Abstract 117: A Six Minute MRI Protocol for Evaluation of Acute Ischemic Stroke: Pushing the Boundaries

Purpose: Multimodal cerebrovascular CT and MR can now provide information about tissue viability, site of occlusion, and collateral status in patients with acute ischemic stroke (AIS). If MRI is to compete with CT for evaluation of AIS, there is need for further improvements in acquisition speed. The purpose of this study was to establish the feasibility of a fast MR protocol with a 6 minute acquisition time for evaluation of AIS. Methods: Patients with suspicion of AIS and absence of MRI contraindications were prospectively enrolled. A combination of echo-planar imaging (EPI) and parallel acquisition technique were used on a 3T MR scanner to accelerate the acquisition time. The imaging protocol included: DWI (1 min), EPI-FLAIR (52 sec), EPI-GRE (50 sec), contrast-enhanced MR angiography (CE-MRA) of the entire supra-aortic arteries (20 sec), and DSC perfusion (2 min). Using a modified 2-phase contrast injection scheme, high spatial resolution CE-MRA of the supra-aortic arteries was performed just before DSC perfusion without the need for additional contrast. Image analysis was performed independently by two neuroradiologists and interobserver agreement was calculated using Kappa test. Results: A total of 50 patients were included. Diagnostic image quality was achieved in 100% of DWI, 96% EPI-FLAIR, 98% EPI-GRE, 90% neck MRA, 96% of brain MRA, and 94% of DSC perfusion scans. Thirty eight patients (76%) had acute infarction. Using Tmax perfusion maps and applying DEFUSE criteria, 42% of patients had perfusion-diffusion mismatch with interobserver agreement of k=0.90. The mean of the signal-intensity-ratio values of the infarction on EPI-FLAIR was 1.08 for patients presenting < 4.5 hours (n=16) and 1.35 for patients presenting > 4.5 hours (n=22) from the time of imaging. Three patients had evidence of intracranial hemorrhage detected on EPI-GRE and confirmed by non-contrast CT. CE-MRA showed 27 segmental stenoses of the extra-cranial arteries and 24 segmental stenoses of the intracranial arteries with interobserver agreement of k= 0.82 and 0.74 respectively. Conclusion: Described multimodal MR protocol is feasible for evaluation of patients with AIS and can result in significant reduction in scan time rivaling that of the multimodal CT protocol.

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APT Weighted MRI as an Effective Imaging Protocol to Predict Clinical Outcome After Acute Ischemic Stroke

Frontiers in Neurology ◽

10.3389/fneur.2018.00901 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 13

Author(s):

Guisen Lin ◽

Caiyu Zhuang ◽

Zhiwei Shen ◽

Gang Xiao ◽

Yanzi Chen ◽

...

Keyword(s):

Ischemic Stroke ◽

Clinical Outcome ◽

Acute Ischemic Stroke ◽

Imaging Protocol

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Six-Minute Magnetic Resonance Imaging Protocol for Evaluation of Acute Ischemic Stroke

Stroke ◽

10.1161/strokeaha.114.005305 ◽

2014 ◽

Vol 45 (7) ◽

pp. 1985-1991 ◽

Cited By ~ 84

Author(s):

Kambiz Nael ◽

Rihan Khan ◽

Gagandeep Choudhary ◽

Arash Meshksar ◽

Pablo Villablanca ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Ischemic Stroke ◽

Magnetic Resonance ◽

Acute Ischemic Stroke ◽

Resonance Imaging ◽

Imaging Protocol ◽

Magnetic Resonance Imaging Protocol

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Regional Mechanical Thrombectomy Imaging Protocol in Patients Presenting with Acute Ischemic Stroke during the COVID-19 Pandemic

American Journal of Neuroradiology ◽

10.3174/ajnr.a6754 ◽

2020 ◽

Vol 41 (10) ◽

pp. 1849-1855

Author(s):

P.S. Dhillon ◽

K. Pointon ◽

R. Lenthall ◽

S. Nair ◽

G. Subramanian ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Mechanical Thrombectomy ◽

Imaging Protocol

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Impact of Initial Imaging Protocol on Likelihood of Endovascular Stroke Therapy

Stroke ◽

10.1161/strokeaha.120.030122 ◽

2020 ◽

Vol 51 (10) ◽

pp. 3055-3063 ◽

Cited By ~ 1

Author(s):

Victor Lopez-Rivera ◽

Rania Abdelkhaleq ◽

Jose-Miguel Yamal ◽

Noopur Singh ◽

Sean I. Savitz ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Odds Ratio ◽

Time Window ◽

Tissue Type ◽

Stroke Therapy ◽

Imaging Protocol ◽

Head Ct ◽

The Impact ◽

Endovascular Stroke Therapy

Background and Purpose: Noncontrast head CT and CT perfusion (CTP) are both used to screen for endovascular stroke therapy (EST), but the impact of imaging strategy on likelihood of EST is undetermined. Here, we examine the influence of CTP utilization on likelihood of EST in patients with large vessel occlusion (LVO). Methods: We identified patients with acute ischemic stroke at 4 comprehensive stroke centers. All 4 hospitals had 24/7 CTP and EST capability and were covered by a single physician group (Neurology, NeuroIntervention, NeuroICU). All centers performed noncontrast head CT and CT angiography in the initial evaluation. One center also performed CTP routinely with high CTP utilization (CTP-H), and the others performed CTP optionally with lower utilization (CTP-L). Primary outcome was likelihood of EST. Multivariable logistic regression was used to determine whether facility type (CTP-H versus CTP-L) was associated with EST adjusting for age, prestroke mRS, National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, LVO location, time window, and intravenous tPA (tissue-type plasminogen activator). Results: Among 3107 patients with acute ischemic stroke, 715 had LVO, of which 403 (56%) presented to CTP-H and 312 (44%) presented to CTP-L. CTP utilization among LVO patients was greater at CTP-H centers (72% versus 18%, CTP-H versus CTP-L, P <0.01). In univariable analysis, EST rates for patients with LVO were similar between CTP-H versus CTP-L (46% versus 49%). In multivariable analysis, patients with LVO were less likely to undergo EST at CTP-H (odds ratio, 0.59 [0.41–0.85]). This finding was maintained in multiple patient subsets including late time window, anterior circulation LVO, and direct presentation patients. Ninety-day functional independence (odds ratio, 1.04 [0.70–1.54]) was not different, nor were rates of post-EST PH-2 hemorrhage (1% versus 1%). Conclusions: We identified an increased likelihood for undergoing EST in centers with lower CTP utilization, which was not associated with worse clinical outcomes or increased hemorrhage. These findings suggest under-treatment bias with routine CTP.

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Abstract TP38: Impact of CT Perfusion Scan Duration on Lesion Volume

Stroke ◽

10.1161/str.47.suppl_1.tp38 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Aimen Kasasbeh ◽

Søren Christensen ◽

Matus Straka ◽

Nishant Mishra ◽

Roland Bammer ◽

...

Keyword(s):

Ischemic Stroke ◽

Radiation Dose ◽

Acute Ischemic Stroke ◽

Arrival Time ◽

Volume Estimation ◽

Patient Specific ◽

Lesion Volume ◽

Scan Time ◽

Stability Point ◽

The Stability

Introduction: There is evidence that CTP volumes are affected by scan duration, but the minimal scan duration needed to obtain reliable volumes has not been established. Hypothesis: The minimal CTP scan duration for individual patients depends on the arrival time and width of the injected bolus. Methods: We included CTP scans of patients who presented with an acute ischemic stroke. To identify the optimal CTP scan duration, we assessed how truncation of the scan (from 90s to 20s) impacts lesion volumes. We included only patients for whom truncation of the final 10.8 sec (from 90 to 79.2 sec) did not affect lesion volumes to ensure that the subjects had been scanned with sufficient duration. For each included patient, further truncation was used to identify a “stability point”, defined as the minimal scan duration needed to achieve stable estimates of the perfusion lesion. For each patient we also determined the arrival time (t0) and width (full width half max - FWHM) of the Venous Output function (VOF). We used a linear model to test if these VOF features could predict the stability point. Results: We analyzed CTP scans of 70 patients with acute ischemic stroke. Of these, 59 (84.3 %) had sufficient scan duration and were included. Both t0 and VOF width were associated with the stability point (R2 = 0.49). Based on the regression model, minimum scan duration is predicted by “t0 + 1.61* FWHM” (p < 0.001) with an interquartile prediction interval from -5 to 7s. Conclusions: The minimum CTP scan duration needed for accurate perfusion lesions are patient specific and depend on width and arrival of the injected bolus as expressed by the easy to measure VOF. This knowledge has important clinical implications. After acquisition, it can be used to rate if a scan is of sufficient duration for reliable lesion volume estimation. Prior to acquisition, a low contrast and radiation dose test bolus scan can be used to inform the optimal scan time, thereby limiting the radiation dose to the minimal necessary amount for accurate measurements. For example in our cohort, 52 of 70 patients could have been scanned for just 60 seconds (33% dose reduction) with the same results as a 90 second scan.

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Stability of MRI radiomic features according to various imaging parameters in fast scanned T2-FLAIR for acute ischemic stroke patients

Scientific Reports ◽

10.1038/s41598-021-96621-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Leehi Joo ◽

Seung Chai Jung ◽

Hyunna Lee ◽

Seo Young Park ◽

Minjae Kim ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Correlation Coefficients ◽

Region Of Interest ◽

Planar Imaging ◽

Concordance Correlation ◽

Repetition Time ◽

Group A ◽

Train Length ◽

Echo Planar

AbstractFrom May 2015 to June 2016, data on 296 patients undergoing 1.5-Tesla MRI for symptoms of acute ischemic stroke were retrospectively collected. Conventional, echo-planar imaging (EPI) and echo train length (ETL)-T2-FLAIR were simultaneously obtained in 118 patients (first group), and conventional, ETL-, and repetition time (TR)-T2-FLAIR were simultaneously obtained in 178 patients (second group). A total of 595 radiomics features were extracted from one region-of-interest (ROI) reflecting the acute and chronic ischemic hyperintensity, and concordance correlation coefficients (CCC) of the radiomics features were calculated between the fast scanned and conventional T2-FLAIR for paired patients (1st group and 2nd group). Stabilities of the radiomics features were compared with the proportions of features with a CCC higher than 0.85, which were considered to be stable in the fast scanned T2-FLAIR. EPI-T2-FLAIR showed higher proportions of stable features than ETL-T2-FLAIR, and TR-T2-FLAIR also showed higher proportions of stable features than ETL-T2-FLAIR, both in acute and chronic ischemic hyperintensities of whole- and intersection masks (p < .002). Radiomics features in fast scanned T2-FLAIR showed variable stabilities according to the sequences compared with conventional T2-FLAIR. Therefore, radiomics features may be used cautiously in applications for feature analysis as their stability and robustness can be variable.

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Abstract T P288: Improvement of Door to Groin Time for Endovascular Therapy in Acute Ischemic Stroke Using Quality Improvement Methods

Stroke ◽

10.1161/str.45.suppl_1.tp288 ◽

2014 ◽

Vol 45 (suppl_1) ◽

Author(s):

Jennifer R Simpson ◽

Alexandra Graves ◽

Annie N Burrus ◽

David E Case ◽

Christina J Denton ◽

...

Keyword(s):

Quality Improvement ◽

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Median Time ◽

Systematic Evaluation ◽

Mri Imaging ◽

Post Intervention ◽

Imaging Protocol ◽

Process Improvements ◽

Set Up

Objective: Time has been identified as a key variable to the success endovascular treatment of acute ischemic stroke. This project was designed to reduce the time from patient arrival to groin puncture for these treatments at a single academic hospital. Methods: Using Plan-Do-Study-Act (PDSA) quality improvement methodology, a multidisciplinary team was created to identify ways to reduce time from patient presentation to groin puncture. A comparison of pre-intervention and post-intervention times was performed. Pre-intervention patients were retrospectively identified using existing databases and post-intervention patients were prospectively identified. Process maps were created to identify areas of delay. Debriefs helped to indentify future process improvements. Four PDSA cycles have been completed. Stroke neurologists instituted an early notification of IR physicians and a unified imaging protocol. Other interventions included a group paging system, standardized order sets, education within each discipline, improved communication, standardized stroke tray set-up, and streamlining preparation of the patients prior to transportation from the ED. Results: The median time from presentation to groin puncture was reduced from 126 minutes to 92 minutes. MRI imaging was associated with a long pre-intervention time to groin puncture, with a median of 182 minutes that was reduced to 99 minutes. Procedures outside of normal business hours were associated with long time to groin puncture, with a median time of 149 minutes that was reduced to 125 minutes. Conclusions: A reduction of time from presentation to groin puncture is possible using PDSA cycles. This QI project decreased time to groin puncture by 26%, showing that a systematic evaluation of institutional-specific workflow can improve the process preceding a time-sensitive procedure.

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Abstract 1910: Hyperperfusion in Acute Ischemic Stroke: Serial Arterial Spin-Labeled MRI of Reperfusion and Hemorrhagic Transformation

Stroke ◽

10.1161/str.43.suppl_1.a1910 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

David S Liebeskind ◽

Danny J Wang ◽

Nerses Sanossian ◽

Albert K Fong ◽

Qing Hao ◽

...

Keyword(s):

Atrial Fibrillation ◽

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Hemorrhagic Transformation ◽

Consecutive Series ◽

Imaging Features ◽

Stroke Patients ◽

Clinical Correlates ◽

Scan Time

Background: Arterial spin-labeled (ASL) MRI facilitates repeated noninvasive evaluation of cerebral blood flow without the use of contrast. Hyperperfusion may be readily detected with ASL and serial imaging may therefore chronicle the dynamics of territorial perfusion from acute to chronic phases after stroke. We characterized hyperperfusion on ASL in a prospective series of acute ischemic stroke patients, describing the clinical correlates, time course and association with reperfusion hemorrhage. Methods: A consecutive series of acute ischemic stroke patients admitted during a 1-year period were evaluated with pseudo-continuous ASL with background suppressed 3D GRASE (delay=2s, matrix=64x64; 26 slices, resolution 3.4x3.4x5mm, scan time 4min). Post-processed ASL CBF maps were visually inspected for detection of hyperperfusion. DSA measures of collaterals and reperfusion were scored when available and hemorrhagic transformation (HT) was graded on GRE in all 198 cases. Univariate and multivariate statistical analyses delineated clinical correlates, timing and other imaging features of hyperperfusion. Results: Among 198 patients, mean age was 69.4±15.7 years and 48.5% were women. Among 77 with serial ASL MRI, interval from initial to follow-up MRI was median 25.0 (IQR 10.3-53.9) hours. Hyperperfusion was detected in 15/198 (7.6%) patients at baseline and 30/77 (39.0%) at follow-up. Trajectories included 7/77 (9.1%) with hyperperfusion at both baseline and follow-up and 38/77 (49.4%) showing hyperperfusion at any timepoint during admission. Hyperperfusion correlated with achievement of reperfusion among patients undergoing endovascular therapy (OR 6.5, 95% CI 1.82-23.25, p=0.018) and history of atrial fibrillation (OR 4.4, 95% CI 1.9-10.6, p<0.001). Analysis of the 42 cases with DSA revealed that hyperperfusion was most common in patients with poor collateral grade followed by more complete TICI reperfusion scores. Overall, HT affected 57/198 (28.8%), including 35/198 (17.7%) HI1, 11/198 (5.6%) HI2, 8/198 (4.1%) PH1 and 3/198 (1.5%) PH2. Multivariate analyses revealed that hyperperfusion at any timepoint was a potent predictor of HT (OR 52.6, 95%CI 12.4-222.6, p<0.001). Conclusions: Hyperperfusion in acute ischemic stroke is frequently demonstrated by ASL MRI, providing novel insight on the dynamics of reperfusion and HT. Hyperperfusion increases the risk of HT 50-fold, likely due to autoregulatory loss. Poor collaterals and sudden reperfusion in vulnerable cases such as those with atrial fibrillation may herald hyperperfusion and HT.

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Effect of Extended CT Perfusion Acquisition Time on Ischemic Core and Penumbra Volume Estimation in Patients with Acute Ischemic Stroke due to a Large Vessel Occlusion

PLoS ONE ◽

10.1371/journal.pone.0119409 ◽

2015 ◽

Vol 10 (3) ◽

pp. e0119409 ◽

Cited By ~ 11

Author(s):

Jordi Borst ◽

Henk A. Marquering ◽

Ludo F. M. Beenen ◽

Olvert A. Berkhemer ◽

Jan Willem Dankbaar ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Ct Perfusion ◽

Volume Estimation ◽

Large Vessel ◽

Acquisition Time ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Ischemic Core

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Association of follow-up infarct volume with functional outcome in acute ischemic stroke: a pooled analysis of seven randomized trials

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2017-013724 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1137-1142 ◽

Cited By ~ 26

Author(s):

Anna M M Boers ◽

Ivo G H Jansen ◽

Ludo F M Beenen ◽

Thomas G Devlin ◽

Luis San Roman ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Functional Outcome ◽

Imaging Modality ◽

Infarct Volume ◽

Pooled Analysis ◽

Acquisition Time ◽

Anterior Circulation ◽

Multivariable Regression Models

BackgroundFollow-up infarct volume (FIV) has been recommended as an early indicator of treatment efficacy in patients with acute ischemic stroke. Questions remain about the optimal imaging approach for FIV measurement.ObjectiveTo examine the association of FIV with 90-day modified Rankin Scale (mRS) score and investigate its dependency on acquisition time and modality.MethodsData of seven trials were pooled. FIV was assessed on follow-up (12 hours to 2 weeks) CT or MRI. Infarct location was defined as laterality and involvement of the Alberta Stroke Program Early CT Score regions. Relative quality and strength of multivariable regression models of the association between FIV and functional outcome were assessed. Dependency of imaging modality and acquisition time (≤48 hours vs >48 hours) was evaluated.ResultsOf 1665 included patients, 83% were imaged with CT. Median FIV was 41 mL (IQR 14–120). A large FIV was associated with worse functional outcome (OR=0.88(95% CI 0.87 to 0.89) per 10 mL) in adjusted analysis. A model including FIV, location, and hemorrhage type best predicted mRS score. FIV of ≥133 mL was highly specific for unfavorable outcome. FIV was equally strongly associated with mRS score for assessment on CT and MRI, even though large differences in volume were present (48 mL (IQR 15–131) vs 22 mL (IQR 8–71), respectively). Associations of both early and late FIV assessments with outcome were similar in strength (ρ=0.60(95% CI 0.56 to 0.64) and ρ=0.55(95% CI 0.50 to 0.60), respectively).ConclusionsIn patients with an acute ischemic stroke due to a proximal intracranial occlusion of the anterior circulation, FIV is a strong independent predictor of functional outcome and can be assessed before 48 hours, oneither CT or MRI.

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