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Hemostasis in the left atrial (LA) appendage (LAA) is an important cause in the formation of thrombi. Determination of the LAA flow velocity (LAAV) could be a quantitative parameter for estimating thromboembolic risk. The objective of this study was to: (1) determine the relationship between LAAV and qualitative parameters with elevated thromboembolic risk (thrombus/spontaneous echocontrast [SEC]); and (2) define factors that influence LAAV.In all, 500 patients with stroke were examined consecutively by transesophageal echocardiography. In addition to measurement of the LAAV, the atrial appendage was examined for the presence of thrombi or SEC.LAAV differed significantly among patients with sinus rhythm (71 +/- 16 cm/s), paroxysmal atrial fibrillation (AF) and in sinus rhythm during transesophageal echocardiography (46 +/- 13 cm/s), paroxysmal AF and AF during transesophageal echocardiography (32 +/- 12 cm/s), and chronic AF (27 +/- 9 cm/s, P.001). Independent of the rhythm, the risk of thrombus/SEC increased significantly at an LAAV less than 55 cm/s. At an LAAV 55 cm/s or more there is only a minimal risk of thrombus/SEC (negative predictive value 100% and 99%, respectively). Multivariate analysis showed that LAAV is the strongest predictor for the occurrence of thrombus/SEC (P.0001). Further multivariate analysis showed that left ventricular ejection fraction, LA size, (paroxysmal) AF, age, and sex are independent parameters influencing LAAV.Independent of the basic rhythm, there is a close relationship between LAAV and qualitative parameters of elevated thromboembolic risk. LAAV could, therefore, be a quantitative surrogate parameter for risk stratification. It is influenced by both cardiac and extracardiac factors.

Background and Purpose— Impaired cerebrovascular reserve capacity (CVC) is a risk factor for ischemic events in patients with high-grade carotid stenosis and occlusion. In this study, the CVC in response to a CO 2 challenge was evaluated with blood oxygen level–dependent (BOLD) MRI and the results compared with those of a transcranial Doppler CO 2 tests. Methods— A T 2 *-weighted single-shot multigradient echo-planar imaging sequence was used to determine cerebral CO 2 reactivity. T 2 * values were calculated for each pixel at rest and during a challenge with 7% CO 2 , and a reference function was fitted to the T 2 * time courses. Whole-brain color-coded ΔT 2 * parameter maps were calculated and visually evaluated for regional differences. Additionally, a region-of-interest analysis was undertaken. Average values for ΔT 2 * normalized to changes in end-tidal P co 2 were calculated. Results were correlated with a transcranial Doppler CO 2 tests in 20 patients with high-grade stenosis or occlusion of the carotid artery. Results— Color parameter maps showed areas of decreased BOLD effect within the internal carotid artery territory in 12 of 13 hemispheres with impaired CVC in transcranial Doppler CO 2 test. Regional normalized ΔT 2 * was highly correlated with changes of middle cerebral artery blood flow velocity in transcranial Doppler CO 2 test. Normalized ΔT 2 * was significantly reduced in hemispheres with impaired CVC in transcranial Doppler ( P Conclusions— BOLD MRI can easily be included in routine MRI exams. The technique is robust and yields diagnostic information concerning the cerebrovascular reserve.

The aim of this study is to analyze the work of the interdisciplinary Brain Tumor Board (BTB) which was established at Freiburg University Hospital in 1998.From January 1998 to December 2003, a total of 1,516 patients were discussed in 259 meetings of the BTB. The protocols of the BTB were analyzed retrospectively.In 79% of the patients, the diagnosis was based on histological findings or a typical radiological appearance of a lesion, or both. This group was composed of 4 subgroups: 28% benign skull base tumors (19% meningiomas, 4% pituitary adenomas, 3% acoustic schwannomas, 2% others), 24% primary brain tumors of glial origin (8% glioblastomas, 12% gliomas other than glioblastomas, 5% oligoastrocytomas or oligodendrogliomas), 19% brain metastases, and 8% other brain or skull base tumors. In 13% of the cases, the exact diagnosis was still unknown when the patient was presented. 8% of the presentations were motivated by nontumorous interdisciplinary problems (e.g. arterio-venous malformations). The recommendations given by the BTB included: 23% further diagnostic procedures (11% non-invasive examinations, 12% stereotactic biopsies), 57% active antitumoral therapy (22% resection, 17% fractionated radiotherapy, 13% radiosurgery, 5% chemotherapy,1% embolization), 20% no treatment (14% watchful waiting, 6% supportive care). 91% of the BTB recommendations were realized within 3 months.Interdisciplinary care seems to be particularly necessary in patients with benign skull base tumors, gliomas and brain metastases. Decisions made in a small interdisciplinary group of experts have a high potential of subsequently being realized.

Introduction: Both for hemicraniectomy and for hypothermia, several reports describe a beneficial effect in patients with malignant supratentorial cerebral ischemia. We compared the safety and the clinical outcome in patients with a malignant supratentorial infarction who were treated with hemicraniectomy alone (HA) or received a combination therapy with hemicraniectomy and hypothermia of 35°C (HH), respectively. Methods: In a prospective and randomized study, 25 consecutive patients were treated after an ischemic infarction of more than two thirds of one hemisphere by HA (n = 13 patients) or the HH combination therapy (n = 12 patients). Safety parameters were compared between both treatment groups, the clinical outcome was assessed during treatment and after 6 months. Results: Age, cranial CT or MRI findings, initial National institutes of Health Stroke Scale Score (NIHSSS) and level of consciousness were not significantly different between both groups. Hemicraniectomy was performed within 15 ± 6 h after the ischemic event. Hypothermia was induced immediately after surgery. Overall mortality was 12% (2/13 vs. 1/12 in the two groups), but none of these 3 patients died due to treatment-related complications. There were no severe side effects of hypothermia. Duration of need for intensive care or for mechanical ventilation and infectious status did not differ significantly between both groups, but the need for catecholamine application was increased in the HH group. The clinical outcome showed a tendency for a better outcome in the HH compared with the HA group with respect to status after 6 months, as assessed by the NIHSSS (10 ± 1 vs. 11 ± 3, p < 0.08). Discussion: The present study suggests that a combined therapy of mild hypothermia and hemicraniectomy in malignant brain infarction does not imply additional risks by side effects and improves functional outcome as compared with hemicraniectomy alone.

Die medikamentose lokale intraarterielle Fibrinolyse (LIF) ist ein mittlerweile anerkanntes und etabliertes Verfahren. Ungeachtet der Wahl des Fibrinolytikums liegen die Rekanalisationszeiten allerdings bei 1–2 h, so dass zunehmend neue mechanische Techniken erprobt werden, die eine Verkurzung der Rekanalisationszeiten ermoglichen sollen. Durch eine schnellere Rekanalisation kann die Infarktgrose verkleinert werden, was zu einem besseren klinischneurologischen Outcome fuhrt. In der vorliegenden Arbeit werden die Technik der Laserlyse und erste Ergebnisse vorgestellt. Die Patienten wurden im Rahmen der „Safety and Performance Study“ bzw. der Folgestudie („Pivotal Study“) eingeschlossen. Vor der Behandlung wurden NIHSS („National Institute of Health Stroke Scale“) sowie mRS („modified Rankin Scale“) erhoben. Der Grad der Rekanalisation wurde anhand der angiographischen Ergebnisse ermittelt. Die klinischen Verlaufsuntersuchungen erfolgten 24 h, 7 Tage und 30 Tage nach Behandlung. 20 Patienten wurden eingeschlossen. 13 Patienten wurden mit Gefasverschlussen im vorderen und sieben Patienten mit Verschlussen im hinteren Stromkreislauf in die Studie aufgenommen. Entsprechend den Vorgaben der Studie wurden zwolf Behandlungen als technisch komplett mit dem EPAR-System und acht Behandlungen als inkomplett eingestuft. In funf von acht Fallen wurde der Laserkatheter eingefuhrt, aber keine Laserbehandlung durchgefuhrt. Die Rekanalisationsergebnisse im vertebrobasilaren Stromgebiet mit einer 86%igen Rekanalisationsrate bei einer mittleren Laserzeit von 7,6 min (1,3–18,9 min) sind viel versprechend, wahrend die Rekanalisationsrate im vorderen Stromkreislauf lediglich 31% betrug (mittlere Laserzeit von 5,5 min [0–15,6 min]). Neben dem Nachweis des Studienziels Sicherheit und technische Machbarkeit erwies sich diese neue Methode als effektiv in Bezug auf eine rasche Rekanalisation, so dass sie eine weitere Therapieoption zur Behandlung des akuten Schlaganfalls darstellen konnte.

The quality of collateral blood supply in carotid disease is pivotal for the resulting hemodynamic compromise. However, the interrelation between different patterns of collateral blood flow and actual impairment of cerebral autoregulation (CAR) has not been analyzed so far. Dynamic CAR was assessed noninvasively by the phase shift between respiratory-induced 0.1-Hz oscillations of arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) in 101 patients with severe unilateral carotid stenosis (> or = 75%) or occlusion. CO(2)-vasomotor reactivity was assessed via inhalation of 7% CO(2). Spontaneously activated collaterals via primary (anterior/posterior communicating artery, type I, n = 65) and secondary (ophthalmic artery / leptomeningeal with or without primary pathways, group II, n = 24) pathways were assessed by transcranial Doppler/duplex sonography. Signs of functional stenosis in the anterior collateral pathways were subsumed under type III (n = 12). Best dynamic CAR (phase shift) on affected sides was observed for type I (n = 65), in which values did not differ significantly from contralateral sides. Reduced phase shift values were present in type II; poorest values were observed for type III. CO(2)-reactivity differed mainly between type I and the other types. A less distinct differentiation of autoregulatory impairment was found when dividing patients into groups of different degrees of stenosis. Symptomatic patients (previous TIA/stroke) were significantly less frequent in the group with type I collateral flow and had significantly lower phase shift and CO(2)-reactivity values. In conclusion, we found that dynamic CAR is substantially impaired if secondary collateral pathways are activated or if functional stenosis in the activated anterior collateral pathway is present. These hemodynamic constellations are also associated with a higher proportion of clinically symptomatic patients. Determination of dynamic CAR by transfer function analysis represents a convenient, sensitive method for detection of cerebral hemodynamic compromise in obstructive carotid disease.

Increased pulsatility of blood flow in the basal cerebral arteries recorded with the use of transcranial Doppler sonography (TCD) corresponds to increased intracranial pressure (ICP) to near the level of the diastolic arterial blood pressure. We describe the case of a 39-year-old woman who developed acute reduction in consciousness, anisocoria, gaze deviation, and right-sided hemiparesis 2 days after resection of a relapsed astrocytoma. MRI revealed only a moderate enlargement of the ventricles, but TCD revealed highly pulsatile waveforms of all basal cerebral arteries, showing a biphasic pattern with diastolic backflow. This pattern was interpreted as a massive increase in ICP with imminent danger of cerebral circulatory arrest corresponding to acute malresorptive hydrocephalus. External cerebrospinal fluid drainage was immediately undertaken, revealing excessive ICP of more than 50 cm H2O. Twenty-four hours after this intervention, both the ICP and the Doppler waveforms had returned to normal. This case illustrates the usefulness of TCD for diagnosing a critical but potentially reversible acute increase in ICP with imminent cerebral circulatory arrest. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:324–327, 2003

Intact cerebral autoregulation is essential to prevent cerebral hypoperfusion during pronounced changes in arterial blood pressure (ABP) in patients with autonomic failure (AF). It is still a matter of debate whether and to what extent cerebral autoregulation is disturbed in these patients. This study evaluates the interaction between cerebral blood flow velocity (CBFV) and ABP during Valsalva maneuver (VM) and tilt-table testing in nine patients with multiple system atrophy including AF and in 14 age-matched controls. CBFV and ABP were recorded noninvasively using transcranial Doppler sonography and the Finapres device. Responses to VM were graded by the autoregulation slope index (ASI). Cerebrovascular resistance changes were estimated by the conventional ratio ABP/CBFV and by the dynamic pressure-velocity relationship. To challenge cerebral autoregulation further, tests were repeated under hypercapnic predilation of cerebral arterioles. During VM, CBFV reincreased in patients despite a pronounced ABP drop and showed an overshoot after the strain, thus, being similar to controls. The ASI was higher in patients than in controls ( p0.05). During 70 degrees head-up tilt, ABP dropped markedly, but the decrease in CBFV was small and did not differ significantly from controls. In patients, both tests were associated with a substantial decrease of the dynamic but not of the conventional pressure-velocity relationship. Under hypercapnia, the CBFV response in patients remained unchanged. We conclude that 1). cerebral arterioles have the capacity for adequate vasodilation during ABP drops in patients with AF and that this ability is still present under hypercapnic predilation. 2). The mechanism of cerebral autoregulation in itself does not seem to be affected by the AF but is rather well exercised. 3) The VM presents, in addition to tilt-table testing, a simple test for clinical evaluation of cerebral autoregulation in patients with AF.

Oscillations of arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) can be used for non-invasive assessment of cerebral autoregulation using transfer function analysis. Either spontaneous oscillations (SPO) around 0.1 Hz or respiratory induced oscillations during deep breathing (DB) at a rate of 6/min have been used so far. We investigated 168 patients with severe carotid stenosis or occlusion to evaluate transfer function analysis and compare the SPO and DB approaches. ABP was assessed non-invasively (Finapres), CBFV was measured in the middle cerebral artery using transcranial Doppler sonography. Transfer function phase (P) and gain (G) were extracted from the respective spectra in a low (0.06-0.12 Hz) and high (0.20-0.30 Hz) frequency range (LF, HF) of SPO and from the 0.1 (LF) and 0.2 (HF) Hz peaks induced by DB. For SPO, significant side-to-side differences and differences between groups of severe and critical stenosis were found for P(LF), while P(HF) did not prove to be a significant parameter. G(LF) showed significant side-to-side differences, while G(HF) additionally differed significantly between severe and critical stenosis and occlusion, respectively. For DB, significant side-to-side differences were found for P(LF, HF). Mainly G(HF) differed significantly between the affected and contralateral sides, while both HF and LF gains showed lower values in groups with a higher degree of stenosis. Correlation between G and P values was generally poor. Using Bland-Altman plots a poor inter-method agreement was found mainly for P. Correlations between SPO and DB were higher for G than for P (LF r = 0.64 versus 0.44, HF 0.69 versus 0.28). Analysing reproducibility in 16 patients, only for P(LF, HF) of DB was a highly significant correlation found (Spearman's r up to 0.78). For G(LF, HF) correlations were significant for both SPO and DB with slightly higher r coefficients for SPO. In conclusion, the present study showed that (1) transfer functions P and G represent different information for characterization of dynamic cerebral autoregulation in the frequency domain. (2) Inter-method agreement between DB and SPO is poor for P and moderate for G values. (3) P extracted from DB has a higher reproducibility. (4) The extraction of P and G from the SPO phase spectra is critical and future work on standardizing this process is needed. (5) At present, the DB protocol might be slightly advantageous as a routine diagnostic tool.

BackgroundBilateral severe obstruction of the internal carotid artery is a hemodynamically critical state. We aimed to (1) analyze dynamic cerebral autoregulation (DCA) in affected patients, and (2) to correlate DCA data with different collateral flow patterns.MethodsDCA was assessed noninvasively by transfer function analysis (phase shift) of respiratory-induced oscillations at 0.1 Hz of arterial blood pressure (Finapres method) and cerebral blood flow velocity (transcranial Doppler) in 30 patients with severe bilateral carotid stenosis (> or =75%) or occlusion. CO(2)-reactivity was measured via inhalation of 7% CO(2). 30 patients with unilateral stenosis were recruited as controls.ResultsPatients with bilateral 75-89% stenosis had a virtually preserved phase shift. A pronounced reduction was found in bilateral critical stenosis or obstruction (90-100%). Patients with ipsilateral 90-100% and contralateral 75-89% stenosis had a significantly less severe reduction of phase shift on the ipsilateral side. CO(2)-reactivity showed a less marked reduction in patients with bilateral critical stenosis or occlusion. Phase shift was best if "Willisian" collaterals were present. Significantly reduced values were found if only secondary collaterals (ophthalmic artery, leptomeningeal flow) were detected. Poorest values occurred with recruitment of functionally stenosed "Willisian" collaterals. CO(2)-reactivity showed poor values with sole recruitment of secondary collaterals, whereas functionally stenosed primary collaterals did not show values as poor as for phase shift. Clinically symptomatic patients had significantly lower phase shift and CO(2)-reactivity values.ConclusionsDCA is severely impaired in bilateral critical carotid stenosis or occlusion. Sole recruitment of secondary collaterals and signs of a functional stenosis in primary ("Willisian") collaterals reflect insufficient collateral supply with a poor hemodynamic status. CO(2)-reactivity assessing the vasodilatory reserve and DCA represent different information for characterizing cerebral hemodynamic impairment. Determining transfer function phase might be a physiologically well supported approach for analysis of cerebral hemodynamic compromise.

The problem of delay time estimation in biological systems is addressed with the focus on practical applicability of methods. Four delay time estimators are described: a cross correlation method and three increasingly sophisticated interpretations of the phase spectrum, ranging from a pointwise interpretation of the phase spectrum in terms of a delay to a Hilbert transform method. The four methods are compared through simulation studies showing that, in general, the Hilbert transform method performs best. The methods are then used to estimate delay times in three physiological systems: vestibular stimulation, cerebral autoregulation, and human orthostatic tremor. In all three cases, the Hilbert transform method yields the best results, leading in some cases to physiologically more sensible interpretations of experiments than the other methods. © 2003 Biomedical Engineering Society. PAC2003: 8710+e, 8780Tq

Dissection of the internal carotid artery (ICAD; Fig. 1) is not only widely accepted as an important component of stroke aetiology, it is also well recognised as a focal cause of lower cranial nerve palsy. In the present patient, a duplex ultrasound revealed a left, submandibular ICAD originating 3 cm distal to the ICA bifurcation. In parallel, a high-grade, long-distance stenosis was confirmed by a time-of-flight magnetic resonance angiogram. Axial T2-weighted MRI showed a crescent-like, hyperintense signal corresponding to an intramural haematoma. In addition, an asymptomatic dissecting vertebral artery (VA) aneurysm on the right V2-segment was

Color-coded sonography is an interesting option for the diagnosis of temporal arteritis. We present our experiences regarding examination technique and diagnostic accuracy, comparing biopsy and clinical results in a series of 83 patients with suspected temporal arteritis. A dark halo around the vessel wall (representing inflammatory oedema), reduced or absent vessel wall pulsations (demonstrated by M mode), and vessel occlusions were used as diagnostic criteria. Forty-eight patients underwent biopsy of the temporal artery following ultrasound examination. Comparing these findings with biopsy yielded a sensitivity of 73%, specificity of 93%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 58%. The halo sign alone had a lower sensitivity (67%). Comparison with overall clinical assessment (n = 83) yielded a sensitivity of 65%, specificity of 100%, PPV of 100%, and NPV of 73%. Irregular atherosclerotic vessel wall changes were the main differential diagnosis. Important pitfalls were false focus setting, too much/less color gain, and 'bifurcation halo'. In conclusion, a positive sonographic result in combination with typical clinical signs might replace the need for biopsy, while a negative result should not be used for exclusion of temporal arteritis. Considering the low PPV and high NPV of the clinical criteria defined by the American College of Rheumatology, color-coded sonography is a useful tool in the noninvasive diagnostic workup of temporal arteritis.

Basilar artery (BA) stenting is an emerging technique with promising results in revascularization of severe arteriosclerotic stenoses. Because of the limitations associated with other noninvasive techniques, we applied transcranial color-coded sonography (TCCS) in the follow-up. Successful stent application in two cases of acute basilar occlusion caused by thrombosis on pre-existing severe midbasilar stenoses was initially confirmed by angiography. Later recanalization was controlled noninvasively by magnetic resonance angiography (MRA), computed tomographic angiography (CTA) and TCCS. Ultrasound (US) was performed through the transtemporal bone window; a contrast-enhancing agent had to be used in one case. TCCS showed an orthograde flow in the distal BA in both patients without signs of severe stenoses. Transtemporal TCCS was demonstrated to be a noninvasive bedside technique in monitoring the patency of the BA after stenting.

The aim of the present prospective study was to investigate whether hyperglycemia influences the clinical outcome or the infarct size after intravenous thrombolysis of focal cerebral ischemia. A consecutive series of hyperglycemic (n = 14) and normoglycemic patients (n = 17) with acute focal cerebral ischemia (

Evaluation of dynamic cerebral autoregulation might yield a physiologically more adequate measure of cerebral hemodynamic impairment in carotid artery stenosis than CO2-reactivity. This study re-evaluates and compares the Valsalva maneuver (VM) and phase shift during deep breathing. Nineteen patients with severe carotid artery stenosis and 17 age-matched controls were examined using transcranial Doppler sonography and non-invasive blood pressure recordings (Finapres). Phase shift was determined by cross-spectral analysis, responses to VM were graded by the formerly-introduced autoregulation slope index (ASI) and the new Valsalva time index (VTI). Phase shift and autoregulatory indices were significantly reduced on the affected side (p0.001). Correlations with CO2-reactivity were significant when pooling values of controls and patients (r from 0.54 to 0.78; p0.001). Correlations except for the VTI (r = -0.65; p = 0.002) were not significant considering only the affected side in patients. Correlations of pooled values between phase shift and VM-derived indices were significant (VTI r = -0.62; p0.001; ASI r = 0.49; p0.001), within patients only when comparing side-to-side differences (VTI r = -0.58; p = 0.009; ASI r = 0.52; p = 0.023). In conclusion, detection of impaired cerebral autoregulation is possible both by deep breathing and VM. The new VTI seems to be more suitable than the conventional ASI. Inter-method agreement concerning the extent of impairment is only acceptable for intra-individual side-to-side differences. Since absolute values of one autoregulation testing method or CO2-reactivity alone might fail, various tests should be combined for comprehensive assessment of cerebral hemodynamic impairment.

Local intra-arterial fibrinolysis (LIF) is the best choice at present for treatment of acute vessel occlusion in the vertebrobasilar territory and also, in selected cases, in the carotid territory. In almost all cases angiography demonstrates the site of occlusion exactly and gives information about collateral circulation. Contrary to this common approach, we report five patients with severe acute thromboembolic stroke in whom angiography revealed no occlusion of relevant arteries or their main branches. Under the hypothesis of persisting occlusion of perforating arteries to the brain stem we performed LIF in patients with a clinical basilar artery syndrome. Outcome in all but one of them was good following LIF. The clinical details are described and possible reasons discussed.

Sirs: There is a frequent observation of reduced regional cerebral blood flow during the aura phase of migraine. Several studies employing different cerebral imaging techniques [2] provided the same evidence of transient, spatially restricted changes in cerebral blood flow during the aura phase of migraine. These changes have not been consistently observed in migraine without aura [5]. Because of the unpredictable episodic onset of migraine attacks, a non-invasive bedside method like transcranial ultrasound is desirable in order to further understand the underlying hemodynamic changes. Transcranial Doppler (TCD) studies has not shown consistent results, probably because it measures cerebral blood flow velocity which is susceptible to changes in vessel diameter. Cerebral ultrasound perfusion imaging (CUPI) is a new technique that utilizes contrast-specific harmonic imaging to display cerebral perfusion through the analysis of bolus injection kinetics. We present a 31-year-old woman, with sudden onset of numbness and weakness of the right hand followed by aphasia, who was emergently admitted to our stroke unit for thrombolytic therapy. The initial TCD assessment showed normal flow velocities in extraand intracranial arteries. CUPI was then immediately performed, about 3 hours after symptom onset, using a GE Logiq 7 system, with harmonic Phase Inversion mode in bilateral approach from the contralateral side to the supposed pathology at the diencephalic plane. CUPI was performed by bolus-kinetics using 2.4 ml SonoVue (Bracco international BV, Germany) flushed by 5 ml saline. The pathologically perfused areas were detected according to the changes in contrast-enhancement on the gray-scale images in cine mode. The perfusion-parameters of these areas were drawn from the time-intensity curves (TIC) of manually selected region of interest (ROI). The reference perfusion-parameters were drawn from apparently normally perfused areas in both hemispheres. CUPI revealed an area of hypoperfusion in the left temporooccipital region with inhomogeneously prolonged time-to-peak (TTP) and diminished peak-intensity (PI) (Fig. 1a) corresponding to the topography of aura symptoms. Despite persisting symptoms, MRI (including diffusion weighted imaging) revealed normal findings. Within one hour, the patient developed left-sided throbbing headache with nausea and photophobia. The patient’s history revealed a similar episode with completely inconspicuous investigations. The episode was defined as migraine with prolonged aura. The neurological deficits gradually subsided with remaining minimal subjective numbness of the left hand and slowing of speech. The EEG depicted regional slowing of EEG activity temporooccipitally matching the hypoperfused area. The postictal ultrasound examination (about 24 hours after symptom onset) then showed a relative hyperperfusion of the previously hypoperfused area (Fig. 1b). These changes were accompanied by a relative flow velocity increase in the left posterior cerebral artery on TCD. A second MRI examination (including DWI and FLAIR) done 4 days after symptom onset and a lumbal puncture revealed normal findings. The clinical and MRI findings did not support ischemic origin [7, 8]. Understanding of migraine pathophysiology has always been impeded by its paroxysmal and unpredictable nature. However, it is widely considered – although not fully understood – that spreading cortical depression may explain the neurological deficits during aura. Spreading depression is either accompanied [10] or followed by [3] spreading oligemia which is not limited to neurovascular territories. However, the extent of CBF reduction is lower than that associated with ischemic injury [10]. Hyperemia following hypoperfusion was also reported in migraine with aura in a SPECT study [1]. Animal experiments have provided evidence of disturbance of the autoregulation of cerebral blood flow in response to hypotension during the initial phase of cortical spreading depression [6]. Data on cerebral autoregulation in migraneurs are scarce and are only available interictally with differing results mainly presenting normal dynamic autoregulation. Ictal autoregulation has not been assessed so far and has not been investigated in the presented patient. LETTER TO THE EDITORS

Vertebral artery dissection may cause upper limb peripheral motor deficit. We report three young patients presenting with nuchal pain followed by a nearly painless proximal paresis of the arm several days later. The cause, as detected by colour-coded Duplex sonography and MRI, was an extracranial dissection of the vertebral artery. The proximity of the intervertebral segment to the vertebral artery and the nerve roots indicated that compression by an intramural haematoma was the likely cause of the disorder. Subsequent examinations during anticoagulation treatment showed almost complete disappearance of the intramural haematoma and of the neurological deficits within a few weeks. We believe that the occurrence of an upper limb peripheral motor deficit should be added to the spectrum of potentially misleading signs of vertebral artery dissection.

Response: We greatly appreciate the thoughtful comments by Dr Gerriets and coworkers. Our finding of blood-brain barrier disruption after 300 kHz insonation in a 62-year-old man with cerebral small-vessel disease1 is substantiated by their remarkable animal study demonstrating vasogenic edema on MRI after 20 kHz insonation.2 Mechanical …

Blood flow velocity of the middle cerebral artery was monitored during cardiopulmonary bypass procedures by means of transcranial Doppler ultrasonography. Our investigation was carried out in a group of 16 patients with severe carotid stenosis or occlusion and in a control group of 42 patients with no or stenosis of less than 50% local diameter reduction. After onset of cardiopulmonary bypass, both groups showed a short unstable phase followed by increased blood flow velocity (10% increase ipsilateral to the obstruction, 27% increase in the control group). Just before rewarming, blood flow velocity was still comparable to (control group -3%) or higher than (ipsilateral to obstructions +14%) prebypass values. Analysis of three patients with postoperative diffuse encephalopathy did not reveal reduced blood flow during cardiopulmonary bypass as a relevant factor. Two of the three showed luxury perfusion. Reduced perfusion due to carotid obstruction was not observed during cardiopulmonary bypass and therefore cannot be considered a significant risk factor for the development of intraoperative stroke.

Wie wenig sich die Geschichten der Rhetorik und der Demokratie unabhangig voneinander erzahlen lassen, zeigt sich bereits an der Konstellation ihrer Geburt. Mit den Reformen des Solon (594 v. Chr.) und des Kleisthenes (508 v. Chr.) beginnen die Burger von Athen erstmals, ihre gemeinsamen Angelegenheiten im Medium offentlicher Reden selbst zu gestalten. Die von ihnen als demokratia bezeichnete neue Form des Zusammenlebens beruht vor allem auf dem Prinzip der isegoria oder Redefreiheit; Demokratie definiert sich als Raum, in dem allen erlaubt ist alles zu sagen.