Acute ischemic stroke with tandem/terminal ICA occlusion - CT perfusion based case selection for mechanical recanalization

Background Color-coded multiphase computed tomography angiography (mCTA) can provide time-variant blood flow information of collateral circulation for acute ischemic stroke (AIS). Purpose To compare the predictive values of color-coded mCTA, conventional mCTA, and CT perfusion (CTP) for the clinical outcomes of patients with AIS. Material and Methods Consecutive patients with anterior circulation AIS were retrospectively reviewed at our center. Baseline collateral scores of color-coded mCTA and conventional mCTA were assessed by a 6-point scale. The reliabilities between junior and senior observers were assessed by weighted Kappa coefficients. Receiver operating characteristic (ROC) curves and multivariate logistic regression model were applied to evaluate the predictive capabilities of color-coded mCTA and conventional mCTA scores, and CTP parameters (hypoperfusion and infarct core volume) for a favorable outcome of AIS. Results A total of 138 patients (including 70 cases of good outcomes) were included in our study. Patients with favorable prognoses were correlated with better collateral circulations on both color-coded and conventional mCTA, and smaller hypoperfusion and infarct core volume (all P < 0.05) on CTP. ROC curves revealed no significant difference between the predictive capability of color-coded and conventional mCTA ( P = 0.427). The predictive value of CTP parameters tended to be inferior to that of color-coded mCTA score (all P < 0.001). Both junior and senior observers had consistently excellent performances (κ = 0.89) when analyzing color-coded mCTA maps. Conclusion Color-coded mCTA provides prognostic information of patients with AIS equivalent to or better than that of conventional mCTA and CTP. Junior radiologists can reach high diagnostic accuracy when interpreting color-coded mCTA images.

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Non-contrast head CT alone for thrombectomy in acute ischemic stroke: analysis of the ANGEL-ACT registry

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2021-017940 ◽

2021 ◽

pp. neurintsurg-2021-017940

Author(s):

Zeguang Ren ◽

Gaoting Ma ◽

Maxim Mokin ◽

Ashutosh P Jadhav ◽

Baixue Jia ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Clinical Outcomes ◽

Primary Outcome ◽

Ct Perfusion ◽

Non Invasive ◽

Vessel Imaging ◽

Baseline Characteristics ◽

Procedural Outcomes ◽

Head Computed Tomography

BackgroudThe goal of this study was to determine if the choice of imaging paradigm performed in the emergency department influences the procedural or clinical outcomes after mechanical thrombectomy (MT).MethodsThis is a retrospective comparative outcome study which was conducted from the ANGEL-ACT registry. Comparisons were made between baseline characteristics and clinical outcomes of patients with acute ischemic stroke undergoing MT with non-contrast head computed tomography (NCHCT) alone versus patients undergoing NCHCT plus non-invasive vessel imaging (NVI) (including CT angiography (with or without CT perfusion) and magnetic resonance angiography). The primary outcome was the modified Rankin Scale (mRS) score at 90 days. Secondary outcomes included change in mRS score from baseline to 90 days, the proportions of mRS 0–1, 0–2, and 0–3, and dramatic clinical improvement at 24 hours. The safety outcomes were any intracranial hemorrhage (ICH), symptomatic ICH, and mortality within 90 days.ResultsA total of 894 patients met the inclusion criteria; 476 (53%) underwent NCHCT alone and 418 (47%) underwent NCHCT + NVI. In the NCHCT alone group, the door-to-reperfusion time was shorter by 47 min compared with the NCHCT + NVI group (219 vs 266 min, P<0.001). Patients in the NCHCT alone group showed a smaller increase in baseline mRS score at 90 days (median 3 vs 2 points; P=0.004) after adjustment. There were no significant differences between groups in the remaining clinical outcomes.ConclusionsIn patients selected for MT using NCHCT alone versus NCHCT + NVI, there were improved procedural outcomes and smaller increases in baseline mRS scores at 90 days.

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Abstract 1122‐000034: Systematic CT‐Perfusion acquisition in All Suspected Stroke Patients Increases Vascular Occlusion Detection and Thrombectomy Rates

Stroke: Vascular and Interventional Neurology ◽

10.1161/svin.01.suppl_1.000034 ◽

2021 ◽

Vol 1 (S1) ◽

Author(s):

Marta Olive‐Gadea ◽

Manuel Requena ◽

Facundo Diaz ◽

Alvaro Garcia‐Tornel ◽

Marta Rubiera ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Clinical Symptoms ◽

Ct Perfusion ◽

False Negative ◽

False Negative Rate ◽

Vascular Occlusion ◽

Stroke Patients ◽

Imaging Protocols ◽

The Impact

Introduction : In acute ischemic stroke patients, current guidelines recommend noninvasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols on VO diagnosis and EVT rates. Methods : We included patients with a suspected acute ischemic stroke that underwent urgent non‐contrast CT, CTA and CTP from April to October 2020. Hypoperfusion areas defined by Tmax>6s delay (RAPID software), congruent with the clinical symptoms and a vascular territory, were considered due to a VO (CTP‐VO). Cases in which mechanical thrombectomy was performed were defined as therapeutically relevant VO (EVT‐VO). For patients that received EVT, site of VO according to digital subtraction angiography was recorded. Two experienced neuroradiologists blinded to CTP but not to clinical symptoms, retrospectively evaluated NCCT and CTA to identify intracranial VO (CTA‐VO). We analyzed CTA‐VO sensitivity and specificity at detecting CTP‐VO and EVT‐VO respecitvely. We performed a logistic regression to test the association of Tmax>6s volumes with CTA‐VO identification and indication of EVT. Results : Of the 338 patients included in the analysis, 157 (46.5%) presented a CTP‐VO, (median Tmax>6s: 73 [29‐127] ml). CTA‐VO was identified in 83 (24.5%) of the cases. Overall CTA‐VO sensitivity for the detection of CTP‐VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with an increased CTA‐VO detection, with an odds ratio of 1.03 (95% confidence interval 1.02‐1.04) (figure). DSA was indicated in 107 patients; in 4 of them no EVT was attempted due to recanalization or a too distal VO in the first angiographic run. EVT was performed in 103 patients (30.5%. Tmax>6s: 102 [63‐160] ml), representing 65.6% of all CTP‐VO. Overall CTA‐VO sensitivity for the detection of EVT‐VO was 69.9%. The CTA‐VO sensitivity for detecting patients with indication of EVT according to clinical guidelines was as follows: 91.7% for ICA occlusions and 84.4% for M1‐MCA occlusions. For all other occlusion sites that received EVT, the CTA‐VO sensitivity was 36.1%. The overall specificity was 95.3%. Among patients who received EVT, CTA‐VO was not detected in 31 cases, resulting in a false negative rate of 30.1%. False negative CTA‐VO cases had lower Tmax>6s volumes (69[46‐99.5] vs 126[84‐169.5]ml, p<0.001) and lower NIHSS (13[8.5‐16] vs 17[14‐21], p<0.001). Conclusions : Systematically including CTP perfusion in the acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

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Abstract 3200: Comparison of CT Perfusion Mismatch with Perfusion-Diffusion MRI in Ischemic Stroke - a Reliable Alternative?

Stroke ◽

10.1161/str.43.suppl_1.a3200 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Bruce C Campbell ◽

Søren Christensen ◽

Christopher R Levi ◽

Patricia M Desmond ◽

Geoffrey A Donnan ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Diffusion Mri ◽

Roc Analysis ◽

Ct Perfusion ◽

Residue Function ◽

Infarct Core ◽

Widespread Application ◽

Time To Peak ◽

Value Decomposition

Background and purpose: CT-perfusion (CTP) is widely and rapidly accessible for imaging acute ischemic stroke. However, there has been limited validation of CTP parameters against the more intensively studied MRI perfusion-diffusion mismatch paradigm. We tested the correspondence of CTP with contemporaneous perfusion-diffusion MRI. Methods: Acute ischemic stroke patients <6hr after onset had CTP and perfusion-diffusion MRI within 1hr, before reperfusion therapies. Relative cerebral blood flow (relCBF) and time-to-peak of the deconvolved tissue-residue-function (Tmax) were calculated (standard singular value decomposition deconvolution). The diffusion lesion was registered to the CTP slabs and manually outlined to its maximal visual extent. CT-infarct core was defined as relCBF<31% contralateral mean as previously published using this software. The volumetric accuracy of relCBF core compared to the diffusion lesion was tested in isolation, but also when restricted to pixels with relative time-to-peak (TTP) >4sec, to reduce artifactual false positive low CBF (eg in leukoaraiosis). The MR Tmax>6sec perfusion lesion (previously validated to define penumbral tissue at risk of infarction) was automatically segmented and registered to the CTP slabs. Receiver operating characteristic (ROC) analysis determined the optimal CT-Tmax threshold to match MR-Tmax>6sec, confidence intervals generated by bootstrapping. Agreement of these CT parameters with MR perfusion-diffusion mismatch on co-registered slabs was assessed (mismatch ratio >1.2, absolute mismatch>10mL, infarct core<70mL). Results: In analysis of 98 CTP slabs (54 patients, median onset to CT 190min, median CT to MR 30min), volumetric agreement with the diffusion lesion was substantially improved by constraining relCBF<31% within the automated TTP perfusion lesion ROI (median magnitude of volume difference 9.0mL vs unconstrained 13.9mL, p<0.001). ROC analysis demonstrated the best CT-Tmax threshold to match MR-Tmax>6sec was 6.2sec (95% confidence interval 5.6-7.3sec, ie not significantly different to 6sec), sensitivity 91%, specificity 70%, AUC 0.87. Using CT-Tmax>6s “penumbra” and relCBF<31% (restricted to TTP>4s) “core”, volumetric agreement was sufficient for 90% concordance between CT and MRI-based mismatch status (kappa 0.80). Conclusions: Automated CTP mismatch classification using relCBF and Tmax is similar to perfusion-diffusion MRI. CTP may allow more widespread application of the “mismatch” paradigm in clinical practice and trials.

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Assessing the Relative Value of CT Perfusion Compared to Non-contrast CT and CT Angiography in Prognosticating Reperfusion-Eligible Acute Ischemic Stroke Patients

Frontiers in Neurology ◽

10.3389/fneur.2021.736768 ◽

2021 ◽

Vol 12 ◽

Author(s):

Andrew Bivard ◽

Christopher Levi ◽

Longting Lin ◽

Xin Cheng ◽

Richard Aviv ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Ct Angiography ◽

Predictive Accuracy ◽

Ct Perfusion ◽

Imaging Modality ◽

Characteristic Curve ◽

Treatment Decision ◽

Receiver Operator Characteristic Curve ◽

Stroke Patients

In the present study we sought to measure the relative statistical value of various multimodal CT protocols at identifying treatment responsiveness in patients being considered for thrombolysis. We used a prospectively collected cohort of acute ischemic stroke patients being assessed for IV-alteplase, who had CT-perfusion (CTP) and CT-angiography (CTA) before a treatment decision. Linear regression and receiver operator characteristic curve analysis were performed to measure the prognostic value of models incorporating each imaging modality. One thousand five hundred and sixty-two sub-4.5 h ischemic stroke patients were included in this study. A model including clinical variables, alteplase treatment, and NCCT ASPECTS was weak (R2 0.067, P < 0.001, AUC 0.605) at predicting 90 day mRS. A second model, including dynamic CTA variables (collateral grade, occlusion severity) showed better predictive accuracy for patient outcome (R2 0.381, P < 0.001, AUC 0.781). A third model incorporating CTP variables showed very high predictive accuracy (R2 0.488, P < 0.001, AUC 0.899). Combining all three imaging modalities variables also showed good predictive accuracy for outcome but did not improve on the CTP model (R2 0.439, P < 0.001, AUC 0.825). CT perfusion predicts patient outcomes from alteplase therapy more accurately than models incorporating NCCT and/or CT angiography. This data has implications for artificial intelligence or machine learning models.

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