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  • 1
    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
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2013
    detail.hit.zdb_id: 1467823-8
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  • 2
    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
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2014
    detail.hit.zdb_id: 1467823-8
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  • 3
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 43, No. suppl_1 ( 2012-02)
    Abstract: Background: The Thrombolysis In Cerebral Infarction (TICI) score is a widely used angiographic score in endovascular stroke studies. Assessment of reperfusion based on perfusion weighted MRI (PWI reperfusion) has been used more commonly in patients treated with intravenous thrombolysis. This analysis of the DEFUSE 2 study data was undertaken to 1) determine the association between TICI and PWI reperfusion and 2) assess the association between TICI-reperfusion and clinical and radiographic outcomes. Methods: Patients undergoing acute endovascular stroke therapy of anterior circulation strokes were enrolled in a prospective multi-center study (DEFUSE 2) if an MRI could be obtained within 90 minutes before endovascular treatment and repeated within 12 hours after the intervention. Only patients with a TICI score of 0 or 1 on baseline digital subtraction angiography (DSA) were included in this analysis. A single blinded reader at the core imaging facility determined pre- and post-procedure TICI scores. TICI-reperfusion was defined as a TICI score of 2B or 3. PWI lesion volumes were assessed using fully automated software (RAPID). PWI-reperfusion was defined as a reduction in PWI(Tmax 〉 6s) lesion volume of 〉 50% between baseline and early follow-up. Infarct growth was defined as the difference between baseline DWI and 5-day FLAIR lesion volume. Favorable clinical response was defined as a NIHSS score of 0-1 at day 30 or an improvement in NIHSS score of ≥8 points between baseline and day 30. Results: This preliminary analysis includes 68 of 101 patients who underwent endovascular therapy and had adequate PWI data to assess reperfusion (final results will be presented at the meeting). At completion of endovascular treatment 30% of the patients remained TICI 0 or 1, 27% improved to TICI 2A, 29% to TICI 2B, and 13% had complete reperfusion (TICI 3). Better TICI-reperfusion scores were associated with higher rates of reperfusion assessed by PWI. PWI-reperfusion was seen in 32% of patients who remained TICI 0-1, 53% with TICI 2A, 98% with TICI 2B, and 100% with TICI 3 reperfusion. Agreement between TICI-reperfusion and PWI-reperfusion was moderate (kappa 0.51). The incidence of favorable clinical response increased with higher TICI scores: 35% with TICI 0-1, 44% with TICI 2A, 72% with TICI 2B, and 67% with TICI 3. Patients who met pre-specified DEFUSE 2 criteria for reperfusion (TICI 2B/3) were more likely to have a favorable clinical response (70% vs 40%; p=0.015), and had less median [IQR] lesion growth (10 [2-56] ml vs 67 [28-122] ml; p=0.001) than patients without TICI-reperfusion. Conclusion: TICI 2B or 3 reperfusion following endovascular therapy for acute anterior circulation stroke is highly correlated with PWI reperfusion. Patients with TICI 2B or 3 reperfusion show less infarct growth and are more likely to have a favorable clinical response.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2012
    detail.hit.zdb_id: 1467823-8
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  • 4
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 43, No. suppl_1 ( 2012-02)
    Abstract: Background: The aim of DEFUSE 2 was to determine if there is a differential response to reperfusion following endovascular therapy according to predefined baseline MRI profiles. Methods: This prospective cohort study was conducted at 9 stroke centers. Consecutive patients, scheduled to undergo acute endovascular therapy within 12 hours of stroke onset, were enrolled if they had an NIHSSS 〉 5 and could undergo an MRI with perfusion (PWI) and diffusion-weighted imaging (DWI) immediately before the intervention. A fully automated image analysis program (RAPID) was used to determine lesion volumes. Patients were classified as Target Mismatch (TMM) if they met these criteria: a ratio of PWI(Tmax 〉 6s) over DWI volume 〉 1.8, DWI 〈 70ml, and a PWI(Tmax 〉 10s) volume 〈 100ml. An early follow-up MRI was obtained 〈 12 hours after endovascular therapy. Early reperfusion was defined as a 〉 50% reduction in Tmax 〉 6s volume between baseline and early follow-up. Favorable clinical response was defined as a ≥8 point improvement on the NIHSSS or an NIHSSS of 0-1 at 30 days. Results: This abstract represents a preliminary analysis of 86 of 101 patients who were treated with endovascular therapy (final results will be presented). The baseline characteristics of patients with TMM (n=70) were: mean age 67, median NIHSS 15, treated with iv tPA 43%, mean time from symptom onset to endovascular treatment 6.7 hrs, mean DWI volume 18 ml, and Tmax 〉 6s volume 82 ml. Early reperfusion was achieved in 64% of the TMM population and favorable clinical response was more common in TMM patients with early reperfusion than in TMM patients who did not reperfuse (69% vs 24%; p 〈 0.001). The baseline characteristics of patients without TMM (n=16) were: mean age 59, median NIHSS 19, treated with iv tPA 81%, mean time from symptom onset to endovascular treatment 5.4 hrs, mean DWI volume 76 ml, and Tmax 〉 6s volume 115 ml. Early reperfusion was achieved in 53% of the patients without TMM but was not associated with favorable clinical response in this population (44% had favorable clinical response with reperfusion vs 86% without reperfusion; p=0.15). The odds ratio for favorable clinical response associated with reperfusion was higher in TMM patients (7.0; 95% CI 2.3-21) than in those without TMM (0.1; 95% CI 0.1-1.6) (p 〈 0.01 for difference between odds ratios). These odds ratios remained similar after adjustment for differences in baseline characteristics (OR 7.8 vs. 0.2; p 〈 0.01 for difference between odds ratios). Conclusion: Early reperfusion following endovascular therapy is associated with substantial clinical benefits in patients with the Target Mismatch profile on baseline MRI. There is no association between reperfusion and favorable clinical outcomes in patients without Target Mismatch. These findings support the use of PWI/DWI selection criteria to identify a patient subgroup that is most likely to benefit from endovascular reperfusion therapy.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2012
    detail.hit.zdb_id: 1467823-8
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  • 5
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 43, No. suppl_1 ( 2012-02)
    Abstract: Background: The aim of DEFUSE 2 is to determine if predefined MRI profiles predict clinical and imaging outcomes following endovascular reperfusion therapy. Methods: This prospective, NIH funded, multi-center study enrolled consecutive acute stroke patients in whom an MRI scan could be obtained immediately prior to intra-arterial therapy. A follow-up MRI was performed within 12 hrs of completion of the procedure and again at 5 days. PWI and DWI lesion volumes were determined using a fully automated software program (RAPID). Lesion growth (infarct volume on 5 day FLAIR - baseline DWI volume) was compared for patients with and without the Target mismatch profile based on whether early reperfusion occurred. The Target mismatch profile was defined as PWI(Tmax 〉 6s) / DWI 〉 1.8, DWI 〈 70 mL and PWI(Tmax 〉 10s) 〈 100 mL. Early reperfusion was defined as a 〉 50% reduction in PWI volume following the procedure. The incidence and extent of DWI reversal was assessed and the fate of PWI lesions that were not reperfused was determined. Favorable clinical response was defined as an improvement in NIHSS ≥8 or 0-1 at 30 days. Results: This abstract represents a preliminary analysis of 71 of 101 patients who were treated with endovascular therapy (final results to be presented). Among the 54 patients with Target mismatch, early reperfusion was achieved in 70% and was associated with less infarct growth (relative median growth 210% vs. 450%, p=0.01) and a higher rate of favorable clinical response (OR=5.4; 95%CI 1.5-19.2). In patients without the Target mismatch profile (N= 13) early reperfusion was not associated with a reduction in infarct growth (relative median growth was 220% in both reperfusers and non-reperfusers; p=0.94) or an increased rate of favorable clinical response (OR=0.1; 95%CI 0.004-2.2). 96% of all voxels that were DWI positive at baseline were incorporated into the final infarct (assessed on the co-registered 5 day FLAIR); only 3 of 71 patients had FLAIR volumes that were smaller than the baseline DWI lesion (mean difference 3 mL). 80% of the voxels that had a PWI lesion (Tmax 〉 6s) on the post-procedure scan were incorporated into the final infarct. The correlation between the union of the baseline DWI + early follow-up PWI lesion and the 5 day FLAIR volume was high (r=0.84; p 〈 0.0001). In 82% of the patients, the day 5 FLAIR volume was as at least as large as the union of the baseline DWI + early follow-up PWI lesion. Conclusion: Patients with the Target mismatch profile who achieve early reperfusion following intra-arterial therapy have less infarct growth and more favorable clinical outcomes. In contrast, no benefit of reperfusion was evident for non-Target mismatch patients. Baseline DWI lesions are virtually always fully incorporated into the final infarct volume, regardless of reperfusion. Tissue that remains hypoperfused (Tmax 〉 6s) following endovascular therapy reliably progresses to infarction.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2012
    detail.hit.zdb_id: 1467823-8
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  • 6
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2017
    In:  Neurology Vol. 88, No. 24 ( 2017-06-13), p. 2254-2259
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 88, No. 24 ( 2017-06-13), p. 2254-2259
    Abstract: To investigate the relationship between acute perfusion-weighted imaging (PWI) lesions occurring within the first hours after a TIA or a minor brain infarction (BI) and the incidence of new BI detected on a systematic MRI at 1 week. Methods: Consecutive patients who experienced a TIA or BI with a neurologic deficit that lasted 〈 24 hours, did not receive any revascularization therapy (thrombolysis/thrombectomy), and underwent DWI/PWI at baseline and fluid-attenuated inversion recovery (FLAIR)/DWI 1 week after symptom onset were enrolled. Investigators blinded to clinical information independently assessed the presence of acute ischemic lesions on baseline DWI/PWI and follow-up DWI and FLAIR. Baseline and follow-up MRIs were then compared to determine the occurrence and location of new infarctions. Results: Sixty-four patients met the inclusion criteria. Median (IQR) ABCD2 score was 4 (3–5). Median delay from onset to baseline and follow-up MRI was 5 (2–10) hours and 6 (5–7) days, respectively. MRI revealed an acute ischemic lesion on DWI and/or PWI in 38 patients. Nine patients (14%) had a new infarction on follow-up MRI. Each had a PWI and 4 had a DWI lesion on baseline MRI. All new BIs except one were asymptomatic and in the same location as the acute PWI lesion. Conclusions: Our results showed that 30% of the acute focal PWI lesions detected after a TIA are associated with a new BI at 1 week. Those new BIs may result from the progression of the initial ischemic injury.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2017
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  • 7
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 46, No. suppl_1 ( 2015-02)
    Abstract: Background and purpose: Fluid-attenuated inversion recovery (FLAIR) vessel hyper-intensities (FVH) have been hypothesized to have a positive correlation with good collaterals and more favorable clinical outcomes in acute stroke patients. We assessed if FVH predict the Target mismatch profile (TMM) and clinical outcomes in the DEFUSE studies. Methods: Patients with technically adequate baseline diffusion weighted images (DWI), perfusion images (PWI), and FLAIR images were included in this pooled analysis of the DEFUSE 1 and 2 studies. The FVH sign was defined as visible hyper-intense vessels on FLAIR images and assessed at basal ganglia levels by two independent raters. Clinical outcomes were assessed using modified Rankin Scale (mRS) at 90 days. The Target mismatch profile was based on baseline DWI and PWI volumes using automated software (RAPID). Results: Seventy seven patients met the inclusion criteria. Median time (IQR) from symptom onset to baseline MRI was 4.6 hours (3.9 - 5.4) and median (IQR) DWI lesion was 13.1 (5.0 - 32.0) ml. Of these, 66 patients (86%) had the FVH sign. Kappa score for inter-rater agreement was 0.621 (95CI: 0.33 - 0.91). Seventy (74%) cases with FVH had TMM profile vs. 33% of No FVH patients (p=0.023). Good clinical outcome (mRS 0-2) did not differ (50% with FVH vs. 73% without FVH, p=0.203). Only 38% of the patients with FVH had good angiographic collaterals and the rate of early reperfusion did not differ (45% with FVH vs. 25% without FVH, p=0.45). Conclusions: FVH is common in acute stroke patients (86%) and is associated with the Target Mismatch profile. However, FVH was not associated with favorable angiographic collaterals, good clinical outcome or early reperfusion in the DEFUSE 1 and 2 cohorts.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2015
    detail.hit.zdb_id: 1467823-8
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  • 8
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 85, No. 8 ( 2015-08-25), p. 708-714
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2015
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  • 9
    In: International Journal of Stroke, SAGE Publications, Vol. 11, No. 1 ( 2016-01), p. 85-92
    Abstract: No definitive criteria are available to confirm the diagnosis of transient ischemic attack. Inter-rater agreement between physicians regarding the diagnosis of transient ischemic attack is low, even among vascular neurologists. We developed the Precise Diagnostic Score, a diagnostic score that consists of discrete and well-defined clinical and imaging parameters, and investigated inter-rater agreement in patients with suspected transient ischemic attack. Methods Fellowship-trained vascular neurologists, blinded to final diagnosis, independently reviewed retrospectively identical history, physical examination, routine diagnostic studies, and brain magnetic resonance imaging (diffusion and perfusion images) from consecutive patients with suspected transient ischemic attack. Each patient was rated using the 8-point Precise Diagnostic Score score, composed of a clinical score (0–4 points) and an imaging score (0–4 points). The composite Precise Diagnostic Score determines a Precise Diagnostic Score Likelihood of Brain Ischemia Scale: 0–1 = unlikely, 2 = possible, 3 = probable, 4–8 = very likely. Results Three raters reviewed data from 114 patients. Using Precise Diagnostic Score, all three raters scored a similar percentage of the clinical events as being “probable” or “very likely” caused by brain ischemia: 57, 55, and 58%. Agreement was high for both total Precise Diagnostic Score (intraclass correlation coefficient of 0.94) and for the Likelihood of Brain Ischemia Scale (agreement coefficient of 0.84). Conclusions Compared with prior studies, inter-rater agreement for the diagnosis of transient brain ischemia appears substantially improved with the Precise Diagnostic Score scoring system. This score is the first to include specific criteria to assess the clinical relevance of diffusion-weighted imaging and perfusion lesions and supports the added value of magnetic resonance imaging for assessing patients with suspected transient ischemic attack.
    Type of Medium: Online Resource
    ISSN: 1747-4930 , 1747-4949
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
    detail.hit.zdb_id: 2211666-7
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  • 10
    In: Stroke, Ovid Technologies (Wolters Kluwer Health), Vol. 43, No. suppl_1 ( 2012-02)
    Abstract: Background: The Malignant MRI profile identifies stroke patients with poor outcomes and an increased incidence of parenchymal hematoma following iv thrombolysis; outcomes following endovascular reperfusion therapy have not been described. Methods: The NIH funded DEFUSE 2 trial enrolled consecutive acute stroke patients in whom endovascular therapy was anticipated. An MRI scan was obtained immediately prior to intra-arterial reperfusion therapy, then repeated following the procedure and on day 5. Perfusion-weighted (PWI) and diffusion-weighted imaging (DWI) maps were created and lesion volumes estimated with an automated software program (RAPID). In the DEFUSE 2, the Malignant profile was pre-specified as a DWI lesion ≥70mL and/or a PWI lesion based on Tmax 〉 10sec threshold (Tmax 〉 10s) ≥100mL. A receiver operating characteristic (ROC) curve analysis was performed to identify Tmax 〉 10s and DWI volumes that predicted poor outcome (defined as a mRS 5-6 at 30 days) with a high specificity. Patients with an M1 or ICA occlusion who did not undergo endovascular therapy based on local site criteria were also included in the ROC analysis. Results: We report a preliminary analysis of the DEFUSE 2 database (full data will be presented at the meeting). One hundred and one patients were triaged to the cath lab for endovascular therapy. Of the 83 patients who had adequate data available for this analysis, 9 (11%) met the predefined criteria for the Malignant profile. 56% of the Malignant patients had poor outcome compared with 30% of the non-Malignant cases (p=0.14). Malignant patients had an increased risk of parenchymal hematoma (PH1 or PH2): 44% vs. 14% (p=0.04). Only 1 of the Malignant patients achieved a mRS of 0-2 at 30 days. Early reperfusion was obtained in 6 of the 9 Malignant patients but was not associated with an increase in favorable clinical outcome or a decrease in the risk of poor outcome. Fifteen patients with an M1 or ICA occlusion did not undergo endovascular therapy based on local site criteria. Ten of these patients had the Malignant profile and 8 of these 10 had a poor outcome. ROC curve analysis identified a DWI lesion of 112 mL and a Tmax 〉 10s lesion of 116 mL as optimal thresholds to predict poor outcome; both achieved a specificity of 98% and sensitivities of 27% and 24% respectively. 81% (13/16) of the Malignant patients identified by the DWI and/or Tmax 〉 10s optimal thresholds had poor outcome. Conclusion: Patients with large baseline DWI and/or large severe PWI lesions are likely to have poor outcomes with or without endovascular reperfusion therapy. Automated imaging software can identify these patients rapidly.
    Type of Medium: Online Resource
    ISSN: 0039-2499 , 1524-4628
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2012
    detail.hit.zdb_id: 1467823-8
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