Defining acute ischemic stroke tissue pathophysiology with whole brain CT perfusion

Bivard, Andrew; Levi, Christopher; Krishnamurthy, Venkatesh; Hislop-Jambrich, Jacqueline; Salazar, Pascal; Jackson, Benjamin; Davis, Stephen M.; Parsons, Mark

doi:10.1016/j.neurad.2013.11.006

Cited by 65 publications

(69 citation statements)

References 24 publications

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“…A previously validated thresholds was applied in order to measure the volume of the acute perfusion lesion (relative DT >3 seconds). 11 Penumbral volume was calculated as the volume of the perfusion lesion (DT threshold >3 seconds) minus the volume of the ischemic core (relative CBF [rCBF] threshold <30% within the DT >3-second lesion).…”

Section: Selection Of Controlsmentioning

confidence: 99%

“…Baseline National Institutes of Health Stroke Scale (median, 15; interquartile range [IQR], [11][12][13][14][15][16][17][18][19], age (median, 65; IQR, 59-80), and time to intravenous treatment (median, 153 minutes; IQR, 82-315) were well matched (all p > 0.05). Despite similar baseline CTP ischemic core volumes using the previously validated measure (relative cerebral blood flow [rCBF], <30%), thrombectomy patients had a smaller median 24-hour infarct core of 17.3ml (IQR, 11.3-32.8) versus 24.3ml (IQR, 16.7-42.2; p 5 0.011) in alteplase-treated controls.…”

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confidence: 95%

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Ischemic core thresholds change with time to reperfusion: A case control study

Bivard

Kleinig

Miteff

et al. 2017

Annals of Neurology

103

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Introduction: We aimed to identify whether acute ischemic stroke patients with known complete reperfusion after thrombectomy had the same baseline computed tomography perfusion (CTP) ischemic core threshold to predict infarction as thrombolysis patients with complete reperfusion. Methods: Patients who underwent thrombectomy were matched by age, clinical severity, occlusion location, and baseline perfusion lesion volume to patients who were treated with intravenous alteplase alone from the International Stroke Perfusion Imaging Registry. A pixel-based analysis of coregistered pretreatment CTP and 24-hour diffusionweighted imaging (DWI) was then undertaken to define the optimum CTP thresholds for the ischemic core. Results: There were 132 eligible thrombectomy patients and 132 matched controls treated with alteplase alone. Baseline National Institutes of Health Stroke Scale (median, 15; interquartile range [IQR], 11-19), age (median, 65; IQR, 59-80), and time to intravenous treatment (median, 153 minutes; IQR, 82-315) were well matched (all p > 0.05). Despite similar baseline CTP ischemic core volumes using the previously validated measure (relative cerebral blood flow [rCBF], <30%), thrombectomy patients had a smaller median 24-hour infarct core of 17.3ml (IQR, 11.3-32.8) versus 24.3ml (IQR, 16.7-42.2; p 5 0.011) in alteplase-treated controls. As a result, the optimal threshold to define the ischemic core in thrombectomy patients was rCBF <20% (area under the curve [AUC], 0.89; 95% CI, 0.84, 0.94), whereas in alteplase controls the optimal ischemic core threshold remained rCBF <30% (AUC, 0.83; 95% CI, 0.77, 0.85). Interpretation: Thrombectomy salvaged tissue with lower CBF, likely attributed to earlier reperfusion. For patients who achieve rapid reperfusion, a stricter rCBF threshold to estimate the ischemic core should be considered.

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Section: Selection Of Controlsmentioning

confidence: 99%

mentioning

confidence: 95%

Ischemic core thresholds change with time to reperfusion: A case control study

Bivard

Kleinig

Miteff

et al. 2017

Annals of Neurology

103

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“…8 Previously validated thresholds were applied to measure the volume of the acute perfusion lesion (relative delay time [DT] >3 s) and acute infarct core (relative cerebral blood flow <30%). 9 Penumbral volume was calculated from the volume of the perfusion lesion (DT threshold >3 s) minus the volume of the infarct core (relative cerebral blood flow threshold <30% within the DT >3 s lesion), the volume of severely hypoperfused tissue (DT >6 s) was also recorded for hemorrhage prediction. 3 All acute CTA scans were assessed for occlusion severity blind to CTP.…”

Section: Ctp Analysis and Classification Of Patientsmentioning

confidence: 99%

Validating a Predictive Model of Acute Advanced Imaging Biomarkers in Ischemic Stroke

Bivard

Levi

Lin

et al. 2017

Stroke

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7However, these criteria were largely empirically derived from limited cohorts and using earlier generation scanners and software. We hypothesized that in individual patients, advanced imaging profiles will accurately predict 3-month functional Background and Purpose-Advanced imaging to identify tissue pathophysiology may provide more accurate prognostication than the clinical measures used currently in stroke. This study aimed to derive and validate a predictive model for functional outcome based on acute clinical and advanced imaging measures. Methods-A database of prospectively collected sub-4.5 hour patients with ischemic stroke being assessed for thrombolysis from 5 centers who had computed tomographic perfusion and computed tomographic angiography before a treatment decision was assessed. Individual variable cut points were derived from a classification and regression tree analysis. The optimal cut points for each assessment variable were then used in a backward logic regression to predict modified Rankin scale (mRS) score of 0 to 1 and 5 to 6. The variables remaining in the models were then assessed using a receiver operating characteristic curve analysis. Results-Overall, 1519 patients were included in the study, 635 in the derivation cohort and 884 in the validation cohort.The model was highly accurate at predicting mRS score of 0 to 1 in all patients considered for thrombolysis therapy (area under the curve [AUC] 0.91), those who were treated (AUC 0.88) and those with recanalization (AUC 0.89). Next, the model was highly accurate at predicting mRS score of 5 to 6 in all patients considered for thrombolysis therapy (AUC 0.91), those who were treated (0.89) and those with recanalization (AUC 0.91). The odds ratio of thrombolysed patients who met the model criteria achieving mRS score of 0 to 1 was 17.89 (4.59-36.35, P<0.001) and for mRS score of 5 to 6 was 8.23 (2.57-26.97, P<0.001). Conclusions-This study has derived and validated a highly accurate model at predicting patient outcome after ischemic stroke.

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“…CBF vs CBV) and its optimal threshold to identify the ischemic core. This variability is attributed to differences in (1) CTP processing algorithms, (2) definitions of the gold standard for ischemic core, and (3) implementations of ROC analysis (definition of true negative region, ROC analysis per-patient or all voxels pooled) [1][2][3][4][5][6][7][8][9] (Table 1). Consequently, there is wide variability in the CTP parameters that are used in clinical practice and trials.…”

Section: Introductionmentioning

confidence: 99%

A benchmarking tool to evaluate computer tomography perfusion infarct core predictions against a DWI standard

Cereda

Christensen

Campbell

et al. 2016

J Cereb Blood Flow Metab

152

160

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Differences in research methodology have hampered the optimization of Computer Tomography Perfusion (CTP) for identification of the ischemic core. We aim to optimize CTP core identification using a novel benchmarking tool. The benchmarking tool consists of an imaging library and a statistical analysis algorithm to evaluate the performance of CTP. The tool was used to optimize and evaluate an in-house developed CTP-software algorithm. Imaging data of 103 acute stroke patients were included in the benchmarking tool. Median time from stroke onset to CT was 185 min (IQR 180-238), and the median time between completion of CT and start of MRI was 36 min (IQR 25-79). Volumetric accuracy of the CTP-ROIs was optimal at an rCBF threshold of <38%; at this threshold, the mean difference was 0.3 ml (SD 19.8 ml), the mean absolute difference was 14.3 (SD 13.7) ml, and CTP was 67% sensitive and 87% specific for identification of DWI positive tissue voxels. The benchmarking tool can play an important role in optimizing CTP software as it provides investigators with a novel method to directly compare the performance of alternative CTP software packages.

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Defining acute ischemic stroke tissue pathophysiology with whole brain CT perfusion

Cited by 65 publications

References 24 publications

Ischemic core thresholds change with time to reperfusion: A case control study

Ischemic core thresholds change with time to reperfusion: A case control study

Validating a Predictive Model of Acute Advanced Imaging Biomarkers in Ischemic Stroke

A benchmarking tool to evaluate computer tomography perfusion infarct core predictions against a DWI standard

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