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  • 1
    Online Resource
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    Ocular Flutter, Generalized Myoclonus, and Trunk Ataxia Associated With Anti-GQ1b Antibodies
    American Medical Association (AMA) ; 2008
    In:  Archives of Neurology Vol. 65, No. 5 ( 2008-05-01)
    Details
    In: Archives of Neurology, American Medical Association (AMA), Vol. 65, No. 5 ( 2008-05-01)
    Type of Medium: Online Resource
    ISSN: 0003-9942
    URL: Article
    DOI: 10.1001/archneur.65.5.659
    RVK:
    XA 10000
    Language: English
    Publisher: American Medical Association (AMA)
    Publication Date: 2008
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  • 2
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    Age related signal decrease in functional magnetic resonance imaging during motor stimulation in humans
    Elsevier BV ; 2001
    In:  Neuroscience Letters Vol. 308, No. 3 ( 2001-8), p. 141-144
    Details
    In: Neuroscience Letters, Elsevier BV, Vol. 308, No. 3 ( 2001-8), p. 141-144
    Type of Medium: Online Resource
    ISSN: 0304-3940
    URL: Article
    DOI: 10.1016/S0304-3940(01)01920-6
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2001
    detail.hit.zdb_id: 1498535-4
    SSG: 12
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  • 3
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    Two Tales: Hemorrhagic Transformation but Not Parenchymal Hemorrhage After Thrombolysis Is Related to Severity and Duration of Ischemia : MRI Study of Acute Stroke Patients Treated With Intravenous Tissue Plasminogen Activator Within 6 Hours
    Ovid Technologies (Wolters Kluwer Health) ; 2007
    In:  Stroke Vol. 38, No. 2 ( 2007-02), p. 313-318
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 38, No. 2 ( 2007-02), p. 313-318
    Abstract: Background and Purpose— Intracerebral hemorrhage represents the most feared complication of treatment with intravenous tissue plasminogen activator. We studied whether perfusion-weighted imaging and diffusion-weighted imaging has the potential to identify patients at risk of severe intracerebral hemorrhage after treatment with intravenous tissue plasminogen activator. Methods— We analyzed data of prospectively studied MRI selected acute ischemic stroke patients treated with intravenous tissue plasminogen activator within 6 hours. All patients were examined by perfusion- and diffusion-weighted imaging ≤6 hours. Perfusion- and diffusion-weighted imaging lesion volumes were calculated. Hemorrhagic transformation was assessed on follow-up CT or MRI and diagnosed as hemorrhagic transformation, parenchymal hemorrhage, or symptomatic intracerebral hemorrhage according to ECASS II criteria. Results— Of 152 patients, hemorrhagic transformation was seen in 60 (39.5%), parenchymal hemorrhage in 15 (9.9%), and symptomatic intracerebral hemorrhage in 4 (2.6%). Multiple logistic regression analysis identified onset to treatment time after 3 to 6 hours ( P 〈 0.001), a larger perfusion-weighted imaging lesion volume ( P =0.002), and, as a tendency, a higher score on the National Institutes of Health Stroke Scale on admission ( P =0.068) as independent predictors of hemorrhagic transformation. Neither MRI lesion volumes nor severity of symptoms, but rather only an older age tended to be associated with parenchymal hemorrhage ( P =0.087). Conclusion— Our results further support the concept of a different pathogenesis for hemorrhagic transformation and parenchymal hemorrhage. Whereas hemorrhagic transformation should be regarded as a clinically irrelevant epiphenomenon of ischemic damage and reperfusion, parenchymal hemorrhage appears to be related to biologic effects of tissue plasminogen activator and other pre-existing pathologic conditions, which deserve further investigation.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/01.STR.0000254565.51807.22
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2007
    detail.hit.zdb_id: 1467823-8
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  • 4
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    MRI-Based and CT-Based Thrombolytic Therapy in Acute Stroke Within and Beyond Established Time Windows : An Analysis of 1210 Patients
    Ovid Technologies (Wolters Kluwer Health) ; 2007
    In:  Stroke Vol. 38, No. 10 ( 2007-10), p. 2640-2645
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 38, No. 10 ( 2007-10), p. 2640-2645
    Abstract: Background and Purpose— The use of intravenous thrombolysis is restricted to a minority of patients by the rigid 3-hour time window. This window may be extended by using modern imaging-based selection algorithms. We assessed safety and efficacy of MRI-based thrombolysis within and beyond 3 hours compared with standard CT-based thrombolysis. Methods— Five European stroke centers pooled the core data of their CT- and MRI-based prospective thrombolysis databases. Safety outcomes were predefined as symptomatic intracranial hemorrhage and mortality. Primary efficacy outcome was a favorable outcome (modified Rankin Scale 0 to 1). We performed univariate and multivariate analyses for all end points, including age, National Institutes of Health Stroke Scale, treatment group (CT 〈 3 hours, MRI 〈 3 hours and 〉 3 hours), and onset to treatment time as variables. Results— A total of 1210 patients were included (CT 〈 3 hours: N=714; MRI 〈 3 hours: N=316; MRI 〉 3 hours: N=180). Median age, National Institutes of Health Stroke Scale, and onset to treatment time were 69, 67, and 68.5 years ( P =0.66); 12, 13, and 14 points ( P =0.019); and 130, 135, and 240 minutes ( P 〈 0.001). Symptomatic intracranial hemorrhage rates were 5.3%, 2.8%, and 4.4% ( P =0.213); mortality was 13.7%, 11.7%, and 13.3% ( P =0.68). Favorable outcome occurred in 35.4%, 37.0%, and 40% ( P =0.51). Age and National Institutes of Health Stroke Scale were independent predictors for all safety and efficacy outcomes. The overall use of MRI significantly reduced symptomatic intracranial hemorrhage (OR: 0.520, 95% CI: 0.270 to 0.999, P =0.05). Beyond 3 hours, the use of MRI significantly predicted a favorable outcome (OR: 1.467; 95% CI: 1.017 to 2.117, P =0.040). Within 3 hours and for all secondary end points, there was a trend in favor of MRI-based selection over standard 〈 3-hour CT-based treatment. Conclusion— Despite significantly longer time windows and significantly higher baseline National Institutes of Health Stroke Scale scores, MRI-based thrombolysis is safer and potentially more efficacious than standard CT-based thrombolysis.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.107.483255
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2007
    detail.hit.zdb_id: 1467823-8
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  • 5
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    Comparison of the 2 Most Popular Deconvolution Techniques for the Detection of Penumbral Flow in Acute Stroke
    Ovid Technologies (Wolters Kluwer Health) ; 2015
    In:  Stroke Vol. 46, No. 10 ( 2015-10), p. 2795-2799
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 46, No. 10 ( 2015-10), p. 2795-2799
    Abstract: Dynamic susceptibility–weighted contrast–enhanced (DSC) magnetic resonance imaging (MRI) is used to identify the tissue-at-risk in acute stroke, but the choice of optimal DSC postprocessing in the clinical setting remains a matter of debate. Using 15O-water positron emission tomography (PET), we validated the performance of 2 common deconvolution methods for DSC-MRI. Methods— In (sub)acute stroke patients with consecutive MRI and PET imaging, DSC maps were calculated applying 2 deconvolution methods, standard and block-circulant single value decomposition. We used 2 standardized analysis methods, a region of interest–based and a voxel-based analysis, where PET cerebral blood flow masks of 〈 20 mL/100 g per minute (penumbral flow) and gray matter masks were overlaid on DSC parameter maps. For both methods, receiver operating characteristic curve analysis was performed to identify the accuracy of each DSC-MR map for the detection of PET penumbral flow. Results— In 18 data sets (median time after stroke onset: 18 hours; median time PET to MRI: 101 minutes), block-circulant single value decomposition showed significantly better performance to detect PET penumbral flow only for mean transit time maps. Time-to-maximum (Tmax) had the highest performance independent of the deconvolution method. Conclusions— Block-circulant single value decomposition seems only significantly beneficial for mean transit time maps in (sub)acute stroke. Tmax is likely the most stable deconvolved parameter for the detection of tissue-at-risk using DSC-MRI.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.115.010246
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2015
    detail.hit.zdb_id: 1467823-8
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  • 6
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    Influence of the Arterial Input Function on Absolute and Relative Perfusion-Weighted Imaging Penumbral Flow Detection : A Validation With 15 O-Water Positron Emission Tomography
    Ovid Technologies (Wolters Kluwer Health) ; 2012
    In:  Stroke Vol. 43, No. 2 ( 2012-02), p. 378-385
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 43, No. 2 ( 2012-02), p. 378-385
    Abstract: Perfusion-weighted imaging maps are used to identify critical hypoperfusion in acute stroke. However, quantification of perfusion may depend on the choice of the arterial input function (AIF). Using quantitative positron emission tomography we evaluated the influence of the AIF location on maps of absolute and relative perfusion-weighted imaging to detect penumbral flow (PF; 〈 20 mL/100 g/min on positron emission tomography CBF ) in acute stroke. Methods— In 22 patients with acute stroke the AIF was placed at 7 sites (M1, M2, M3 ipsi- and contralateral and internal carotid artery–M1 contralateral to the infarct). Comparative 15 O-water positron emission tomography and AIF-dependent perfusion-weighted imaging (cerebral blood flow, cerebral blood volume, mean transit time, and time to maximum) were performed. A receiver operating characteristic curve analysis described the threshold independent performance (area under the curve) of the perfusion-weighted maps for all 7 AIF locations and identified the best AIF-dependent absolute and relative thresholds to identify PF. These results were compared with AIF-independent time-to-peak maps. Results— Quantitative perfusion-weighted imaging maps of cerebral blood flow and time to maximum performed best. For PF detection, AIF placement did significantly influence absolute PF thresholds. However, AIF placement did not influence (1) the threshold independent performance; and (2) the relative PF thresholds. AIF placement in the proximal segment of the contralateral middle cerebral artery (cM1) was preferable for quantification. Conclusions— AIF-based maps of cerebral blood flow and time to maximum were most accurate to detect the PF threshold. The AIF placement significantly altered absolute PF thresholds and showed best agreement with positron emission tomography for the cM1 segment. The performance of relative PF thresholds, however, was not AIF location-dependent and might be along with AIF-independent time-to-peak maps, more suitable than absolute PF thresholds in acute stroke if detailed postprocessing is not feasible.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.111.635458
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2012
    detail.hit.zdb_id: 1467823-8
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  • 7
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    Outcome and Symptomatic Bleeding Complications of Intravenous Thrombolysis Within 6 Hours in MRI-Selected Stroke Patients : Comparison of a German Multicenter Study With the Pooled Data of ATLANTIS, ECASS, and NINDS tPA Trials
    Ovid Technologies (Wolters Kluwer Health) ; 2006
    In:  Stroke Vol. 37, No. 3 ( 2006-03), p. 852-858
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 37, No. 3 ( 2006-03), p. 852-858
    Abstract: Background and Purpose— We compared outcome and symptomatic bleeding complications of intravenous tissue plasminogen activator (IV-tPA) within 6 hours of symptom onset in MRI-selected patients with acute middle cerebral artery infarction with the pooled data of the large stroke tPA trials. Methods— Patients were examined by perfusion-weighted and diffusion-weighted imaging ≤6 hours. Within 3 hours, patients were treated according to Second European-Australasian Acute Stroke Study (ECASS II) criteria. After 3 to 6 hours, treatment with IV-tPA was performed based on MRI findings. Favorable outcome was assessed after 90 days using a dichotomized modified Rankin scale score of 0 to 1. Intracerebral bleeding complications were assessed on follow-up MRI or computed tomography. Data were compared with the pooled placebo and pooled tPA patients of the ATLANTIS, ECASS, and National Institute of Neurological Disorders and Stroke (NINDS) tPA trials. Results— From 174 MRI-selected tPA patients, 62% (n=108) were treated in ≤3 hours and 38% (n=66) after 3 to 6 hours. Favorable outcome was more frequent in MRI-selected tPA patients (48% [95% CI, 39 to 54]) compared with pooled placebo (33% [95% CI, 31 to 36] ; P 〈 0.001) and pooled tPA patients (40% [95% CI, 37 to 42]; P =0.046). Odds ratios for favorable outcome in the MRI-selected tPA group were 1.82 (1.32 to 2.51) compared with the pooled placebo and 1.39 (1.01 to 1.92) compared with the pooled tPA group. The rate of symptomatic intracerebral hemorrhage in MRI-selected tPA patients (3% [95% CI, 0 to 5]) was lower than in the pooled tPA group (8% [95% CI, 7 to 10] ; P =0.012) and comparable to the pooled placebo group (2% [95% CI, 1 to 3]; P =0.392). Conclusions— This study supports that it is safe and effective to expand the time window for IV-tPA up to 6 hours in patients with tissue at risk as defined by MRI.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/01.STR.0000204120.79399.72
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2006
    detail.hit.zdb_id: 1467823-8
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  • 8
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    MRI-based mismatch detection in acute ischemic stroke: Optimal PWI maps and thresholds validated with PET
    SAGE Publications ; 2017
    In:  Journal of Cerebral Blood Flow & Metabolism Vol. 37, No. 9 ( 2017-09), p. 3176-3183
    Details
    In: Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 37, No. 9 ( 2017-09), p. 3176-3183
    Abstract: Perfusion-weighted (PW) magnetic resonance imaging (MRI) is used to detect penumbral tissue in acute stroke, but the selection of optimal PW-maps and thresholds for tissue at risk detection remains a matter of debate. We validated the performance of PW-maps with 15O-water-positron emission tomography (PET) in a large comparative PET-MR cohort of acute stroke patients. In acute and subacute stroke patients with back-to-back MRI and PET imaging, PW-maps were validated with 15O-water-PET. We pooled two different cerebral blood flow (CBF) PET-maps to define the critical flow (CF) threshold, (i) quantitative (q)CBF-PET with the CF threshold 〈 20 ml/100 g/min and (ii) normalized non-quantitative (nq)CBF-PET with a CF threshold of 〈 70% (corresponding to 〈 20 ml/100 g/min according to a previously published normogram). A receiver operating characteristic (ROC) curve analysis was performed to specify the accuracy and the optimal critical flow threshold of each PW-map as defined by PET. In 53 patients, (stroke to imaging: 9.8 h; PET to MRI: 52 min) PW-time-to-maximum (Tmax) with a threshold 〉 6.1 s (AUC = 0.94) and non-deconvolved PW-time-to-peak (TTP) 〉 4.8 s (AUC = 0.93) showed the best performance to detect the CF threshold as defined by PET. PW-Tmax with a threshold 〉 6.1 s and TTP with a threshold 〉 4.8 s are the most predictive in detecting the CF threshold for MR-based mismatch definition.
    Type of Medium: Online Resource
    ISSN: 0271-678X , 1559-7016
    URL: Article
    DOI: 10.1177/0271678X16685574
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2017
    detail.hit.zdb_id: 2039456-1
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  • 9
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    Abstract WP50: MRI Biomarkers in Acute Stroke: Addition of Clinical Parameters Improves the Identification of Patients Eligible for Thrombolysis
    Ovid Technologies (Wolters Kluwer Health) ; 2016
    In:  Stroke Vol. 47, No. suppl_1 ( 2016-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 47, No. suppl_1 ( 2016-02)
    Abstract: Introduction: Patients with unknown time from stroke onset, e.g. in wake-up stroke, are not eligible for thrombolyic treatment. Relative signal intensities (rSI) of DWI and FLAIR MRI are biomarkers for eligibility for thrombolysis, but have shown heterogeneous results to date. We investigated if the addition of available clinical parameters improves the prediction of the thrombolysis time window in patients with acute stroke. Hypothesis: Inclusion of clinical parameters improves the prediction of the thrombolysis time window by quantitative MRI biomarkers Methods: Patients from two centers with proven stroke and stroke-onset 〈 12 hours were included in a retrospective design. The DWI lesion was segmented and overlaid on ADC and FLAIR maps. rSI mean and standard deviation (std) were calculated: mean VOI value/mean value of the unaffected hemisphere. Prediction of the thrombolysis time window was evaluated by the area-under-the-curve (AUC) of receiver-operating-characteristic (ROC) curve analysis. Age, NIHSS, MRI field strength, lesion size, vessel occlusion and Wahlund-Score were included in adjusted and stratified regression models. Results: 82 patients were included. In the unadjusted analysis, DWI-mean and -std (AUC: 0.86, 0.87) performed best. Adjustment for clinical parameters significantly improved the performance of FLAIR-mean (0.87) and DWI-std (0.91). The best performance was found for the final stratified and adjusted models of DWI-std (0.94) and FLAIR-mean (0.96). ADC-rSIs showed no clinically acceptable performance in all models. Conclusion: rSIs of DWI and FLAIR MRI predict eligibility for thrombolysis in acute stroke with high precision, when easily available clinical parameters are included in the prediction.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.47.suppl_1.wp50
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
    detail.hit.zdb_id: 1467823-8
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  • 10
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    Early Ischemic Edema on Cerebral Computed Tomography: Its Relation to Diffusion Changes and Hypoperfusion within 6 h after Human Ischemic Stroke
    S. Karger AG ; 2006
    In:  Cerebrovascular Diseases Vol. 21, No. 5-6 ( 2006), p. 336-339
    Details
    In: Cerebrovascular Diseases, S. Karger AG, Vol. 21, No. 5-6 ( 2006), p. 336-339
    Abstract: 〈 i 〉 Background: 〈 /i 〉 Brain tissue hypoattenuation on early computed tomography is frequently included in decision making in acute stroke management. However, its pathophysiological counterpart needs further evaluation. 〈 i 〉 Methods: 〈 /i 〉 By comparative imaging with diffusion-weighted imaging and 〈 sup 〉 15 〈 /sup 〉 O-water positron emission tomography we aimed to interpret early ( 〈 6 h) hypoattenuation. 〈 i 〉 Results: 〈 /i 〉 In 11 patients, the hypoattenuation corresponded to a decreased proton diffusion (median 115.9% relative DWI value) measured by magnetic resonance imaging and to a severe hypoperfusion (below 12 ml/100 g/ min) assessed by positron emission tomography. The volume of parenchymal hypoattenuation correlated to the tissue with disturbed diffusion (Spearman’s rho = 0.73), but largely underestimated the hypoperfusion below 20 ml/100 g/min. 〈 i 〉 Conclusions: 〈 /i 〉 Early hypoattenuation reflects the coupling of the severity of ischemia and resulting diffusion changes. It allows an estimate of the infarct core but underestimates the penumbral hypoperfusion.
    Type of Medium: Online Resource
    ISSN: 1015-9770 , 1421-9786
    URL: Article
    DOI: 10.1159/000091539
    Language: English
    Publisher: S. Karger AG
    Publication Date: 2006
    detail.hit.zdb_id: 1482069-9
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