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ZusammenfassungDie nicht traumatische Subarachnoidalblutung (SAB) ist meist auf die Ruptur eines intrakraniellen Aneurysmas zurückzuführen. Aber es gibt weitere, sehr unterschiedliche Erkrankungen, die mögliche Differenzialdiagnosen sind. Sie richtig zu diagnostizieren, ist alleine schon von Relevanz, weil sich Ätiologie, Behandlung, Komplikationen, Prognose und sogar die Folgebildgebung unterscheiden.

Zusammenfassung Hintergrund Der Artikel gibt einen Überblick über die aktuellen diagnostischen Einsatzmöglichkeiten sonographischer Anwendung in der neurologischen Intensivmedizin. Methoden Selektive Literaturrecherche mit kritischer Beurteilung ab dem Jahr 1984 sowie nationaler und internationaler Leitlinien sowie Expertenmeinung. Ergebnisse Neben der raschen validen Abklärung akuter Schlaganfälle bieten verschiedene neurosonografische Monitoring-verfahren gerade in der Intensivmedizin spezifische Vorteile wie die beliebig häufige Wiederholbarkeit am Patientenbett selbst und die Darstellung in Echtzeit. Innovative Entwicklungen machen die Neurosonografie auch wissenschaftlich zu einem interessanten Gebiet. Schlussfolgerung Die neurosonografische Diagnostik nimmt seit Jahren einen wichtigen Stellenwert in der neurologischen Intensivmedizin ein. Weitere Anstrengungen sind notwendig, um die Verbreitung der Methode zu fördern und durch wissenschaftliche Evidenz zu stärken.

Diagnostic ultrasound is a powerful non-invasive tool that enables bedside monitoring which is readily available and repeatable. The combination of B-mode, pulsed-wave Doppler and colour flow imaging can be effectively used in the examination of the extra- and intracranial parenchymatous and vascular structures via transcutaneous and transcranial insonation. This chapter gives an overview of the strengths and domain of up-to-date neurovascular sonography, current fields of research as well as an outlook on future applications.

Background: Transient ischemic attack (TIA) patients are at high risk of short-term stroke, myocardial infarction and vascular death. Stroke risk is reduced by immediate treatment initialization. Stroke unit treatment is recommended for TIA patients. We established an outpatient TIA clinic to address the question whether outpatient evaluation of suspected TIA is safe. Methods: TIA workup included cerebral imaging, duplex sonography, transcranial Doppler screening for patent foramen ovale, electrocardiography, blood tests, ABCD2 score and ankle-brachial index within one day. TIA patients received secondary prophylaxis immediately. TIA patients fulfilling predefined criteria for high early stroke risk (ABCD2 score ≧4 points and TIA within 72 h, symptomatic stenosis, newly detected atrial fibrillation, recurrent TIA) were referred to the stroke unit. The remaining patients were discharged home. 90-day telephone follow-up was obtained. Results: 123 consecutive patients with suspected TIA (53 male, age 59 ± 17.2 years) were prospectively evaluated. TIA or minor stroke was diagnosed in 69 (56%), and TIA mimics in 54 (44%) patients. Median time from symptom onset to presentation was 48 h (1 h to 3 months). Patients with TIA/minor stroke presented significantly more frequently with ABCD2 score ≧4 points (p = 0.021). Twelve patients (9.8%) were admitted to the stroke unit. There were 2 strokes during follow-up. The stroke rate was 1.6% within all patients, and 2.9% within the subgroup of patients with TIA/minor stroke, compared to 5.7% predicted by the ABCD2 score. Other vascular end points were not found. Conclusion: Based on risk stratification, outpatient evaluation of TIA is safe. TIA mimics are frequent.

Our purpose was to evaluate the agreement of transcranial color-coded duplex sonography (TCCS) measurements and intra-arterial digital subtraction angiography (DSA) findings in determining the extent of spontaneous cross-flow via the anterior communicating artery (AcoA) in patients with internal carotid artery (ICA) stenosis.Thirty adult patients with suspected uni- or bilateral high-grade carotid artery stenosis were prospectively examined by DSA and angle-corrected TCCS. The extent of cross-flow was determined considering retrograde flow in the ipsilateral anterior cerebral artery (ACA) and sideto-side differences of the A1-segments of the ACA and middle cerebral arteries (MCAs) by both techniques. Cross-flow was angiographically categorized by means of a four-step scale. DSA findings were correlated with side-to-side differences in mean blood flow velocity as well as flow direction measured by TCCS.Twenty-seven of 30 patients had a uni- or bilateral ICA stenosis of49%. Excellent agreement between TCCS and DSA was evaluated for the detection of lack (grades 0 and 1) or presence (grades 2 and 3) of reversed flow in the ACA (sensitivity 100%, specificity 93%, positive predictive value 94%). Post hoc analysis of the mean velocities in the ACA and MCA revealed a side-to-side difference of 25 cm/s as a cutting point allowing for definition of a corresponding four-grade scale for ultrasound. However, full agreement, i.e.same grade of cross-flow detected by both techniques, was only found in 17(57%) of 30 cases.Non-invasive TCCS is reliable for detecting reversed flow in the ACA in patients with ICA stenosis. However, there is only a moderate agreement between angiography and TCCS in quantifying the extent of spontaneous anterior cross-flow because different information on the intracranial hemodynamics may be obtained.

Background and Purpose: The major limitation of native transcranial colour-coded duplex sonography (TCCS) in older stroke patients is the relatively frequent occurrence of an insufficient temporal window. Our goal was to investigate the relationship between the in vivo Doppler ultrasound image quality of the temporal bone, and computed tomography (CT)-determined thickness, density, and homogeneity of cadaver temporal bone. Methods: Thirty-three moribund neurological patients who eventually died were examined by TCCS using the transtemporal approach. The sonographer categorized the quality of the TCCS image (excellent, intermediate, and poor). During autopsy, a rectangular sample of the temporal squama was removed, which corresponded to the area of the in vivo acoustic window. The thickness of the whole temporal bone, cortical, and cancellous (= diploe) bone as well as the density and homogeneity were determined by high-resolution CT. Results: Thirty-seven temporal bones were obtained. The quality of the acoustic window was classified as excellent in 13, intermediate in 6 and poor in 18 cases. A significant correlation between the complete bone thickness, as well as between the absolute thickness of the diploe and the quality of the acoustic window was found: the thinner the bone/diploe, the better the colour Doppler signal. The thickness of the cortical plates and the homogeneity of the bones were identical in the three image quality categories. Conclusion: The transtemporal TCCS image quality depends mainly on the thickness of the cancellous component of the temporal bone.

Clinically silent circulating microembolic signals (MES) can be identified by transcranial Doppler ultrasound (TCD). It is not yet clear whether their occurrence is always linked to the presence of embolic sources. 24 terminally ill patients (7 women, 17 men; mean age 68 years) were investigated by TCD of the middle cerebral arteries. These findings were correlated with a complete post-mortem examination of potential embolic pathways. Four patients out of the 24 under investigation showed MES, 2 of them bilaterally. All these 4 MES-positive patients had a definite embolic source, i. e. bilateral carotid artery occlusive disease, endocarditis with thrombotic valvular adhesions and severe plaques in the aortic arch, dilated left atrium and a patent foramen ovale, or severe plaques in the aortic arch and a dilated left atrium, respectively. In the investigated patient group, we could demonstrate that MES can only be found when an embolic source is present. The finding of MES justifies an extensive clinical and laboratory search for potential embolic sources including extracranial and intracranial colour-coded duplex ultrasound, ECG, Holter-ECG, and TEE.

Our objectives were to evaluate the safety of intravenous 1.0-M gadobutrol injections in patients with an indication for contrast-enhanced magnetic resonance angiography (CE MRA) of supra-aortal, pelvic, or peripheral arteries by examining and assessing adverse events, laboratory values, vital signs and ECG findings for clinical significance. In 435 patients, recruited in three multicenter trials for safety evaluations of the new contrast agent 1.0-M gadobutrol, CE MRA was performed with 1.0- to 1.5-T scanners using three-dimensional gradient-echo sequences and phased-array coils. The study population comprised 312 men and 123 women with a mean age of 60.9 years. Two hundred seven patients had an indication for imaging of body arteries and 228 had an indication for imaging of peripheral arteries. Blood laboratory values and urinalysis results of 124 patients as well as heart rate, blood pressure, and 12-lead-electrocardiogram readings of 93 patients obtained during a follow-up period of up to 72 h after the injection of contrast media were available for safety analysis. Contrast media application was performed as intravenous bolus injection of 1.0-M gadobutrol in fixed doses according to the patients' body weight (b.w.) and indication for CE MRA and was followed by a 20- to 40-ml saline flush. Mean dose actually applied was 0.1 0.27 mmol/kg b.w. Flow rate ranged between 0.2 and 2.0 ml/s. Safety evaluations found a good tolerability with only 4.6% of at least "possibly related" adverse reactions and no clinically relevant changes in blood and urine samples including no transmetallation effect on serum zinc values. Analysis of renal tolerance showed no influence on renal function irrespective of preexisting renal impairment. The ECG analysis (rhythm analysis, pace-setting disturbances, conduction disturbances, and time interval measurements, including uncorrected and corrected QT) showed no clinically relevant effect of the injection of 1.0-M gadobutrol on the cardiac conduction system. Intravenous injection of 1.0-M gadobutrol at a dose of up to 0.1 0.27 mmol/kg b.w. in the indication CE MRA is safe and causes no clinically relevant changes in safety parameters such as heart rate, blood pressure, blood and urine laboratory values, and cardiac conduction system.

Background and Purpose —This study aimed to determine the correlation of in vivo ultrasound measurements of intima-media thickening (IMT), lumen diameter, and cross-sectional area of the common carotid artery (CCA) with corresponding measurements obtained by gross pathology and histology. Methods —Sixty-six moribund neurological patients (mean age 71 years) underwent B-mode ultrasound of the CCA a few days before death. During autopsy, carotid specimens were removed in toto. Carotid arteries were ligated and cannulated for injection of a hydrophilic embedding material under standardized conditions. The carotid bifurcation was frozen and cut manually in 3-mm cross slices. Digital image analysis was carried out to determine the diameter and the cross-sectional area of the frozen slices of the CCA. IMT was assessed by light microscope. Ultrasonic and planimetric data were compared. Results —Mean measurements of lumen diameter and cross-sectional area were 7.13±1.27 mm and 0.496±0.167 cm 2 , respectively, by ultrasound, and 7.81±1.45 mm and 0.516±0.194 cm 2 , respectively, by planimetric analysis of the unfixed redistended carotid arteries ( R 2 =0.389 and 0.497). The mean IMT was 1.005±0.267 mm by ultrasound and 0.67±0.141 mm histologically, resulting in a mean difference of −31%. Conclusions —Transcutaneous B-mode ultrasound provides a reliable approach for in vivo measurements of the cross-sectional area and, less exactly, of the lumen diameter of the CCA. Compared with histological results, in vivo ultrasound measurements of the IMT are systematically larger.

Background and Purpose —Transcranial color-coded sonography (TCCS) via the suboccipital approach allows direct and continuous visualization of the basilar artery (BA). In this study, we intended to evaluate the ability of native TCCS in visualizing the length of the BA by means of a comparison with postmortem measurements. Methods —The BA was prospectively studied by TCCS shortly before death (median 3 days) in 46 moribund neurological patients (mean±SD age 71.1±13.1 years). The length of the BA was determined by measuring the distance between the vertebrobasilar junction and the deepest available flow signal in the top of the BA. During autopsy, photos of the vertebrobasilar system were taken to evaluate the true anatomic length and variations of the course of BA in situ, eg, straight, curved, or S-shaped. Results —Comparison of the in vivo ultrasound measurements of BA length and postmortem data was possible in 44 of 46 cases. In the 2 remaining patients, the BA was occluded. The mean insonation depth of the vertebrobasilar junction was found at 66.9±7.1 mm. The mean BA length was 21.5±6.8 mm by color-coded duplex and 32.9±6 mm anatomically ( P Conclusions —Color duplex imaging enables correct visualization of the proximal two thirds of the BA, but only exceptionally of its distal one third. A tortuous course of the BA leads to an underestimation of its anatomic length.

In carotid artery stenosis both the degree of the lesion and its plaque morphology are thought to be associated with the carrier's thromboembolic risk. In this study we evaluated the diagnostic preciseness of non-invasively B-mode ultrasound in predicting the histopathological plaque structure. We examined 44 patients with > 50% ICA stenosis by B-mode within 6 weeks prior to carotid endarterectomy. At the affected bifurcations, up to 10 different regions of interest (ROI) per artery were investigated. Plaque appearance was classified according to 6 subtypes considering different ultrasonic plaque features. Postoperatively, plaque specimens were examined histopathologically for their relative content of calcification, fibrous tissue and different soft tissue. B-mode ultrasound was compared with histopathological features in ROI. A total of 265 regions of interest were evaluated. In mainly echolucent types of plaques, atheromatous debris was most frequently seen, whereas fibrosis was rare. Homogeneous echolucent plaques showed a high proportion of cholesterol and/or recent haemorrhage. Thrombosis at the plaque surface was often seen in "completely echolucent" plaque type (each P

The present study was designed to perform follow-up transcranial Doppler investigations for microembolic signals (MES) in acute stroke patients by means of a strict protocol. The number of MES was correlated with stroke etiology and the strength of antithrombotic treatment. Concurrently, we wanted to demonstrate that MES in acute stroke patients are solid in nature and not gaseous. Nineteen patients with middle cerebral artery ischemic events, 16 with completed stroke and 3 with transient ischemic attack (TIA) were investigated within 24 h following the onset of symptoms. Six 1-hour recordings on days 1, 2, 3, 4, 7 and 14 were performed from the affected middle cerebral artery. The four-gate technique and recently established criteria for the identification of MES were used. Eight of 19 patients showed MES in at least one recording. Variability was high and showed no uniform tendency with respect to time since onset of symptoms or treatment. All 3 patients with internal carotid artery dissection showed MES. In 3 patients with lacunar stroke, no MES were detected. Two patients with MES suffered recurrent TIAs during the observation period, whereas none of the patients without MES suffered a recurrent ischemic event. In the acute phase following stroke, ongoing, emerging and vanishing embolization in some patients may reflect individual active processes of remodelling, healing and disruption or disappearance of the embolic source.

Besides the established factors "presence of symptoms" and "degree of stenosis", plaque echolucency is considered to be associated with increased risk of stroke in patients with carotid artery disease. An evaluation was carried out as to whether the prevalence and number of microembolic signals (MES) detected by transcranial Doppler ultrasound were higher in patients with echolucent carotid plaques. One hundred and five patients with carotid artery stenosis from 20%-99% or occlusion underwent clinical investigations, duplex ultrasound of the carotid arteries, and a 1 hour recording from the middle cerebral artery downstream to the carotid artery pathology using the four gate technique. The presence of MES was more frequent and the number greater in symptomatic patients (21 out of 64 patients (33%); mean number of MES in all 64 patients 3.1) than in asymptomatic patients (four out of 41 patients (10%); mean number of MES in all 41 patients 0.3) (p=0.007, and p=0.006, respectively). Echogenicity of the lesions did not affect either number or presence of MES. Positivity for MES and the number of MES increased with increasing degree of stenosis (both p=0.002). Four out of 12 patients with carotid artery occlusion showed MES. No MES could be detected in carotid artery stenosis below 80%. There was a decline in positivity of MES and of the number of MES with the time after the ischaemic event. After 80 days or more after the index event, only one patient showed MES. In conclusion, increasing degree of stenosis and presence of symptoms similarly affect macroembolic and microembolic risk. Thus MES may be a surrogate parameter for risk of stroke. The presence of MES in a few asymptomatic patients suggests that clinically silent circulating microemboli may give additional information on the pending embolic potential of carotid artery stenoses. Echolucency of the plaque was not related to an increased number of MES.

Objective: Embolus detection by transcranial Doppler ultrasound is very time consuming and semi-automated detection is mandatory. The device studied, a TC4040, Nicolet-EME, uses the four-gate technique and allows for audiovisual off-line verification of the recorded events. Methods: Twenty controls, 10 patients with mechanical prosthetic heart valves and 12 patients with occlusive carotid artery disease were investigated by transcranial colour-coded duplex sonography and, subsequently, underwent a 1-h unilateral embolus detection from the middle cerebral artery using four-gate TCD. We investigated the Doppler spectrum background, microembolic signals (MES) and artefacts produced. A detection threshold of 5 dB or more was defined taking into account natural fluctuations of the Doppler spectrum. Results: Sensitivity of the software was 91.9% and observer–software agreement on MES was 7.8% in the valve patients, and 77.7% and 7.5% in the carotid artery disease patients, respectively. Weaker MES were more likely not to be detected in all four channels. The artefact signal rejection rate was 62%. MES produced either positive or zero time delays in adjacent channels. Artefact signals produced either no delay, or a positive or a negative time delay. Duration of MES ranged from 1–88 ms. Conclusions: Besides refined recognition of MES using the time delay, four gates give faint MES no less than four opportunities to overcome the detection threshold. With this device’s satisfying sensitivity, regions of interest in a 1-h recording can audiovisually be evaluated off-line in a few minutes by an investigator.

Background and Purpose —Cardiac right-to-left shunts can be identified by transcranial Doppler ultrasound (TCD) with the use of different contrast agents and by transesophageal echocardiography (TEE). Systematic data are available on neither the reproducibility of contrast TCD, the comparison of different contrast agents, nor the comparison of simultaneous bilateral to unilateral recordings. Furthermore, we assessed the side distribution of thus provoked artificial cardiac emboli. Methods —Fifty-four patients were investigated by TEE and by bilateral TCD of the middle cerebral artery. The following protocol was performed twice: injection of 9 mL of agitated saline without Valsalva maneuver, injection of 9 mL of agitated saline with Valsalva maneuver, injection of 5 mL of a commercial galactose-based contrast agent without Valsalva maneuver, and injection of 5 mL of the galactose-based contrast agent with Valsalva maneuver. Results —In 18 patients, a right-to-left shunt was demonstrated by TEE and contrast TCD (shunt positive). Twenty-nine patients were negative in both investigations, 1 was positive on TEE and negative on TCD, and 6 patients were only positive on TCD. Both bilateral and repeated recordings increased the sensitivity of contrast TCD. There was a symmetrical distribution of microembolic signals in the right and left middle cerebral artery. Conclusions —TCD performed twice and with the use of saline or a galactose-based contrast agent is a sensitive method in the identification of cardiac right-to-left shunts also identified by TEE. The cardiac microemboli in this study did not show any side preference for one of the middle cerebral arteries.

Background and Purpose —Embolus detection using transcranial Doppler ultrasound is a useful method for the identification of active embolic sources in cerebrovascular diseases. Automated embolus detection systems have been developed to reduce the time of evaluation in long-term recordings and to provide more “objective” criteria. The purpose of this study was to evaluate the critical conditions of automated embolus detection by means of a trained neural network (EMBotec V5.1 One, STAC GmbH, Germany). Methods —In 11 normal volunteers and in 11 patients with arterial or cardiac embolic sources, we performed simultaneous recordings from both middle or both posterior cerebral arteries. In the normal subjects, we produced 1342 additional artifacts to use the latter as false-positives. Detection of microembolic signals (MES) was done offline from digital audiotapes (1) by an experienced blinded investigator used as a reference and (2) by a trained 3-layer–feed-forward neural network. Results —From the 1342 provoked artifacts the neural network labeled 216 events as microemboli, yielding an artifact rejection of 85%. In microembolus-positive patients the neural network detected 282 events as emboli, among these 122 signals originating from artifacts; 58 “real” events were not detected. This result revealed a sensitivity of 73.4% and a positive predictive value of 56.7. The spectral power of the detected artifact signals was 16.5±5 dB above background signal. MES from patients with artificial heart valves had a spectral power of 6.4±2.1 dB; however, in patients with other sources of emboli, MES had an averaged energy reflection of 2.7±0.9 dB. Conclusions —The neural network is a promising tool for automated embolus detection, the formal algorithm for signal identification is unknown. However, extreme signal qualities, eg, strong artifacts, lead to misdiagnosis. Similar to other automated embolus detection systems, good signal quality and verification of MES by an experienced investigator is still mandatory.

Background and Purpose —Ultrasonography (US) is a well-established method used to assess the brain-supplying arteries in the acute stroke setting. However, several technical and anatomic limitations are known to reduce its diagnostic accuracy and confidence level. Echocontrast agents (ECA) are known to improve the signal-to-noise ratio by enhancing the intensity of the reflecting Doppler signal. We undertook this prospective study to evaluate the diagnostic value of ECA in a consecutive, nonselected cohort of acute stroke patients with insufficient native US investigations. Methods —During a 1-year period, 25 patients were examined within 48 hours of the onset of stroke. The need for ECA was due to an insufficient transtemporal (n=18), transforaminal (n=4), or extracranial (n=3) imaging of arteries potentially involved in the ischemic event. In 12 patients, a diagnostic suspicion could natively be raised, whereas in the other 13 patients, the strongly reduced image quality did not allow for any neurovascular conclusions. Four grams of Levovist was injected at a concentration of 200 mg/mL and 400 mg/mL for the extracranial and transcranial insonations, respectively. The effect of the echocontrast enhancement was assessed with respect to (1) signal enhancement, (2) image quality, (3) final diagnostic confidence, and (4) the need for additional neurovascular imaging methods. Results —In all but one patient (96%), a strong signal enhancement was noted, leading to a moderate (n=11) or strong improvement (n=10) of the transcranial image quality. Thus in a total of 18 patients (72%), the echoenhancement provided a neurovascular diagnosis of sufficient confidence. This led to the confirmation of the previously suspected findings and disclosed three further occlusions and four stenoses of the intracranial arteries. In contrast, for the three extracranial examinations the image quality was not sufficiently improved because of persistent color artifacts derived from adjacent neck vessels. Besides the seven patients with inconclusive examinations, five patients with conclusive echoenhanced US studies (48% in total) demanded additive neurovascular imaging studies, based on the clinical decision of the attending physicians. This led to confirmation of all high-confident sonographic diagnoses. Conclusions —In summary, in approximately three fourths of our acute stroke patients with insufficient native US investigations, echocontrast enhancement enabled a reliable neurovascular diagnosis, allowing the cancellation of additive neurovascular imaging procedures in half of our cohort. Our preliminary results suggest that ECA can reasonably support the early cerebrovascular workup in the acute stroke setting.

Transcranial Doppler sonography has become a widely used method for detecting cerebral circulating microemboli (ME) arising from the carotid arteries or the heart. Yet, studies on subgroups of patients with distinct cardiac sources of embolism are still limited. The same holds true for investigations on the relationship between microembolization and hemorheological parameters. A total of 142 patients suffering from left ventricular aneurysm (LVA, n = 52), severe left ventricular dysfunction (LVD, n = 43), or chronic atrial fibrillation (AF, n = 47) were enrolled in this study. All patients had been neurologically asymptomatic for at least 1 month. Further relevant embolic disorders of the carotid arteries and the heart had been excluded. Unilateral monitoring for ME over the middle cerebral artery was performed for 30 min. Blood was drawn after each monitoring for determination of plasmatic coagulation parameters, as well as plasma viscosity, and platelet reactivity. The overall prevalence of ME was 31%, with a slightly higher prevalence in patients with LVA (37%) compared to patients suffering from AF (30%) or LVD (26%). With single-factor analysis, a trend towards higher ME prevalences was found with (a) a history of remote embolic events, (b) ineffective anticoagulation, (c) increased platelet aggregation, or (d) increased plasma viscosity (all p > 0.1). The combination of ineffective anticoagulation in conjunction with increased platelet aggregation, however, was significantly associated with higher ME rates even after adjustment for other factors by logistic regression analysis. Our results demonstrate a low ongoing microembolic activity in asymptomatic patients suffering from LVA, LVD and AF. An activated plasmatic coagulation system together with increased platelet aggregation contributes to ME generation.

Multiple endovascular devices have been used for mechanical thrombectomy (MT) in basilar artery occlusion (BAO) for10 years. Based on a single-center experience during the course of one decade, we present data on safety and efficacy of previous MT devices compared with modern stent retriever and suction thrombectomy.Eighty-one patients (29 women, 52 men, mean age 61.5 years, range 17-90) with angiographically confirmed BAO that had been treated by MT between 2001 and 2011 were retrospectively evaluated. Patients in group 1 (n = 60) had been treated between 2001 and 2008 with different devices available at that time. Patients in group 2 (n = 21) had been treated by modern stent retriever or local suction devices between 2008 and 2011. Recanalization rate, needle to recanalization time, procedure-related complications, and distal embolization of thrombotic material were recorded and compared.Recanalization rates of 95% were high in both groups. Procedure-related dissection (n = 5) and subarachnoid hemorrhage (n = 9) occurred in group 1 but not in group 2 (p0.016). Needle-to-recanalization time was less than half in group 2 compared with group 1 (54.6 vs. 132.3 min, p0.01). Frequency of distal embolization was comparable in both groups (47%).High recanalization rates have been achieved since the introduction of MT in BAO. However, modern stent retriever and suction devices allow for safer and more rapid recanalization compared with previous MT devices.

Lymphomas can arise within the central nervous system (CNS) as primary CNS lymphoma (PCNSL) typically involving the brain and less often the leptomeninges, eyes, and spinal cord. In contrast to PCNSL, secondary CNS lymphoma (SCNSL) is considered to originate as quasi metastasis from systemic lymphoma spreading to the CNS. Both types of CNS lymphomas are predominantly tumours of the diffuse large B-cell type and represent aggressive diseases necessitating a rapid diagnosis. Following neuroimaging based on magnetic resonance imaging, stereotaxy and histopathological diagnosis of CNS lymphoma currently remain obligatory to plan treatment. However, progress in cytopathological, immunophenotypic, and molecular genetic analyses of the cerebrospinal fluid (CSF) has been achieved recently and potentially will facilitate lymphoma diagnosis in the future. This review describes the diagnostic procedures in patients with suspected CNS lymphomas, primarily PCNSL. In addition to a summary of the standard diagnostic work-up, an overview and discussion of current data on different techniques for evaluation of the CSF in CNS lymphoma are given.

Twenty carotid bifurcations were examined. During autopsy, carotid bifurcations were removed in toto. Unfixed carotids were ligated and cannulated for injection of an angiographic contrast medium followed by injection of a tissue-embedding medium at physiologic pressure and temperature. The carotid bifurcation was frozen and cut manually in 3-mm cross-sections. Photographs were then taken of every slice. Angiography, filling with tissue-embedding material, and sectioning were successful in all cases. In the macropathologic sections, the extent, configuration and location of atherosclerotic lesions could be identified.

Background and Purpose —There is growing evidence for affection of cerebral vessels during human immunodeficiency virus (HIV) infection. We prospectively evaluated cerebrovascular reserve capacity (CRC) in HIV-seropositive patients by transcranial Doppler sonography (TCD) after systemic administration of acetazolamide. We hypothesized that a disturbed vasoreactivity would reflect the cerebral arteries’ involvement in HIV infection. Methods —We assessed the mean blood flow velocity (BFV) of the middle cerebral artery and its increase after intravenous administration of 1 g acetazolamide (CRC) in 31 HIV-infected individuals without symptoms of cerebrovascular disease (mean±SD age, 39±11 years). Stenotic or occlusive lesions of the large brain-supplying arteries were excluded by color-coded duplex and transcranial imaging. BFV and CRC were also measured in an age-matched group of 10 healthy control subjects. Patients were classified according to clinical, laboratory, and neurophysiological parameters. We also performed cerebral MRI (n=25) and rheumatological blood tests (n=26). Results —Baseline BFV and CRC both were significantly reduced in HIV-infected patients as compared with control subjects ( P t test). These findings did not correlate with duration of seropositivity, helper cell count, or other clinical, rheumatological, and neuroradiological findings. Conclusions —Our findings support the hypothesis of a cerebral vasculopathy etiologically associated with HIV infection.

Two patients with refractory symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) were treated by continuous intra-arterial nimodipine infusion via a catheter placed in the internal carotid artery or vertebral artery for 3 and 12 days, respectively. Recovery of the neurological deficits, normalization of MR perfusion, a decrease in the elevated mean flow velocity measured by transcranial duplex sonography, and angiographic recanalization were observed. Continuous intra-arterial nimodipine might be a treatment option in severe refractory vasospasm following SAH.

Endovascular treatment of intracerebral wide-necked aneurysms carries the risk of incomplete embolisation and recanalisation of the aneurysm as well as coil protrusion into the parent artery and embolic complications. We present preliminary results with the placement of a novel tightly braided stent across the aneurysm neck which might lead to thrombosis of these aneurysms. A bifurcation artery aneurysm was created in a male New Zealand White Rabbit. After 4 weeks, a novel highly flexible stent with a central tightly braided mesh was placed across the aneurysm neck. Diagnostic angiography was performed during the procedure and immediately after stent deployment as well as 2 and 4 weeks following stent placement. Histological analyses, including microscopic investigations for evaluating intra-aneurysmal thrombosis and proliferation of the intima, were performed after 1 month. Intra-aneurysmal flow reduction due to stent placement was achieved as early as 45 min after deployment. Unchanged complete occlusion of the aneurysm could be observed by angiography 2 and 4 weeks post-stent deployment. Histological analysis confirmed angiographical findings of complete aneurysm occlusion and excluded significant neointimal coverage. This newly designed flexible stent may offer the potential to expand endovascular treatment of wide-necked intracranial aneurysms.

Background —Reopening of an occluded internal carotid artery (ICA) is often seen in dissections but only rarely occurs in atherothrombotic occlusion of the internal carotid artery. Case Description —A 60-year-old man suffered a minor stroke with dysphasia in March 1995. Color-coded duplex ultrasonography of his neck arteries revealed a left ICA occlusion. He was placed on a regimen of aspirin and followed up clinically and with ultrasonography. At follow-up 18 months later, the patient was asymptomatic. On duplex ultrasonography his left occluded ICA was found to be reopened, with a residual, proximal, high-grade stenosis. However, intra-arterial digital subtraction angiography demonstrated a persistent ICA occlusion and a vas vasorum originating from the carotid bulb and draining into the ICA distal to the occlusion. Conclusions —The rare collateralization of an occluded ICA by vasa vasorum seems to take several months. It can be a pitfall in the ultrasound diagnosis of carotid artery occlusive disease.

Purpose Prospective evaluation of diagnostic accuracy of single field-of-view contrast-enhanced MR Angiography (ceMRA) with 1.0 M gadobutrol compared to intraarterial DSA in body arteries. Materials and methods In an European multicenter study 179 patients underwent ceMRA and DSA. For each indication five prospectively defined vessel segments were evaluated by local investigators onsite and by three site-independent blinded readers (BR) independently. Results The agreement between ceMRA and DSA diagnosis was statistically significant in the onsite (96.6%) and blinded reader (86.6–90.2%) evaluation. Sensitivity, specificity, accuracy, positive (PPV) and negative predictive values (NPV) for detection of relevant stenosis (>50%) were calculated for the right and left internal carotid arteries, and common and external iliac arteries: Sensitivity was 95–98% (onsite) and 76–96% (BR), specificity 94–96% (onsite) and 86–94% (BR), accuracy 96% (onsite) and 87–93% (BR), NPV 98–99% (onsite) and 84–98% (BR), and PPV 79–93% (onsite) and 44–91% (BR), respectively. Conclusion CeMRA of body arteries using 1.0 M gadobutrol provides diagnostic information comparable to intraarterial DSA.

BACKGROUND AND PURPOSE: Despite improved patient outcomes because of intraarterial fibrinolysis, vertebrobasilar thromboembolism remains a fatal disease with a death rate of more than 50%. The outcome depends on the success of recanalization. Fibrinolysis achieves recanalization in only 50%–70% of the cases. Therefore, we investigated the feasibility of using a coronary mechanical device to increase the recanalization rate. METHODS: Twelve patients with acute vertebrobasilar occlusion were included in the pilot study. The older 5F and the new 4F versions of the Possis Angiojet catheter, which use a waterjet to attract, fragment, and extract the thrombus, were used. Inclusion depended on the presence of acute multisegmental intracranial or any extracranial vertebrobasilar occlusion. Exclusion criteria included coma lasting >8 hours and age >80. The Angiojet treatment did not exclude other therapeutic options. RESULTS: The Angiojet catheter accessed the thrombosed site in 10 of 12 patients. Combined treatment with the Angiojet and additional fibrinolysis or angioplasty resulted in a recanalization rate of 100%. Of 37 occluded vertebrobasilar segments, 30 were primarily recanalized with the Angiojet. Three symptomatic and two asymptomatic hemorrhages were detected by CT. Five of the 12 patients died. Fifty percent of all patients obtained a moderate to excellent outcome (Modified Rankin Scale 0–3). CONCLUSIONS: Use of the coronary Angiojet in the vertebrobasilar system is feasible. The device has the potential to increase the recanalization rate, especially in cases of extensive thrombosis, and, thus, improve patient outcomes.

Transient cortical blindness following intra-arterial catheter angiography is a known rare complication. We report the case of a 56-year-old man who suffered from transient cortical blindness and neuropsychological deficits after coronary angiography. Serial CT scans revealed reversible pathologic parenchymal contrast enhancement of the right occipital lobe as well as left middle cerebral artery infarction at the same time. CT changes and time course of clinical symptoms are presented and discussed for both lesions of presumably different etiology.

to analyse whether ultrasound contrast agent (UCA) improves the diagnostic accuracy to differentiate between benign and malignant superficial lymph node enlargement by using colour-coded duplex sonography (CCDS) and power Doppler (PD).32 patients with suspected malignant superficial lymph node enlargement prospectively underwent standardised ultrasound examinations using B-mode sonography and native and contrast-enhanced CCDS and PD immediately before biopsy. Solbiati-Index (longitudinal-transverse diameter ratio) and intranodal flow patterns by using different vascularisation types were assessed. Histological and sonographical findings were correlated.27 malignant and 5 benign lymph nodes were found. Solbiati-Index was lower in malignant lymph nodes than in benign nodes (mean 1.5 vs. 2.4, P0.045). More intranodal flow patterns could be detected after UCA (53 vs. 43) but the number of correctly identified malignant nodes decreased after UCA (26 vs. 24) and the number of correctly identified benign nodes remained constant compared with native CCDS and PD. In 31% of the colour-mode studies, PD was considered to visualise more clearly intranodal vascular flow patterns than CCDS.despite depicting more intranodal vascular patterns, the use of an ultrasound contrast agent seems not to improve the diagnostic value of CCDS and PD compared with native colour-mode studies in superficial lymph node enlargement.

Background and Purpose— The correct detection and quantification of carotid artery disease are of decisive impact on patient prognosis and adequate treatment. In this study, we evaluated the ability of ultrasonography to detect and to grade carotid artery stenosis through a comparison of the in vivo ultrasound findings with the planimetric analysis of the corresponding postmortem specimens. Methods— Shortly before their death, 59 critically ill neurological patients (mean age, 70 years) were prospectively examined by extracranial and intracranial Doppler sonography and color-coded duplex ultrasound. Carotid stenosis was classified by hemodynamic and morphological ultrasound criteria. Carotid specimens were removed in toto during autopsy. Under standardized conditions, specimens were redistended, sectioned, and histologically processed. Computerized planimetric measurements of the arteries were carried out and compared with the ultrasound findings. Correlation of the ultrasound and postmortem planimetric findings was available in 93 carotid bifurcations. Results— Through both techniques, 46 carotid arteries were found to be normal. Steno-occlusive carotid lesions ranged from 8.5% to 100% lumen reduction. Overall, r =0.96 and adjusted R 2 =0.90. For the steno-occlusive carotid lesions, r =0.91. Conclusions— Extracranial and intracranial Doppler and color-coded duplex ultrasound permits reliable detection and quantification of carotid artery stenoses and occlusions even under difficult examination conditions in critically ill patients.

Objective. A meta-analysis was carried out of clinical trials published between 1987 and 2001 in respect of the clinical pharmacology and safety as well as the diagnostic efficacy of gadolinium-DTPA (Gd-DTPA) for direct intra-articular injection before MRI examination. Design. Scientific papers (clinical, postmortem and experimental studies) and information from the manufacturer regarding intra-articular injection of Gd-DTPA that addressed questions of mode of action, optimal concentration and dose, elimination and safety were reviewed. Clinical studies were classified according to their study design. The sensitivity, specificity and accuracy of MR arthrography (MRA) were compared with a "gold standard" (arthroscopy, arthrotomy) and other radiological evidence for different joints. Results. Fifty-two clinical studies of the overall 112 studies addressed aspects of diagnostic efficacy of MRA in patients or in healthy volunteers. The shoulder was the most assessed joint (29 of 52 studies). Good (>80%) or even excellent (90–100%) sensitivity, specificity and accuracy were found for MRA in most indications, especially for the shoulder and knee joints and induced extension of rotator cuff lesions, labrum abnormalities and postoperative meniscal tears. Two millimoles per liter has proven to be the best concentration for intra-articular administration of Gd-DTPA. After passive complete diffusion from the joint within 6–24 h, complete and rapid renal elimination takes place after intra-articular injection. Local safety proved to be excellent after intra-articular administration of Gd-DTPA. Regarding systemic tolerance almost no side effects have been reported, but the same safety considerations apply for intra-articular administration of Gd-DTPA as for intravenous injection. Conclusions. The diagnostic efficacy of intra-articular MRA in most clinical conditions affecting major joints is greater than that of plain MRI. In some diagnostic problems MRA achieves almost the same sensitivity and specificity as the surgical gold standard. Given a sterile application, the intra-articular administration of Gd-DTPA in a concentration of 2 mmol/l prior to MRI is a safe procedure.

Objective: To determine the patency of coronary internal mammary artery bypass (IMAB) with CT-angiography (CTA) and to evaluate the morphology of a covering Gore-tex IMAB-sleeve (PIMAS) used to protect the bypass at possible reoperation. Materials and Methods: Sixty-five patients with IMAB wrapped with PIMAS (67 grafts) were prospectively investigated by CTA for bypass patency and sleeve morphology 6 months postoperatively with a standardised radiological and clinical protocol. Results: All patent bypass arteries (62/62) were identified by CTA as open. In the remaining five cases, CTA revealed a bypass occlusion, which could be proven by coronary angiography in two cases (two patients refused angiography, one bypass was open angiographically). Morphology of the PIMAS could be imaged exactly in all cases. Sleeve implantation did not lead to adverse effects in terms of bypass occlusion or compression. In four patients, additional clinically relevant information were achieved. Conclusion: PIMAS implantation proved to be a safe procedure with good short-term results. CTA is a valuable method to exclude occlusion of sleeved IMA bypasses. Depiction of the wrapped IMAB by CTA supplies important information for preparing strategy in case of reoperation.

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80%. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred.

Atrial fibrillation (AF) is a well-recognized independent risk factor of ischemic stroke. The aim of this study was to investigate the amount of microembolic signals (MES) in 15 patients with ‘lone’ AF representing the subgroup of AF patients with the lowest lifelong risk of stroke. All patients had been put on effective anticoagulation due to a scheduled electric cardioversion. Additional cardiac and arterial sources of embolism were excluded by echocardiography and extracranial color-coded duplex sonography of the carotid arteries. Unilateral one-hour transcranial Doppler monitorings revealed complete absence of MES in this series. This observation fits the concept that the amount of microembolisation is related to the risk of manifest thromboembolism. Further studies on this patient group treated with less intensive antihemostatic therapy should be undertaken to define more clearly the disease-specific microembolic activity. [Neurol Res 1999; 21: 566–568]

Objectives - By means of transcranial colour-coded duplex sonography (TCCD) through the foramen magnum, the intracranial vertebral artcries (VAs) and the basilar artery (BA) can be investigated. In this study we evaluated the additional diagnostic value of echocontrast administration in patients with an insufficient pre-contrast TCCD investigation of the vertebrobasilar system. Material and methods - In 22 patients the intracranial VAs and the proximal, middle and distal BA were evaluated before and after the application of 4 g of the echocontrast agent Levovist®. The length of the different vessel segments visualized on colour modc before and after echocontrast, and the diagnostic benefit and the diagnostic confidence were assessed. Results - Echocontrast enlarged in cach vessel segment the length that could be visualized. Using echocontrast, in 5/22 patients (23%) definite and probable pathological findings unnoted in the native scans were detected. In 12 additional paticnts (55%) the investigator and the clinician became confident with thc vascular diagnosis by echocontrast to a degree that angiography could be avoided. In only 3/22 patients (14%) no gain and in 2/22 paticnts (9%) an insufficient diagnostic gain was noted. Conclusions - Our study demonstrates that echocontrast provides effective Doppler signal enhancement and considerably increases the diagnostic gain of TCCD in the intracranial vertebral and basilar vasculature.

Background and Purpose Clinically silent circulating microemboli can be detected by transcranial Doppler sonography. The composition of these emboli in different clinical conditions is unclear. Methods We performed 1-hour transcranial Doppler sonographic recordings from the middle cerebral or posterior cerebral artery in 20 patients with mechanical prosthetic heart valves, in 78 patients with an arterial embolic source, and in 20 control subjects. During 30 minutes of this recording, the patients inspired room air and 6 L of oxygen per minute via a loosely fitting facial mask; during the remaining 30 minutes, they breathed room air only. Results There was a significant decline of embolic signals (ES) under oxygen in the patients with mechanical prosthetic cardiac valves (144 ES without oxygen versus 63 ES with oxygen; P =.002) but not in the patients with arterial embolic sources (145 ES without oxygen versus 135 ES with oxygen; P=NS). In the control subjects, no ES were found. Conclusions ES in patients with mechanical prosthetic cardiac valves correspond mainly to gas bubbles. Oxygen inhibits the cavitation process of mechanical prosthetic heart valves or speeds up redissolution of gas bubbles generated by cavitation. In contrast, solid microemboli originating from thrombus or atheroma cannot be suppressed by oxygen inhalation. This simple method of oxygen inhalation should help to clarify the composition of microemboli in various clinical and experimental settings.

Albeit still unproven, it is supposed that the presence and number of asymptomatic circulating cerebral microemboli detected by transcranial Doppler ultrasound (TCD) may be an indicator of stroke risk. Little research has been done to assess the reproducibility of these data and the required time for recording. We examined one middle cerebral artery in 7 subjects with carotid, aortic or cardiac embolic source for 24 h by TCD. Analysis for embolic signals was done off line completely blinded to the diagnosis and the time of the day during the recording. Embolic signals were found in all 7 subjects varying from 0 per h to 13 per h. Embolic signals occurred throughout the day with a nonsignificant tendency towards higher values in the early morning hours. Half an hour recording would not have been suitable to rule out or to confirm the presence of embolic signals as there were too many gaps between embolic signals of more than 1/2 h. One hour is the required minimum. Concerning the number of embolic signals, even a recording of four hours yielded variabilities of 0.25 and 8 embolic signals per hour in the same person. We recommend to perform follow-up studies the same time of the day. In patients with a low number of embolic signals longer recordings or a lower detection threshold with a higher number of detected embolic signals are necessary to compare frequencies of embolic signals.

To the Editor: With great interest we read the meta-analysis on the therapy of basilar artery occlusion (BAO) by Lindsbergh and Mattle1 published in the March issue of Stroke . The authors compared the pooled data from 13 retrospective studies (3 studies including 76 patients treated by intravenous thrombolysis [IVT], and 10 studies including 344 patients treated by intra-arterial thrombolysis [IAT]) in patients with BAO. The authors draw the conclusions that the route of drug delivery for treatment of BAO does not make a difference in clinical outcome and that the odds for survival without a handicap improve equally after IVT and IAT. We agree with the authors that the recanalization …