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  • Ovid Technologies (Wolters Kluwer Health)  (8)
  • Bivard, Andrew  (8)
  • 1
    Online Resource
    Online Resource
    Role of Computed Tomography Perfusion in Identification of Acute Lacunar Stroke Syndromes
    Ovid Technologies (Wolters Kluwer Health) ; 2021
    In:  Stroke Vol. 52, No. 1 ( 2021-01), p. 339-343
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 52, No. 1 ( 2021-01), p. 339-343
    Abstract: Lacunar syndromes correlate with a lacunar stroke on imaging in 50% to 60% of cases. Computed tomography perfusion (CTP) is becoming the preferred imaging modality for acute stroke triage. We aimed to estimate the sensitivity, specificity, and predictive values for noncontrast computed tomography and CTP in lacunar syndromes, and for cortical, subcortical, and posterior fossa regions. Methods: A retrospective analysis of confirmed ischemic stroke patients who underwent acute CTP and follow-up magnetic resonance imaging between 2010 and 2018 was performed. Brain noncontrast computed tomography and CTP were assessed independently by 2 stroke neurologists. Receiver operating characteristic curve analysis was performed to estimate sensitivity, specificity, and area under the curve (AUC) for the detection of strokes in patients with lacunar syndromes using different CTP maps. Results: We found 106 clinical lacunar syndromes, but on diffusion-weighted imaging, these consisted of 59 lacunar, 33 cortical, and 14 posterior fossa strokes. The discrimination of ischemia identification was very poor using noncontrast computed tomography in all 3 regions, but good for cortical (AUC, 0.82) and poor for subcortical and posterior regions (AUCs, 0.55 and 0.66) using automated core-penumbra maps. The addition of delay time and mean transient time maps substantially increased subcortical (AUC, 0.80) and slightly posterior stroke detection (AUC, 0.69). Conclusions: Analysis of mean transient time and delay time maps in combination with core-penumbra maps improves detection of subcortical and posterior strokes.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.120.030455
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
    detail.hit.zdb_id: 1467823-8
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  • 2
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    Online Resource
    Comparison of Computed Tomography Perfusion and Multiphase Computed Tomography Angiogram in Predicting Clinical Outcomes in Endovascular Thrombectomy
    Ovid Technologies (Wolters Kluwer Health) ; 2022
    In:  Stroke Vol. 53, No. 9 ( 2022-09), p. 2926-2934
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 53, No. 9 ( 2022-09), p. 2926-2934
    Abstract: In patients with acute stroke who undergo endovascular thrombectomy, the relative prognostic power of computed tomography perfusion (CTP) parameters compared with multiphase CT angiogram (mCTA) is unknown. We aimed to compare the predictive accuracy of mCTA and CTP parameters on clinical outcomes. Methods: We included patients with acute ischemic stroke who had anterior circulation large vessel occlusion within 24 hours of onset in Melbourne Brain Centre at the Royal Melbourne Hospital. All patients underwent CTP for endovascular thrombectomy, and the mCTA collateral score was determined using CTP-reconstructed mCTA images. The primary outcome was 90-day functional outcomes defined by modified Rankin Scale. Multivariable logistic regression models analyzed associations between mCTA and CTP parameters and 90-day functional outcomes. The ability to discriminate 90 days-functional outcomes was compared between mCTA collateral score and CTP parameters using receiver operating curve analysis and C statistics. Results: One hundred and twenty patients were included. The median age was 69 years (interquartile range, 60–79), the median baseline National Institutes of Health Stroke Scale score was 14 (interquartile range, 9–19). The baseline ischemic core volume, defined by CTP-based relative cerebral blood flow 〈 30%, was associated with excellent functional outcome (modified Rankin Scale score 0–1; odds ratio, 0.942 [−0.897 to −0.989]; P =0.015) and poor functional outcome (modified Rankin Scale score 5–6; odds ratio, 1.032 [1.007–1.056]; P =0.010) at 90 days in the analysis of multivariable regression. There was no significant association between the mCTA score and excellent functional outcome ( P =0.58) or poor functional outcome ( P =0.155). The relative cerebral blood flow 〈 30%-based regression model best fit the data for the 90-day poor functional outcome (C statistic, 0.834). Conclusions: The CTP-based ischemic core volume may provide better discrimination for 90-day functional outcomes for patients with acute stroke undergoing endovascular thrombectomy than the mCTA collateral score.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.122.038576
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
    detail.hit.zdb_id: 1467823-8
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  • 3
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    Association of Endovascular Thrombectomy With Functional Outcome in Patients With Acute Stroke With a Large Ischemic Core
    Ovid Technologies (Wolters Kluwer Health) ; 2022
    In:  Neurology Vol. 99, No. 13 ( 2022-09-27), p. e1345-e1355
    Details
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 99, No. 13 ( 2022-09-27), p. e1345-e1355
    Abstract: Endovascular thrombectomy (EVT) is effective for patients with large vessel occlusion (LVO) stroke with smaller volumes of CT perfusion (CTP)-defined ischemic core. However, the benefit of EVT is unclear in those with a core volume 〉 70 mL. We aimed to compare outcomes of EVT and non-EVT patients with an ischemic core volume ≥70 mL, hypothesizing that there would be a benefit from EVT for fair outcome (3-month modified Rankin scale [mRS] 0–3) after stroke. Methods A retrospective analysis of patients enrolled into a multicenter (Australia, China, and Canada) registry (2012–2020) who underwent CTP within 24 hours of stroke onset and had a baseline ischemic core volume ≥70 mL was performed. The primary outcome was the estimation of the association of EVT in patients with core volume ≥70 mL and within 70–100 and ≥100 mL subgroups with fair outcome. Results Of the 3,283 patients in the registry, 299 had CTP core volume ≥70 mL and 269 complete data (135 had core volume between 70 and 100 mL and 134 had core volume ≥100 mL). EVT was performed in 121 (45%) patients. EVT-treated patients were younger (median 69 vs 75 years; p = 0.011), had lower prestroke mRS, and smaller median core volumes (92 [79–116.5] mL vs 105.5 [85.75–138] mL, p = 0.004). EVT-treated patients had higher odds of achieving fair outcome in adjusted analysis (30% vs 13.9% in the non-EVT group; adjusted odds ratio [aOR] 2.1, 95% CI 1–4.2, p = 0.038). The benefit was seen predominantly in those with 70–100 mL core volume (71/135 [52.6%] EVT-treated), with 54.3% in the EVT-treated vs 21% in the non-EVT group achieving a fair outcome (aOR 2.5, 95% CI 1–6.2, p = 0.005). Of those with a core volume ≥100 mL, 50 of the 134 (37.3%) underwent EVT. Proportions of fair outcome were very low in both groups (8.1% vs 8.7%; p = 0.908). Discussion We found a positive association of EVT with the 3-month outcome after stroke in patients with a baseline CTP ischemic core volume 70–100 mL but not in those with core volume ≥100 mL. Randomized data to confirm these findings are required. Classification of Evidence This study provides Class III evidence that EVT is associated with better motor outcomes 3 months after CTP-defined ischemic stroke with a core volume of 70–100 mL.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    URL: Article
    DOI: 10.1212/WNL.0000000000200908
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2022
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  • 4
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    Online Resource
    Abstract WP71: Gradient of Tissue Injury on Diffusion Tensor Imaging After Stroke: Rethinking the Infarct vs Non-infarcted Dichotomy
    Ovid Technologies (Wolters Kluwer Health) ; 2020
    In:  Stroke Vol. 51, No. Suppl_1 ( 2020-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. Suppl_1 ( 2020-02)
    Abstract: Objective: To evaluate the degree of variability in microstructural injury within and adjacent to regions identified as infarcted tissue using Diffusion Tensor Imaging (DTI). Methods: Perfusion CT was performed in 18 patients within 12 hours of ischemic stroke onset followed by Fluid-attenuated Inversion recovery (FLAIR) and DTI one month after stroke. Four regions of interest (ROIs) corresponding to the severity of hypoperfusion on CT perfusion within and beyond the radiological infarct lesion defined on FLAIR were segmented. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified for each ROI and compared to a mirror homologue in the contralateral hemisphere. Ipsilateral to contralateral FA and MD ratios were compared across ROIs. Results: Lower FA and higher MD values were observed within both the infarct lesion and the peri-infarct tissue compared with their homologous contralateral brain regions (all comparisons p≤0.01). No difference was observed in FA and MD between remote non-hypoperfused tissue and its contralateral homologous region (FA p=0.42, MD p≥0.99). The magnitude of asymmetry (ipsilateral/contralateral ratios) of FA and MD was greater with increasing severity of hypoperfusion in a dose-response pattern. Asymmetry greatest in the area of infarction with severe hypoperfusion, followed by infarction with moderate hypoperfusion, the peri-infarct hypoperfused tissue and lastly the remote non-hypoperfused normal tissue (median on clustered quantile regression p≤0.01). Conclusion: A gradient of microstructural injury corresponding to the severity of ischemic insult is present within and beyond conventionally-defined infarct boundaries. The traditional dichotomized notion of infarcted versus non-infarcted tissue widely adopted in clinical research and in practice warrants re-examination.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.51.suppl_1.WP71
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
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  • 5
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    Abstract WP30: Delay and Dispersion Correction Leads to More Accurate Core Estimation for Endovascular Thrombectomy Patients
    Ovid Technologies (Wolters Kluwer Health) ; 2020
    In:  Stroke Vol. 51, No. Suppl_1 ( 2020-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. Suppl_1 ( 2020-02)
    Abstract: Objective: Endovascular thrombectomy (EVT) significantly improves clinical outcomes in acute ischemic stroke with large vessel occlusion. Clinical benefits are inversely proportional to size of the pre-treatment ischemic core. Therefore, accurate measurement of the size of core is critical in selecting patients for EVT. Different post-processing perfusion algorithms for automated core calculation on perfusion CT (CTP) are based on variations of deconvolution of the tissue concentration time curve with the arterial input function (single value decomposition, or SVD). In this study, we compared ischemic core estimated by two different CTP automated algorithms to the final infarct volume as demonstrated by follow up diffusion weighted imaging (DWI). Methods: We performed a retrospective analysis of patients who underwent EVT. Inclusion criteria were CT perfusion scan prior to EVT, successful EVT with mTICI 2b-3 reperfusion, and DWI scan 24-48 hours post-EVT. CTP data were processed by two different post-processing algorithms: ‘delay-insensitive’ single value decomposition (DISVD) and delay and dispersion corrected single value decomposition (ddSVD) using the respective commercially available automated CTP software. CTP core volumes from both methods were compared with DWI final infarct volumes using an independent software (MRIcron) for concordance. The agreement between a given algorithm and MRI was estimated using Lin’s concordance coefficient and further investigated using reduced major axis regression. Results: One hundred and three patients who underwent EVT and achieved successful mTICI 2b-3 reperfusion were included. Both algorithms had excellent agreement with MRI (Lin’s concordance coefficients: DISVD 0.8 (95% CI: 0.73; 0.87), ddSVD 0.92 (95% CI: 0.89; 0.95). Compared to ddSVD (reduced major axis slope = 0.95), DISVD exhibited larger extent of proportional bias (slope = 1.12). Conclusion: Both algorithms showed excellent agreement with FIV calculated on MRI but DISVD post-processing overestimated the larger ischemic cores, which may lead to unnecessary exclusion of patients from EVT due to a 'large core'.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.51.suppl_1.WP30
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
    detail.hit.zdb_id: 1467823-8
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  • 6
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    Online Resource
    Mobile Stroke Units Facilitate Prehospital Management of Intracerebral Hemorrhage
    Ovid Technologies (Wolters Kluwer Health) ; 2021
    In:  Stroke Vol. 52, No. 10 ( 2021-10), p. 3163-3166
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 52, No. 10 ( 2021-10), p. 3163-3166
    Abstract: Mobile stroke units (MSUs) improve reperfusion therapy times in acute ischemic stroke (AIS). However, prehospital management options for intracerebral hemorrhage (ICH) are less established. We describe the initial Melbourne MSU experience in ICH. Methods: Consecutive patients with ICH and AIS treated by the Melbourne MSU were included. We describe demographics, proportions of patients receiving specific therapies, and bypass to comprehensive/neurosurgical centers. We also compare operational time metrics between patients with MSU-ICH and MSU-AIS. Results: During a 2-year period, the Melbourne MSU managed 49 patients with ICH, mean (SD) age 74 (12) years, median (interquartile range) National Institutes of Health Stroke Scale 17 (12–20). Intravenous antihypertensives were the commonest treatment provided (46.9%). Bypass of a primary center to a comprehensive center with neurosurgical expertise occurred in 32.7% of patients with MSU-ICH compared with 20.5% of patients with MSU-AIS. Compared with patients with MSU-AIS, patients with MSU-ICH had faster onset-to-emergency-call, and onset-to-scene-arrival times at the median and 75th percentiles. Conclusions: MSUs can facilitate ultra-early ICH diagnosis, management, and triage.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.121.034592
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
    detail.hit.zdb_id: 1467823-8
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  • 7
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    Does Intravenous Thrombolysis Within 4.5 to 9 Hours Increase Clot Migration Leading to Endovascular Inaccessibility?
    Ovid Technologies (Wolters Kluwer Health) ; 2021
    In:  Stroke Vol. 52, No. 3 ( 2021-03), p. 1083-1086
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 52, No. 3 ( 2021-03), p. 1083-1086
    Abstract: Distal clot migration is a recognized event following intravenous thrombolysis (IVT) in the setting of acute ischemic stroke. Of note, clots that were initially retrievable by endovascular thrombectomy may migrate to a distal nonretrievable location and compromise clinical outcome. We investigated the incidence of clot migration leading to clot inaccessibility following IVT in the time window of 4.5 to 9 hours. Methods: We performed a retrospective analysis of the EXTEND trial (Extending the Time for Thrombolysis in Emergency Neurological Deficits) data. Baseline and 12- to 24-hour follow-up clot location was determined on computed tomography angiogram or magnetic resonance angiogram. The incidence of clot migration leading to a change from retrievable to nonretrievable location was identified and compared between the two treatment groups (IVT versus placebo). Results: Two hundred twenty patients were assessed. Clot migration from a retrievable to nonretrievable location occurred in 37 patients: 21 patients (19.3%) in the placebo group and 16 patients (14.4%) in the IVT group. No significant difference was identified in the incidence of clot migration leading to inaccessibility between groups ( P =0.336). Conclusions: Our results did not show increased clot migration leading to clot inaccessibility in patients treated with IVT.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/STROKEAHA.120.030661
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
    detail.hit.zdb_id: 1467823-8
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  • 8
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    Abstract 100: Reperfusion Improves Clinical Outcome Across the 4.5-9h and Wake-Up Stroke Time Continuum in EXTEND and EPITHET
    Ovid Technologies (Wolters Kluwer Health) ; 2020
    In:  Stroke Vol. 51, No. Suppl_1 ( 2020-02)
    Details
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 51, No. Suppl_1 ( 2020-02)
    Abstract: Introduction: Intravenous alteplase reduces disability after ischemic stroke in patients 4.5-9h after onset and with wake-up onset stroke who have favorable perfusion imaging. We examined the benefit of reperfusion in reducing disability, including by onset to randomization time strata in the EXTEND and EPITHET randomized trials. Methods: Patients were randomized to alteplase or placebo after perfusion mismatch imaging. Reperfusion was defined as 〉 90% reduction in Tmax 〉 6s lesion volume at 24h. Ordinal logistic regression adjusted for baseline age and NIHSS was used to analyze functional improvement in day 90 modified Rankin scale overall, including a reperfusion*time to randomization interaction term, and in the 4.5-6h, 6-9h and wake-up time strata. Symptomatic hemorrhage was defined as large parenchymal hematoma with ≥4 point NIHSS increase (SITS). Results: Reperfusion was assessable in 270/294 (92%) patients, 68/133 (51%) alteplase and 38/137 (28%) placebo reperfused (p 〈 0.001). Median age 76 (IQR 66-81) in reperfused vs 74 (IQR 64.5-81) in non-reperfused, median baseline NIHSS 10 (IQR 7-15) in reperfused vs 12 (IQR 8-17.5) in non-reperfused. Overall, reperfusion was associated with common odds ratio 7.7 (95%CI 4.6-12.8, p 〈 0.0001) in ordinal “shift” analysis. There was no heterogeneity in the beneficial effect of reperfusion effect by time to randomization (p=0.63). Reperfusion was associated with significantly improved functional outcome in each of the 4.5-6h, 6-9h and wake-up time strata (figure). Symptomatic hemorrhage, assessed in all 294 patients, occurred in 3/51 (5.9%) 4.5-6h, 2/28 (7.1%) 6-9h, 4/73 (5.5%) wake-up stroke in the alteplase-treated patients (van Elteren p=0.66). Conclusions: Strong benefits of reperfusion in all time strata without differential risk in symptomatic hemorrhage support the durable treatment effect of alteplase in perfusion mismatch-selected patients throughout the 4.5-9h and wake-up stroke time window.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    URL: Article
    DOI: 10.1161/str.51.suppl_1.100
    RVK:
    XA 10000
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2020
    detail.hit.zdb_id: 1467823-8
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