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

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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The anesthetic approach for endovascular recanalization therapy depends on the lesion site in acute ischemic stroke

Neuroradiology ◽

10.1007/s00234-021-02762-3 ◽

2021 ◽

Author(s):

Kilian Fröhlich ◽

Gabriela Siedler ◽

Svenja Stoll ◽

Kosmas Macha ◽

Thomas M. Kinfe ◽

...

Keyword(s):

Ischemic Stroke ◽

Middle Cerebral Artery ◽

Acute Ischemic Stroke ◽

Cerebral Artery ◽

Posterior Circulation ◽

Neurological Deficits ◽

Stroke Severity ◽

Lesion Volume ◽

Middle Cerebral Artery Territory ◽

Cerebral Lesion

Abstract Purpose Endovascular therapy (EVT) of large-vessel occlusion in acute ischemic stroke (AIS) may be performed in general anesthesia (GA) or conscious sedation (CS). We intended to determine the contribution of ischemic cerebral lesion sites on the physician’s decision between GA and CS using voxel-based lesion symptom mapping (VLSM). Methods In a prospective local database, we sought patients with documented AIS and EVT. Age, stroke severity, lesion volume, vigilance, and aphasia scores were compared between EVT patients with GA and CS. The ischemic lesions were analyzed on CT or MRI scans and transformed into stereotaxic space. We determined the lesion overlap and assessed whether GA or CS is associated with specific cerebral lesion sites using the voxel-wise Liebermeister test. Results One hundred seventy-nine patients with AIS and EVT were included in the analysis. The VLSM analysis yielded associations between GA and ischemic lesions in the left hemispheric middle cerebral artery territory and posterior circulation areas. Stroke severity and lesion volume were significantly higher in the GA group. The prevalence of aphasia and aphasia severity was significantly higher and parameters of vigilance lower in the GA group. Conclusions The VLSM analysis showed associations between GA and ischemic lesions in the left hemispheric middle cerebral artery territory and posterior circulation areas including the thalamus that are known to cause neurologic deficits, such as aphasia or compromised vigilance, in AIS-patients with EVT. Our data suggest that higher disability, clinical impairment due to neurological deficits like aphasia, or reduced alertness of affected patients may influence the physician’s decision on using GA in EVT.

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Associations of Ischemic Lesion Volume With Functional Outcome in Patients With Acute Ischemic Stroke

Stroke ◽

10.1161/strokeaha.116.015156 ◽

2017 ◽

Vol 48 (5) ◽

pp. 1233-1240 ◽

Cited By ~ 20

Author(s):

Amber Bucker ◽

Anna M. Boers ◽

Joseph C.J. Bot ◽

Olvert A. Berkhemer ◽

Hester F. Lingsma ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Functional Outcome ◽

Lesion Volume ◽

Ischemic Lesion

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Successful recanalization for acute ischemic stroke via the transbrachial approach

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2014-011451 ◽

2014 ◽

Vol 8 (2) ◽

pp. 122-125 ◽

Cited By ~ 13

Author(s):

Masakazu Okawa ◽

Satoshi Tateshima ◽

David Liebeskind ◽

Latisha K Ali ◽

Michael L Thompson ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Patient Specific ◽

Ischemic Stroke Patient ◽

Transfemoral Approach ◽

Acute Ischemic Stroke Patient ◽

Transbrachial Approach ◽

Stent Retrievers ◽

Endovascular Approach ◽

Specific Factors

The recent development of revascularization devices, including stent retrievers, has enabled increasingly higher revascularization rates for arterial occlusions in acute ischemic stroke. Patient-specific factors such as anatomy, however, may occasionally limit endovascular deployment of these new devices via the conventional transfemoral approach. We report three cases of acute ischemic stroke where a transbrachial endovascular approach to revascularization was used, resulting in successful recanalization. These examples suggest that a transbrachial approach may be considered as an alternative in the endovascular treatment of acute ischemic stroke.

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Abstract P348: Perfusion Collateral Index vs. Hypoperfusion Intensity Ratio in Assessment of Angiographic Collateral Scores in Patients With Acute Ischemic Stroke

Stroke ◽

10.1161/str.52.suppl_1.p348 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Brian Tsui ◽

Iris Chen ◽

Joe Qiao ◽

Kasra Khatibi ◽

Lucido Ponce Mejia ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Perfusion Imaging ◽

Intensity Ratio ◽

Roc Analysis ◽

Cerebral Blood Volume ◽

Imaging Biomarker ◽

Lesion Volume ◽

Significant Difference ◽

Sensitivity Specificity

Background and Purpose: In acute ischemic stroke (AIS), perfusion imaging, while not directly visualizing collateral vessels, can provide important insight into collateral robustness, indexed by perfusion lesion volume and by perfusion lesion heterogeneity. Two proposed perfusion lesion heterogeneity measures indexing collateral status are the Perfusion Collateral Index (PCI) and Hypoperfusion Intensity Ratio (HIR), but their accuracy compared with direct collateral assessment on DSA has been incompletely characterized. Methods: Consecutive AIS patients with anterior circulation large vessel occlusion who underwent pre-endovascular thrombectomy MRI perfusion imaging were included. MRI measures analyzed were: 1) Perfusion Collateral Index ( PCI) - the volume of moderately hypoperfused tissue (arterial tissue delay time between 2 and 6 seconds: ATD 2-6sec ) multiplied by its corresponding relative cerebral blood volume using Olea software; 2) Hypoperfusion Intensity Ratio (HIR) ratio of moderate TMax >6 s lesion volume versus severe Tmax >10 s lesion volume with the RAPID software program. DSA collateral scores were evaluated by ASITN grading and dichotomized to inadequate (ASTIN <2) vs. adequate (ASTIN ≥3). Results: Among 48 patients meeting entry criteria, age (mean ± SD) was 70 (± 15.2), 54% were female, and NIHSS (median, IQR) was 15 (10-19). For HIR, there was no significant difference in score values in patients with adequate vs inadequate collaterals: 0.35 ± 0.20 vs 0.39 ± 0.25, p=0.68. ROC analysis using previously described cut-off of 0.4 resulted in an AUC of 0.52 and sensitivity/specificity of 71% / 33%. For PCI, score values were significantly higher in patients with adequate vs inadequate collaterals, 117 ± 61 vs. 57 ± 41, p=0.002. ROC analysis using previously described cut-off of 62 resulted in an AUC of 0.8 and sensitivity/specificity of 84% / 78%. Conclusion: Collateral status can be accurately assessed on perfusion MRI with the Perfusion Collateral Index, which outperformed the Hypoperfusion Intensity Ratio. MRI-PCI is an informative imaging biomarker of collateral status in patients with AIS.

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Abstract WP39: Mechanical Embolectomy for Acute Ischemic Stroke Beyond Six Hours From Symptom Onset Using Advanced MR Imaging

Stroke ◽

10.1161/str.48.suppl_1.wp39 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Ryan McTaggart ◽

Shadi Yaghi ◽

Daniel C Sacchetti ◽

Richard Haas ◽

Shawna Cutting ◽

...

Keyword(s):

Ischemic Stroke ◽

Mr Imaging ◽

Acute Ischemic Stroke ◽

Large Vessel ◽

Lesion Volume ◽

Large Artery ◽

Large Vessel Occlusion ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Good Outcome

Background: There is very limited data on the use of advanced neuroimaging to select patients with acute ischemic stroke and large vessel occlusion for intraarterial therapy beyond 6 hours from onset. Our aim is to report the outcome of patients with acute ischemic stroke and large artery occlusion who presented beyond 6 hours from onset, had favorable MRI imaging profile, and underwent mechanical embolectomy. Methods: This is a single institution retrospective study between December 1st, 2015, and July 30 th , 2016 with acute ischemic stroke and anterior circulation large vessel occlusion (LVO) with ASPECTS of 6 or more and beyond 6 hours from symptoms onset. Favorable imaging profile was defined as 1) DWI lesion volume (as defined as apparent diffusion coefficient < 620 X 10-6 mm2/s) of 70 mL or less AND 2) Penumbra volume (as defined by volume of tissue with Tmax >6 sec) of 15 mL or greater AND 3) A mismatch ratio of 1.8 or more AND 4) Volume of tissue with perfusion lesion with Tmax > 10 sec is less than 100 mL. Good outcome was defined as a 90 day mRS≤2. Results: In the study period, 41 patients met the inclusion criteria; 22 (53.6%) had favorable imaging profile and underwent mechanical embolectomy. The median age was 75 years (59-92), 68.2% were females; the median time from last known normal to groin puncture was 684.5 minutes (range 363-1628) and the median admission NIHSS score was 17.5 (range 4-28). The rate of good outcomes in this series was similar to that in a patient level pooled meta-analysis of the recent endovascular trials (68.2% vs. 46.0%, p=0.07). The rate of good outcome matches that of the EXTEND-IA trial that selected patients using perfusion imaging (68.2% vs. 71.0%, p = 1.00). None of the patients in our cohort had symptomatic intracereberal hemorrhage. Conclusion: Advanced MR imaging may help select patients with acute ischemic stroke and anterior circulation large vessel occlusion for embolectomy beyond the treatment window used in most endovascular trials.

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Abstract TMP89: Collaterals and Reperfusion Mediate Blood Pressure Changes in Acute Ischemic Stroke

Stroke ◽

10.1161/str.48.suppl_1.tmp89 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

David S Liebeskind ◽

Graham W Woolf ◽

Nerses Sanossian ◽

Jason D Hinman ◽

Radoslav Raychev ◽

...

Keyword(s):

Blood Pressure ◽

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Endovascular Therapy ◽

Arterial Occlusion ◽

Patient Specific ◽

Pressure Data ◽

Blood Pressure Data ◽

Pressure Changes ◽

Continuous Blood Pressure

Background: The pathophysiology and optimal management of blood pressure changes in acute ischemic stroke remain unknown. Blood pressure guidelines do not consider patient-specific or serial data on dynamic blood pressure readings. We investigated continuous blood pressure data during endovascular therapy for acute stroke to discern changes associated with collaterals, recanalization and reperfusion. Methods: Continuous monitoring blood pressure data was collected in consecutive cases of endovascular therapy for acute ischemic stroke due to ICA or proximal MCA occlusion. Angiography details were independently analyzed to document site of arterial occlusion, baseline collateral grade, time of device deployments, time of recanalization, time of final reperfusion, final AOL recanalization and final TICI reperfusion. Statistical analyses correlated instantaneous and serial blood pressure changes with these angiographic parameters. Results: 80 patients (median age 73 years; 33 women) were studied. Arterial lesions included 37 ICA and 41 proximal M1 MCA occlusions. Collateral grade prior to intervention included 2 ASITN grade 4, 26 grade 3, 23 grade 2, 6 grade 1 and 0 grade 0. oTICI2C reperfusion scores after thrombectomy included 2 TICI 3 (100%), 22 TICI 2C (90-99%), 25 TICI o2B (67-89%), 9 TICI m2B (50-66%), 19 TICI 2A (<50%) and 3 TICI 0/1. More robust collateral grade was associated with greater reperfusion scores (r=0.32, p=0.028). The change in blood pressure (ΔBP) from earliest BP to time of recanalization was mean 59% of ΔBP during the entire procedure. Better collaterals were associated with lower BP prior to recanalization (r=-0.377, p=0.012). Lower BP prior to recanalization was linked with greater TICI reperfusion (r=-0.242, p=0.050). Higher TICI reperfusion scores were also associated with a greater drop or ΔBP at the time of recanalization (r=0.269, p=0.031). AOL recanalization was not related to ΔBP. Conclusions: Collaterals and reperfusion, but not recanalization, mediate blood pressure changes in acute ischemic stroke. Prospective, precision medicine stroke studies should leverage patient-specific, real-time data on continuous blood pressure with imaging correlates to define BP goals of future in-hospital management.

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Abstract TP292: Discrepancies in Arrival Time for Acute Ischemic Stroke Patients

Stroke ◽

10.1161/str.49.suppl_1.tp292 ◽

2018 ◽

Vol 49 (Suppl_1) ◽

Author(s):

Scott J Mendelson ◽

Christopher T Richards ◽

Shyam Prabhakaran

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Arrival Time ◽

Stroke Patients

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Structural integrity of white matter tracts as a predictor of acute ischemic stroke outcome

International Journal of Stroke ◽

10.1177/1747493020915251 ◽

2020 ◽

Vol 15 (9) ◽

pp. 965-972

Author(s):

Deepthi Rajashekar ◽

Pauline Mouchès ◽

Jens Fiehler ◽

Bijoy K Menon ◽

Mayank Goyal ◽

...

Keyword(s):

Ischemic Stroke ◽

White Matter ◽

Acute Ischemic Stroke ◽

Support Vector Regression ◽

Support Vector ◽

Stroke Severity ◽

Lesion Volume ◽

White Matter Tract ◽

Support Vector Regression Model ◽

White Matter Tracts

Background and purpose Clinical assessment scores in acute ischemic stroke are only moderately correlated with lesion volume since lesion location is an important confounding factor. Many studies have investigated gray matter indicators of stroke severity, but the understanding of white matter tract involvement is limited in the early phase after stroke. This study aimed to measure and model the involvement of white matter tracts with respect to 24-h post-stroke National Institutes of Health Stroke Scale (NIHSS). Material and methods A total of 96 patients (50 females, mean age 66.4 ± 14.0 years, median NIHSS 5, interquartile range: 2–9.5) with follow-up fluid-attenuated inversion recovery magnetic resonance imaging data sets acquired one to seven days after acute ischemic stroke onset due to proximal anterior circulation occlusion were included. Lesions were semi-automatically segmented and non-linearly registered to a common reference atlas. The lesion overlap and tract integrity were determined for each white matter tract in the AALCAT atlas and used to model NIHSS outcomes using a supervised linear-kernel support vector regression method, which was evaluated using leave-one-patient-out cross validation. Results The support vector regression model using the tract integrity and tract lesion overlap measurements predicted the 24-h NIHSS score with a high correlation value of r = 0.7. Using the tract overlap and tract integrity feature improved the modeling accuracy of NIHSS significantly by 6% (p < 0.05) compared to using overlap measures only. Conclusion White matter tract integrity and lesion load are important predictors for clinical outcome after an acute ischemic stroke as measured by the NIHSS and should be integrated for predictive modeling.

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