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Bernd Eckert

Publications and source records attributed to Bernd Eckert.

13 recordsLinked to original sources
PubMed2004

Screening for cerebellopontine angle tumors: is a CISS sufficient?

This study attempted to evaluate the reliability of ultra-thin T2-weighted imaging with a constructive interference in steady state (CISS) sequence as a screening method for tumors in the cerebellopontine angle. A retrospective study of 200 CISS examinations was made by five investigators. The examinations were inspected on plain film supported by clinical information. The interobserver agreement in the detection of lesions was analyzed. Fourteen cases (50% of the contrast-enhancing lesions) were rated pathological by all five readers. One case of subarachnoid lymphoma infiltration was overlooked by all five readers. Overall, six pathological lesions (median = 6, range 1-9) were not identified. The interobserver agreement for all pathological lesions was moderate (kappa=0.53; 95% CI, 0.43-0.62). The mean sensitivity was 77.8% (range 72.0-96.3%), and the mean specificity was 97.6% (range 94.8-100%). The median sensitivity for pathological lesions concerning only patients with acute sensorineural hearing loss (n=148, patients with 20 contrast-enhancing cases) was 86.6% (range 80-100%), and median specificity was 95.2% (range 84.4-96.9%) with a moderate interobserver agreement (kappa=0.55; 95% CI, 0.44-0.66). In our opinion the CISS sequence is a valuable addition to the examination of the cerebellopontine angle but lacks sufficient reliability for the detection of tumors of small size or of tumors adjacent to brain parenchyma or the temporal bone.

Cerebellar Neoplasms↗
PubMed2004

Predictors of apparent diffusion coefficient normalization in stroke patients.

BACKGROUND AND PURPOSE: We sought to describe the frequency of normalization of apparent diffusion coefficient (ADC) values that are decreased in hyperacute stroke and to identify characteristics of tissue demonstrating normalization. METHODS: Sixty-eight acute ischemic stroke patients underwent MRI examination (including diffusion/perfusion imaging and MR angiography) within 6 hours (mean, 2.8 hours) after symptom onset, after 24 hours, and again 4 to 7 days later. Lesion volumes with decreased ADC and delayed time to peak in perfusion imaging were determined. In patients showing ADC normalization, volumes with ADC decrease graded as <50%, 50% to 60%, 60% to 70%, and 70% to 80% of the contralateral value were determined by thresholding. Patients were categorized as normalizers (demonstrating ADC normalization in >5 mL tissue with initially decreased ADC) or nonnormalizers (demonstrating ADC normalization in <5 mL tissue). RESULTS: Fourteen patients (19.7%) were classified as normalizers. Eleven of 31 patients (35.5%) initially imaged <3 hours after stroke onset and 3 of 37 (7.5%) of those imaged 3 to 6 hours after onset were normalizers. ADC normalization occurred predominantly in the basal ganglia and white matter after thrombolytic therapy in patients with more distal vessel occlusions. All normalizers demonstrated at least partial tissue reperfusion. Tissue with more severe initial decrease in ADC was less likely to demonstrate normalization. CONCLUSIONS: ADC normalization is not a rare event in acute stroke after tissue reperfusion. Brain tissue with initially decreased ADC, especially within 3 hours after stroke onset, may include "tissue at risk."

Acute Disease↗
PubMed2004

Cerebral perfusion impairment correlates with the decrease of CT density in acute ischaemic stroke.

Within the first 6 h of ischaemic stroke, changes on computed tomography (CT) scans are known as early ischaemic signs. We tested the hypothesis that the severity of perfusion impairment correlates with the degree of CT density decrease. Water uptake in ischaemic brain tissue results in a subtle decrease of CT density, and was quantified by delineation of the corresponding decrease of the apparent diffusion coefficient (ADC). Regions of decreased ADC and CT density in 29 acute-stroke patients were superimposed on the corresponding magnetic resonance perfusion images. Mean values of ADC and CT density decrease were correlated with the corresponding relative changes of cerebral blood flow (rCBF) and volume (rCBV), mean transit time (rMTT) and time-to-peak (rTTP). The decrease of CT density was 1.2 +/- 0.6 Hounsfield units and showed a linear correlation with rCBF (0.42, p < 0.01) as well as rCBV (0.62, p < 0.01), but not with the prolongation of rMTT (1.43, p = 0.78) or rTTP (1.34, p = 0.26). Therefore, the reduction of rCBF determines the severity of the early ischaemic oedema (EIOE) on CT, as well as reduction of the ADC. These findings provide a coherent view on the pathophysiology of the EIOE.

Adult↗
PubMed2004

Hemodynamic changes of the cerebral circulation after stent-protected carotid angioplasty.

BACKGROUND AND PURPOSE: Stent-protected carotid angioplasty (SPAC) is an option for treating cervical symptomatic high-grade internal carotid artery (ICA) stenosis. So far, knowledge about hemodynamic changes in the early postinterventional phase is limited. The purpose of this study was to evaluate these changes. METHODS: Thirty-four consecutive patients with a high-grade ICA stenosis (according to European Carotid Surgery Trial criteria) and 10 healthy volunteers were enrolled. Hemodynamics of the cerebral circulation were assessed before and within 6 hours after SPAC. ICA flow volume, cerebral blood volume flow (CBVF), and collateral flow volume were sonographically assessed. The ratio of flow velocities in the middle cerebral artery (MCA) ipsilateral to the ICA stenosis was calculated and compared with that in the contralateral MCA. This ratio was designated rMCA. RESULTS: Preinterventional CBVF, ICA flow volume, and rMCA were significantly reduced compared with results in healthy volunteers. After SPAC, CBVF, ICA flow volume, and rMCA increased significantly. The rMCA did not exceed 1.0. Collateral flow volume decreased in patients with posterior collateral flow only. Postinterventional CBVF and ICA flow volume in patients did not differ from values in healthy volunteers. CONCLUSION: Cerebral hemodynamics appear to be impaired in patients with symptomatic high-grade ICA stenosis. After SPAC, hemodynamic parameters normalize within 6 hours. We did not detect hyperperfusion. However, flow volume in the contralateral ICA remains increased in patients with former anterior cross-filling.

Adult↗
PubMed2003

Endovascular treatment of internal carotid artery stenosis: effect of primary stent application on debris particle release in human cadaveric specimens.

PURPOSE: To compare debris release with primary stent application (self-expanding stent application at stenosis and then balloon dilation through the opened stent) and that with secondary stent application (balloon angioplasty of stenosis and afterward additional stent application) for high-grade internal carotid artery stenosis in human cadaveric specimens. MATERIALS AND METHODS: Fresh human cadaveric internal carotid artery specimens were attached to a tube system. High-grade stenoses (>66%) were selected, randomized for primary or secondary stent application, and then treated, with fluoroscopic guidance, while the system was rinsed in a pulsating flow. Fluid was collected and filtered, and debris particles were examined with a light microscope. Particles were analyzed according to those consecutively caught by 100 x 100-microm and 11 x 11-microm mesh filters. Results were evaluated in relation to stent application. For statistical analyses of group differences, the exact Mann-Whitney U test was used. RESULTS: Thirteen high-grade human cadaveric internal carotid artery stenoses were analyzed. Five specimens were randomly assigned to secondary stent application, and eight were assigned to primary stent application. No significant difference could be demonstrated for debris release with primary or secondary stent application. P values ranged from.051 to.754. CONCLUSION: The reported superiority of primary stent application may not be related to debris reduction.

Arteriosclerosis↗
PubMed2003

Local intra-arterial fibrinolysis in acute hemispheric stroke: effect of occlusion type and fibrinolytic agent on recanalization success and neurological outcome.

BACKGROUND: To evaluate the effect of occlusion type and fibrinolytic agent on recanalization success and clinical outcome in patients undergoing local intra-arterial fibrinolysis (LIF) in acute hemispheric stroke. METHODS: LIF was performed in 137 patients with angiographically established occlusion in the carotid circulation within 6 h of stroke onset. Retrospective analysis included recanalization success, recanalization time, type of occlusion and fibrinolytic treatment mode. Five types of occlusion were categorized: intracranial bifurcation (carotid 'T') of the internal carotid artery (ICA; n = 35); proximal segment of the middle cerebral artery (MCA; n = 66); distal segment of the MCA (n = 20); extracranial ICA with MCA embolism (n = 8); multiple peripheral branches of the anterior cerebral artery and the MCA (n = 8). Neurologic outcome was evaluated after 3 months by Barthel Index (BI) as good (BI >90), moderate (BI 50-90), poor (BI <50) or death. RESULTS: Recanalization was achieved in 74 patients (54%). Mean recanalization time in recanalized patients was 91 min. Neurologic outcome was good in 48 patients (35%), moderate in 34 (25%), poor in 30 (22%) and 25 died (18%). Outcome was significantly better in recanalized than in nonrecanalized patients (p < 0.001). Treatment results were significantly better in proximal and distal MCA occlusion than in carotid 'T' occlusions (p < 0.001). Recanalization success hardly differed between urokinase and rt-PA. Combined treatment with rt-PA and lys-plasminogen tended toward a faster recanalization. Parenchymal hemorrhage occurred in 13 patients (9%). CONCLUSION: The type of occlusion is of high prognostic value for successful fibrinolysis in the anterior circulation. However, recanalization is a time-consuming process even with an intra-arterial approach. Recanalization did not differ between type or dosage of plasminogen activators. Further innovative attempts are warranted towards hastening recanalization time in endovascular acute stroke treatment.

Adolescent↗
PubMed2003

Sensitivity and interrater agreement of CT and diffusion-weighted MR imaging in hyperacute stroke.

BACKGROUND AND PURPOSE: Previous acute stroke studies found diffusion-weighted (DW) imaging superior to CT for detection of early ischemic signs (EIS). However, these findings were confounded by a large time interval in favor of DW imaging. We compared DW images and CT scans obtained with a short time delay in patients with acute stroke to define the sensitivity and interrater agreement of both imaging techniques. METHODS: CT scans and DW images were obtained within 6 hours of symptom onset in 46 patients with acute stroke. Three neuroradiologists and three neurologists reviewed the images for EIS in five regions of the middle cerebral artery (MCA) territory and estimated the extent of EIS (< or > one-third of the MCA territory). RESULTS: The mean delay between imaging with both modalities was 24.5 minutes (range, 10-41 minutes). Forty-five of 46 patients had an ischemic stroke. EIS were seen on 33 of 45 CT scans (73% sensitivity; 95% confidence interval [CI]: 58-85%) and on 42 of 45 DW images (93% sensitivity; 94% CI: 82-99%). Interrater agreement was moderate (kappa = 0.57) for CT and excellent (kappa = 0.85) for DW imaging. CT studies had a moderate interrater agreement for estimation of EIS greater than one-third of the MCA territory (kappa = 0.40), whereas DW imaging showed good results (kappa = 0.68). Sensitivity for detection of greater than one-third of the MCA territory was equally poor (57%, 95% CI: 29-82%) for both CT and DW imaging. CONCLUSION: DW imaging helped identify EIS with higher sensitivity than that of CT. The interrater variability of the one-third rule was high for CT, and thus the clinical applicability of CT is limited. Our results support the application of stroke MR imaging for the treatment of patients with acute stroke.

Acute Disease↗
PubMed2003

Horner syndrome related to ipsilateral carotid wall hematoma after stent placement for the treatment of carotid stenoses.

BACKGROUND AND PURPOSE: We prospectively studied the incidence and natural history of Horner syndrome following stent-supported percutaneous angioplasty of the carotid artery (SPAC). We assessed the hypothesis that postinterventional Horner syndrome is related to ipsilateral carotid wall hematoma. METHODS: We performed duplex sonography of the carotid arteries and clinical examination in 28 consecutive patients before and 4 hours +/- 2, 24 hours +/- 2, and 7 days +/- 1 after SPAC. RESULTS: Within 24 hours +/- 2 after SPAC, 11 of the 28 patients developed ipsilateral Horner syndrome. Ten of these 11 patients had a postinterventional sonographic appearance of a carotid wall hematoma, whereas only two of the 17 patients without Horner syndrome had this finding (P <.001). In all patients, both Horner syndrome and carotid wall hematoma had resolved 7 days +/- 1 after SPAC. CONCLUSION: Horner syndrome appears to be a common yet transient event after SPAC. Although postinterventional Horner syndrome is significantly related to ipsilateral carotid wall hematoma, causality of the procedure-related formation of a carotid wall hematoma and oculosympathetic disturbance remains unproven.

Adult↗
PubMed2002

Endovascular therapy of acute vertebrobasilar occlusion: early treatment onset as the most important factor.

In view of the poor prognosis for patients with acute intracranial vertebrobasilar occlusion (VBO), factors were sought that predict survival and good neurologic outcome after acute endovascular treatment by means of local intra-arterial fibrinolysis (LIF) and percutaneous transluminal angioplasty (PTA). LIF was performed in 83 patients with angiographically established acute VBO. A significant residual stenosis after LIF was treated by additional PTA in 8 patients. The types of occlusion were classified as either embolic occlusion (EO) or atherothrombotic occlusion (AO). Outcome was evaluated after 3 months by the Barthel Index (BI) as favorable (BI >90), unfavorable (BI <90) or death and compared for each of 3 diagnostic or treatment variables: recanalization success, occlusion type and time to treatment. Four fibrinolytic treatment modes [urokinase, low-dose and high-dose recombinant tissue-type plasminogen activator (rt-PA), rt-PA + Lys-plasminogen] were also analyzed. The outcome was favorable in 19 patients (23%), unfavorable in 14 (17%) and 50 died (60%). Recanalization was successful in 54 patients (66%). The neurologic outcome was better in recanalized than in nonrecanalized patients (favorable outcome: 30 vs. 10%, mortality: 54 vs. 72%; p = 0.118). The neurologic outcome was better in EO than in AO (favorable outcome: 31 vs. 17%, mortality: 47 vs. 70%, p = 0.112). Under combined treatment by LIF and PTA in 8 patients with AO, 4 survived, 3 with a favorable outcome (38%). Early treatment onset ( 6 h; favorable outcome: 36 vs. 7%, mortality: 52 vs. 70%, p = 0.005). Although no statistically significant differences were found between the types of fibrinolytic agents, treatment with rt-PA and Lys-plasminogen tended toward better results. Early treatment onset proved to be the most important factor for successful endovascular therapy in acute VBO, whereas recanalization and presence of an embolic occlusion also tended toward better results. Additional PTA may be a promising therapy in cases of significant residual stenosis after LIF.

Acute Disease↗
PubMed2002

Acute basilar artery occlusion treated with combined intravenous Abciximab and intra-arterial tissue plasminogen activator: report of 3 cases.

BACKGROUND: Acute vertebrobasilar occlusion remains a disease with a high mortality even after treatment by local intra-arterial fibrinolysis. Adjunctive treatment with platelet glycoprotein IIb/IIIa receptor inhibitors such as abciximab may facilitate recanalization and improve the neurological outcome. Results after treatment of 3 patients by combined intravenous abciximab and local intra-arterial tissue plasminogen activator (tPA) are reported. CASE DESCRIPTIONS: Treatment was performed within 6 hours of stroke onset. Angiography revealed embolic occlusion of the basilar artery in 2 patients and atherothrombotic occlusion at the vertebrobasilar junction in 1 patient. Therapy consisted of intravenous abciximab bolus administration (0.25 mg/kg) followed by 12-hour infusion therapy (0.125 microg/kg per minute) and local intra-arterial thrombolysis with tPA (10 mg/h). Heparin was only applied for catheter flushing (500 IU/h). The patient with the atherothrombotic occlusion was treated with additional percutaneous transluminal angioplasty and stenting. Complete recanalization of the basilar artery occurred in 2 patients, whose conditions improved clinically to functional independence. In the third patient only partial recanalization was seen, with only slight clinical improvement. This patient died of cardiac failure 2 months later. Besides a subtle subarachnoid hemorrhage (n=1), no intracranial or extracranial bleeding complication was observed. CONCLUSIONS: The combination of glycoprotein IIb/IIIa receptor inhibitor with local intra-arterial tPA might be a promising therapy for patients with acute vertebrobasilar occlusion. Further studies are necessary to define the clinical benefit and the bleeding rate of this new pharmacological approach.

Abciximab↗
PubMed2002

Correlation of apparent diffusion coefficient and computed tomography density in acute ischemic stroke.

BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging is very sensitive for the detection of restricted molecular water diffusion in acute ischemic stroke. CT is sensitive to net water uptake in ischemic edema. We compared the decrease in the apparent diffusion coefficient (ADC) in diffusion-weighted MR imaging with CT density changes to study the correlation between diffusion restriction and water uptake in acute stroke patients. METHODS: Twenty-five patients with acute ischemic stroke of the anterior cerebral circulation underwent MR and CT imaging 1.3 to 5.4 hours after symptom onset. ADC and CT data were transferred into a common 3-dimensional space, and regions of decreased ADC (dADC) were superimposed onto the corresponding CT. Mean values of ADC and Hounsfield units (HU) were determined in comparison with the nonaffected hemisphere. RESULTS: Mean decrease in ADC (dADC) was 170+/-53x 10(-6) mm2/s and corresponded to a decrease (dCT) in CT density of 1.3+/-0.7 HU. dCT showed a continuous linear decrease of 0.4 HU/h (r=0.55, P<0.01), whereas the decrease is ADC was almost complete after 1.5 hours. A correlation between the decrease in ADC and dCT was found (r=0.41, P=0.04). CONCLUSIONS: The severity of diffusion restriction correlates with net water uptake in acute ischemic stroke. However, the underlying pathophysiology and different time courses indicate a common reason rather than a direct causality for both phenomena. The time delay and low value of CT density changes provide a reasonable explanation for the higher sensitivity of MR imaging in ischemic stroke.

Acute Disease↗
PubMed2002

Cerebral blood flow predicts lesion growth in acute stroke patients.

BACKGROUND AND PURPOSE: We sought to study the role of MRI-derived cerebral blood flow (CBF) measurements for the prediction of lesion development in acute stroke patients. METHODS: Thirty-two patients were treated with tissue plasminogen activator. Diffusion-weighted (DWI) and perfusion-weighted MRI, T2-weighted imaging, and MR angiography were performed before treatment (2.8+/-0.9 hours after symptom onset) and on follow-up (days 1 and 7). CBF thresholds (12 and 22 mL/100 g per minute) were applied to bolus tracking MRI maps to determine predictive cutoff levels. RESULTS: In 21 patients (group A), the terminal lesion volume (T2-weighted imaging) was larger than the initial DWI lesion volume (89+/-93 versus 21+/-38 mL). In 11 patients (group B), the terminal lesion volume was smaller than the initial DWI lesion volume (7+/-27 versus 15+/-29 mL). The initial DWI lesion volume did not differ between both groups. The presence of a tissue volume > or =50 mL with a CBF value < or =12 mL/100 g per minute was predictive for lesion enlargement to day 7 in T2-weighted imaging (positive predictive value, 0.80). CONCLUSIONS: The presence of a tissue volume > or =50 mL with a CBF value < or =12 mL/100 g per minute predicts further lesion growth in hyperacute stroke patients. MRI-derived CBF values, with all their present limitations, are valuable in early estimation of prognosis of stroke patients.

Acute Disease↗