this study is to assess cerebrovascular flow velocities and regulation in PS children. Methods: Noninvasive ultrasonographic measurements were made in 51 children (age:9 ± 4years) who have been exposed to tobacco smoking since intrauterine life and 35 age-matched children without PS. Using transcranial color Doppler sonography, peak systolic (PSV), end-diastolic (EDV), and average peak flow (APV) velocities of middle cerebral artery were measured during supine rest and 3 minutes-upright posture. Pulsatile index as a parameter of vascular resistance was calculated. Pulsatile index was defined as (PSV-EDV)/APV. Quantitative B-mode ultrasound scans were used to measure intima-media thickness and diameters of the common carotid artery. Urine cotinine concentrations were assessed. Results: Flow velocities and pulsatile index were not significantly different between controls and PS children (p > 0.05). In controls and PS children with urine cotinine concentrations <5ng/ml (n = 26), pulsatile index did not change during upright position (p > 0.05). However, in PS children with urine cotinine concentrations ≥ 5ng/ml (n = 25), there was a significant increase in pulsatile index during upright position (0.93 ± 0.14 vs. 0.87 ± 0.12, p < 0.01), because APV and EDV were significantly lower (69 ± 16 vs. 76 ±17 cm/sec and 44 ± 9 vs. 50 ± 11 cm/sec, p <0.05, respectively), although PSV was not significantly different. The percent change in pulsatile index during an upright position correlated significantly with urine cotinine level (r =0.57, p < 0.01). Intima-media thickness at carotid artery and stiffness did not correlate with cerebral blood flow velocities. Conclusions: The present study indicates that passive smoking can adversely affect cerebral blood flow and regulation in the cerebrovascular bed in childhood. Passive smoking not only is a risk factor for later cardiovascular disease, but also is associated with significant impairment of cerebral flow dynamics.

Chronic cerebrospinal venous insufficiency and venous stenoses in multiple sclerosis

The traditional view that multiple sclerosis (MS) is an autoimmune disease has recently been challenged by the claim that MS is caused by chronic cerebrospinal venous insufficiency (CCSVI). Although several studies have questioned this vascular theory, the CCSVI controversy is still ongoing. Our aim was to assess the prevalence of CCSVI in Danish MS patients using sonography and compare these findings with MRI measures of venous flow and morphology. We investigated cervical and cerebral veins in 24 patients with relapsing-remitting MS (RRMS) and 15 healthy controls, using extracranial high-resolution ultrasound colour Doppler (US-CD) and transcranial colour Doppler sonography (TCDS), as well as magnetic resonance imaging (MRI) and phase-contrast MR blood flow measurements (PC-MR) of the cervical veins. US-CD could not identify the left internal jugular vein (IJV) in one MS patient, other ultrasound examinations were normal in patients with MS. There was no difference in mean cross-sectional area of the IJV in MS patients compared with controls. Only one patient with MS and two healthy controls fulfilled one CCSVI criterion, and none fulfilled more than one CCSVI criterion. MR venography showed insignificant IJV stenosis (1-49%) in two patients with MS, whereas 50-69% IJV stenosis was detected in two healthy controls. There was no difference in PC-MR measurements of mean IJV blood flow between patients with MS and controls. Our results do not corroborate the presence of vascular pathology in RRMS and we found no evidence supporting the CCSVI hypothesis.

Intellectual impairment and TCD evaluation in children with sickle cell disease and silent stroke

BackgroundSickle cell disease (SCD) may impair intellectual activity; 25% of SCD patients have a significant cognitive deficit. Our aim was to verify in a cohort of children with HbSS if the presence of silent strokes or altered Time Averaged Mean velocities of Maximum blood flow (TAMM) detected by Transcranial Color Doppler (TCD) Sonography are indicators of impaired intellectual ability. MethodsThirty-five consecutive SCD patients (17 males; mean age: 8.6±3.22) were subdivided into two groups according to neuro-psycological deficits. Cognitive function was assessed by WISC III (for the children aged 6–16 years) and WPPSI (for the children aged 4–6 years). All patients underwent a TCD scan of the main intracranial arteries, in order to detect any increase of TAMM velocities (normal <170cm/s; altered >170cm/s) and a cerebral MRI to reveal any silent stokes. ResultsAccording to the neuro-psycological evaluation, 29/35 (82.8%) patients (Group 1) had a “normal” Total Intelligence Quotient (TIQ ≥70), while 6/35 (17.2%) patients (Group 2) were defined intellectually impaired (TIQ <69).TCD detected altered velocities in 8/35 (22.8%) patients. No significant differences were found in the percentage of altered TAMM velocities between the two groups (Fisher's exact test: p=0.42).MRI detected silent ischemic lesions in 14/35 patients (40.0%). No significant differences were found in silent stroke frequencies (Fisher's exact test: p=0.25) between Group 1 and Group 2. ConclusionWith the limitations of the study sample, according to our results, altered TAMM values and silent strokes do not seem to be indicators of impaired intellectual ability in SCD patients.

Comparison of transcranial color Doppler sonography without and with contrast enhancement for detection and characterization of intracranial aneurysms

To compare the diagnostic value of transcranial color Doppler sonography (TCCS) with contrast-enhanced transcranial color Doppler sonography (CE-TCCS) for the detection and characterization of intracranial aneurysms. Thirty patients highly suspected of having an intracranial aneurysm were imaged using TCCS and CE-TCCS. The ability to detect the aneurysms and determine their size and location accurately was compared with findings from digital subtraction angiography. The overall sensitivity of CE-TCCS was greater than that of TCCS (24/30 versus 20/30, respectively) (p = 0.125), but the difference was not significant. Neither TCCS nor CE-TCCS could detect the three small (≤5 mm diameter) aneurysms. The detection rate for larger aneurysms (5-15 mm diameter, n = 17) was nonsignificantly greater with CE-TCCS (14/17) than with TCCS (11/17) (p = 0.438). Similarly, CE-TCCS detected more large or giant aneurysms (>16 mm diameter) than TCCS (10/10 versus 9/10, respectively) but the difference was not significant (p = 1.000). The benefit of contrast enhancement was identical for aneurysms ≥10 mm or <10 mm in diameter. All (7/7) middle cerebral artery aneurysms were detected by both TCCS and CE-TCCS. CE-TCCS yielded similar or slightly better results than TCCS for all other aneurysm locations. CE-TCCS can improve the sensitivity and detection rate of intracranial aneurysms ≥5 mm in size.

Progressive multiple sclerosis is not associated with chronic cerebrospinal venous insufficiency

Chronic cerebrospinal venous insufficiency (CCSVI) had been suggested to play a major pathogenetic role in multiple sclerosis (MS), but recent data on early stages of MS have not confirmed this theory. Nonetheless, CCSVI could represent a late phenomenon of MS or be associated with progression of disability. Thus, we studied CCSVI prevalence in primary progressive (PP) and secondary progressive (SP) MS, to clarify whether CCSVI characterizes the progressive forms of this disease. A total of 35 patients with SPMS, 25 patients with PPMS, and 60 age- and gender-matched normal controls (NC) were enrolled into a cross-sectional study. Extracranial and transcranial high-resolution venous echo color Doppler sonography (ECDS-TCDS) was performed in all patients and NC. Those patients having any abnormal ultrasound finding were asked to undergo selective venography (VGF). Patients with PPMS (11 women, 14 men; mean age 47 ± 11 years) had a disease duration of 11 ± 7 years and Expanded Disability Status Scale (EDSS) score of 6.0 ± 0.5. Patients with SPMS (22 women, 13 men; mean age 45 ± 14.5 years) had a disease duration of 18 ± 14 years and EDSS score of 6.0 ± 0.8. TCDS was normal in all patients. ECDS showed one or more abnormal findings in 9/60 (15.0%) patients (7/35 [20.0%] SPMS, 2/25 [8.0%] PPMS) and in 14/60 (23.3%) NC (p not significant for all comparisons). CCSVI criteria were fulfilled in 0 NC and 4 (6.7%) patients with MS: 3 SPMS and 1 PPMS. VGF, performed in 6/9 patients, was abnormal only in one case who had bilateral internal jugular vein stenosis. Our findings indicate that CCSVI is not a late secondary phenomenon of MS and is not associated with disability.

P03-207 Blood flow of carotid arteries in schizophrenic patients

Background:Based on new imaging, some results have led to the hypothesis, indicating left hemispheric dysfunction in schizophrenic patients,Transcranial color Doppler sonography also showed significant blood flow velocity changes in schizophrenic patients.Our study tried to clarify possible differences between carotid blood flow of each side, in symptom positive and symptom negative schizophrenic patients, as well as differences of blood flow between schizophrenic patients versus control cases.Methods:31 schizophrenic patients which had been selected randomly were divided in two separate groups of symptom positive (14 cases) and symptom negative (17 cases) patients, according to PANSS test. Then carotid color Doppler sonography was performed for them and for 32 control cases.Velosities (PSV, DV) and Doppler indices (RL, PI) were measured to be compared statistically in patients and control cases.Results:According to P value &lt; 0.05 as level of significance in all comparisons, no evidence of any significant differences is seen between two sides of patients(positive symptoms and negative symptoms) as though between control cases and patients. No positive conclusion also derived based on sex interference.Conclusion:So examination reveals no differences between carotid blood flows of two sides in schizophrenic patients(positive and negative symptom).There is no differences between carotid blood flow of patients and control group, even when sex interfered as a variety.

Transcranial color Doppler sonography on healthy pre-school children: Flow velocities and total cerebral blood flow volume

Transcranial color Doppler sonography (TCCD) is a useful tool for intracranial investigation. Using TCCD to calculate total cerebral blood flow volume (TCBFV) can be a useful indicator for intracranial hemodynamic status. We performed a series study of TCCD on 60 healthy kindergarten students. Peak-systolic, end-diastolic, and mean blood velocities of major cerebral arteries, and depth of flow waves were measured. We also collected Gosling pulsatile index (PI) and Pourcelot resistance index (RI) of the arteries. TCBFV was calculated from the mean blood flood velocity and vessel chamber size of the internal carotid artery (ICA) and basilar artery (BA). Fifty children completed the examinations. The TCBFV was 1538 ± 416 ml/min with mean cerebral blood flow volume of 571 ± 241 ml/min for the ICA system and 983 ± 343 ml/min for the BA system. PI, RI, and the velocities of A1, A2, M1, M2, BA, ICA, and TCBFV were not significantly different between girls and boys in this age group. In this study, we used TCCD to determine the normal data of main cerebral arteries and TCBFV of pre-school children in Taiwan. The reference data of velocities and other parameters of main cerebral arteries from our study may serve as a guide for additional pediatric cerebral hemodynamic studies.

Comparison Between Transcranial Color Doppler Ultrasonography and Angiography in the Confirmation of Brain Death

Objective Cerebral blood flow tests have increasingly been advocated for the confirmation of brain death (BD). Angiography has been considered the gold standard in the diagnosis of BD but is invasive. We validated transcranial color Doppler ultrasonography (TCD) to confirm BD by comparing it to angiography. Patients and methods Forty patients experienced the clinical diagnosis of brain death due to head injury in 19 cases (47.5%), cerebral hemorrhage in 11 (27.5%), subarachnoid hemorrhage in 7 (17.5%), and cerebral infarction in 3 (7.5%). Blood pressure, heart rate, S PO2, and P CO2 were monitored throughout the study. Patients were excluded if episodes of hypoxia, arrhythmia, and hypotension occurred during examinations, or if the TCD was not technically feasible. Results Both angiography and TCD confirmed BD in all patients. The agreement between the above methods to confirm BD was 100%. Angiography showed the absence of filling of intracranial arteries, while TCD revealed: (1) brief systolic forward flow or systolic spikes and diastolic reversed flow (50%); (2) brief systolic forward flow or systolic spikes and no diastolic flow (25%); (3) no demonstrable flow in a patient in whom flow had been clearly documented on a previous TCD examination (12.5%). Five patients required repeated TCD examinations, because of initial detection of a diastolic to-and-fro flow pattern. BD was confirmed by TCD in the above patients after 30 hours of clinical BD. Conclusion TCD was a sensitive tool to diagnose BD, affording a reliable alternative examination to standard angiography.

Color Doppler Sonographic Evaluation of Collateral Circulation in Patients with Cerebral Aneurysms and the Occlusion of the Brachiocephalic Vessels

The objective of this study was to assess the collateral circulation and blood flow velocity in arteries forming collateral circulation in patients with cerebral aneurysms and the occlusion of the brachiocephalic vessels. Between 1989 and 2004 we examined a group of seven consecutive patients with diagnosed cerebral aneurysm and occlusion of the extracranial artery by means of cerebral angiography, transcranial color-coded sonography (TCCS) and color Doppler sonography of extracranial arteries. The Doppler examination results achieved in this group were compared with the Doppler results of 40 healthy subjects from a control group. Three patients were diagnosed with an occluded innominate artery. In four other cases an occlusion of the extracranial segment of the internal carotid artery was found. The aneurysms were located on intracranial arteries of collateral flow. The innominate artery occlusion resulted in a hemodynamic effect which was a complete vertebral steal and systolic deceleration (in one case) or alternating flow (in two cases) in the right common carotid artery. An additional route of collateral circulation in all these cases led from extracranial carotid branches through the right external carotid artery to the ipsilateral internal carotid artery. In all seven patients, 13 intracranial collateral pathways were examined. In eight of them, including four cases with cerebral aneurysms, an increase in blood flow velocity was observed. In the remaining five cases, including three cases with cerebral aneurysms, the mean blood velocity was within the normal range. The anterior communicating artery (AComA) formed the main intracranial collateral pathway which was found in seven patients, including three patients with diagnosed AComA aneurysm. Blood flow velocity in ipsilateral (on the obstructed side) and contralateral (on the unobstructed side) anterior cerebral artery, as well as pulsatility and resistance indexes in contralateral anterior cerebral and middle cerebral arteries were higher compared with healthy control subjects. In the ipsilateral middle cerebral artery a relative, insignificant decrease of pulsatility and resistance indexes was detected. Ipsilateral and contralateral middle cerebral artery blood flow velocities were lower compared with the control group. Occlusion of the brachiocephalic vessels leads to formation of collateral circulation through the circle of Willis and the extracranial collaterals connecting the external and internal carotid arteries. An increase in blood flow velocity is commonly observed in intracranial arteries forming a collateral pathways. In some cases, not excluding arteries with a cerebral aneurysm, the increase in blood flow velocity is insignificant or none at all. This study shows that formation of a cerebral aneurysm is not always related to an increase in the flow velocity of collateral arteries.

Standardization of flow velocities with respect to age and sex improves the accuracy of transcranial color Doppler sonography of middle cerebral artery spasm.

The overall accuracy of transcranial Doppler sonography in the diagnosis of middle cerebral artery spasm has not been established. Moreover, the factors of age and sex have not been addressed in most studies. In this article, we present receiver operating characteristic (ROC) curve analysis of the accuracy of transcranial color Doppler sonography in diagnosing middle cerebral artery spasm on the basis of flow velocities standardized for age and sex. SUBJECTS AND METHODS. We prospectively studied 214 consecutive patients (110 male, 104 female; age range, 12-77 years) who were routinely referred for cerebral angiography. Middle cerebral artery spasm was graded as mild (</= 25% of vessel caliber reduction) and moderate to severe (> 25% reduction). Angle-corrected blood velocity measurements were obtained using a 2.5-MHz probe. The velocity values were reexpressed as a percentage of the mean of normal reference values for the relevant age, for subjects younger than 40 years, and for sex. The prevalence of spasm among 335 arteries studied was 8.1% for mild and 12.8% for moderate to severe middle cerebral artery narrowing. For distinguishing all or moderate to severe vasospasm from lesser grades of vasospasm, peak systolic velocity was the best parameter. Areas under ROC curves for all and moderate to severe middle cerebral artery spasms were 0.83 and 0.92, respectively. After standardization, the ROC areas increased significantly (p < 0.05) for all, to 0.86, and only slightly, to 0.93, for moderate to severe spasms. For all grades of middle cerebral artery spasm, the best efficiencies were found at standardized velocity value of 170%. The accuracy of transcranial color Doppler sonography is high in the identification of middle cerebral artery spasm. Standardization of velocities with respect to age and sex increases the accuracy of the method in diagnosing mild middle cerebral artery spasms.

Cerebral Arteriovenous Malformation: Presentation by Three-Dimensional Substraction Color Power Angiography

Background Recent advances in ultrasound technology now allow the sonographer to obtain three-dimensional color power angiography (3D-CPA) vascular images and to enhance these images by rotation and subtraction. The purpose of this report is to demonstrate the sonographic presentation of a cerebral arteriovenous malformation (AVM) using these advanced techniques. Patient During an emergency operation to evacuate a large subdural hematoma, the surgeon noted several aneurysmal veins, suggesting the presence of an underlying AVM. Angiography showed a compact AVM arising from a posterior temporal branch of the right posterior cerebral artery (PCA). Findings Transcranial color Doppler ultrasonography (CDU) revealed an AVM in the right temporal lobe with a feeder arising from the P1 segment of the right PCA. 3D-CPA images of the AVM were then developed, rotated, and subtracted. These enhanced images provided superior definition of the arterial and venous architecture and were comparable to the angiogram. Conclusion 3D-CPA provided high-resolution, accurate, noninvasive images of a cerebral AVM. The added anatomic detail allowed by this technique was complementary to the hemodynamic information provided by CDU.

Diagnosis and follow-up of craniopharyngiomas with transcranial Doppler sonography.

Craniopharyngiomas are the most common parasellar neoplasms in children. Because it is difficult to diagnose subtle visual or endocrinologic changes in young children at an early stage, craniopharyngiomas may grow to a considerable size before diagnosis. We used transcranial Doppler sonography to diagnose and follow up 5 patients with craniopharyngiomas. There were 3 girls and 2 boys aged from 6 years 4 months to 10 years. The initial manifestations were visual defects (n = 4), headaches (n = 3), and growth restriction (n = 1). One patient had a diagnosis of a craniopharyngioma on the basis of sonography before brain computed tomography. All 5 patients were examined with transcranial color Doppler sonography before surgery and for postoperative follow-up. Sonography showed a cystic component with calcification in 4 patients and a solid component in 1 patient; these findings were compatible with the computed tomographic findings. Displacement of the vessels of the circle of Willis was found. Tumor recurrences were detected early on transcranial sonography in 4 patients at 1 to 8 months' follow-up; these were proved by computed tomography. Transcranial Doppler sonography is a convenient tool for the diagnosis, evaluation, and follow-up of craniopharyngiomas. It can adequately describe vessels around the tumors and show tumor recurrence at an early stage.

Accuracy of transcranial color Doppler ultrasonography in the diagnosis of middle cerebral artery spasm determined by receiver operating characteristic analysis.

The value of transcranial Doppler ultrasonography for the detection of middle cerebral artery (MCA) spasm has been asserted. None of the published studies, however, has adequately scrutinized the overall diagnostic accuracy of this procedure. There are only sporadic reports concerning the utility of transcranial color Doppler (TCCD) ultrasonography, although this method has been proved to be more precise. In this study the authors attempted to estimate the performance of TCCD ultrasonography in detecting MCA narrowing by using receiver operating characteristic (ROC) curve analysis, based on TCCD studies obtained in a relatively large, randomly selected population of patients. Transcranial color Doppler ultrasonography studies were obtained in 100 consecutive patients (54 men and 46 women ages 18-74 years, median age 50 years) routinely referred by neurosurgeons for intraarterial angiography. The M1 segment of the MCA was insonated using a 2.5-MHz probe via a temporal acoustic window, and angle-corrected flow velocities were obtained. Angiographically depicted vasospasm was graded as none, mild (< or = 25% vessel caliber reduction), and moderate to severe (> 25% vessel caliber reduction). The effectiveness of TCCD ultrasonography in diagnosing MCA spasm was evaluated by calculating the areas under the ROC curves (Az). Of the 200 MCAs examined, 173 were successfully visualized with the aid of TCCD ultrasonography. Mild vasospasm was angiographically diagnosed in 15 arteries and moderate-to-severe vasospasm in 28. The best-performing TCCD parameter for the detection of MCA narrowing was revealed to be peak systolic velocity. The Az value for moderate-to-severe vasospasm only was 0.93 and that for all vasospasms was 0.8. The best efficiency, that is, the optimal tradeoff between sensitivity and specificity in diagnosing vasospasms, was associated with a peak systolic velocity of 182 cm/second. The performance of TCCD ultrasonography in the diagnosis of advanced MCA narrowing is very good, and is acceptable for all vasospasms. The best-performing parameter was peak systolic velocity.

Transcranial Colour Doppler Sonography in the Management of a Patient with Spontaneous Intracranial Haematoma

We present a case which demonstrates the merits of transcranial colour Doppler sonography (TCCD) in the diagnosis and monitoring of patients with spontaneous intracerebral haematoma. With this method it was possible to follow up disturbances of cerebral circulation, which allowed for the identification of critical states early enough to make decisions as to neurosurgical intervention. It should be emphasized that TCCD enabled us to discriminate between conditions in which the cerebral circulation was efficiently maintained and those in which it was insufficient, whilst increases in intracranial pressure and CT findings were similar in both situations. It appears that TCCD could be helpful in the detection of both hyperaemia and cerebral vasospasm.

Transcranial color Doppler sonography in the emergency diagnosis of middle cerebral artery occlusion in a patient after head injury: Case report

The purpose of this report is to highlight the utility of transcranial color Doppler sonography (TCCDS) in the emergency diagnosis of an ischemic stroke in a 64-year-old patient after head injury. An emergency CT identified a subdural hematoma, subarachnoid hemorrhage, a brain contusion and edema. The patient's status deteriorated after admission, and a second CT revealed an intracerebral hematoma and marked mass effect. Transcranial color sonography revealed no flow in the ipsilateral middle and anterior cerebral arteries, which was consistent with ischemic stroke. This case demonstrates that transcranial color Doppler sonography performed early after head injury may be useful in detecting associated occlusion of cerebral vessels.

A guide to the identification of major cerebral arteries with transcranial color Doppler sonography.

A Guide to the Identification of Major Cerebral Arteries with Transcranial Color Doppler SonographyJ. Krejza1, Z. Mariak2, E. R. Melhem3 and R. J. Bert4Audio Available | Share

Endovascular treatment of cerebral vasospasm: assessment of treatment effect by cerebral angiography and transcranial colour Doppler sonography.

In a retrospective study of 30 consecutive patients with symptomatic vasospasm the mean degree of narrowing as compared to the initial angiogram was 35% (+/- 24%) in 12 intradural internal carotid arteries (ICA), 42% (+/- 17%) in 42 proximal middle cerebral (MCA) and 38% (+/- 19%) in 27 anterior cerebral arteries (ACA). The corresponding increase in mean flow velocities from baseline values obtained by transcranial colour Doppler sonography (TCD) within 12 h of the first angiogram to the time of clinical vasospasm was considerably higher, with 49% (+/- 34%) in the ICA 119% (+/- 92%) in the MCA and 147% (+/- 170%) in the ACA. Following superselective intra-arterial papaverine application in 66 arteries and balloon angioplasty of 15 arteries, 78 (96.3%) of 81 dilated. Sustained clinical improvement was achieved in 22 patients (73.3%). The mean reversal of angiographic vasospasm was 71% for the ICA (range 10-100%), 81% for the MCA (range 9-100%) and 82% (range 0-100%) for the A1 segment. The mean reduction of flow velocities after treatment was much less with 23% (+/- 21%) in the ICA, 32% (+/- 24%) in the MCA and 25% (+/- 22%) in the A1 segment.

内頚動脈および中大脳動脈閉塞症例における内頚動脈血流速度波形の解析

We measured end-diastolic flow velocities (EDFVs) of the internal carotid artery (ICA) bilaterally by duplex ultrasonography and calculated their side-to-side ratios in 14 healthy volunteers (normal group) and 29 patients with unilateral occlusion of the middle cerebral artery (MCA, n=5), distal internal carotid artery (distal ICA, n=7) or the origin of the ICA (ICA origin, n=17) . The site of arterial occlusion was confirmed by digital subtraction angiography, magnetic resonance angiography or transcranial color Doppler ultrasonography. The side-to-side ratio was 1.11±0.06 in the normal group. In the MCA occlusion group, it was 1.73±0.39 and exceeded 1.23 (the mean+2SD of the side-to-side ratio in the normal group) in four patients. In four patients with distal ICA occlusion, EDFVs were zero. However, in the other three patients with a flow to the posterior communicating artery or to moyamoya vessels, there was residual flow in the end-diastolic phase, and EDFV ratios were greater than 1.23. In the ICA origin occlusion group, no flow could be detected throughout the systolic and diastolic phases. In conclusion, measurement of EDFV and calculation of EDFV ratios of the ICA seem useful as screening measures to determine the site of occlusion of the ICA or MCA.

Transcranial Doppler: state of the art

Introduction. Transcranial color Doppler sonography permits the accurate assessment of intracranial arteries. The latest Doppler units, using the color and power techniques, can show even very small flow volumes (1×1 mm). Low frequency (2–2.5 MHz) and very focused transducers are used in transcranial color Doppler. The skull is a very strong barrier for ultrasounds, which requires the use of some acoustic windows like some thin portions of the skull bone or some natural skull foramina. The use of echocontrast agents in color Doppler seems to increase the applications of transcranial studies. Objective. (1) To report on transcranial color Doppler technique and findings. (2) To assess the role of contrast agents in the visualization of intracranial vessels. (3) To define the main indications of this technique. Material and methods. The temporal, the orbital and the suboccipital are the main acoustic windows used for transcranial color Doppler studies. We use phased-array transducers (2–2.5 MHz) and, preferrably, the echocontrast agent. We examined 15 patients with severe internal carotid artery stenoses after the infusion of Levovist™ (Schering AG, Berlin, Germany) suspension (8 ml at 300 mg Galactose/ml, infused at 0.5 ml/s). Results. Levovist™ infusion permitted to depict the main intracranial vessels in all cases. The middle and the anterior cerebral arteries are shown through the temporal window. The former is the main cerebral artery, it is the easiest to identify and presents the highest peak systolic velocity. The orbital window can be used to visualize the ophthalmic artery and the internal carotid artery siphon, while the vertebral and the basilar arteries are demonstrated through the suboccipital window. Discussion. We report the most important findings and discuss the main indications of transcranial color Doppler studies. In addition to flow presence and direction, the main indices of arterial flow can be measured thanks to contrast agent administration, namely the peak systolic velocity, the end diastolic velocity, the resistance index and the pulsatility index. A morphological assessment of the Willis circle can also be carried out with color and power Doppler. Functional studies can be performed to assess the residual autoregulatory function of the cerebral circle in the patients with internal carotid artery stenosis or occlusion. The development of intracranial collateral circles can also be studied in these patients. Moreover, the M1 segment of the middle cerebral artery and the internal carotid artery siphon can be demonstrated directly. Transcranial color Doppler is also a useful tool to detect vasospasm after subarachnoid hemorrhage and to monitor blood flow velocity in the middle cerebral artery during carotid endarterectomy. The assessment of blood supply to arteriovenous malformations and to intracranial neoplasms is another application. Conclusion. With reference to internal carotid stenoses, the main applications of transcranial color Doppler are the study of intracranial vessels, of intracranial arterial stenosis, of arteriovenous malformations and of Willis circle aneurysms, as well as the monitoring of blood flow velocity during carotid endarterectomy. Echocontrast agents play an important role in the visualization of intracranial vessels.