Early CT perfusion mismatch in acute stroke is not time-dependent but relies on collateralization grade

2016 ◽  
Vol 58 (4) ◽  
pp. 357-365 ◽  
Author(s):  
Louisa von Baumgarten ◽  
Kolja M. Thierfelder ◽  
Sebastian E. Beyer ◽  
Alena B. Baumann ◽  
Christine Bollwein ◽  
...  
Author(s):  
Dylan Blacquiere ◽  
Miguel Bussière ◽  
Cheemun Lum ◽  
Dar Dowlatshahi

Avascularity on CT angiography source images (CTASI) may better predict final infarct volume in acute stroke as compared to early ischemic changes on non-contract CT. These CTASI findings may represent infarct core and help determine the extent of salvageable tissue. However, the extent of avascularity on CTASI may overestimate infarct volume if transit of contrast is prolonged due to proximal artery occlusion. We present a case where CT-perfusion (CTP) and time-resolved CT-angiography (CTA) identified salvageable tissue thought to be infarcted on CTASI.


2011 ◽  
Vol 30 (6) ◽  
pp. E4 ◽  
Author(s):  
Peter T. Kan ◽  
Kenneth V. Snyder ◽  
Parham Yashar ◽  
Adnan H. Siddiqui ◽  
L. Nelson Hopkins ◽  
...  

Computed tomography perfusion scanning generates physiological flow parameters of the brain parenchyma, allowing differentiation of ischemic penumbra and core infarct. Perfusion maps, along with the National Institutes of Health Stroke Scale score, are used as the bases for endovascular stroke intervention at the authors' institute, regardless of the time interval from stroke onset. With case examples, the authors illustrate their perfusion-based imaging guidelines in patient selection for endovascular treatment in the setting of acute stroke.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Tareq Kass-Hout ◽  
Maxim Mokin ◽  
Omar Kass-Hout ◽  
Emad Nourollahzadeh ◽  
David Wack ◽  
...  

Objective: To use the Computed Tomography Perfusion (CTP) parameters at the time of hospital admission, including Cerebral Blood Volume (CBV) and Permeability Surface area product (PS), to identify patients with higher risk to develop hemorrhagic transformation in the setting of acute stroke therapy with intravenous thrombolysis. Methods: Retrospective study that compared admission CTP variables between patients with Hemorrhagic Transformation (HT) acute stroke and those with no hemorrhagic transformation. Both groups received standard of care intravenous thrombolysis with tPA. Twenty patients presented to our stroke center between the years 2007 - 2011 within 3 hours after stroke symptoms onset. All patients underwent two-phase 320 slice CTP which creates CBV and PS measurements. Patients were divided into two groups according to whether or not they had HT on a follow up CT head without contrast, done within 36 hours of the thrombolysis therapy. Clinical, demographic and CTP variables were compared between the HT and non-HT groups using logistic regression analyses. Results: HT developed in 8 (40%) patients. Patients with HT had lower ASPECT score ( P =.03), higher NIHSS on admission ( P= .01) and worse outcome ( P= .04) compared to patients who did not develop HT. Baseline blood flow defects were comparable between the two groups. The mean PS for the HT group was 0.53 mL/min/100g brain tissue, which was significantly higher than that for the non-HT group of 0.04 mL/min/100g brain tissue ( P <.0001). The mean area under the curve was 0.92 (95% CI). The PS threshold of 0.26 mL/min/100g brain tissue had a sensitivity of 80% and a specificity of 92% for detecting patients with high risk of hemorrhagic transformation after intravenous thrombolysis. Conclusions: Admission CTP measurements might be useful to predict patients who are at higher risk to develop hemorrhagic transformation after acute ischemic stroke therapy.


Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Nili E Steiner ◽  
Nicole Wolber ◽  
Betty Robertson ◽  
Paula Rosenfield ◽  
Laurie Paletz

Background: Brain ischemia kills 2 million nerve cells per minute. As time elapses, the odds of favorable outcome become less likely. By providing treatment rapidly, patient outcome is markedly improved. We recognized an opportunity for improvement by shortening our door-to-needle time. The door-to-needle time is defined by the time the patient arrives in the emergency department to the time the patient receives intravenous tissue plasminogen activator (IV t-PA). Methods: We evaluated the system in place to look at opportunities for improvement. We met monthly to assess every acute stroke patient case, particularly to evaluate delays in acute stroke treatment. We analyzed the results of all the acute stroke patient cases from January 2008 to January 2012. We implemented the following interventions: staff education, reducing unnecessary CT angiogram and CT perfusion studies on patients, RN telephone triage for acute stroke patients. pre-hospital activation of the stroke team for patients exhibiting acute stroke symptoms, ED pharmacist at bedside upon patient arrival with t-PA, and placing patients on portable monitors immediately upon ED arrival. Conclusion: The average door-to-needle time from January 2008 to October 2011 was 1 hour and 32 minutes. After implementing the changes above, from November 2011 to January 2012, our average door-to-needle time was 38 minutes to 54 minutes, which is within the target of less than 60 minutes. By implementing these changes, we have successfully and safely reduced and improved our door-to-needle time. Monthly quality improvement meetings are on-going to assess continuing quality improvement.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Waimei A Tai ◽  
Archana Purushotham ◽  
Matus Straka ◽  
Rebecca M Sugg ◽  
Naveed Akhtar ◽  
...  

Introduction: The use of mismatch between the ischemic core and penumbra to select patients who are likely to benefit from acute stroke therapy has gained popularity. Interpretation of the ischemic core and penumbra on standard CT-perfusion (CTP) maps is subjective. This may lead to variability among physicians in the decision if a patient is a good candidate for acute stroke therapy. A CTP-Mismatch map with outlines of the ischemic core and penumbra could limit this variability. The goal of this study was to determine if inter-observer agreement regarding a patient’s suitability for acute stroke therapy improves with the use of a CTP-Mismatch map. The figure shows a typical CTP-Mismatch map. Methods: Ninety-six consecutive patients evaluated with CTP prior to intra-arterial therapy at St. Lukes Hospital in 2008-09 were included. 79 patients had adequate quality CTP for this analysis. Standard CTP maps (CBV, CBF, MTT, and Tmax) and a CTP-Mismatch map were generated with a fully automated program for processing of CTP source images (RAPID). RAPID assessed the ischemic core using a CBF threshold <30% of the contralateral hemisphere (rCBF<30%). The ischemic penumbra was defined by a Tmax threshold of >6 sec (Tmax>6s). The standard CTP maps and the CTP-Mismatch map were independently analyzed by two vascular neurologists in a blinded fashion. The raters assessed a patient's suitability for intra-arterial therapy based on the following mismatch criteria: (1) a ratio between (Tmax>6s) and (rCBF<30%) volumes >1.8 and (2) an absolute difference between (Tmax>6s) and (CBF<30%) volumes >15ml. Interobserver reliability was assessed with Cohen’s kappa. Results: When assessment of suitability for intra-arterial therapy was based on interpretation of standard CTP maps, the two raters agreed in 58 of 79 patients (kappa=0.46; 95% CI=0.24-0.60). The agreement between observers improved when suitability was determined using CTP-Mismatch maps (agreement in 76 of 79 cases; kappa=0.92; 95% CI=0.75-0.92; p<0.001 for difference between kappa values). The 3 cases with inter-observer disagreement had artifact on the CTP-Mismatch map. Following concensus adjudication of these 3 cases, 40 of the 79 patients (51%) were deemed suitable candidates for acute stroke therapy. Conclusion: CTP-Mismatch maps with estimates of ischemic core and penumbra volumes markedly improve inter-observer agreement regarding assessment of suitability for acute stroke therapy. Such maps, which can be generated automatically, may help standardize decision making algorithms for evaluation of potential intra-arterial therapy candidates.


Author(s):  
Evan Kolesnick ◽  
Evan Kolesnick ◽  
Alfredo Munoz ◽  
Kaiz Asif ◽  
Santiago Ortega‐Gutierrez ◽  
...  

Introduction : Stroke is a leading cause of morbidity, mortality and healthcare spending in the United States. Acute management of ischemic stroke is time‐dependent and evidence suggests improved clinical outcomes for patients treated at designated certified stroke centers. There is an increasing trend among hospitals to obtain certification as designated stroke centers. A common source or integrated tool providing both information and location of all available stroke centers in the US irrespective of the certifying organization is not readily available. The objective of our research is to generate a comprehensive and interactive electronic resource with combined data on all geographically‐coded certified stroke centers to assist in pre‐hospital triage and study healthcare disparities in stroke including availability and access to acute stroke care by location and population. Methods : Data on stroke center certification was primarily obtained from each of the three main certifying organizations: The Joint Commission (TJC), Det Norske Veritas (DNV) and Healthcare Facilities Accreditation Program (HFAP). Geographic mapping of all stroke center locations was performed using the ArcGIS Pro application. The most current data on stroke centers is presented in an interactive electronic format and the information is frequently updated to represent newly certified centers. Utility of the tool and its analytics are shown. Role of the tool in improving pre‐hospital triage in the stroke systems of care, studying healthcare disparities and implications for public health policy are discussed. Results : Aggregate data analysis at the time of submission revealed 1,806 total certified stroke centers. TJC‐certified stroke centers represent the majority with 106 Acute Stroke Ready (ASR), 1,040 Primary Stroke Centers (PSCs), 49 Thrombectomy Capable Centers (TSCs) and 197 Comprehensive Stroke Centers (CSCs). A total of 341 DNV‐certified programs including 36 ASRs, 162 PSCs, 16 PSC Plus (thrombectomy capable) and 127 CSCs were identified. HFAP‐certified centers (75) include 16 ASRs, 49 PSCs, 2 TSCs and 8 CSCs. A preliminary map of all TJC‐certified CSCs and TSCs is shown in the figure (1). Geospatial analysis reveals distinct areas with currently limited access to certified stroke centers and currently, access to certified stroke centers is extremely limited to non‐existent in fe States (for example: Idaho, Montana, Wyoming, New Mexico and South Dakota). Conclusions : Stroke treatment and clinical outcomes are time‐dependent and prompt assessment and triage by EMS directly to appropriate designated stroke centers is therefore critical. A readily available electronic platform providing location and treatment capability for all nearby certified centers will enhance regional stroke systems of care, including enabling more rapid inter‐hospital transfers for advanced intervention. Identifying geographic areas of limited access to treatment can also help improve policy and prioritize the creation of a more equitable and well‐distributed network of stroke care in the United States.


2005 ◽  
Vol 26 (6) ◽  
pp. 404-421 ◽  
Author(s):  
Sanjay K. Shetty ◽  
Michael H. Lev
Keyword(s):  

2018 ◽  
Vol 19 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Stevan Christopher Wing ◽  
Hugh S Markus

CT perfusion images can be rapidly obtained on all modern CT scanners and easily incorporated into an acute stroke imaging protocol. Here we discuss the technique of CT perfusion imaging, how to interpret the data and how it can contribute to the diagnosis of acute stroke and selection of patients for treatment. Many patients with acute stroke are excluded from reperfusion therapy if the onset time is not known or if they present outside of traditional treatment time windows. There is a growing body of evidence supporting the use of perfusion imaging in these patients to identify patterns of brain perfusion that are favourable for recanalisation therapy.


Stroke ◽  
2021 ◽  
Author(s):  
Raul G. Nogueira ◽  
Jason M. Davies ◽  
Rishi Gupta ◽  
Ameer E. Hassan ◽  
Thomas Devlin ◽  
...  

Background and Purpose: The degree to which the coronavirus disease 2019 (COVID-19) pandemic has affected systems of care, in particular, those for time-sensitive conditions such as stroke, remains poorly quantified. We sought to evaluate the impact of COVID-19 in the overall screening for acute stroke utilizing a commercial clinical artificial intelligence platform. Methods: Data were derived from the Viz Platform, an artificial intelligence application designed to optimize the workflow of patients with acute stroke. Neuroimaging data on suspected patients with stroke across 97 hospitals in 20 US states were collected in real time and retrospectively analyzed with the number of patients undergoing imaging screening serving as a surrogate for the amount of stroke care. The main outcome measures were the number of computed tomography (CT) angiography, CT perfusion, large vessel occlusions (defined according to the automated software detection), and severe strokes on CT perfusion (defined as those with hypoperfusion volumes >70 mL) normalized as number of patients per day per hospital. Data from the prepandemic (November 4, 2019 to February 29, 2020) and pandemic (March 1 to May 10, 2020) periods were compared at national and state levels. Correlations were made between the inter-period changes in imaging screening, stroke hospitalizations, and thrombectomy procedures using state-specific sampling. Results: A total of 23 223 patients were included. The incidence of large vessel occlusion on CT angiography and severe strokes on CT perfusion were 11.2% (n=2602) and 14.7% (n=1229/8328), respectively. There were significant declines in the overall number of CT angiographies (−22.8%; 1.39–1.07 patients/day per hospital, P <0.001) and CT perfusion (−26.1%; 0.50–0.37 patients/day per hospital, P <0.001) as well as in the incidence of large vessel occlusion (−17.1%; 0.15–0.13 patients/day per hospital, P <0.001) and severe strokes on CT perfusion (−16.7%; 0.12–0.10 patients/day per hospital, P <0.005). The sampled cohort showed similar declines in the rates of large vessel occlusions versus thrombectomy (18.8% versus 19.5%, P =0.9) and comprehensive stroke center hospitalizations (18.8% versus 11.0%, P =0.4). Conclusions: A significant decline in stroke imaging screening has occurred during the COVID-19 pandemic. This analysis underscores the broader application of artificial intelligence neuroimaging platforms for the real-time monitoring of stroke systems of care.


2017 ◽  
Vol 10 (7) ◽  
pp. 657-662 ◽  
Author(s):  
Shlomi Peretz ◽  
David Orion ◽  
David Last ◽  
Yael Mardor ◽  
Yotam Kimmel ◽  
...  

PurposeThe region defined as ‘at risk’ penumbra by current CT perfusion (CTP) maps is largely overestimated. We aimed to quantitate the portion of true ‘at risk’ tissue within CTP penumbra and to determine the parameter and threshold that would optimally distinguish it from false ‘at risk’ tissue, that is, benign oligaemia.MethodsAmong acute stroke patients evaluated by multimodal CT (NCCT/CTA/CTP) we identified those that had not undergone endovascular/thrombolytic treatment and had follow-up NCCT. Maps of absolute and relative CBF, CBV, MTT, TTP and Tmax as well as summary maps depicting infarcted and penumbral regions were generated using the Intellispace Portal (Philips Healthcare, Best, Netherlands). Follow-up CT was automatically co-registered to the CTP scan and the final infarct region was manually outlined. Perfusion parameters were systematically analysed – the parameter that resulted in the highest true-negative-rate (ie, proportion of benign oligaemia correctly identified) at a fixed, clinically relevant false-negative-rate (ie, proportion of ‘missed’ infarct) of 15%, was chosen as optimal. It was then re-applied to the CTP data to produce corrected perfusion maps.ResultsForty seven acute stroke patients met selection criteria. Average portion of infarcted tissue within CTP penumbra was 15%±2.2%. Relative CBF at a threshold of 0.65 yielded the highest average true-negative-rate (48%), enabling reduction of the false ‘at risk’ penumbral region by ~half.ConclusionsApplying a relative CBF threshold on relative MTT-based CTP maps can significantly reduce false ‘at risk’ penumbra. This step may help to avoid unnecessary endovascular interventions.


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