Source of cerebral microembolic signals in occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: There are several possible sources of cerebral embolic ischaemia distal to an occlusion of the internal carotid artery (ICA). Our aim was to identify the source of microembolic signals in the ipsilateral middle cerebral artery (MCA) by taking simultaneous bitemporal transcranial Doppler ultrasound recordings of the ipsilateral MCA and the contralateral ACA to find the route of potential microembolic material to MCA. SUBJECTS AND METHODS: The study group consisted of 38 patients with an occlusion of the ICA. With extracranial duplex sonography (ACUSON 128 XP; 7 MHz), performed by an experienced sonographer, the echo intensity and echo structure of the occluded ICA in the extracranial part (proximal) were classified as homogeneous or inhomogeneous. In addition, affected segments of the ipsilateral and contralateral carotid artery with arteriosclerotic vessel walls were compared. Microembolic signals were recorded with transcranial Doppler (TCD) monitoring. The microemboli counts in the MCA and ACA were added to the sum scores. RESULTS: The number of affected segments of the carotid artery on the ipsilateral (the bifurcation, the external or common carotid artery) and contralateral side of occluded ICA were equally distributed. In ipsilateral MCA 3.1, 7.1 microemboli (average mean, SD) with a range of between 0 and 34 were counted, in the contralateral ACA 0.3, 0.6 (range of between 0 and 2). Regression analysis confirmed the non-predictability of the microemboli variance on the ipsilateral side of the occlusion from the variance on the contralateral side (multiple r: 0.024). We found no significant correlation between the echo intensity or echo structure of the occluded artery and an increased rate of microemboli in the ipsilateral MCA. CONCLUSIONS: Our results indicate a predominantly ipsilateral source for cerebral microemboli in ICA occlusion. The rate of cerebral microembolic signals was not influenced by the echo structure and echo intensity of the occluded ICA.

Tolerability and antidepressive effect of brofaromine, a short-acting reversible MAO inhibitor--an open study.

The tolerability and antidepressive effect of brofaromine, a selective MAO-A inhibitor was tested in 14 depressive patients. None of the patients showed blood pressure or pulse frequency changes after ingesting tyramine-enriched meals. Four instances of agitation were observed as side effects. In two of these cases, the appearance of paranoid thinking and suicidal tendencies led to premature termination of the study. In 3 cases sleep disturbances, in particular difficulties in falling asleep, were observed. In the test of antidepressive effectiveness (measured on the HAMD-scale) significant improvement was observed from day 14 onwards.

Side effects from increased doses of carbamazepine on neuropsychological and posturographic parameters of humans.

Patients taking anticonvulsant drugs display a broad spectrum of side-effects. Particularly, in the beginning of treatment and with increasing doses of carbamazepine, side effects such as dizziness, ataxia, drowsiness and reduction of alertness occur, which improve some days after the dose has reached a stable level. Our aim was to find objective parameters for grading these side effects and to differentiate between neurophysiological and neuropsychological side effects of carbamazepine in a clinical situation. Twenty-two patients with trigeminal neuralgia were included for a follow-up study with increasing carbamazepine doses (0 mg to 600 mg). The effect of carbamazepine on postural stability was quantified by posturography. Different neuropsychological tests to study cognitive effects of carbamazepine were performed. The composite equilibrium score showed a significant reduction of postural stability with increasing doses of carbamazepine. In sensory analysis the somatosensory ratio was significantly influenced by increased doses of carbamazepine during the study. Mean reaction time of tonic alertness and physical alertness varied significantly with different doses of carbamazepine. There was a significant influence in patients attention during trail making tests and divided attention tests with increase in carbamazepine. In conclusion our observations show that the rate of change of carbamazepine doses is an important determinant of cognitive and motor functions in the phase of increasing doses.

Diagnostic value of three-dimensional transcranial contrast duplex sonography.

This study evaluated intracranial cerebral arteries using a new data acquisition system for transcranial three-dimensional (3D) ultrasonography with and without an echo contrast agent, with confirmation by cerebral angiography. Ten patients, studied with diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic window was performed using a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. A color transcranial duplex system with a power Doppler mode was used, and 3D data sets were acquired before and after the injection of transpulmonary-stable ultrasound contrast medium. Ipsilateral to the transducer, the anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 60%, all three or more branches of the MCA in 60%, posterior cerebral artery (PCA) in 60%, and posterior communicating artery (PCoA) in 60% were successfully imaged without the echo contrast agent. With the contrast agent, the ACA, MCA, three or more branches of the MCA, PCA, and PCoA were visible in 100%. The anterior communicating artery was visualized in 40% without contrast enhancement and in 90% with contrast enhancement. Contralateral to the transducer, the ACA (60%), MCA (30%), all three or more branches of the MCA (10%), PCA (20%), and PCoA (20%) were successfully imaged without contrast. Contrast enhancement improved the imaging success rate for the ACA (90%), MCA (80%), three or more branches of the MCA (80%), PCA (100%), and PCoA (100%). A transpulmonary-stable ultrasound contrast agent used in combination with 3D transcranial duplex ultrasonography can significantly improve the success rate for transcranial color duplex imaging of intracranial arteries.

Development and applications of 4-D ultrasound (dynamic 3-D) in neurosonology.

The development and application of color-coded data in three-dimensional (3-D) reconstruction or four-dimensional (4-D) imaging (equal to dynamic 3-D) are demonstrated. In 4-D imaging, electrocardiography-triggered data acquisition of consecutive phases during the heart cycle are stored to form a multiphase 3-D data set. The option of color-coded data gives a new insight into such hemodynamic information. In the past, 3-D reconstructions were simple unicolor images, as in power mode, and the color-coded hemodynamic information was lost. These new options are presented here, along with color-coded data in examples of angiographically controlled pathologic results in extracranial and intracranial vessels.

Transcranial 3D B-mode imaging in a case of cerebral hemorrhage.

The case of a patient with temporal lobe hemorrhage is presented. This is the first report of use of a new three-dimensional data acquisition system that entails free-hand scanning with three-dimensional transcranial duplex sonography. Three-dimensional image reconstruction reduced the spatial asymmetry inherent in oblique two-dimensional ultrasonography, making evaluation of the precise location, size, and anatomic relations of intracranial hemorrhage easier.

Influence of ECG-triggered data acquisition on reliability for carotid plaque volume measurements with a magnetic sensor three-dimensional ultrasound system.

Three-dimensional (3D) ultrasound reconstructions of the carotid arteries are based on multiple sections of two-dimensional data. Some 3D systems use an electrocardiography (ECG)-triggered data acquisition for 3D reconstructions of pulsatile vessels such as carotid arteries. No systematic comparison of 3D data, acquired with and without ECG triggering, has been reported. We used a new magnetic sensor system allowing freehand scanning for data acquisition. Our aim was to test the effect of ECG triggering on the reliability of plaque volume measurements in the carotid arteries. Data acquisition in the carotid arteries in 25 patients (one plaque from each patient) was performed using two different procedures for data acquisition: 1) a magnetic sensor system for a data acquisition without ECG-triggering, and 2) a magnetic sensor system with ECG-triggered data acquisition. All plaque volumes were measured using manual tracing of the outlines of the plaques. The following reliability data (mean values) were obtained: magnetic sensor system without ECG triggering: intrareader variability 13.3%, interreader variability 16.7%, follow-up variability 16.3%; magnetic sensor system with ECG triggering: intrareader variability 4.6%, interreader variability 4.5%, follow-up variability 5.2%. Carotid plaque volume measurements obtained using a magnetic sensor system with freehand scanning and ECG triggering is highly reliable. ECG triggering is necessary, because a magnetic sensor system without ECG triggering resulted in reduced reliability for plaque volume measurements.

Effect of echo contrast media on the visualization of transverse sinus thrombosis with transcranial 3-D duplex sonography.

Transcranial duplex sonography has the capacity of detecting venous flow as in the transverse sinus. During a 6-month period, 28 consecutive patients (mean age 55 y) with a clinically suspected diagnosis of cerebral sinus thrombosis were included in the study. All patients were examined using 3-D ultrasound equipment within 24 h of having undergone either venous computerized tomography (CT), venous magnetic resonance imaging (MRI) or cerebral angiography. A total of 22 healthy patients had a normal venous CT, venous MRI or cerebral angiography of both transverse sinuses. Before echo contrast enhancement, the transverse sinus could be visualized in only 2 of these 44 sinuses (22 patients). A total of 6 patients with an unilaterally missed transverse sinus in 3-D ultrasound suffered from sinus thrombosis (n = 3), hypoplasia (n = 2) or aplasia (n = 1) of the unilateral transverse sinus in neuroradiological tests. In none of the patients with an thrombosis of the transverse sinus did ultrasound contrast media application improve the visualization of the affected sinus. Our study confirms that the normal transverse sinus, insonated through the contralateral temporal bone, often cannot be visualized without the use of contrast agents. With transcranial 3-D duplex sonography, a differentiation between thrombosis, hypoplasia and aplasia of the sinus was not possible.

Quantification of atherosclerotic plaques in carotid arteries by three-dimensional ultrasound.

The aim of this study was to develop three-dimensional (3D) ultrasound imaging of the carotid arteries in order to reduce intraexaminer and interexaminer variabilities of volume measurements in follow-up scans of atherosclerotic plaques. The non-invasive quantification of human atherosclerosis by 3D ultrasound was performed using a three-dimensional computer based image reconstruction. The linear movements of the transducer were driven by a motor triggered by electrocardiography. The method included an option to change angle of insonation and a correction of skin contact adaptation. Repeated measurements were performed at weekly intervals in 70 patients. Variabilities and ranges of three newly developed evaluation procedures of plaque volumes (manual tracing, threshold procedure, watershed algorithm) were used. Intraexaminer variability varied between 2.8% (watershed algorithm) and 4.1% (threshold procedure). Interexaminer variability ranged from 4.2% (manual tracing) to 7.6% (threshold procedure), follow-up measurements from 5.2% (watershed algorithm) to 9.4% (threshold procedure). Pearson correlation coefficients of interexaminer agreement and also those between all three measurement procedures were highly significant (p < 0.01). We conclude that the newly developed 3D computer based image reconstruction allows repeated quantification of moderate atherosclerosis with a high reliability.

[Doppler and duplex sonography of the vertebral arteries]. / Die Doppler- und Duplexsonographie der Vertebralarterien.

In a prospective study 451 patients were examined with extracranial CW-Doppler sonography (mastoidal slope), suboccipital transcranial Doppler sonography and colour-coded duplex sonography to evaluate unusual vertebral arteries (hypoplasia, stenosis and occlusion). Colour duplex sonography was used as reference method. CW-Doppler sonography had a sensitivity of 100% and a specificity of 27% for the detection of an unusual vertebral artery. For transcranial Doppler sonography these values are 38% and 58%. Our study showed that CW-Doppler is a useful screening examination for identifying pathological findings of vertebral arteries. In case of abnormalities in CW-Doppler, duplex sonography, especially colour-coded duplex sonography, should be added.

Vascular risk factors for atherosclerotic plaque progression in carotid artery.

Two-dimensional ultrasound is a widely used technique for the clinical assessment of carotid atherosclerosis. We measured volumes of atherosclerotic plaques in carotid arteries in 70 patients with a newly developed and tested three-dimensional ultrasound method over a period of twelve months to determine the relation between progression or regression of plaque volume and vascular risk factors. In multiple regression analysis of age, size, smoking, total cholesterol, HDL-cholesterol, HDL/total cholesterol ratio, LDL-cholesterol, triglycerides, HbA1, diastolic and systolic blood pressure, the strongest predictor of plaque progression (p < 0.01) was diastolic blood pressure, diabetes came next (p < 0.05). The optimal adjustment of all risk factors showed a significant influence on plaque progression (r: 0.76).

Carotid body tumor: appearance on color-flow Doppler sonography.

Color doppler sonography permits differentiation of vascular malformations in the neck from solid and cystic tumors. This case report of a 67-yearly-old woman demonstrates the hypervascularized nature of a carotid body tumor displacing the internal carotid artery and fed by branches of the external carotid artery.

[A new method for imaging intracranial cerebral arteries--3-dimensional transcranial duplex ultrasonography with image enhancement]. / Ein neues Verfahren zur Darstellung der intrakraniellen Hirnarterien--die dreidimensionale transkranielle Duplexsonographie mit Signalverstärkung.

AIM: A new data acquisition system for transcranial 3 D-ultrasonography was used. The present study examines the evaluation of intracranial cerebral arteries by 3 D-ultrasound and echo contrast agents in comparison to cerebral angiography. METHODS: Ten patients, who underwent diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic bone window was performed with a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. We used a transcranial duplex system with power mode and stored a 3 D-data set before injection of transpulmonary stable contrast medium and afterwards. RESULTS: Ipsilateral to the transducer anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 90%, three or more branches of MCA in 60% and posterior cerebral artery (PCA) in 40% were analysed without injecting an echo contrast agent. After the contrast injection ACA, MCA, branches of MCA and PCA in 100% were visible. In 70% of cases the posterior and anterior communicating arteries were visualised only by means of a contrast agent. CONCLUSION: Application of a transpulmonary stable ultrasound contrast agent in combination with 3 D transcranial duplex ultrasonography significantly enhances the visualisation of intracranial arteries.

[The value of color duplex for sonography of the vertebral artery]. / Die Bedeutung des Farb-Duplex für die Sonographie der A. vertebralis.

The prognosis of patients with carotid artery disease in combination with symptoms of vertebrobasilar TIA is worse than that of patients with single carotid territory transient ischemic attacks. We investigated 30 patients with stenosis or occlusion of the carotid arteries into two groups. All patients underwent color duplex imaging of the vertebral artery between the transverse processes of the cervical spine (pars costotransversaria). Diameter, systolic and diastolic velocities were measured. Nearly all patients with clinical signs of vertebrobasilar TIA showed a stenosis or a hypoplasia of vertebral artery in addition to carotid artery disease.

[Operation and angioplasty in cerebrovascular disorders]. / Operation und Angioplastie bei zerebralen Durchblutungsstörungen.

Carotid endarterectomy until recently was performed to prevent the progression of a stenosis to an occlusion and hemodynamically induced strokes in patients with tight stenosis. Operation of ulcerated plaques or stenosis was supposed to prevent embolic stroke. The operation has no indication for a stenosis of the internal carotid artery (ICA) > 50% and < 90% in asymptomatic persons. Whether persons with an asymptomatic stenosis > 90% show a preventive effect of the operation is not known at this time. According to the Mayo-Clinic study, persons with asymptomatic ICA stenosis should be treated with aspirin to prevent myocardial infarction. Two large controlled trials have shown that endarterectomy can prevent stroke in patients with transient ischemic attacks (TIA) or minor stroke and an ICA-stenosis > 70%. This preventive effect is lost when the complication rate of the procedure is higher than 5% (mortality and morbidity). In patients with stenosis < 30% the operation has no preventive effect. Both studies continue to recruit patients with symptomatic stenoses between 30 and 70%. Patients with severe neurological deficits or a large lesion in CT should not be operated as would be patients with an acute stroke. The extra-intracranial bypass operation did not prevent stroke in patients with an occlusion of the ICA or severe stenosis or occlusion of the middle cerebral artery. Angioplasty has been applied to dilate stenoses of the subclavian artery in patients with subclavian-steal syndrome and disabling vertebro-basilar TIA. Angioplasty in the carotid artery is still an experimental procedure, which should only be applied in controlled trials.

[Neurological diagnosis and therapeutic measures in cerebral embolism]. / Neurologische Diagnostik und therapeutische Massnahmen bei zerebralen Embolien.

UNLABELLED: Stroke is caused by intracerebral or subarachnoid hemorrhage in about 15% of clinical presentations and the remaining 85% result from ischemia. About 15% of ischemic strokes are caused by emboli arising from the heart. In younger patients (18 to 50 years) with ischemic strokes or transient ischemic attacks (TIA), the incidence of cardiac embolism is increased to 23 to 36%. DIAGNOSIS: a) SYMPTOMS: Individual neurologic symptoms of stroke do not provide sensitive or specific indications of the underlying mechanism. In 25 to 82% of patients with possible embolic stroke, there is an acute onset with initially maximal manifestation of neurologic deficits as well an initial loss of consciousness in 20%. Antecedent TIAs occur in 11 to 30% but are more frequently associated with arteriosclerotic vascular disease. Stroke due to cardiac embolism mostly involves the cortex of both hemispheres and causes its symptoms through occlusion of isolated arterial branches. Cerebral infarctions with isolated Wernicke aphasia, global aphasia without hemiparesis and isolated syndromes of the posterior cerebral artery are frequently due to cardiac embolism. The strokes in 16 to 22% of those caused by cardiac embolism are found in subcortical regions. Amaurosis fugax is most frequently due to high-grade stenosis of the internal carotid artery. In association with cardiac embolism, secondary hemorrhage into the infarcted zone can frequently be seen on CT scans. b) DIAGNOSTIC PROCEDURES: In the case of cardiac embolism, the computer tomography (CT) usually shows infarction in or near the cortex in the region of the middle or posterior cerebral artery. About 10 to 20% of strokes due to cardiac embolism show secondary hemorrhage after the event, more frequently in association with large infarcts and in patients on anticoagulant treatment. Angiography can provide indirect evidence of embolic origin by showing occlusion of an intracerebral artery in the absence of arteriosclerotic changes. Traditional echocardiography may detect a possible source of embolism in 10% of all patients with ischemic stroke, only in 1.5%, however, in patients with no clinical signs of heart disease. Transesophageal echocardiography has a higher sensitivity for detection of sources of cardiac embolism. The use of magnetic resonance tomography and ultrafast CT will assume greater importance in the future. Holter monitoring of the ECG in patients with acute ischemic stroke or TIAs detects arrhythmias possibly responsible for emboli in about 2%. High-risk patients: The most common cause of cardiac embolism is atrial fibrillation (45%), followed by ischemic heart disease (15%) and in 10% each, aneurysm, rheumatic heart disease, prosthetic valve replacement and other cardiac diseases.(ABSTRACT TRUNCATED AT 400 WORDS)

3D ultrasound measurement of atherosclerotic plaque volume in carotid arteries.

The aim of the present study was to measure the volume of atherosclerotic plaques using three-dimensional (3D) ultrasound imaging of the carotid arteries and to reduce intra- and interexaminer variabilities in follow-up scans of atherosclerotic plaques. The noninvasive quantification of human atherosclerosis by 3D ultrasound was performed by a 3D computer-based image reconstruction (3D ultrasound). The linear movements of the transducer were driven by a motor triggered by ECG. The method included an option to change angle insonation and a correction of skin contact adaptation. Repeated measurements were performed in a weekly interval in 60 patients. Three evaluation procedures (manual tracing, threshold procedure, watershed algorithm) were developed. Intraexaminer mean variability varied between 2.8 (watershed algorithm) and 4.4% (threshold procedure). Interexaminer mean variability ranged from 3.8 (manual tracing) to 6.8% (threshold procedure), follow-up measurements from 5.3 (watershed algorithm) to 8.9% (threshold procedure). The newly developed 3D computer-based image reconstruction allows repeated quantification of moderate atherosclerosis with a low variability and will be applied in prospective studies of the regression or progression of atherosclerosis.

[Various ultrasound methods for studying the vertebral artery--a comparative evaluation]. / Die verschiedenen Ultraschallmethoden zur Untersuchung der Arteria vertebralis--eine vergleichende Wertung.

In a prospective study 451 patients were examined with extracranial continuous-wave (CW) Doppler sonography, transcranial Doppler sonography and color coded duplex sonography in order to evaluate the diagnostic accuracy of the three methods for vertebral artery pathology (hypoplasia, proximal and distal stenosis and occlusion). Color duplex sonography was used as the reference method. CW-Doppler sonography (mastoidal slope) had a sensitivity of 100% and a specificity of 27% for the detection of pathological changes in vertebral arteries (VA). For suboccipital transcranial Doppler sonography these values were 38% and 58%. Extracranial Doppler sonography and transcranial Doppler sonography are often unsuitable for differentiating between proximal stenosis and hypoplasia of VA. Transcranial Doppler sonography of the terminal segments of VA resulted in normal flow parameters in 27% of cases with proximal stenosis and in 50% in cases of proximal occlusion. Flow was normal in these particular cases owing to a more distal collateralisation of the VA. The terms "hypoplasia" and "asymmetric" of VA are discussed.

Color-coded duplex sonography in the evaluation of vertebral arteries.

The vertebral arteries of 100 healthy subjects were studied with color-coded duplex sonography. All subjects experienced no clinical symptoms attributable to the vertebrobasilar system. Diastolic and systolic flow velocities could be measured in color-coded duplex sonography in 94% of the right and 92% of the left vertebral arteries. The anechogenic band between the transverse processes of the cervical spine which helps to identify the vertebral artery could not be discerned reliably in 18% of the subjects. In these cases the colored blood flow signals were used as a guide line to place the doppler sample volume exactly within the arterial lumen. Thus color coded duplex sonography is a useful tool for a rapid and definitely identification of vertebral artery and for pulsed Doppler flow measurements with velocity spectrum. For measurements in diameter of hypoplastic and normal vertebral arteries gray scale methodic is a more accurate assessment, as some artifacts of color-coded duplex sonography exist.