Clot Burden Score Research Articles

Dual-Energy Computed Tomography in Stroke Imaging: Technical and Clinical Considerations of Virtual Noncontrast Images for Detection of the Hyperdense Artery Sign.

The technical feasibility of virtual noncontrast (VNC) images from dual-energy computed tomography (DECT) for the detection of the hyperdense artery sign (HAS) in ischemic stroke patients was investigated. True noncontrast (TNC) scans of 60 patients either with or without HAS (n = 30 each) were investigated. Clot presence and characteristics were assessed on VNC images from DECT angiography and compared with TNC images. Clot characterization included the level of confidence for diagnosing HAS, a qualitative clot burden score, and quantitative attenuation (Hounsfield unit [HU]) measurements. Sensitivity, specificity, and accuracy of VNC for diagnosing HAS were 97%, 90%, and 93%, respectively. No significant differences were found regarding the diagnostic confidence (P = 0.18) and clot burden score (P = 0.071). No significant HU differences were found among vessels with HAS in VNC (56 ± 7HU) and TNC (57 ± 8HU) (P = 0.691) images. Virtual noncontrast images derived from DECT enable an accurate detection and characterization of HAS.

Abstract TP129: Factor VIII in Acute Cerebral Ischemia Trial - Biomarker in Patients with Large Vessel Occlusion?

Introduction: Baseline elevated Factor VIII (FVIII) level is a significant independent predictor of stroke occurrence and severity. We conducted a prospective serial laboratory cohort study to assess the correlation of FVIII levels in response to thrombolysis in patients with large vessel occlusion (LVO) and acute ischemic stroke (AIS). Methods: AIS patients with anterior circulation LVO were enrolled within 4.5 hours from last seen normal. Baseline and serial FVIII levels were obtained to determine whether FVIII serves as a surrogate marker of clot burden and if FVIII levels or changes predict (1) recanalization with intravenous tissue plasminogen activator (IV tPA) or (2) symptomatic intracranial hemorrhage (sICH) following tPA. Linear and logistic regression analyses were used to determine significant predictors. Results: Patients (n=29) had a mean age of 71years, median NIHSS of 15, 62% were of black race and 48% were female. Baseline pre -tPA FVIII was not significantly correlated with clot burden score (-0.15, p=0.45) or vessel recanalization (-0.13, p=0.50). Median FVIII decreased significantly from baseline to 6hrs post-tPA (282% to 161%, p=0.0024), but delta in FVIII level did not correlate with vessel recanalization (0.01, p=0.95). No patient had sICH. There was no difference between median FVIII level at baseline and 90 days post AIS. Interpretation: FVIII level decreased significantly after tPA, but baseline FVIII level and early change in FVIII level were not significant predictors of clot burden, vessel recanalization after treatment with IV tPA, or symptomatic hemorrhage. This trial provided no evidence to support the value of acute FVIII level as a biomarker in AIS due to LVO. The physiology behind the decrease in FVIII level after tPA remains unknown.

Computed Tomography-Based Thrombus Imaging for the Prediction of Recanalization after Reperfusion Therapy in Stroke.

The prediction of successful recanalization following thrombolytic or endovascular treatment may be helpful to determine the strategy of recanalization treatment in acute stroke. Thrombus can be detected using noncontrast computed tomography (CT) as a hyperdense artery sign or blooming artifact on a T2*-weighted gradient-recalled image. The detection of thrombus using CT depends on slice thickness. Thrombus burden can be determined in terms of the length, volume, and clot burden score. The thrombus size can be quantitatively measured on thin-section CT or CT angiography/magnetic resonance angiography. The determination of thrombus size may be predictive of successful recanalization/non-recanalization after intravenous thrombolysis and endovascular treatment. However, cut-offs of thrombus size for predicting recanalization/non-recanalization are different among studies, due to different methods of measurements. Thus, a standardized method to measure the thrombus is necessary for thrombus imaging to be useful and reliable in clinical practice. Software-based measurements may provide a reliable and accurate assessment. The measurement should be easy and rapid to be more widely used in practice, which could be achieved by improvement of the user interface. In addition to prediction of recanalization, sequential measurements of thrombus volume before and after the treatment may also be useful to determine the efficacy of new thrombolytic drugs. This manuscript reviews the diagnosis of thrombus, prediction of recanalization using thrombus imaging, and practical considerations for the measurement of thrombus burden and density on CT.

Diagnostic value of clot burden score of susceptibility vessel sign in arterial thrombosis of acute ischemic stroke and its association with prognosis

Objective: To analysis the value of susceptibility vessel sign (SVS) in susceptibility weighted imaging (SWI) in detecting thrombogenesis in middle cerebral artery (MCA) and its association with clinical prognosis. Methods: From December 2014 to December 2015 in People's Hospital of Zhengzhou University, we retrospectively examined clinical, imaging and experimental datafrom 104 consecutive patients with acute ischemic strokeand compared the consistency of detecting thrombus between SWI and magnetic resonance angiography (MRA) using Kappa analysis. Clot Burden Score (CBS) was used to analysis extent and scope of thrombus. The association between CBS and clinical prognosiswere analyzed by Spearman rank correlation. Results: Mean age was 60 years old of the 104 patients with acute cerebral infarction and female accounted for 32%. There were 39 patients (37.5%) with SVS positive in SWI and 32 patients (30.8%) with both SVS positive and MRA occlusion or severe stenosis. The consistency in predicting arterial thrombosis of occlusion or severe stenosis between MRA and SVS in SWI was statistically significant (Kappa=0.502, P<0.001). There were 6 cases with SVS positive and none stenosis in MRA, and all the clots in this 6 case were located in distal artery. CBS was significantly associated with 3-month outcome (Spearman ρ =-0.472; P<0.001). Conclusion: SWI is superior to MRA for the detection of intracranial distal thrombus in patients with acute ischemic stroke of the MCA territory. Higher clot burden(lower CBS) could be an important clinical tool to estimate poor outcome in patients with acutecerebral infarction.

Clot Burden Score on Baseline Computerized Tomographic Angiography and Intra-Arterial Treatment Effect in Acute Ischemic Stroke.

A high clot burden score (CBS) is associated with favorable outcome after intravenous treatment for acute ischemic stroke. The added benefit of intra-arterial treatment might be less in these patients. The aim of this exploratory post hoc analysis was to assess the relation of CBS with neurological improvement and endovascular treatment effect. For 499 of 500 patients in the MR CLEAN study (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands), the CBS was determined. Ordinal logistic regression models with and without main baseline prognostic variables were used to assess the association between CBS (continuous or dichotomized at CBS of 6) and a shift toward better outcome on the modified Rankin Scale. The model without main baseline prognostic variables only included treatment allocation and CBS. Models with and without a multiplicative interaction term of CBS and treatment were compared using the χ2 test to assess treatment effect modification by CBS. Higher CBS was associated with a shift toward better outcome on the modified Rankin Scale; adjusted common odds ratio per point CBS was 1.12 (95% confidence interval, 1.04-1.20]. Dichotomized CBS had an adjusted common odds ratio of 1.67 (95% confidence interval, 1.12-2.51). Both effect estimates were slightly attenuated by adding baseline prognostic variables. The addition of the interaction terms did not significantly improve the fit of the models. There was a small and insignificant increase of intra-arterial treatment efficacy in the high CBS group. A higher CBS is associated with improved outcome and may be used as a prognostic marker. We found no evidence that CBS modifies the effect of intra-arterial treatment. URL: http://www.trialregister.nl. Unique identifier: NTR1804. URL: http://www.controlled-trials.com. Unique identifier: ISRCTN10888758.

Number needed to screen for acute revascularization trials in stroke: Prognostic and predictive imaging biomarkers.

Objective To systematically assess imaging biomarkers on CT-based multimodal imaging for their being predictive versus prognostic biomarkers for intravenous and endovascular (IA) revascularization therapy, and for their prevalence. Methods Our retrospective study included patients suspected of acute ischemic stroke with admission work-up including a non-contrast head CT, perfusion CT, and CT angiography. Modified Rankin scores at 90 days were used as outcomes. For each imaging biomarker, the effect size of the test of interaction between the presence of the biomarker and the treatment effect was calculated, allowing the inference of a total sample size. The total sample size required was combined with the prevalence of the biomarker to determine the number needed to screen. Results In the 0-4.5-h time window, the two predictive biomarkers associated with the smallest number needed to screen were perfusion CT penumbra ≥ 20% (404 NNS) and CT angiography collateral score ≥ 2 (581 NNS). In the 3-9-h time window, the four predictive biomarkers associated with the smallest number needed to screen were clot burden score (CBS) on CT angiography (1181 NNS), clot length ≥ 10 mm (1924 NNS), CBS and clot length ≥ 10 mm (1132 NNS), and CBS and perfusion CT penumbra ≥ 100% (1374 NNS). Perfusion CT ischemic core was a prognostic biomarker in both time windows. Interpretation Predictive biomarkers need to be differentiated from prognostic biomarkers when being considered to select patients for a trial, and their prevalence should be assessed to determine the number needed to screen and overall feasibility of the trials.

Association of clot burden score with radiographic and clinical outcomes following Solitaire stent retriever thrombectomy: analysis of the SWIFT PRIME trial

BackgroundThe clot burden score (CBS) was developed as a tool to evaluate the extent of intracranial thrombus burden in patients with anterior circulation acute ischemic stroke. CBS is based on...

Relation Among Clot Burden, Right-Sided Heart Strain, and Adverse Events After Acute Pulmonary Embolism

Computed tomography pulmonary angiogram (CTPA) provides a volumetric assessment of clot burden in acute pulmonary embolism (PE). However, it is unclear if clot burden is associated with right-sided heart strain (RHS) or adverse clinical events (ACE). We prospectively enrolled Emergency Department patients with PE (in CTPA) from 2008 to 2011. We assigned 1 to 9 points as clot burden score, based on whether emboli were saddle, central, lobar, segmental, and subsegmental. We evaluated a novel score (the "CT-PASS") based on the sum (in millimeters) of the largest filling defects in the right and left pulmonary vasculature. Our primary outcome was RHS, defined by imaging (echocardiography or CTPA) or cardiac biomarkers. Our secondary outcomes included 5-day ACE. We included 271 patients (50% women), with a mean age of 59 ± 17years. Based on CTPA, 131 patients (48%) had central PE (clot burden score ≥5 points). The median CT-PASS was 9.1mm (interquartile range 4.9 to 16.4). In univariate analysis, higher clot burden (highest quartile CT-PASS) was associated with RHS (p= 0.003). In multivariate analysis, after adjusting for RHS, age, and gender, central PE (odds ratio [OR] 2.92, 95% confidence interval [CI] 1.10 to 7.81) and CT-PASS >20mm (OR 3.54, 95% CI 1.39 to 8.97) were significantly associated with ACE. However, this association of central PE with ACE was not statistically significant after excluding patients with shock index >1 (OR 2.56, 95% CI 0.62 to 10.64). In conclusion, highest quartile CT-PASS was associated with RHS and central PE and ACE, but this association was not statistically significant in hemodynamically stable PE [corrected].

Role of atherosclerosis, clot extent, and penumbra volume in headache during ischemic stroke.

To investigate the role of large vessel atherosclerosis, blood clot extent, and penumbra volume in relation to headache in ischemic stroke patients. In this cross-sectional study, we performed noncontrast CT, CT angiography (CTA), and CT perfusion (CTP) in 284 participants from the Dutch Acute Stroke Study and Leiden Stroke Cohort within 9 hours after ischemic stroke onset. We collected headache characteristics prospectively using a semi-structured questionnaire. Atherosclerosis was assessed by evaluating presence of plaques in extracranial and intracranial vessels and by quantifying intracranial carotid artery calcifications. Clot extent was estimated by the clot burden score on CTA and penumbra volume by CTP. We calculated risk ratios (RRs) with adjustments (aRR) for possible confounders using multivariable Poisson regression. Headache during stroke was reported in 109/284 (38%) participants. Headache was less prevalent in patients with than in patients without atherosclerosis in the extracranial anterior circulation (35% vs 48%; RR 0.72; 95% confidence interval [CI] 0.54-0.97). Atherosclerosis in the intracranial arteries was also associated with less headache, but this association was not statistically significant. Penumbra volume (aRR 1.08; 95% CI 0.63-1.85) and clot extent (aRR 1.02; 95% CI 0.86-1.20) were not related with headache. Headache in the early phase of ischemic stroke tends to occur less often in patients with atherosclerosis than in patients without atherosclerosis in the large cerebral arteries. This finding lends support to the hypothesis that vessel wall elasticity is a necessary contributing factor in the occurrence of headache during acute ischemic stroke.

Intravenous Thrombolysis and Passes of Thrombectomy as Predictors for Endovascular Revascularization in Ischemic Stroke

Patient selection for endovascular revascularization treatment (ERT) in acute ischemic stroke depends on the expected benefit-risk ratio. As rapid revascularization is a major determinant of good functional outcome, we aimed to identify its predictors after ERT. Consecutive stroke patients from a single stroke center with distal internal carotid artery-, proximal middle cerebral artery- or T-occlusions treated with ERT were retrospectively selected. We assessed admission noncontrast computed tomography and computed tomography angiography for thrombus location, thrombus load (clot burden score), and collateral status. Clinical data were extracted from medical charts. Univariate and multivariate regression analyses were performed to identify predictors of revascularization (thrombolysis in cerebral infarction ≥2b) after ERT. A total of 63 patients were identified (median age, 73 years; interquartile range: 62-77; 40 females). Sixteen patients (25.4%) underwent intravenous thrombolysis (ivT) before ERT. Twenty-two patients (34.9%) had additional intra-arterial application of recombinant tissue plasminogen activator. The overall recanalization rate was 66.7%, and 9.5% had symptomatic intracranial bleeding. In-hospital mortality was 15%, and 30% reached good functional outcome at discharge. In the univariate analysis, preceding ivT and the number of passes for thrombectomy (dichotomized ≤2 versus >2) were associated with recanalization. There was a trend for number of thrombectomy passes (as continuous variable) and multimodal ERT. In the multivariate regression analysis, ivT prior to ERT and passes of thrombectomy were identified as independent predictors for recanalization. ivT and lower passes of thrombectomy are associated with recanalization after ERT for ischemic stroke with proximal vessel occlusions.

Collateral state and the effect of endovascular reperfusion therapy on clinical outcome in ischemic stroke patients.

PurposeClinically successful endovascular therapy (EVT) in ischemic stroke requires reliable noninvasive pretherapeutic selection criteria. We investigated the association of imaging parameters including CT angiographic collaterals and degree of reperfusion with clinical outcome after EVT.MethodsIn our database, we identified 93 patients with large vessel occlusion in the anterior circulation treated with EVT. Besides clinical data, we assessed the baseline Alberta Stroke Program Early CT score (ASPECTS) on noncontrast CT (NCCT) and CT angiography (CTA) source images, collaterals (CT‐CS) and clot burden score (CBS) on CTA and the degree of reperfusion after EVT on angiography. Three readers, blinded to clinical information, evaluated the images in consensus. Data‐driven multivariable ordinal regression analysis identified predictors of good outcome after 90 days as measured with the modified Rankin Scale.ResultsSuccessful angiographic reperfusion (OR 26.50; 95%‐CI 9.33–83.61) and good collaterals (OR 9.69; 95%‐CI 2.28–59.27) were independent predictors of favorable outcome along with female sex (OR 0.35; 95%‐CI 0.14–0.85), younger age (OR 0.88; 95%‐CI 0.83–0.92) and higher NCCT ASPECTS (OR 2.54; 95%‐CI 1.01–6.63). Outcome was best in patients with good collaterals and successful reperfusion, but there was no statistical interaction between collaterals and reperfusion.Conclusions CTA‐collateral status was the strongest pretherapeutic predictor of favorable outcome in ischemic stroke patients treated with EVT. CTA‐collaterals are thus well suited for patient selection in EVT. However, the independent effect of reperfusion on outcome tended to be stronger than that of CTA‐collaterals.

Factors associated with successful revascularization using the aspiration component of ADAPT in the treatment of acute ischemic stroke

IntroductionADAPT (a direct aspiration first pass technique) has been shown to be fast, cost-effective, and associated with excellent angiographic and clinical outcomes in the treatment of acute ischemic stroke (AIS).ObjectiveTo...

Clinical and radiological outcome after mechanical thrombectomy in acute ischemic stroke: What matters?

Recent studies have shown the efficacy of mechanical thrombectomy in acute ischemic stroke. We sought to identify prognostic parameters for clinical and radiological outcome after mechanical thrombectomy. In 34 patients (age 72 ± 13 years, 64.7% women) with acute occlusion of the distal ICA and/or M1 segment who were treated with mechanical thrombectomy, the Spearman correlation was performed to assess potential prognostic outcome parameters (age, NIHSS, ASPECT, thrombus length (TL), clot burden score (CBS), relative filling time delay (rFTD), time to recanalization (TTR) and TICI score). The modified Rankin scale (mRS) and the Alberta Stroke Program Early CT (ASPECT) score were used for clinical and radiological outcome, respectively. Receiver operating characteristic (ROC) analysis was performed to assess parameters predicting favorable clinical (ΔmRS ≤ 2) and radiological outcome (ΔASPECT ≤ 2). Variables associated with favorable clinical outcome included NIHSS, TL, TTR and TICI score (p ≤ 0.01) with NIHSS ≤ 15 (p = 0.001, area under the curve (AUC) 0.87), TL ≤ 2 cm (p = 0.017, AUC 0.75), TTR ≤ 231 min (p = 0.001 AUC 0.88) and TICI ≥ 2b (p = 0.050, AUC 0.70). Shorter TTR and higher TICI scores were associated with favorable radiological outcome (p < 0.001) with TTR ≤ 224 min (p = 0.023, AUC 0.77) and TICI ≥ 2b (p = 0.000, AUC 0.86). Fast and complete recanalization is essential to achieve a favorable radiological and functional outcome after mechanical thrombectomy in acute ischemic stroke. Age, CBS and collateral supply play a subordinate role.

Abstract WP29: Clot Size: Speaking the Same Language in Endovascular Stroke Therapy Across the Globe

Background: Clot size in acute ischemic stroke has been ascribed to time from onset, used in imaging selection with varying techniques or definitions, and cited as a factor in both revascularization success and clinical outcomes. We analyzed clot size on noncontrast CT, CT angiography (CTA) and digital subtraction angiography (DSA) in the multicenter TREVO and TREVO 2 trials. Methods: Imaging core labs of the TREVO and TREVO 2 trials conducted pooled analyses of the CT/CTA and DSA datasets. Clot size was independently measured by hyperdense middle cerebral artery sign (HMCAS) length on noncontrast CT thin-slice reconstruction, CTA length, clot burden score (CBS) and DSA prior to thrombectomy. Statistical analyses included descriptive statistics and correlation analyses among clot size measures, and time from onset to CT or onset to DSA. Logistic regression analysis was used to model 90-day good outcome and revascularization success. Results: 116 TREVO and TREVO 2 subjects from the pooled imaging dataset were analyzed with respect to clot size. Clot size estimated from thin-slice reconstruction of HMCAS was mean 7.6±9.2 mm, however, 41% of cases with proven arterial occlusion did not have HMCAS. CTA length of clots was mean 12.3±7.3 mm, with corresponding HMCAS CTA length in 41%. CBS (range 0-10) was mean 6.7±1.8. DSA clot length was mean 10.6±5.7 mm. Moderate correlations were noted between clot size on CT, CTA and DSA. Time from onset to CT or onset to DSA was unrelated to any clot size, yet worse ASPECTS scores were linked with larger clots (HMCAS length, ρ=-0.290, p=0.004; CTA length, ρ=-0.302, p=0.009). Revascularization success (TICI≥2B) was lower with CTA clot length &gt; 8 mm (OR 0.32 [0.11, 0.99], p=0.047) when distal opacification via collaterals was present, yet unrelated to any HMCAS clot length. Good clinical outcome (mRS 0-2 at 90 days) was unrelated to any measure of clot size. Conclusions: Clot size varies depending on imaging technique and definitions, with a substantial proportion of occlusions that cannot be measured on either noncontrast CT or CTA and “time is clot” requires further study. Larger clots are associated with worse ASPECTS, possibly negating potential clinical benefit of successful revascularization.

Effect of Collaterals on Clinical Presentation, Baseline Imaging, Complications, and Outcome in Acute Stroke.

Good CTA collaterals independently predict good outcome in acute ischemic stroke. Our aim was to evaluate the role of collateral circulation and its added benefit over CTP-derived total ischemic volume as a predictor of baseline NIHSS score, total ischemic volume, hemorrhagic transformation, final infarct size, and a modified Rankin Scale score >2. This was a retrospective study of 395 patients with stroke dichotomized by recanalization (recanalization positive/recanalization negative) and collateral status. Clot burden score was quantified on baseline CTA. Total ischemic volumes were derived from thresholded CTP maps. Final infarct size was assessed on follow-up CT/MRI. We performed uni-/multivariate analyses for each outcome, adjusting for rtPA status, using general linear (continuous variables) and logistic (binary variables) regression. Model comparison with collateral score and total ischemic volume was performed using the F or likelihood ratio test. Collateral presence independently and inversely predicted all outcomes except hemorrhagic transformation in patients who were recanalization negative and mRS >2 in patients who were recanalization positive. The greatest collateral benefit occurred in patients who were recanalization negative, contributing 16.5% and 19.2% of the variability for final infarct size and mRS >2. The collateral score model is superior to the total ischemic volume for mRS >2 prediction, but a combination of total ischemic volume and collateral score is superior for mRS >2 and final infarct prediction (24% and 28% variability, respectively). In patients who were recanalization positive, a model including collateral score and total ischemic volume was superior to that of total ischemic volume for hemorrhagic transformation and final infarct prediction but was muted compared with patients who were recanalization negative (11.3% and 16.9% variability). Collateral circulation is an independent predictor of all outcomes, but the magnitude of significance varies, greater in patients who were recanalization negative versus recanalization positive. Total ischemic volume assessment is complementary to collateral score in many cases.

Association of intitial clot burden score with recanalization and clinical outcome after mechanical thrombectomy for acute ischemic stroke

Association of intitial clot burden score with recanalization and clinical outcome after mechanical thrombectomy for acute ischemic stroke

Performance and Predictive Value of a User-Independent Platform for CT Perfusion Analysis: Threshold-Derived Automated Systems Outperform Examiner-Driven Approaches in Outcome Prediction of Acute Ischemic Stroke.

Treatment strategies in acute ischemic stroke aim to curtail ischemic progression. Emerging paradigms propose patient subselection using imaging biomarkers derived from CT, CTA, and CT perfusion. We evaluated the performance of a fully-automated computational tool, hypothesizing enhancements compared with qualitative approaches. The correlation between imaging variables and clinical outcomes in a cohort of patients with acute ischemic stroke is reported. Sixty-two patients with acute ischemic stroke and MCA or ICA occlusion undergoing multidetector CT, CTA, and CTP were retrospectively evaluated. CTP was processed on a fully operator-independent platform (RApid processing of PerfusIon and Diffusion [RAPID]) computing automated core estimates based on relative cerebral blood flow and relative cerebral blood volume and hypoperfused tissue volumes at varying thresholds of time-to-maximum. Qualitative analysis was assigned by 2 independent reviewers for each variable, including CT-ASPECTS, CBV-ASPECTS, CBF-ASPECTS, CTA collateral score, and CTA clot burden score. Performance as predictors of favorable clinical outcome and final infarct volume was established for each variable. Both RAPID core estimates, CT-ASPECTS, CBV-ASPECTS, and clot burden score correlated with favorable clinical outcome (P < .05); CBF-ASPECTS and collateral score were not significantly associated with favorable outcome, while hypoperfusion estimates were variably associated, depending on the selected time-to-maximum thresholds. Receiver operating characteristic analysis demonstrated disparities among tested variables, with RAPID core and hypoperfusion estimates outperforming all qualitative approaches (area under the curve, relative CBV = 0.86, relative CBF = 0.81; P < .001). Qualitative approaches to acute ischemic stroke imaging are subject to limitations due to their subjective nature and lack of physiologic information. These findings support the benefits of high-speed automated analysis, outperforming conventional methodologies while limiting delays in clinical management.

Clot Characteristics on Computed Tomography and Response to Thrombolysis in Acute Middle Cerebral Artery Stroke

Clinical and computer tomography angiography (CTA) correlates of hyperdense middle cerebral artery sign (HMCAS) and dot sign were revisited in patients treated for acute MCA stroke. Temporal evolution of these signs over 24hours was assessed quantitatively by density (Hounsfield unit [HU]) measurements. Maximum pixel-sized HUs throughout proximal MCA and its insular fissure branches were determined in 131 patients with acute MCA stroke treated by intravenous thrombolysis and/or interventional thrombolysis/thrombectomy; 14 patients treated for vertebrobasilar stroke (VBS) and 42 nonstroke control subjects. Utility of visually determined HMCAS and dot sign, absolute HU of proximal and distal MCA, side-to-side HU ratio and difference, and hyperdense MCA burden score for the prediction of early dramatic recovery (EDR) and third-month favorable prognosis were evaluated. The clinical value of the changes in vessel hyperdensity over 24hours was identified in subjects who received intravenous thrombolysis (99 MCA stoke and 11 VBS). A multivariate model with adjustment for age, baseline stroke severity (National Institutes of Health Stroke Scale [NIHSS]), and CTA-based modified clot burden score (mCBS) was used to determine independent predictors of short- and long-term clinical outcome. The presence of HMCAS and dot sign, their density indices (maximum HU, ipsilateral-to-contralateral HU ratio, and difference), and changes in quantitative attenuation over 24hours were not significantly associated with EDR and favorable third-month outcome in the multiple regression models, whereas NIHSS and mCBS were found to be significant independent "negative predictors" of both EDR and favorable prognosis, while age was a strong "negative indicator" only for 3-month good outcome. Average HU decrease over the first day was 5.7 HU in HMCAS (+) and 2.9 HU in dot sign (+) arteries. The densities of thrombi in MCA and insular branches were not different in subjects with and without cardioembolism. CTA provides dependable (high sensitivity and specificity) information regarding clot size and location, whereas hyperdense artery signs have low sensitivity and just acceptable specificity levels in this regard. However, the prognostic and diagnostic information generated by the presence of hyperdense artery signs and temporal change in attenuation can be useful in acute stroke settings where CTA is not readily available. Quantitative measures, rather than qualitative evaluation have a higher yield in determination of temporal change of the hyperdensity signs and its possible clinical correlates.

Abstract W P18: Evaluating Clot Burden and the Vascular Basis of Pial Collaterals with a Bimodal Angiographic Score

Treatment decision for endovascular recanalization in acute ischemic stroke is based on validated outcome predictors such as age, initial infarct size, collaterals and clot burden. The CTA-based Clot Burden Score (CBS) only considers occlusions of the A1-segment of the anterior cerebral artery (ACA), but patency of the ipsilateral A2-segment is mandatory for collateral formation in a typical middle cerebral artery (MCA) occlusion. Secondly, CTA often cannot differentiate between an extra- or intra-cranial internal carotid artery (ICA) occlusion due to non-contrasting of the whole ICA in both. Thirdly, a 4-vessel angiogram, necessary to grasp the vascular basis of all pial collaterals, is often not done during acute recanalization therapy for reasons of time. To bypass these inadequacies, we propose a combined CTA/DSA score (ALITA) to assess pre-therapeutic thrombus load. We hypothesized a good outcome prediction of this score. We evaluated the ALITA score in a retrospective study including consecutive patients of the years 2010-12, who received endovascular therapy for acute stroke in the ICA-territory. Final outcome was measured with the modified Rankin Scale score (mRS) at 90 days. Reperfusion (mTICI), collaterals (CT-CS), clot burden (CBS), and the ALITA score were independently assessed. ALITA evaluates patency of the ACA and MCA in CTA and of the ICA in DSA. Data-driven ordinal regression analysis modeled outcome prediction of all scores. Of 99 patients 60% had a good reperfusion (mTICI 2b/3) and 29% had a good outcome (mRS 0-2), mortality was 23%. Age and reperfusion were independent predictors of good outcome (p&lt;.001). CT-CS (p&lt;.01), CBS (p&lt;.01) and ALITA (p&lt;.05) were significant predictors, but showed interaction regarding outcome. In the considered model CBS was a stronger predictor than ALITA. Although ALITA assesses all vessels of the anterior circulation contributing to collaterals the score was statistically different from CT-CS. This is consistent with results that describe pial collaterals as genetically determined. In conclusion, the combined CTA/DSA clot burden score better depicts the vascular basis of pial collaterals and predicts outcome in acute stroke patients.

Contribution and additional impact of imaging to the SPAN-100 score.

Stroke Prognostication by Using Age and NIHSS score (SPAN-100 index) facilitates stroke outcomes. We assessed imaging markers associated with the SPAN-100 index and their additional impact on outcome determination. Of 273 consecutive patients with acute ischemic stroke (<4.5 hours), 55 were characterized as SPAN-100-positive (age +NIHSS score ≥ 100). A comprehensive imaging review evaluated differences, using the presence of the hyperattenuated vessel sign, ASPECTS, clot burden score, collateral score, CBV, CBF, and MTT. The primary outcome assessed was favorable outcome (mRS ≤ 2). Secondary outcomes included recanalization, lack of neurologic improvement, and hemorrhagic transformation. Uni- and multivariate analyses assessed factors associated with favorable outcome. Area under the curve evaluated predictors of favorable clinical outcome. Compared with the SPAN-100-negative group, the SPAN-100-positive group (55/273; 20%) demonstrated larger CBVs (<0.001), poorer collaterals (P < .001), and increased hemorrhagic transformation rates (56.0% versus 36%, P = .02) despite earlier time to rtPA (P = .03). Favorable outcome was less common among patients with SPAN-100-positive compared with SPAN-100-negative (10.9% versus 42.2%; P < .001). Multivariate regression revealed poorer outcome for SPAN-100-positive (OR = 0.17; 95% CI, 0.06-0.38; P = .001), clot burden score (OR = 1.14; 95% CI, 1.05-1.25; P < .001), and CBV (OR = 0.58; 95% CI, 0.46-0.72; P = .001). The addition of the clot burden score and CBV improved the predictive value of SPAN-100 alone for favorable outcome from 60% to 68% and 74%, respectively. SPAN-100-positivity predicts a lower likelihood of favorable outcome and increased hemorrhagic transformation. CBV and clot burden score contribute to poorer outcomes among high-risk patients and improve stroke-outcome prediction.