Abstract WMP18: CT Work-Up of Patients Suspected of Acute Ischemic Stroke: Perfusion-CT Adds Value Compared to Clinical Evaluation, Noncontrast Head CT and CT-Angiogram in Terms of Predicting Outcome

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Guangming Zhu ◽  
Patrik Michel ◽  
Amin Aghaebrahim ◽  
James T Patrie ◽  
Wenjun Xin ◽  
...  

BACKGROUND AND PURPOSE: To determine whether Perfusion-CT (PCT) adds value to Noncontrast head CT (NCT), CT-Angiogram (CTA) and clinical assessment in patients suspected of acute ischemic stroke. METHODS: We retrospectively reviewed the clinical and imaging data collected in 165 patients with acute ischemic stroke. ASPECTS score was calculated from NCT. CTA was reviewed for site of occlusion and collateral flow score. PCT was used to calculate the volumes of infarct core and ischemic penumbra on admission. Recanalization status was assessed on follow-up imaging. Clinical data included age, time from onset to baseline imaging, time from baseline imaging to reperfusion therapy, time from baseline imaging to recanalization imaging, NIHSS at baseline, treatment type and modified Rankin score (mRS) at 90 days. In a first multivariate regression analysis, we used volume of PCT penumbra and infarct core as outcome, and assessed whether they could be predicted from clinical variables, NCT and/or CTA. In a second multivariate regression analysis, we used mRS at 90 days as outcome, and determined which imaging and clinical variables predicted it best. RESULTS: 165 patients were identified. Mean±SD time from onset to baseline imaging was 6.7±8.7 hrs. 76 had a good outcome (90-day mRS 0-2), 89 had a poor outcome. Mean±SD PCT infarct was 44.8±46.5 ml. Mean±SD PCT penumbra was 47.0±33.9 ml. PCT infarct could be predicted by clinical data, NCT, CTA, and combinations of this data (P<0.05); the best predictive model included the clinical data, plus NCT and CTA. PCT Penumbra could NOT be predicted by clinical data, NCT, and CTA. In terms of predicting mRS at 90 days, all of variables but NCT and CTA were significantly associated with 90-day mRS outcome. The single most important predictor was recanalization status (P<0.001). PCT penumbra volume (P=0.001) was also a predictor of clinical outcome, especially when considered in conjunction with recanalization through an interaction term (P<0.001). CONCLUSION: PCT penumbra represents independent information, which cannot be predicted by clinical, NCT, and CTA data. PCT penumbra is an important determinant of clinical outcome, and adds relevant clinical information compared to a stroke CT work-up including NCT and CTA.

US Neurology ◽  
2010 ◽  
Vol 06 (01) ◽  
pp. 50 ◽  
Author(s):  
Sachin Rastogi ◽  
David S Liebeskind ◽  
◽  

Stroke is the third leading cause of death in the US, affecting 795,000 individuals annually. Currently, only a small percentage of acute stroke patients receive thrombolytic treatment. A significant limitation is the current use of strict time criteria in the decision to treat. As there are significant interindividual variations in response to an acute vascular occlusion, the goal of modern imaging such as multimodal computed tomography (CT) is to rapidly identify acute ischemic stroke patients and determine which patients are likely to benefit from treatment based on tissue perfusion status rather than time of presentation alone. Multimodal CT consists of a non-contrast head CT, CT angiogram (CTA) of the head and neck, and CT perfusion (CTP). The non-contrast head CT allows rapid triage of a patient with hemorrhagic versus ischemic stroke. The CTA allows identification of the site of vascular pathology with similar quality to digital subtraction angiography. The CTP scan allows for determination of the infarct core and surrounding ischemic penumbra, which remains at risk for infarction if perfusion is not restored. This allows the potential to prospectively treat only those patients likely to benefit from thrombolysis while protecting those patients unlikely to benefit from the risks associated with treatment.


2020 ◽  
pp. 028418512098177
Author(s):  
Yu Lin ◽  
Nannan Kang ◽  
Jianghe Kang ◽  
Shaomao Lv ◽  
Jinan Wang

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.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Bruce C Campbell ◽  
Søren Christensen ◽  
Christopher R Levi ◽  
Patricia M Desmond ◽  
Geoffrey A Donnan ◽  
...  

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.


Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
H. B Brouwers ◽  
Svetlana Lorenzano ◽  
Lyndsey H Starks ◽  
David M Greer ◽  
Steven K Feske ◽  
...  

Purpose: Hemorrhagic transformation (HT) is a common and potentially devastating complication of ischemic stroke, however its prevalence, predictors, and outcome remain unclear. Early anticoagulation is thought to be a risk factor for HT which raises the clinical question when to (re)start anticoagulation in ischemic stroke patients who have a compelling indication, such as atrial fibrillation. We conducted a prospective cohort study to address this question and to identify association of hemorrhagic transformation with outcome measures in patients with atrial fibrillation in the setting of acute ischemic stroke. Materials and Methods: We performed a prospective study which enrolled consecutive patients admitted with acute ischemic stroke presenting to a single center over a three-year period. As part of the observational study, baseline clinical data and stroke characteristics as well as 3 month functional outcome were collected. For this sub-study, we restricted the analysis to subjects diagnosed with atrial fibrillation. CT and MRI scans were reviewed by experienced readers, blinded to clinical data, to assess for hemorrhagic transformation (using ECASS 2 criteria), microbleeds and infarct volumes in both admission and follow-up scans. Clinical and outcome data were analyzed for association with hemorrhagic transformation. Results: Of 94 patients, 63 had a history of atrial fibrillation (67.0%) and 31 had newly discovered atrial fibrillation (33.0%). We identified HT in 3 of 94 baseline scans (3.2%) and 22 of 48 follow-up scans (45.8%) obtained a median of 3 days post-stroke. In-hospital initiation of either anti-platelet (n = 36; OR 0.34 [95% CI 0.10-1.16], p-value = 0.09) or anticoagulation with unfractionated intravenous heparin or low molecular weight heparin (n = 72; OR 0.25 [95% CI 0.06-1.15], p-value = 0.08) was not associated with HT. Initial NIH Stroke Scale (NIHSS) score (median 13.0 [IQR 15.0] vs. 7.0 [IQR 10.0], p-value = 0.029) and baseline infarct volume (median 17 [IQR 42.03] vs. 5 [IQR 10.95], p-value = 0.011) were significantly higher in patients with HT compared to those without. Hemorrhagic transformation was associated with a significantly higher 48-hour median NIHSS score (20 [IQR 3.0] vs. 2 [IQR 3.25], p-value = 0.007) and larger final infarct volume (81.40 [IQR 82.75] vs. 9.95 [IQR 19.73], p-value < 0.001). Finally, we found a trend towards poorer 3-month modified Rankin Scale scores in subjects with HT (OR 11.25 [95% CI 0.97-130.22], p-value = 0.05). Conclusion: In patients with atrial fibrillation, initial NIHSS score and baseline infarct volume are associated with hemorrhagic transformation in acute ischemic stroke. Early initiation of antithrombotic therapy was not associated with hemorrhagic transformation. Patients with hemorrhagic transformation were found to have a poorer short and long term outcome and larger final infarct volumes.


Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Marcelo Rocha ◽  
William T Delfyett ◽  
Amin Aghaebrahim ◽  
Ashutosh Jadhav ◽  
Tudor Jovin

Background and Purpose: CT angiography yields rapid detection of a major cerebral vessel occlusion during the evaluation of patients with acute ischemic stroke leading to its widespread use in rapidly triaging for IA trial enrollment. In such trials, patients who have an extracranial carotid occlusion in tandem to the intracranial target lesion are typically excluded. However, ICA terminus occlusions may be misidentified as cervical carotid occlusions on CTA. The goal of this study is to determine the accuracy of CTA in identifying ICA terminus occlusions from tandem carotid occlusions (cervical and intracranial segments). Methods: Retrospective review of a prospectively maintained database containing patients treated at our comprehensive stroke center between 1996 and 2014 in whom catheter angiogram and CT angiogram were available on PACS. A Neuroradiologist, blinded to catheter angiographic results reviewed the CT angiography identifying the presence of intracranial stenoses and concomitant cervical carotid occlusions. Results: Of 196 patients presenting with intracranial carotid occlusions on catheter based angiogram, 101 patients were identified with good quality CT angiography and subsequent catheter angiograms. Mean ages for identified patients was 65 +/- 14, of which 52% women and 48% men. Forty-four percent of patients had an ASPECT score of 9-10. The overall rate of agreement between retrospective CTA and conventional angiography readings was 77%. Of 72 isolated intracranial occlusions on conventional angiography, CT angiography misidentified 23 cervical carotid occlusions. The sensitivity of CTA for detecting isolated carotid terminus occlusion was 68% in this cohort. Specific factors associated with CT and catheter based angiographic discrepancy are reviewed. Conclusions: The study raises systematic considerations for maximizing inclusion of patients with target arterial occlusions who are most likely to benefit from intra-arterial therapy in future clinical trials. Future steps will include determination of specificity, predictive value of CTA for localization of specific carotid occlusion sites. Clinical variables associated with lower CTA accuracy will also be examined.


2021 ◽  
pp. neurintsurg-2021-017510
Author(s):  
Arne Potreck ◽  
Fatih Seker ◽  
Matthias Anthony Mutke ◽  
Charlotte Sabine Weyland ◽  
Christian Herweh ◽  
...  

ObjectivesAutomated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation.MethodsUsing a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values.ResultsWhile CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of −5.3 (−14 to 3.5) mL for subtle head movement and −7.0 (−14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (−25 to 44) mL and +35 (−14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (−1.5 to 3.0) for subtle head movement and +1.9 (−1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement.ConclusionsMotion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Alvaro Garcia-Tornel ◽  
Matias Deck ◽  
Marc Ribo ◽  
David Rodriguez-Luna ◽  
Jorge Pagola ◽  
...  

Introduction: Perfusion imaging has emerged as an imaging tool to select patients with acute ischemic stroke (AIS) secondary to large vessel occlusion (LVO) for endovascular treatment (EVT). We aim to compare an automated method to assess the infarct ischemic core (IC) in Non-Contrast Computed Tomography (NCCT) with Computed Tomography Perfusion (CTP) imaging and its ability to predict functional outcome and final infarct volume (FIV). Methods: 494 patients with anterior circulation stroke treated with EVT were included. Volumetric assessment of IC in NCCT (eA-IC) was calculated using eASPECTS™ (Brainomix, Oxford). CTP was processed using availaible software considering CTP-IC as volume of Cerebral Blood Flow (CBF) <30% comparing with the contralateral hemisphere. FIV was calculated in patients with complete recanalization using a semiautomated method with a NCCT performed 48-72 hours after EVT. Complete recanalization was considered as modified Thrombolysis In Cerebral Ischemia (mTICI) ≥2B after EVT. Good functional outcome was defined as modified Rankin score (mRs) ≤2 at 90 days. Statistical analysis was performed to assess the correlation between EA-IC and CTP-IC and its ability to predict prognosis and FIV. Results: Median eA-IC and CTP-IC were 16 (IQR 7-31) and 8 (IQR 0-28), respectively. 419 patients (85%) achieved complete recanalization, and their median FIV was 17.5cc (IQR 5-52). Good functional outcome was achieved in 230 patients (47%). EA-IC and CTP-IC had moderate correlation between them (r=0.52, p<0.01) and similar correlation with FIV (r=0.52 and 0.51, respectively, p<0.01). Using ROC curves, both methods had similar performance in its ability to predict good functional outcome (EA-IC AUC 0.68 p<0.01, CTP-IC AUC 0.66 p<0.01). Multivariate analysis adjusted by confounding factors showed that eA-IC and CTP-IC predicted good functional outcome (for every 10cc and >40cc, OR 1.5, IC1.3-1.8, p<0.01 and OR 1.3, IC1.1-1.5, p<0.01, respectively). Conclusion: Automated volumetric assessment of infarct core in NCCT has similar performance predicting prognosis and final infarct volume than CTP. Prospective studies should evaluate a NCCT-core / vessel occlusion penumbra missmatch as an alternative method to select patients for EVT.


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Lacy S Handshoe ◽  
Joshua Santucci ◽  
Takashi Shimoyama ◽  
Ken Uchino

Background: Non-occlusive thrombus in an intracranial artery in acute ischemic stroke is an uncommon occurrence. We compared the clinical course and outcome of intracranial subocclusive to occlusive thrombi. Methods: We conducted a review of patients who presented with acute ischemic stroke and received CT angiogram at a single comprehensive stroke center from January 2018 to December 2019. Patients with intracranial subocclusive thrombus were compared to a control group with complete occlusion matched for occlusion location. Subocclusive thrombus was reviewed by two raters on CT angiography, disagreement resolved by consensus. Patient and stroke characteristics and the clinical course were analyzed. Neurological deterioration was defined as an increase in NIH Stroke Scale (NIHSS) score > 4 compared from baseline to 48 hours. Good outcome at discharge was defined as modified Rankin Score of ≤2. Results: Among 1151 acute ischemic strokes, there were 896 patients with CT angiograms. Sixteen out of 896 (1.8%) patients had intracranial subocclusive thrombus. Thirty-two with comparable intracranial occlusions were identified. In the subocclusive group, 3 of 16 (19%) of received acute endovascular intervention, compared to 13 of 32 (41%) in the occluded group. Sex, median age or time from last known well to hospital arrival did not differ between the two groups. The subocclusive thrombus group had less severe strokes, with median NIHSS score at arrival 3 compared to 8.5 in the occlusion group (p<0.01) and median NIHSS at discharge 1 compared to 5.5 in the occlusive group (p<0.01). Frequency of neurological deterioration in hospital did not differ between the subocclusive and occluded groups at 48 hours (15% vs 15% p=1.00). The subocclusive group was associated with a good outcome at discharge, OR 0.5.71, 95% confidence interval 1.41-23.1. Conclusion: Intracranial subocclusive thrombus in acute ischemic stroke has a more mild presentation compared to complete intracranial occlusion without a high rate of neurological deterioration.


Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Laura Blanco-García ◽  
Elisa Cortijo ◽  
Mercedes De Lera ◽  
Ana Calleja ◽  
María Usero ◽  
...  

Objective: We aimed to evaluate the parameter core growth speed (CGS) as a marker of collateral circulation status (CC) in acute ischemic stroke, and to compare it with other brain perfusion-derived markers of collateral capacity. Methods: We retrospectively studied acute ischemic stroke patients who were evaluated with urgent computed tomography perfusion (CTP) and CT angiography. Inclusion criteria comprised known time of onset and anterior circulation proximal occlusion. Collateral circulation was assessed on CTP-source images and rated as poor (0-1) vs. good (2-3) following a previously published scale. CTP maps were computed using Neuroscape 2.0 software by Olea Medical. Infarct core volume was calculated as the brain tissue with >70% reduction in cerebral blood flow (CBF) as compared to the unaffected side. CGS was obtained by dividing core volume by the time from stroke onset to CTP acquisition. Relative cerebral blood volume (rCBV), relative CBF, and hypoperfusion index ratio (HIR = Tmax>10s/Tmax>6s) were used as comparators. Results: We included 41 patients (mean age 71 years; median NIHSS 17; median onset-CTP time 150 minutes). We observed a positive correlation between CGS and HIR (ρ= 0.517 p< 0.001), and negative correlations between rCBV and CGS (ρ= -0.669 p<0.0001), and rCBF and CGS (ρ= -0.749 p<0.0001). Collateral circulation was categorized as poor or good in 15 and 26 patients respectively. A gradual descend in CGS was seen as CC improved (p=0.0005). A logistic regression model adjusted by rCBV, rCBF and HIR identified CGS as independently associated with CC. The association of CGS with good CC in a ROC curve was highly significant (p=0.002, area under the curve 0.8). Conclusion: Core growth speed is robustly associated with collateral circulation status. This parameter can be directly obtained from infarct core volume without the need to process other perfusion or angiographic images, if the time of onset is well known.


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