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  • 1
    Online Resource
    Online Resource
    Acute Stroke Imaging Research Roadmap
    Ovid Technologies (Wolters Kluwer Health) ; 2008
    In:  Stroke Vol. 39, No. 5 ( 2008-05), p. 1621-1628
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 39, No. 5 ( 2008-05), p. 1621-1628
    Abstract: The recent “Advanced Neuroimaging for Acute Stroke Treatment” meeting on September 7 and 8, 2007 in Washington DC, brought together stroke neurologists, neuroradiologists, emergency physicians, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB), industry representatives, and members of the US Food and Drug Administration (FDA) to discuss the role of advanced neuroimaging in acute stroke treatment. The goals of the meeting were to assess state-of-the-art practice in terms of acute stroke imaging research and to propose specific recommendations regarding: (1) the standardization of perfusion and penumbral imaging techniques, (2) the validation of the accuracy and clinical utility of imaging markers of the ischemic penumbra, (3) the validation of imaging biomarkers relevant to clinical outcomes, and (4) the creation of a central repository to achieve these goals. The present article summarizes these recommendations and examines practical steps to achieve them.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.107.512319
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2008
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  • 2
    Online Resource
    Online Resource
    Abstract 6: Patient Selection is a Better Predictor of Good Outcome Than Time to Reperfusion in Acute Ischemic Stroke
    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: Intra-arterial therapy has become standard-of-care for stroke patients with large vessel occlusions presenting within 6 hours of symptom onset. Treatment effectiveness at later times is currently unknown. Using data from the CT Perfusion (CTP) to predict Response to recanalization in Ischemic Stroke Project (CRISP), we assessed the effect of time to treatment on the probability of good outcomes. Hypothesis: Symptom onset-to-reperfusion time is not associated with probability of favorable outcomes in patients with target mismatch who achieve reperfusion. Methods: All patients enrolled underwent baseline CTP. For this analysis, we included data from patients with target mismatch (ratio of Tmax 〉 6s lesion to core volume of 〉 1.8) who achieved endovascular reperfusion. We determined reperfusion status by early follow-up MRI or CTP, or final TICI score 2b-3 if early follow-up perfusion imaging is unavailable. We defined good functional outcome (GFO) as mRS 0-2 at day 90. We assessed the probability of good outcome as a function of onset-to-reperfusion time using logistic regression, with prespecified adjustment for age and baseline NIHSS. Results: Following intra-arterial intervention performed within 18 hours, 102 patients with target mismatch achieved reperfusion. Median onset-to-reperfusion time was 6.6 hours (IQR 5.2-9.5). In univariate analysis, onset-to-reperfusion time was not associated with GFO (p=0.19), whereas age and NIHSS were. Similarly, in multivariate analysis, age and NIHSS were associated with GFO, while onset-to-reperfusion time was not. The adjusted relative risk per hour of delay is 0.994 (95% CI 0.97-1.02). GFO was achieved in 71.4% of patients treated within 6 hours, and in 61.7% of patients treated after 6 hours. Conclusion: The lack of significant association between onset-to-reperfusion time and GFO, and the high proportion of patients achieving good outcomes at 6-18 hours, suggest that endovascular interventions may be beneficial beyond 6 hours with a CTP target mismatch profile, supporting randomized controlled trials of endovascular therapy in the extended time window in selected patients.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.47.suppl_1.6
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
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  • 3
    Online Resource
    Online Resource
    Time From Imaging to Endovascular Reperfusion Predicts Outcome in Acute Stroke
    Ovid Technologies (Wolters Kluwer Health) ; 2018
    In:  Stroke Vol. 49, No. 4 ( 2018-04), p. 952-957
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 49, No. 4 ( 2018-04), p. 952-957
    Abstract: This study aims to describe the relationship between computed tomographic (CT) perfusion (CTP)-to-reperfusion time and clinical and radiological outcomes, in a cohort of patients who achieve successful reperfusion for acute ischemic stroke. Methods— We included data from the CRISP (Computed Tomographic Perfusion to Predict Response in Ischemic Stroke Project) in which all patients underwent a baseline CTP scan before endovascular therapy. Patients were included if they had a mismatch on their baseline CTP scan and achieved successful endovascular reperfusion. Patients with mismatch were categorized into target mismatch and malignant mismatch profiles, according to the volume of their Tmax 〉 10s lesion volume (target mismatch, 〈 100 mL; malignant mismatch, 〉 100 mL). We investigated the impact of CTP-to-reperfusion times on probability of achieving functional independence (modified Rankin Scale, 0–2) at day 90 and radiographic outcomes at day 5. Results— Of 156 included patients, 108 (59%) had the target mismatch profile, and 48 (26%) had the malignant mismatch profile. In patients with the target mismatch profile, CTP-to-reperfusion time showed no association with functional independence ( P =0.84), whereas in patients with malignant mismatch profile, CTP-to-reperfusion time was strongly associated with lower probability of functional independence (odds ratio, 0.08; P =0.003). Compared with patients with target mismatch, those with the malignant mismatch profile had significantly more infarct growth (90 [49–166] versus 43 [18–81] mL; P =0.006) and larger final infarct volumes (110 [61–155] versus 48 [21–99] mL; P =0.001). Conclusions— Compared with target mismatch patients, those with the malignant profile experience faster infarct growth and a steeper decline in the odds of functional independence, with longer delays between baseline imaging and reperfusion. However, this does not exclude the possibility of treatment benefit in patients with a malignant profile.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.117.018858
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2018
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  • 4
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    Online Resource
    Abstract TMP16: Hypoperfusion Severity Is Associated With Poor Collaterals And Progresses Over Time
    Ovid Technologies (Wolters Kluwer Health) ; 2013
    In:  Stroke Vol. 44, No. suppl_1 ( 2013-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 44, No. suppl_1 ( 2013-02)
    Abstract: Background: We hypothesized that cerebral perfusion deficits are more severe in acute stroke patients with poor collaterals and that the severity would increase over time if reperfusion does not occur. Methods: This is a substudy of DEFUSE 2. Collaterals were assessed on conventional angiography and dichotomized as poor vs. good flow. DWI and PWI were performed before and within 12 hrs after endovascular therapy; PWI lesion volumes were determined using a Tmax 〉 6sec threshold. The hypoperfusion ratio (HR) was calculated by determining the proportion of the PWI lesion that had severe Tmax delay ( 〉 10sec). Acute lesion growth was defined as the difference between the baseline and follow-up DWI volume. Part 1: In patients with an ICA or M1 occlusion we compared the HR to the collateral score. An ROC curve assessed whether the HR predicts the collateral score. Part 2: Among patients who did not experience early reperfusion, the difference between the baseline and follow-up HR was assessed and correlated with early infarct growth. Results: Part 1: Fifty six patients were eligible. Poor collateral flow was associated with larger baseline PWI lesion volume, p=0.012 and a higher HR compared to patients with good flow [median HR 45% (IQR: 35-52%) vs. 34% (IQR 14-41), p=0.003]. A HR 〉 41% predicted poor collateral flow with an AUC=0.73 (sensitivity 65%, specificity 78%, p=0.003). Part 2: Thirty two patients who did not achieve reperfusion were included; PWI Tmax 〉 6sec lesions volumes at baseline and follow-up were similar (median volume 75 mL at both time points). The median HR at follow-up was significantly higher than baseline [46% IQR (34-65) vs. 40% (24-48), p=0.007; median difference = 13% (IQR: 3.5-17)]. Patients who had worsening of their HR between baseline and follow-up were more likely to experience early ischemic lesion growth (R=0.53, p=0.002). Conclusion: The size and severity of Tmax lesions are associated with angiographic collateral scores. Patients who have a high percentage of their PWI lesion comprised of severe Tmax delays are likely to have poor collaterals. When early reperfusion is not achieved, the severity of hypoperfusion progresses and this progression is associated with early infarct growth.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.44.suppl_1.ATMP16
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2013
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  • 5
    Online Resource
    Online Resource
    Hypoperfusion Intensity Ratio Predicts Infarct Progression and Functional Outcome in the DEFUSE 2 Cohort
    Ovid Technologies (Wolters Kluwer Health) ; 2014
    In:  Stroke Vol. 45, No. 4 ( 2014-04), p. 1018-1023
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 45, No. 4 ( 2014-04), p. 1018-1023
    Abstract: We evaluate associations between the severity of magnetic resonance perfusion-weighted imaging abnormalities, as assessed by the hypoperfusion intensity ratio (HIR), on infarct progression and functional outcome in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2). Methods— Diffusion-weighted magnetic resonance imaging and perfusion-weighted imaging lesion volumes were determined with the RAPID software program. HIR was defined as the proportion of TMax 〉 6 s lesion volume with a Tmax 〉 10 s delay and was dichotomized based on its median value (0.4) into low versus high subgroups as well as quartiles. Final infarct volumes were assessed at day 5. Initial infarct growth velocity was calculated as the baseline diffusion-weighted imaging (DWI) lesion volume divided by the delay from symptom onset to baseline magnetic resonance imaging. Total Infarct growth was determined by the difference between final infarct and baseline DWI volumes. Collateral flow was assessed on conventional angiography and dichotomized into good and poor flow. Good functional outcome was defined as modified Rankin Scale ≤2 at 90 days. Results— Ninety-nine patients were included; baseline DWI, perfusion-weighted imaging, and final infarct volumes increased with HIR quartiles ( P 〈 0.01). A high HIR predicted poor collaterals with an area under the curve of 0.73. Initial infarct growth velocity and total infarct growth were greater among patients with a high HIR ( P 〈 0.001). After adjustment for age, DWI volume, and reperfusion, a low HIR was associated with good functional outcome: odds ratio=4.4 (95% CI, 1.3–14.3); P =0.014. Conclusions— HIR can be easily assessed on automatically processed perfusion maps and predicts the rate of collateral flow, infarct growth, and clinical outcome.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.113.003857
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2014
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  • 6
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    Abstract WP34: Associations Between CTP Ischemic Core Volume, ASPECTS Scores and Clinical Outcomes After Endovascular Reperfusion
    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: ASPECTS and CT perfusion (CTP) lesion volumes have been used to triage patients with large artery occlusions to endovascular therapy. Specifically, ASPECTS ≤5 and CTP infarct core 〉 50 mL excluded patients from some recent endovascular trials. It is unclear how well these criteria select patients who will have poor functional outcomes despite reperfusion and if the criteria are interchangeable. Hypothesis: ASPECTS and CTP infarct volumes are correlated and both predict clinical outcome. Methods: Patients with anterior circulation strokes were enrolled in a prospective multi-center study (CRISP) if CTP could be obtained 〈 90 minutes before endovascular treatment, and intervention performed 〈 18h from onset. Reperfusion was defined as 〉 50% reduction from baseline Tmax 〉 6s volume on early follow-up MRI ( 〈 36h from baseline CT) or final TICI 2b/3 if follow-up MRI unavailable. A single blinded reader at the core imaging facility determined ASPECTS on baseline CT. Baseline ischemic core volumes were assessed using automated software (RAPID). Good outcome was defined as mRS 0-2 and poor outcome as mRS 5-6. Results: This analysis includes 165 patients with reperfusion after endovascular therapy. Baseline ASPECTS and infarct core volume are inversely associated (p=0.009). Lower ASPECTS and larger infarct core were associated with a lower chance of good outcome in univariate analysis: OR for good outcome was 0.8 (95% CI 0.7-1.0) per point decrease in ASPECTS and 0.8 (95% CI 0.6-0.9) per 10mL increase in infarct core. Adjusted for baseline NIHSS and age, core remained a predictor of good outcomes (p=0.025) while ASPECTS showed a strong trend (p=0.072). The PPV for poor outcome despite reperfusion was 38% (5/13) for infarct core 〉 50 mL and 0% (0/7) for ASPECTS ≤5 (p=0.1 for difference in PPV). No patient met both criteria. Conclusions: The ASPECTS and ischemic core volume criteria used to exclude patients from some endovascular therapy trials, did not agree in identifying patients with presumed poor outcomes. Neither criterion had a high specificity for identifying patients destined to have a poor outcome despite reperfusion. Randomized trials are warranted to assess the efficacy of endovascular therapy in patients with ischemic core lesions 〉 50 ml and ASPECTS ≤5.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.47.suppl_1.wp34
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
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  • 7
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    Online Resource
    Acute Stroke Imaging Research Roadmap III Imaging Selection and Outcomes in Acute Stroke Reperfusion Clinical Trials : Consensus Recommendations and Further Research Priorities
    Ovid Technologies (Wolters Kluwer Health) ; 2016
    In:  Stroke Vol. 47, No. 5 ( 2016-05), p. 1389-1398
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 47, No. 5 ( 2016-05), p. 1389-1398
    Abstract: The Stroke Imaging Research (STIR) group, the Imaging Working Group of StrokeNet, the American Society of Neuroradiology, and the Foundation of the American Society of Neuroradiology sponsored an imaging session and workshop during the Stroke Treatment Academy Industry Roundtable (STAIR) IX on October 5 to 6, 2015 in Washington, DC. The purpose of this roadmap was to focus on the role of imaging in future research and clinical trials. Methods— This forum brought together stroke neurologists, neuroradiologists, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), industry representatives, and members of the US Food and Drug Administration to discuss STIR priorities in the light of an unprecedented series of positive acute stroke endovascular therapy clinical trials. Results— The imaging session summarized and compared the imaging components of the recent positive endovascular trials and proposed opportunities for pooled analyses. The imaging workshop developed consensus recommendations for optimal imaging methods for the acquisition and analysis of core, mismatch, and collaterals across multiple modalities, and also a standardized approach for measuring the final infarct volume in prospective clinical trials. Conclusions— Recent positive acute stroke endovascular clinical trials have demonstrated the added value of neurovascular imaging. The optimal imaging profile for endovascular treatment includes large vessel occlusion, smaller core, good collaterals, and large penumbra. However, equivalent definitions for the imaging profile parameters across modalities are needed, and a standardization effort is warranted, potentially leveraging the pooled data resulting from the recent positive endovascular trials.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.115.012364
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
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  • 8
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    A benchmarking tool to evaluate computer tomography perfusion infarct core predictions against a DWI standard
    SAGE Publications ; 2016
    In:  Journal of Cerebral Blood Flow & Metabolism Vol. 36, No. 10 ( 2016-10), p. 1780-1789
    Details
    In: Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 36, No. 10 ( 2016-10), p. 1780-1789
    Abstract: Differences in research methodology have hampered the optimization of Computer Tomography Perfusion (CTP) for identification of the ischemic core. We aim to optimize CTP core identification using a novel benchmarking tool. The benchmarking tool consists of an imaging library and a statistical analysis algorithm to evaluate the performance of CTP. The tool was used to optimize and evaluate an in-house developed CTP-software algorithm. Imaging data of 103 acute stroke patients were included in the benchmarking tool. Median time from stroke onset to CT was 185 min (IQR 180-238), and the median time between completion of CT and start of MRI was 36 min (IQR 25-79). Volumetric accuracy of the CTP-ROIs was optimal at an rCBF threshold of 〈 38%; at this threshold, the mean difference was 0.3 ml (SD 19.8 ml), the mean absolute difference was 14.3 (SD 13.7) ml, and CTP was 67% sensitive and 87% specific for identification of DWI positive tissue voxels. The benchmarking tool can play an important role in optimizing CTP software as it provides investigators with a novel method to directly compare the performance of alternative CTP software packages.
    Type of Medium: Online Resource
    ISSN: 0271-678X , 1559-7016
    URL: Article
    DOI: 10.1177/0271678X15610586
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
    detail.hit.zdb_id: 2039456-1
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  • 9
    Online Resource
    Online Resource
    Acute Stroke Imaging Research Roadmap II
    Ovid Technologies (Wolters Kluwer Health) ; 2013
    In:  Stroke Vol. 44, No. 9 ( 2013-09), p. 2628-2639
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 44, No. 9 ( 2013-09), p. 2628-2639
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.113.002015
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2013
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  • 10
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    Online Resource
    Abstract 57: Main Results of the CTP to Predict Response to Recanalization in Ischemic Stroke Project (CRISP)
    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: Background: Recent acute stroke trials showed benefit from intra-arterial thrombectomy (IAT) up to 6 hrs. We aimed to assess CT Perfusion (CTP) for selection of patients for endovascular therapy up to 18 hrs. Hypothesis: CTP target mismatch profile (TMM) identifies patients likely to benefit from IAT. Methods: The CTP to predict Response to recanalization in Ischemic Stroke Project (CRISP) is an NIH funded multicenter cohort study of consecutive acute stroke patients scheduled to undergo IAT within 90 min after a baseline CTP. Volumes for the CTP ischemic core (rCBF 〈 30%) and critically hypoperfused tissue (Tmax 〉 6s) were computed with automated software (RAPID). Target Mismatch (TMM) was defined as a CBF core 〈 70 mL, a Tmax 〉 6s – core difference 〉 15mL, a Tmax 〉 6s : core ratio 〉 1.8, and a Tmax 〉 10s lesion 〈 100 mL. Reperfusion was defined as 〉 50% reduction in Tmax 〉 6s lesion volume between baseline CTP and follow-up MRI (obtained 〈 36 hrs after CTP), or TICI 2b/3 at completion of IAT if follow-up MRI was not performed/technically inadequate. Good functional outcome (GFO) was defined as mRS 0-2 on day 90. Results: Of the 201 patients enrolled, 6 had inadequate baseline CTP (3%), 3 did not undergo angiography, and 2 were lost to follow-up. Therefore, 190 patients were included; mean age 66 yrs, median NIHSS 16, median time from symptom onset to IAT 5.2 hrs ( 〉 6 hrs in 40%). Rate of reperfusion was 89% (87% TICI 2b/3) and 55% had GFO. In patients with TMM (n=131), reperfusion was associated with higher odds of GFO (66% vs 29%; OR=4.3; 95% CI 1.4-13). This association remained significant when adjusted for age and NIHSS (OR=8.4; 95% CI 2.5-28). In patients without TMM (n=51), the effect of reperfusion could not be assessed, since almost all patients (95%) reperfused. Independent of reperfusion status, patients with TMM had a higher rate of GFO (61%) than those without TMM (42%, p=0.02). Conclusion: In this multicenter study, a technically adequate baseline CTP was obtained in nearly all patients and almost half underwent IAT beyond 6 hrs. Patients with the TMM profile had a high rate of GFO (61%) and a robust association between reperfusion and good outcome. These results support the feasibility of a randomized trial of IAT in an extended window using the CTP-TMM profile for patient selection.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.47.suppl_1.57
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
    detail.hit.zdb_id: 1467823-8
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