Automated CT Perfusion for Ischemic Core Volume Prediction in Tandem Anterior Circulation Occlusions

Background/Aim: CT perfusion (CTP) predicts ischemic core volumes in acute ischemic stroke (AIS); however, assumptions made within the pharmacokinetic model may engender errors by the presence of tracer delay or dispersion. We aimed to evaluate the impact of hemodynamic disturbance due to extracranial anterior circulation occlusions upon the accuracy of ischemic core volume estimation with an automated perfusion analysis tool (RAPID) among AIS patients with large-vessel occlusions. Methods: A prospectively collected, interventional database was retrospectively reviewed for all cases of endovascular treatment of AIS between September 2010 and March 2015 for patients with anterior circulation occlusions with baseline CTP and full reperfusion (mTICI3). Results: Out of 685 treated patients, 114 fit the inclusion criteria. Comparison between tandem (n = 21) and nontandem groups (n = 93) revealed similar baseline ischemic core (20 ± 19 vs. 19 ± 25 cm3; p = 0.8), Tmax >6 s (175 ± 109 vs. 162 ± 118 cm3; p = 0.6), Tmax >10 s (90 ± 84 vs. 90 ± 91 cm3; p = 0.9), and final infarct volumes (45 ± 47 vs. 37 ± 45 cm3; p = 0.5). Baseline core volumes were found to correlate with final infarct volumes for the tandem (r = 0.49; p = 0.02) and nontandem (r = 0.44; p < 0.01) groups. The mean absolute difference between estimated core and final infarct volume was similar between patients with and those without (24 ± 41 vs. 17 ± 41 cm3; p = 0.5) tandem lesions. Conclusions: The prediction of baseline ischemic core volumes through an optimized CTP analysis employing rigorous normalization, thresholding, and voxel-wise analysis is not significantly influenced by the presence of underlying extracranial carotid steno-occlusive disease in large-vessel AIS.

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Abstract TP77: Impact of Time and Aspects on Clinical Core Mismatch in Large Vessel Occlusion Strokes

Stroke ◽

10.1161/str.51.suppl_1.tp77 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Shashvat Desai ◽

Bradley J Molyneaux ◽

Marcelo Rocha ◽

Matthew Starr ◽

Tudor G Jovin ◽

...

Keyword(s):

Patient Selection ◽

Time Window ◽

Ct Perfusion ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Ct Head ◽

Ischemic Core ◽

The Impact ◽

Core Volume

Introduction: Patient selection for endovascular thrombectomy (EVT) for anterior circulation large vessel occlusion (LVO) strokes in the 6-24-hour time window is dependent on delineating clinical core mismatch (CCM) as defined by DAWN trial criteria. In contrast, patient selection in the early window (0-6 hours) can be performed using ASPECTS on CT head. We aim to determine the prevalence of DAWN-CCM in LVO strokes and the impact of time and ASPECTS. Methods: Retrospective analysis of large vessel occlusion [internal carotid and middle cerebral artery-M1] strokes at a CSC. Consecutive patients who underwent CT perfusion or MRI within 120 minutes of CT head were included in the study (treated and untreated). Ischemic core volume was assessed using RAPID [IschemaView] and ASPECTS using automated ASPECTS [Brainomix]. CCM was defined using DAWN trial criteria [DAWN-CCM: NIHSS ≥10 and core <31 ml, NIHSS ≥20 and core <51 ml]. Results: A total of 116 patients were included. Mean age was 71 ±14 and 62% were females. Mean ischemic core volume and median ASPECTS were 46 ±65 ml and 8 (6-9), respectively. In patients with NIHSS score ≥10 (98), 57% had DAWN-CCM in the 0-24-hour window. Proportion of patients with DAWN-CCM in 6-24-hour window was 70% (6-12 hours), 50% (12-18 hours), and 50% (18-24 hours) [p=0.35]. Proportion of patients with DAWN-CCM by ASPECTS group was 88% (ASPECTS 9-10), 64% (ASPECTS 6-8) and 13% (ASPECTS 0-5) [p=<0.01] (Figure 1). Probability of DAWN-CCM declines by 7% for every 2 hours increase in TLKW to imaging, and by 13% for every 1-point decrease in ASPECTS. Conclusion: Approximately 57% of LVO strokes have clinical core mismatch. LVO strokes with DAWN-CCM decline with increasing time and decreasing ASPECTS. ASPECTS alone may be sufficient to identify patients with DAWN-CCM in a resource limited setting and avoid time consuming advanced imaging.

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Abstract P331: Accuracy of CT Perfusion Core Estimates for Predicting Infarct Size in the SELECT Study

Stroke ◽

10.1161/str.52.suppl_1.p331 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Amrou Sarraj ◽

Bruce Campbell ◽

Clark Sitton ◽

Soren Christensen ◽

Shekhar Khanpara ◽

...

Keyword(s):

Cohort Study ◽

White Matter ◽

Infarct Size ◽

Ct Perfusion ◽

Infarct Volume ◽

Estimation Accuracy ◽

Ct Perfusion Imaging ◽

Ischemic Core ◽

The Difference ◽

Core Volume

Background: The accuracy of CT perfusion imaging for estimating the ischemic core has been questioned. Methods: In SELECT, a prospective cohort study of imaging selection, pts who achieved complete reperfusion after EVT were stratified on time from LKW to imaging acquisition and time from imaging to reperfusion. The difference between baseline CTP core volume and f/up infarct volume (on DWI after EVT) was classified as over-estimation (core >10 cc larger than infarct), adequate, or under-estimation (≥ 25 cc smaller). F/up DWI lesion was outlined using a semiautomated algorithm and co-registered to CTP. Results: Of 361 enrolled, 117 achieved TICI 3. F/up MRIs were acquired at 21 (13-30) hrs from EVT with median infarct volume of 16.4 cc, median 8.1 cc larger than baseline core. Median (IQR) time from imaging acquisition to groin puncture (GP) was 70 (50-95) min. Reperfusion was achieved at 35 (25-54) min of GP. The frequency of overestimation decreased as time LKW to imaging increased: < 90 min 6 (14%), 90 – 270 min 3 (6%) and > 270 min 1 (4%), and adequate estimation increased (< 90 min 21 (50%), 90 – 270 min 32 (65%) and > 270min 19 (73%), p for trend 0.048) Fig 1. Overestimation primarily occurred in pts imaged within 90 min who had short imaging to reperfusion times Fig 2. Volumetric correlation between pre-procedure and f/up imaging improved as LKW time to imaging acquisition increased; Spearman’s ρ: <90 min: 0.41 (p=0.007), 90-270 min: 0.35 (p=0.01), >270 min: 0.79 (p<0.0001). Spatially, overestimation occurred predominantly in white matter juxtacortical areas. Adjusting rCBF threshold from < 30% to < 20% in the 6 pts with overestimation ≤ 90 min from LKW resulted in adequate core estimation in all 6, Fig 3. Conclusion: In patients who achieve reperfusion, the correlation between baseline CTP ischemic core volume and f/up DWI volume improved as time LKW to imaging increased. Core estimation accuracy improved by using the < 20% CBF threshold for patients imaged within 90 minutes of LKW.

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Abstract TP74: Aspects Scoring Applied to CTA Source Images is Predictive of Final Infarct Volume and Good Functional Outcome

Stroke ◽

10.1161/str.51.suppl_1.tp74 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Joseph F Carrera ◽

Joseph H Donahue ◽

Prem P Batchala ◽

Andrew M Southerland ◽

Bradford B Worrall

Keyword(s):

Linear Regression ◽

Functional Outcome ◽

Infarct Volume ◽

Univariate Analysis ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Good Outcome ◽

The Impact

Introduction: CTP and MRI are increasingly used to assess endovascular thrombectomy (EVT) candidacy in large vessel occlusion stroke. Unfortunately, availability of these advanced neuroimaging techniques is not widespread and this can lead to over-triage to EVT-capable centers. Hypothesis: ASPECTS scoring applied to computed tomography angiography source images (CTA-SI) will be predictive of final infarct volume (FIV) and functional outcome. Methods: We reviewed data from consecutive patients undergoing EVT at our institution for anterior circulation occlusion between 01/14 - 01/19. We recorded demographics, comorbidities, NIHSS, treatment time parameters, and outcomes as defined by mRS (0-2 = good outcome). Cerebrovascular images were assessed by outcome-blinded raters and collateral score, TICI score, FIV, and both CT and CTA-SI ASPECTS scores were noted. Patients were grouped by ASPECTS score into low (0-4), intermediate (5-7), and high (8-10) for some analyses. FIV was predicted using a linear regression with NIHSS, good reperfusion (TICI 2b/3), collateral score, CT to groin puncture, CT and CTA-SI ASPECTS as independent variables. After excluding those with baseline mRS≥2, a binary logistic regression was performed including covariates of age, NIHSS, good reperfusion, and diabetes (factors significant at p<0.05 on univariate analysis) to assess the impact of CTA-SI ASPECTS group on outcome. Results: Analysis included 137 patients for FIV and 102 for outcome analysis (35 excluded for baseline mRS≥ 2). Linear regression found CTA-SI ASPECTS (Beta -10.8, p=0.002), collateral score (Beta -42.9, p=0.001) and good reperfusion (Beta 72.605, p=0.000) were independent predictors of FIV. Relative to the low CTA-SI ASPECTS group, the high CTA-SI ASPECTS group was more likely to have good outcome (OR 3.75 [95% CI 1.05-13.3]; p=0.41). CT ASPECTS was not predictive of FIV or good outcome. Outcomes: In those undergoing EVT for anterior circulation occlusion, CTA-SI ASPECTS is predictive of both FIV and functional outcome, while CT ASPECTS predicts neither. CTA-SI ASPECTS holds promise as a lower-cost, more widely available option for triage of patients with large vessel occlusion. Further study is needed comparing CTA-SI ASPECTS to CTP parameters.

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Abstract 38: Brain CT Perfusion is Superior to Non-contrast CT Aspects in the Evaluation of Hyperacute Infarct Volume

Stroke ◽

10.1161/str.48.suppl_1.38 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Jelle Demeestere ◽

Carlos Garcia-Esperon ◽

Pablo Garcia-Bermejo ◽

Fouke Ombelet ◽

Patrick McElduff ◽

...

Keyword(s):

Computed Tomography ◽

Ischemic Stroke ◽

Ct Perfusion ◽

Infarct Volume ◽

Lesion Volume ◽

Infarct Core ◽

Anterior Circulation ◽

C Statistic ◽

Contrast Ct ◽

Core Volume

Objective: To compare the predictive capacity to detect established infarct in acute anterior circulation stroke between the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on non-contrast computed tomography (CT) and CT perfusion. Methods: Fifty-nine acute anterior circulation ischemic stroke patients received brain non-contrast CT, CT perfusion and hyperacute magnetic resonance imaging (MRI) within 100 minutes from CT imaging. ASPECTS scores were calculated by 4 independent vascular neurologists, blinded from CT perfusion and MRI data. CT perfusion infarct core volumes were calculated by MIStar software. The accuracy of commonly used ASPECTS cut-off scores and a CT perfusion core volume of ≥ 70 mL to detect a hyperacute MRI diffusion lesion of ≥ 70 ml was evaluated. Results: Median ASPECTS score was 9 (IQR 7-10). Median CT perfusion core volume was 22 ml (IQR 10.4-71.9). Median MRI diffusion lesion volume was 24,5 ml (IQR 10-63.9). ASPECTS score of < 6 had a sensitivity of 0.37, specificity of 0.95 and c-statistic of 0.66 to predict an acute MRI lesion ≥ 70 ml. In comparison, a CT perfusion core lesion of ≥ 70 ml had a sensitivity of 0.76, specificity of 0.98 and c-statistic of 0.92. The CT perfusion core lesion covered a median of 100% of the acute MRI lesion volume (IQR 86-100%). Conclusions: CT perfusion is superior to ASPECTS to predict hyperacute MRI lesion volume in ischemic stroke.

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Abstract TP91: Unfavorable Baseline Hypoperfusion Intensity Ratio is Associated With Infarct Growth and Poor Outcome in Patients With Distal MCA Occlusions

Stroke ◽

10.1161/str.51.suppl_1.tp91 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Adam MacLellan ◽

Michael Mlynash ◽

Stephanie Kemp ◽

Soren Christensen ◽

Michael Marks ◽

...

Keyword(s):

Functional Outcome ◽

Intensity Ratio ◽

Ct Perfusion ◽

Anterior Circulation ◽

Excellent Functional Outcome ◽

The Mean ◽

Ischemic Core ◽

Core Volume ◽

Distal Middle Cerebral Artery

Background: A low hypoperfusion intensity ratio (HIR) predicts good collateral vessel status and correlates with infarct growth and functional outcome in early window patients with proximal large vessel anterior circulation occlusions. Its performance in predicting clinical and radiologic outcome has not been assessed in patients with more distal occlusions. In this retrospective analysis of the CT Perfusion to Predict Response to Recanalization in Ischemic Stroke (CRISP) study, we hypothesized that a favorable baseline HIR would predict less infarct growth in patients with distal middle cerebral artery (MCA) occlusions. Methodology: Patients with occlusions of an M2 or M3 branch of the MCA on catheter angiography were included; all patients underwent mechanical thrombectomy with TICI2B/3 reperfusion. Baseline ischemic core volume and HIR (Tmax >10s / Tmax >6s) were assessed with RAPID software; late follow-up infarct volumes (>36 hours from initial CT perfusion) were manually determined from DWI MRI. Excellent functional outcome was defined as a modified Rankin score of 0-1. Results: Fourteen patients with baseline perfusion and late follow-up imaging were included; nine patients presented with M2 occlusions, and 5 with M3 occlusions. The mean baseline HIR of 0.48 was used to dichotomize patients into favorable or unfavorable baseline profiles. Patients with a favorable baseline HIR had significantly smaller baseline ischemic core volumes (0 mL [IQR 0-3.3] vs. 14.0 mL [IQR 8.7-22.1], p=0.01), smaller final infarct volumes (16.1 mL [IQR 12.7-41.2] vs. 71.4 mL [IQR 43.8-113.5], p=0.01) and less infarct growth (16.1 mL [IQR 9.4-31.9] vs. 49.0 mL [IQR 31.1-100.8], p=0.03). Excellent functional outcome was achieved in 6/6 (100%) of those with favorable baseline HIR, versus 3/8 (37.5%) with unfavorable baseline profile (p=0.03). Conclusion: In patients with distal MCA occlusions, poor collateral status at baseline as demonstrated by a high HIR score is associated with more infarct growth and worse clinical outcomes. HIR may be helpful for guiding thrombectomy decisions in patients with distal occlusions and warrants further prospective study in this population.

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P-006 Presenting Diffusion-Restricted Core Volume, Not Time, Predicts Final Infarct Volume after Thrombectomy in Anterior Circulation Large Vessel Occlusion Stroke

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2016-012589.48 ◽

2016 ◽

Vol 8 (Suppl 1) ◽

pp. A30-A30

Author(s):

B Cristiano ◽

M Pond ◽

S Basu ◽

U Oyoyo ◽

J Jacobson

Keyword(s):

Infarct Volume ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Core Volume

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Abstract WP19: Reliability of CT Perfusion in the Posterior Circulation in Comparison to the Anterior Circulation

Stroke ◽

10.1161/str.51.suppl_1.wp19 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Srijan Adhikari ◽

Justin Moore ◽

Abid Y Qureshi

Keyword(s):

Ct Perfusion ◽

Infarct Volume ◽

Posterior Circulation ◽

Large Vessel ◽

Anterior Circulation ◽

Kendall’S Tau ◽

Mean Velocity ◽

Vessel Occlusion ◽

Kendall's Tau ◽

Nonparametric Correlation

Background: DAWN and DEFUSE-3 excluded posterior-circulation cases, but in practice endovascular therapy (EVT) is common due to life-threatening large-vessel occlusions. Often CT perfusion (CTP) is acquired to aid in the decision-making of these cases, but the reliability of using CT perfusion in the posterior-circulation is unknown Hypothesis: Given the differences in hemodynamics (~20% of total CBF to the basilar, reduced mean velocity, and differences in collateral supply) penumbra estimates using RAPID software will be less accurate in predicting the final infarct volume on DWI. Methods: In patients who did not receive any treatment (tPA or EVT), the Tmax >6s, as operationally defined as penumbra, should approximate the infarct on DWI. As such, only posterior circulation patients without EVT or tPA were included. Anterior circulation patients were matched on demographics, medical history, outcomes. A ratio of Tmax/DWI was calculated to assess how closely perfusion approximated final infarct folume. Nonparametric correlation with Kendall’s tau-b was also performed. Results: Eleven patients with a posterior circulation large-vessel occlusion (pc-LVO) were compared to 30-matched patients with anterior circulation (ac-LVO). Age was 62.4±16 for ac-LVO vs. 64.5±13 for pc-LVO. Significant differences were seen in sex with ac-LVO 82% male, and pc-LVO 46% male (t=-2.06 p=0.046). Pc-LVO also had more subjects with an unknown last known well. Mean admission NIHSS was 15.6±8 ac-LVO, and 16.4±10 in pc-LVO group was similar. Mean discharge NIHSS was 12.6±9 ac-LVO vs 12.4±10 pc-LVO. NO signficicant difference in 30d mRS, 24h NIHSS, or mortality within 90d. As excpected in the anterior circulation cases final infarct volume correlated with Tmax>6s Kendall’s tau-b=0.57 (p=0.000013), and Tmax>8s (tau-b=0.55), Tmax>10s (tau-b=0.55. Whereas, In the posterior circulation Tmax>6s (tau-b=0.41, N.S.), but Tmax>8s (tau-b=0.64, p=0.007) and Tmax>10(tau-b=0.69, p=0.005). Seen another way the ratio of Tmax>6s:DWI = 2.47 (ac-LVO) vs 5.84 (pc-LVO) (t=-1.22, p=0.004, but Tmax>8s 1.57 vs 1.50 (t=0.11, p=9.12). Conclusion: Final infarct volume was not significantly associated with Tmax>6s in posterior circulation cases. Instead Tmax>8s is more reliable.

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Abstract 60: Impact of Monthly Testing and Tutorials on Accuracy and Confidence of Telestroke Nurse Recognition of Anterior Circulation Large Vessel Occlusion CT Perfusion Patterns

Stroke ◽

10.1161/str.51.suppl_1.60 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Emily K Snider ◽

Brenda Chang ◽

Anna Maria Helms ◽

Laura Williams ◽

Sam Singh ◽

...

Keyword(s):

Good Accuracy ◽

Internal Carotid ◽

Ct Perfusion ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Confidence Levels ◽

Lower Confidence ◽

The Impact

Introduction: A distinguishing feature of our Stroke Network is Telestroke (TS) nurses (RNs) who remotely facilitate TS evaluations. To facilitate expeditious transfer the TS RNs, need to immediately identify CT perfusion (CTP) studies demonstrating patterns consistent with internal carotid artery (ICA), middle cerebral artery (M1), and first branch of the M1 (M2) large vessel occlusion (LVO) acute ischemic strokes (AIS). Methods: We developed a 6-month series of tutorials and tests (12 CTP scans/month) for 16 TS RNs to recognize CTP patterns consistent with ICA, M1 or M2 LVO AIS. We simultaneously conducted a prospective cohort study of these nurses on the impact of these tutorials and tests. Results: TS nurses demonstrated good accuracy in detecting ICA, M1 or M2 LVO presence during the first three months of teaching (83-94% accurate).This improved to excellent during the last three months (99-100%), during which the likelihood of correctly identifying the presence of any one of these LVOs was greater than in the first three months (OR 1.99, 95% CI: 1.83-2.17, p<0.001). The probability of correctly identifying ICA or M1 occlusions was much higher than correctly identifying all other LVOs (OR 68, 95% CI: 45-102, p<0.001). The likelihood of being at a higher confidence level compared to lower confidence levels in identifying any LVOs as being ICA or M1 was higher than in identifying other LVOs (OR 2.14, 95% CI: 1.6-2.8, p<0.001), but over time confidence for determining LVO presence did not differ significantly after controlling for subject variation. Conclusion: A series of structured tutorials significantly increased the odds of TS nurses correctly identifying anterior circulation LVOs, with the benefit of these tutorials and test reviews peaking and plateauing at four months. Participating in TS nurse tutorials was associated with high odds and confidence for correctly identifying LVOs as being ICA or M1.

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