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R von Kummer

Publications and source records attributed to R von Kummer.

119 records · Page 7Linked to original sources
PubMedDate not supplied

The ECASS 3-hour cohort. Secondary analysis of ECASS data by time stratification. ECASS Study Group. European Cooperative Acute Stroke Study.

OBJECTIVES: (1) To determine whether and how outcome measurements in the ECASS trial are influenced by a shorter time window (0-3 vs. 3-6 h) between onset of symptoms and start of thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke. (2) To discuss the results of the ECASS 0- to 3-hour cohort with the results of the National Institute of Neurological Disorders and Stroke Study (NINDSS). DESIGN AND ANALYSIS: Analysis of the 0- to 3-hour and the 3- to 6-hour cohort in accordance with the ECASS protocol. Comparative analysis of the ECASS and NINDSS results following the NINDSS protocol using dichotomized endpoints. MAIN OUTCOME MEASURES: Primary endpoints: modified Rankin Scale, Barthel Index; secondary endpoints: combined Barthel/Rankin, long-term Scandinavian Stroke Scale, National Institutes of Health Stroke Scale, mortality at 30 and 90 days, occurrence of intracranial hemorrhage. NINDS trial endpoint: favorable outcome as defined in the NINDS trial. RESULTS: In ECASS, 87 patients were randomized within 3 h of stroke onset. Differences in favor of rt-PA treatment can be found for all primary and secondary outcome measures in the ECASS 0- to 3-hour cohort, except for mortality at day 30, which is somewhat higher in the rt-pA-treated group. However, due to the small sample size, the differences do not reach statistical significance. Early infarct signs (as defined by the ECASS protocol) are found as early as 2 h after stroke onset. Parenchymal hemorrhages are found significantly more often among rt-PA-treated patients. The results in the ECASS 0- to 3-hour cohort fit well with the results in NINDSS. CONCLUSION: Data from the 3-hour ECASS cohort support the efficacy of early thrombolytic therapy in acute hemispheric stroke patients. Comparing bleeding complications between the ECASS and NINDSS is difficult because of differences in the definition and occurrence of hemorrhagic events.

Aged↗
PubMedDate not supplied

Noninvasive assessment of the circle of Willis in cerebral ischemia: the potential of CT angiography and contrast-enhanced transcranial color-coded duplexsonography.

Thirty-four patients with acute hemispheric ischemic strokes underwent both CT angiography and contrast-enhanced transcranial color-coded duplexsonography (TCCD) to study the effectiveness of the combined noninvasive techniques for evaluation of the circle of Willis. In 3/34 patients, CT angiography and contrast-enhanced TCCD demonstrated middle cerebral artery (MCA) occlusion, in 5 others MCA stenosis. A severe posterior cerebral artery stenosis was missed by CT angiography. In 8 patients, contrast-enhanced TCCD failed because of poor bone windows. In these patients, CT angiography was normal. CT angiography and contrast-enhanced TCCD are complementary noninvasive diagnostic tools. Disagreements between the diagnostic findings of these methods still need further evaluation by digital subtraction angiography.

Aged↗
PubMedDate not supplied

In vivo quantification of brain volumes in subcortical vascular dementia and Alzheimer's disease. An MRI-based study.

Quantitative magnetic resonance imaging (MRI) was used to assess global and regional cerebral volumes in patients with a clinical diagnosis of subcortical vascular dementia (VD) and Alzheimer's disease (AD). Whole brain volume, cerebrospinal fluid volume, volumes of the temporal, frontal and parietal lobes, the cerebellum and the amygdala-hippocampus complex were determined using a personal computer-based software. Seventeen patients with VD, 22 patients with AD and 13 healthy controls were included. Analysis of covariance using age as covariate demonstrated significant mean differences between controls and dementia groups with respect to all morphological parameters. However, apart from the volume of the cerebellum no significant volumetric differences were found between VD and AD. These results indicate that MRI-based volumetry allows differentiation between AD or VD from normal controls and that measurement of cerebellar volume may be of use to separate vascular and degenerative dementia. However, since the distribution of cerebral atrophy in both dementia groups is very similar, it is suggested that the atrophic changes are not specific to the underlying cause but rather reflect the selective vulnerability of neuronal structures.

Aged↗
PubMedDate not supplied

Local vascular response to change in carbon dioxide tension. Long term observation in the cat's brain by means of the hydrogen clearance technique.

Thirty six small hydrogen sensitive electrodes were inserted into the brains of 6 cats to evaluate the local vascular response to change in PaCO2, of cortex, subcortical white matter, and caudate nucleus. Repeated measurements (617) of local cerebral blood flow (ICBF) were performed over a period of 12 weeks. Within a PaCO2 range from 19 to 96 mmHg the local response of CBF was linear in most of the regions measured. The absolute local CO2 reactivity (CO2-R) showed a positive correlation to ICBF at PaCO2 = 40 mmHg (ICBF40) with the regression line: absolute CO2-R = 0.02 ICBF40 + 0.22, r = 0.71 (p less than 0.01). Therefore relative ICBF change was calculated in relation to ICBF40 to make comparisons between the CO2 response of different measuring days and of different regions examined. No significant change in relative CO2-R was observed during the 12 weeks interval. Differences of relative CO2-R between investigated regions were insignificant. The uniformity of relative CO2 response might support the hypothesis of a direct effect of PaCO2 or pH on the vessel wall. For comparison of CBF, the individual determination of CBF40 and relative CO2-R would be necessary.

Animals↗
PubMedDate not supplied

Echo-enhanced transcranial color-coded duplex sonography in the diagnosis of cerebrovascular events: a validation study.

BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography (TCCD) is a diagnostic technique for evaluation of intracranial arteries in patients with acute stroke. Echo-enhancing contrast agents (EEAs) are necessary to visualize intracranial vessels in up to 30% of patients because of limited acoustic bone windows. In this study, we assessed the diagnostic efficacy of echo-enhanced TCCD (eTCCD) in correlation with the gold standard, digital subtraction angiography (DSA). METHODS: We prospectively evaluated all patients with eTCCD who subsequently underwent DSA for evaluation of cerebrovascular symptoms over a 24-month period. We administered Levovist as an EEA. Two blinded reviewers analyzed all eTCCD findings and correlated them with DSA. RESULTS: We included 132 consecutive patients (40 women, 92 men; mean age, 58 +/- 14 years) with 164 datasets: 24/164 had normal findings, 98/164 had abnormalities of extracranial carotid arteries, 32/164 had abnormalities of intracranial arteries, and 21/164 had abnormalities in vertebrobasilar circulation as determined by DSA. For eTCCD, we found a sensitivity of 82% (95% confidence interval [CI]: 75%-90%), a specificity of 98% (95% CI: 90%-100%), a positive predictive value of 99% (95% CI: 94%-100%), and a negative predictive value of 75% (95% CI: 64%-85%); 7/164 (4%) examinations were inconclusive because of insufficient bone windows. The interobserver agreement was almost perfect (kappa value, 0.92; 95% CI: 0.87-0.97). CONCLUSION: eTCCD provides high diagnostic validity for the status of the major intracranial arteries. In particular, a normal vessel status reliably assessed by an experienced sonographer could supersede further imaging procedures. In patients with acute ischemic stroke not eligible for established angiographic techniques, eTCCD may be useful as an alternative imaging technique.

Adolescent↗
PubMedDate not supplied

Thrombolytic therapy in acute occlusion of the intracranial internal carotid artery bifurcation.

PURPOSE: To evaluate efficacy and clinical benefit of early thrombolytic therapy in intracranial internal carotid artery occlusion. METHODS: Thirty-two patients (mean age, 56 years) with acute intracranial internal carotid artery occlusion were studied clinically and with CT and angiography before and after thrombolytic therapy with intravenous alteplase (n = 16), superselective intraarterial alteplase (n = 8), and superselective intraarterial urokinase (n = 8). RESULTS: Initial CT showed a large parenchymal hypodensity in 11 (34%) patients, a small hypodensity in 15 (47%) patients, and no hypodensity in 6 (19%) patients. Recanalization after thrombolytic therapy was observed in 4 patients (12.5% in each treatment group). Follow-up CT showed six hemorrhagic infarcts and four parenchymal hematomas unrelated to recanalization, alteplase, or urokinase administration, but commonly associated with intraarterial treatment. Clinical outcome was fatal in 53%, poor in 31%, and moderate or good in 16% of the patients. Outcome was equal in different treatment groups and closely linked to both the quality of leptomeningeal collaterals and the extent of parenchymal hypodensity on the first CT. CONCLUSION: Because intravenous or intraarterial treatment with alteplase or urokinase fails to recanalize the vascular obstruction, it does not improve the prognosis of intracranial internal carotid artery occlusion over that of the natural course. Improved results may be possible with novel recanalization techniques.

Adult↗
PubMedDate not supplied

Potential of CT angiography in acute ischemic stroke.

PURPOSE: To study the ability of CT angiography to show intracranial arterial occlusion and collateral blood flow in patients with acute stroke. METHODS: Twenty-one patients with acute nonhemorrhagic stroke were studied prospectively with conventional CT, CT angiography, and digital subtraction angiography. On the basis of CT angiographic findings, two neuroradiologists independently assessed the site of arterial occlusion, the contrast enhancement in arterial branches beyond the occlusion as a measure of collateral blood supply, and the extent of diminished parenchymal enhancement; they then predicted the extent of ischemic infarction. RESULTS: Both raters correctly assessed all trunk occlusions of the basilar artery (n = 4), the internal carotid artery (n = 4), and the middle cerebral artery (n = 9). The chance adjusted interrater agreement was kappa = .78. The assessment of branch occlusions of the middle cerebral artery was less reliable. The agreement rate in judging the collateral state in 17 occlusions in the anterior cerebral circulation was 88%. The size of 21 (62%) of 34 hemispheric infarctions was predicted correctly. CONCLUSION: CT angiography quickly and reliably adds important information to conventional CT studies in cases of acute ischemic stroke. It shows the site of occlusion, the length of the occluded arterial segment, and the contrast-enhanced arteries beyond the occlusion as an estimate of collateral blood flow.

Adult↗