Imaging Review of Pediatric Monogenic CNS Vasculopathy with Genetic Correlation.

Monogenic cerebral vasculopathy is a rare but progressively recognizable cause of pediatric cerebral vasculopathy manifesting as early as fetal life. These monogenic cerebral vasculopathies can be silent or manifest variably as fetal or neonatal distress, neurologic deficit, developmental delay, cerebral palsy, seizures, or stroke. The radiologic findings can be nonspecific, but the presence of disease-specific cerebral and extracerebral imaging features can point to a diagnosis and guide genetic testing, allowing targeted treatment. The authors review the existing literature describing the frequently encountered and rare monogenic cerebral vascular disorders affecting young patients and describe the relevant pathogenesis, with an attempt to categorize them based on the defective step in vascular homeostasis and/or signaling pathways and characteristic cerebrovascular imaging findings. The authors also highlight the role of imaging and a dedicated imaging protocol in identification of distinct cerebral and extracerebral findings crucial in the diagnostic algorithm and selection of genetic testing. Early and precise recognition of these entities allows timely intervention, preventing or delaying complications and thereby improving quality of life. It is also imperative to identify the specific pathogenic variant and pattern of inheritance for satisfactory genetic counseling and care of at-risk family members. Last, the authors present an image-based approach to these young-onset monogenic cerebral vasculopathies that is guided by the size and predominant radiologic characteristics of the affected vessel with reasonable overlap. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Influence of Time of Admission on Endovascular Thrombectomy (EVT): Comparison of Outcomes During Business Hours Versus Off-Business Hours.

Purpose:To investigate the differences in endovascular thrombectomy (EVT) outcomes of patients treated for acute ischaemic stroke (AIS) during business versus off-business hours. Methods: A single-centre retrospective cohort study of patients with AIS treated with EVT from February 1, 2015, to May 31, 2021, was performed at a comprehensive stroke centre (CSC). Patients were divided into business (Monday to Friday, 8 AM-5 PM) versus off-business hours groups. The primary outcome was functional neurological disability, scored using the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included the rate of successful reperfusion and procedural workflow time delays. Differences in proportions were assessed using Fisher's exact and Chi-Square tests as appropriate. For continuous variables, differences in medians between groups were assessed using Mann-Whitney U tests. Results: A total of 676 patients were included, with 399 patients (59%) comprising the off-business-hour group. No significant differences were seen in age, sex, ASPECTS score, or NIHSS at arrival. Off-business hours strokes had a longer delay between CSC arrival to groin puncture (minutes: 81 vs 44, P < .0001) and between imaging to groin puncture (minutes: 67 vs 32, P < .0001) compared to the business hours strokes. There were no differences in the rate of successful reperfusion (mTICI ≥2b) between groups (82% vs 83%, P = .61). At 90 days, 65% of patients in both groups had an mRS ≤2 (P = .91). Conclusion: Despite workflow delays in initiating EVT during off-business hours, there were no differences in the rate of successful reperfusion or functional outcomes.

Time Course of Early Hematoma Expansion in Acute Spot-Sign Positive Intracerebral Hemorrhage: Prespecified Analysis of the SPOTLIGHT Randomized Clinical Trial.

BACKGROUND: In the SPOTLIGHT trial (Spot Sign Selection of Intracerebral Hemorrhage to Guide Hemostatic Therapy), patients with a computed tomography (CT) angiography spot-sign positive acute intracerebral hemorrhage were randomized to rFVIIa (recombinant activated factor VIIa; 80 µg/kg) or placebo within 6 hours of onset, aiming to limit hematoma expansion. Administration of rFVIIa did not significantly reduce hematoma expansion. In this prespecified analysis, we aimed to investigate the impact of delays from baseline imaging to study drug administration on hematoma expansion. METHODS: Hematoma volumes were measured on the baseline CT, early post-dose CT, and 24 hours CT scans. Total hematoma volume (intracerebral hemorrhage+intraventricular hemorrhage) change between the 3 scans was calculated as an estimate of how much hematoma expansion occurred before and after studying drug administration. RESULTS: Of the 50 patients included in the trial, 44 had an early post-dose CT scan. Median time (interquartile range) from onset to baseline CT was 1.4 hours (1.2-2.6). Median time from baseline CT to study drug was 62.5 (55-80) minutes, and from study drug to early post-dose CT was 19 (14.5-30) minutes. Median (interquartile range) total hematoma volume increased from baseline CT to early post-dose CT by 10.0 mL (-0.7 to 18.5) in the rFVIIa arm and 5.4 mL (1.8-8.3) in the placebo arm (P=0.96). Median volume change between the early post-dose CT and follow-up scan was 0.6 mL (-2.6 to 8.3) in the rFVIIa arm and 0.7 mL (-1.6 to 2.1) in the placebo arm (P=0.98). Total hematoma volume decreased between the early post-dose CT and 24-hour scan in 44.2% of cases (rFVIIa 38.9% and placebo 48%). The adjusted hematoma growth in volume immediately post dose for FVIIa was 0.998 times that of placebo ([95% CI, 0.71-1.43]; P=0.99). The hourly growth in FFVIIa was 0.998 times that for placebo ([95% CI, 0.994-1.003]; P=0.50; Table 3). CONCLUSIONS: In the SPOTLIGHT trial, the adjusted hematoma volume growth was not associated with Factor VIIa treatment. Most hematoma expansion occurred between the baseline CT and the early post-dose CT, limiting any potential treatment effect of hemostatic therapy. Future hemostatic trials must treat intracerebral hemorrhage patients earlier from onset, with minimal delay between baseline CT and drug administration. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01359202.

Clinical Features, Non-Contrast CT Radiomic and Radiological Signs in Models for the Prediction of Hematoma Expansion in Intracerebral Hemorrhage.

PURPOSE: Rapid identification of hematoma expansion (HE) risk at baseline is a priority in intracerebral hemorrhage (ICH) patients and may impact clinical decision making. Predictive scores using clinical features and Non-Contract Computed Tomography (NCCT)-based features exist, however, the extent to which each feature set contributes to identification is limited. This paper aims to investigate the relative value of clinical, radiological, and radiomics features in HE prediction. METHODS: Original data was retrospectively obtained from three major prospective clinical trials ["Spot Sign" Selection of Intracerebral Hemorrhage to Guide Hemostatic Therapy (SPOTLIGHT)NCT01359202; The Spot Sign for Predicting and Treating ICH Growth Study (STOP-IT)NCT00810888] Patients baseline and follow-up scans following ICH were included. Clinical, NCCT radiological, and radiomics features were extracted, and multivariate modeling was conducted on each feature set. RESULTS: 317 patients from 38 sites met inclusion criteria. Warfarin use (p=0.001) and GCS score (p=0.046) were significant clinical predictors of HE. The best performing model for HE prediction included clinical, radiological, and radiomic features with an area under the curve (AUC) of 87.7%. NCCT radiological features improved upon clinical benchmark model AUC by 6.5% and a clinical & radiomic combination model by 6.4%. Addition of radiomics features improved goodness of fit of both clinical (p=0.012) and clinical & NCCT radiological (p=0.007) models, with marginal improvements on AUC. Inclusion of NCCT radiological signs was best for ruling out HE whereas the radiomic features were best for ruling in HE. CONCLUSION: NCCT-based radiological and radiomics features can improve HE prediction when added to clinical features.

Rule-based natural language processing for automation of stroke data extraction: a validation study.

PURPOSE: Data extraction from radiology free-text reports is time consuming when performed manually. Recently, more automated extraction methods using natural language processing (NLP) are proposed. A previously developed rule-based NLP algorithm showed promise in its ability to extract stroke-related data from radiology reports. We aimed to externally validate the accuracy of CHARTextract, a rule-based NLP algorithm, to extract stroke-related data from free-text radiology reports. METHODS: Free-text reports of CT angiography (CTA) and perfusion (CTP) studies of consecutive patients with acute ischemic stroke admitted to a regional stroke center for endovascular thrombectomy were analyzed from January 2015 to 2021. Stroke-related variables were manually extracted as reference standard from clinical reports, including proximal and distal anterior circulation occlusion, posterior circulation occlusion, presence of ischemia or hemorrhage, Alberta stroke program early CT score (ASPECTS), and collateral status. These variables were simultaneously extracted using a rule-based NLP algorithm. The NLP algorithm's accuracy, specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were assessed. RESULTS: The NLP algorithm's accuracy was > 90% for identifying distal anterior occlusion, posterior circulation occlusion, hemorrhage, and ASPECTS. Accuracy was 85%, 74%, and 79% for proximal anterior circulation occlusion, presence of ischemia, and collateral status respectively. The algorithm confirmed the absence of variables from radiology reports with an 87-100% accuracy. CONCLUSIONS: Rule-based NLP has a moderate to good performance for stroke-related data extraction from free-text imaging reports. The algorithm's accuracy was affected by inconsistent report styles and lexicon among reporting radiologists.

Intraoperative imaging reveals spot sign with surgical correlate during early endoscopic ICH evacuation.

Intracerebral hemorrhage (ICH) is the most devastating form of stroke. Intraoperative imaging and management of intracavity bleeding during early endoscopic ICH evacuation may mitigate rebleeding, hematoma expansion, and neurological worsening. Here we document a case of intraoperative spot sign, detected in the angio suite using cone beam CT with contrast protocol, in a patient with spontaneous supratentorial ICH undergoing evacuation 13 hours after last known well. The spot sign was detected after endoscopic evaluation of the evacuated hematoma cavity demonstrated sufficient hemostasis, but before completion of the case and skin closure, prompting second-pass hematoma evacuation as well as identification and cauterization of the specific correlating bleeding vessel, resulting in near-complete evacuation of the hematoma. Spot sign detection on intraoperative cone beam CT followed by endoscopic ICH evacuation may provide an opportunity to specifically target and treat active bleeding and mitigate impending expansion and neurologic worsening, especially in high-risk patients, including those undergoing early ICH evacuation.

Imaging for Predicting Hemorrhagic Transformation of Acute Ischemic Stroke-A Narrative Review.

Hemorrhagic transformation is caused by extravasation of blood products from vessels after acute ischemic stroke. It is an undesirable and potentially devastating complication, which occurs in 10%-40% of clinical cases. Hemorrhagic transformation is classified into four subtypes based on European cooperative acute stroke study II. Predicting hemorrhagic complications at presentation can be useful life saving/altering decisions for the patient. Also, understanding the mechanisms of hemorrhagic transformation can lead to new treatments and intervention measures. We highlighted various imaging techniques that have been used to predict hemorrhagic transformation. Specifically, we looked at the usefulness of perfusion and permeability imaging for hemorrhagic transformation. Use of imaging to predict hemorrhagic transformation could change patient management that may lead to the prevention of hemorrhagic transformation before it occurs. We concluded that the current evidence is not strong enough to rely on these imaging parameters for predicting hemorrhagic transformation and more studies are required.

Permeability Measures Predict Hemorrhagic Transformation after Ischemic Stroke.

OBJECTIVE: We sought to examine the diagnostic utility of existing predictors of any hemorrhagic transformation (HT) and compare them with new perfusion imaging permeability measures in ischemic stroke patients receiving alteplase only. METHODS: A pixel-based analysis of pretreatment CT perfusion (CTP) was undertaken to define the optimal CTP permeability thresholds to predict the likelihood of HT. We then compared previously proposed predictors of HT using regression analyses and receiver operating characteristic curve analysis to produce an area under the curve (AUC). We compared AUCs using χ2 analysis. RESULTS: From 5 centers, 1,407 patients were included in this study; of these, 282 had HT. The cohort was split into a derivation cohort (1,025, 70% patients) and a validation cohort (382 patients or 30%). The extraction fraction (E) permeability map at a threshold of 30% relative to contralateral had the highest AUC at predicting any HT (derivation AUC 0.85, 95% confidence interval [CI], 0.79-0.91; validation AUC 0.84, 95% CI 0.77-0.91). The AUC improved when permeability was assessed within the acute perfusion lesion for the E maps at a threshold of 30% (derivation AUC 0.91, 95% CI 0.86-0.95; validation AUC 0.89, 95% CI 0.86-0.95). Previously proposed associations with HT and parenchymal hematoma showed lower AUC values than the permeability measure. INTERPRETATION: In this large multicenter study, we have validated a highly accurate measure of HT prediction. This measure might be useful in clinical practice to predict hemorrhagic transformation in ischemic stroke patients before receiving alteplase alone. ANN NEUROL 2020;88:466-476.

Controversies in Imaging of Patients With Acute Ischemic Stroke: AJR Expert Panel Narrative Review.

The development of reperfusion therapies has profoundly impacted stroke care, initially with the advent of IV thrombolytic treatment and, more recently, with the development and refinement of endovascular treatment (EVT). Progress in neuroim-aging has supported the paradigm shift of stroke care, and advanced neuroimaging now has a fundamental role in triaging patients for both IV thrombolytic treatment and EVT. As the standard of care for acute ischemic stroke (AIS) evolves, controversies remain in certain clinical scenarios. This article explores the use of multimodality imaging for treatment selection of patients with AIS in the context of recent guidelines, highlighting controversial topics and providing guidance for clinical practice. The results of major randomized trials supporting EVT are reviewed. The advantages and disadvantages of CT, CTA, MRI, and MRA in stroke diagnosis are summarized with attention to level 1 evidence supporting the role of vascular imaging and perfusion imaging. Patient selection is compared between approaches based on time thresholds and physiologic approaches based on infarct core measurement using imaging. Moreover, various imaging approaches to core measurement are described. As ongoing studies push treatment boundaries, advanced imaging is expected to help identify a widening range of patients who may benefit from therapy.

Near-occlusion is difficult to diagnose with common carotid ultrasound methods.

PURPOSE: To assess the sensitivity and specificity of common carotid ultrasound method for carotid near-occlusion diagnosis. METHODS: Five hundred forty-eight patients examined with both ultrasound and CTA within 30 days of each other were analyzed. CTA graded by near-occlusion experts was used as reference standard. Low flow velocity, unusual findings, and commonly used flow velocity parameters were analyzed. RESULTS: One hundred three near-occlusions, 272 conventional ≥50% stenosis, 162 <50% stenosis, and 11 occlusions were included. Carotid ultrasound was 22% (95%CI 14-30%; 23/103) sensitive and 99% (95%CI 99-100%; 442/445) specific for near-occlusion diagnosis. Near-occlusions overlooked on ultrasound were found misdiagnosed as occlusions (n = 13, 13%), conventional ≥50% stenosis (n = 65, 63%) and < 50% stenosis (n = 2, 2%). No velocity parameter or combination of parameters could identify the 65 near-occlusions mistaken for conventional ≥50% stenoses with >75% sensitivity and specificity. CONCLUSION: Near-occlusion is difficult to diagnose with commonly used carotid ultrasound methods. Improved carotid ultrasound methods are needed if ultrasound is to retain its position as sole preoperative modality.

Original and Modified Graeb Score Correlation With Intraventricular Hemorrhage and Clinical Outcome Prediction in Hyperacute Intracranial Hemorrhage.

Background and Purpose- The Graeb score is a visual rating scale of intraventricular hemorrhage (IVH) on noncontrast head CT. Little data exist in the hyperacute (<6 hour) period for reliability and predictive value of the modified Graeb Score (mGS) or the original Graeb Score (oGS) for clinical outcomes or their correlation with quantitative IVH volumes. Methods- A retrospective analysis of multicenter prospective intracranial hemorrhage study was performed. oGS and mGS inter-observer agreement and IVH volume correlation on the baseline noncontrast head CT were calculated by intraclass correlation coefficient and Pearson coefficient respectively. Predictors of poor outcome (modified Rankin Scale scores ≥4) at 3 months were identified using a backward stepwise selection multivariable analysis. oGS and mGS performance for modified Rankin Scale scores ≥4 was determined by receiver operating characteristic analysis. Results- One hundred forty-one patients (65±12 years) with median (interquartile range) time to CT of 82.5 (70.3-157.5) minutes were included. IVH was observed in 43 (30%) patients. Inter-observer agreement was excellent for both oGS (intraclass correlation coefficient, 0.90 [95% CI, 0.80-0.95]) and mGS (intraclass correlation coefficient, 0.97 [95% CI, 0.84-0.99]). mGS (R=0.79; P<0.01) correlated better than oGS (R=0.71; P<0.01) with IVH volumes (P=0.02). Models of thresholded oGS and mGS were not different from a model of planimetric baseline intracranial hemorrhage and IVH volume for poor outcome prediction. Area under the curves were 0.70, 0.73, and 0.72, respectively. Conclusions- Excellent correlation for oGS and mGS with IVH volume was seen. Thresholded oGS and mGS are reasonable surrogates for planimetric IVH volume for hyperacute intracranial hemorrhage studies.

Calculation of Prognostic Scores, Using Delayed Imaging, Outperforms Baseline Assessments in Acute Intracerebral Hemorrhage.

Background and Purpose- Patients with intracerebral hemorrhage (ICH) are often subject to rapid deterioration due to hematoma expansion. Current prognostic scores are largely based on the assessment of baseline radiographic characteristics and do not account for subsequent changes. We propose that calculation of prognostic scores using delayed imaging will have better predictive values for long-term mortality compared with baseline assessments. Methods- We analyzed prospectively collected data from the multicenter PREDICT study (Prediction of Hematoma Growth and Outcome in Patients With Intracerebral Hemorrhage Using the CT-Angiography Spot Sign). We calculated the ICH Score, Functional Outcome in Patients With Primary Intracerebral Hemorrhage (FUNC) Score, and modified ICH Score using imaging data at initial presentation and at 24 hours. The primary outcome was mortality at 90 days. We generated receiver operating characteristic curves for all 3 scores, both at baseline and at 24 hours, and assessed predictive accuracy for 90-day mortality with their respective area under the curve. Competing curves were assessed with nonparametric methods. Results- The analysis included 280 patients, with a 90-day mortality rate of 25.4%. All 3 prognostic scores calculated using 24-hour imaging were more predictive of mortality as compared with baseline: the area under the curve was 0.82 at 24 hours (95% CI, 0.76-0.87) compared with 0.78 at baseline (95% CI, 0.72-0.84) for ICH Score, 0.84 at 24 hours (95% CI, 0.79-0.89) compared with 0.76 at baseline (95% CI, 0.70-0.83) for FUNC, and 0.82 at 24 hours (95% CI, 0.76-0.88) compared with 0.74 at baseline (95% CI, 0.67-0.81) for modified ICH Score. Conclusions- Calculation of the ICH Score, FUNC Score, and modified ICH Score using 24-hour imaging demonstrated better prognostic value in predicting 90-day mortality compared with those calculated at presentation.

Redefining Hematoma Expansion With the Inclusion of Intraventricular Hemorrhage Growth.

Background and Purpose- Definitions of significant hematoma expansion traditionally focus on changes in intraparenchymal volume. The presence of intraventricular hemorrhage (IVH) is a predictor of poor outcome, but current definitions of hematoma expansion do not include IVH expansion. We evaluated whether including IVH expansion to current definitions of hematoma expansion improves the ability to predict 90-day outcome. Methods- Using data from the PREDICT-ICH study (Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT), we compared a standard definition of hematoma expansion (≥6 mL or ≥33%) to revised definitions that includes new IVH development or expansion (≥6 mL or ≥33% or any IVH; ≥6 mL or ≥33% or IVH expansion ≥1 mL). The primary outcome was poor clinical outcome (modified Rankin Scale score, 4-6) at 90 days. Diagnostic accuracy measures were calculated for each definition, and C statistics for each definition were compared using nonparametric methods. Results- Of the 256 patients eligible for primary analysis, 127 (49.6%) had a modified Rankin Scale score of 4 to 6. Sensitivity and specificity for the standard definition (n=80) were 45.7% (95% CI, 36.8-54.7) and 82.9% (95% CI, 75.3-88.9), respectively. The revised definition, ≥6 mL or ≥33% or any IVH (n=113), possessed a sensitivity of 63.8% (95% CI, 54.8-72.1) and specificity of 75.2% (95% CI, 66.8-82.4). Overall accuracy was significantly improved with the revised definition (P=0.013) and after adjusting for relevant covariates, was associated with a 2.55-fold increased odds (95% CI, 1.31-4.94) of poor outcome at 90 days. A second revised definition, ≥6 mL or ≥33% or IVH expansion ≥1 mL, performed similarly (sensitivity, 56.7% [95% CI, 47.6-65.5]; specificity, 78.3% [95% CI, 40.2-85.1]; aOR, 2.40 [95% CI, 1.23-4.69]). Conclusions- In patients with mild-to-moderate ICH, including IVH expansion to the definition of hematoma expansion improves sensitivity with only minimal decreases to specificity and improves overall prediction of 90-day outcome.

Standards for Detecting, Interpreting, and Reporting Noncontrast Computed Tomographic Markers of Intracerebral Hemorrhage Expansion.

Significant hematoma expansion (HE) affects one-fifth of people within 24 hours after acute intracerebral hemorrhage (ICH), and its prevention is an appealing treatment target. Although the computed tomography (CT)-angiography spot sign predicts HE, only a minority of ICH patients receive contrast injection. Conversely, noncontrast CT (NCCT) is used to diagnose nearly all ICH, so NCCT markers represent a widely available alternative for prediction of HE. However, different NCCT signs describe similar features, with lack of consensus on the optimal image acquisition protocol, assessment, terminology, and diagnostic criteria. In this review, we propose practical guidelines for detecting, interpreting, and reporting NCCT predictors of HE. ANN NEUROL 2019;86:480-492.

Carotid near-occlusion is often overlooked when CT angiography is assessed in routine practice.

OBJECTIVE: Assess the sensitivity and specificity of computed tomography angiography (CTA) for carotid near-occlusion diagnosis interpreted in clinical practice against expert assessment. METHODS: CTAs were graded by two expert interpreters for near-occlusion. Findings were compared with clinical reports in 383 consecutive cases with symptomatic ≥ 50% carotid stenosis. In addition, 14 selected CTA exams (8 near-occlusions and 6 controls) were analyzed in a national effort by 13 radiologists experienced with carotid CTA. RESULTS: In clinical practice, imaging reports were 20% (95% CI 12-28%) sensitive for near-occlusion, ranging 0-58% between different radiologists; specificity was 99%. Among the 13 radiologists reviewing the same 8 near-occlusions, the average sensitivity was 8%, ranging 0-75%; specificity was 100%. CONCLUSIONS: Carotid near-occlusion is systematically under-reported in clinical routine practice, caused by limited application of grading criteria when assessing CTA. KEY POINTS: • Carotid near-occlusion is severe stenosis with distal artery collapse; this collapse is often subtle. • A fifth of near-occlusions were detected in routine practice. Many readers mistake near-occlusion for stenosis without distal artery collapse, either by not actively searching for subtle collapses or by not interpreting the collapse correctly when noticed. • On the other hand, the novice diagnostician should be cautioned to not over-diagnose near-occlusion; other causes of extracranial ICA asymmetry also exist such as distal disease and Circle of Willis anatomical variants.

Atherosclerotic ICA stenosis coinciding with ICA asymmetry associated with Circle of Willis variations can mimic near-occlusion.

Differentiating carotid near-occlusion (tight atherosclerotic stenosis causing distal artery size reduction) from conventional stenosis is the first step when grading carotid stenoses with NASCET method. The internal carotid artery (ICA) can be asymmetrically associated with Circle of Willis variations. When such ICA asymmetry coincides with stenosis, it may mimic near-occlusion. We studied ICA anatomical variant prevalence in 4042 consecutive CTA exams from all indications, 53 excluded due to carotid occlusion, 814 with any ≥ 50% steno-occlusive disease intra- or extracranially, 3228 without. Of the 3989 included cases, 568 (14%) had ICA asymmetry, of which 335 (59%) were from associated with Circle of Willis variations. Of 3228 patients without ≥ 50% stenosis or other steno-occlusive disease intra- and extracranially; 257 (8.0%) demonstrated ICA asymmetry associated with Circle of Willis variations, equally common among sexes and age unrelated and most frequently attributed to an ipsilateral A1 hypoplasia/aplasia, less often attributed to large contralateral posterior communicating artery. As ICA asymmetry associated with Circle of Willis variations are common, caution should be exercised diagnosing near-occlusion on asymmetry alone.

Qualitative Posttreatment Diffusion-Weighted Imaging as a Predictor of 90-day Outcome in Stroke Intervention.

PURPOSE: The aim was to assess the ability of post-treatment diffusion-weighted imaging (DWI) to predict 90-day functional outcome in patients with endovascular therapy (EVT) for large vessel occlusion in acute ischemic stroke (AIS). METHODS: We examined a retrospective cohort from March 2016 to January 2018, of consecutive patients with AIS who received EVT. Planimetric DWI was obtained and infarct volume calculated. Four blinded readers were asked to predict modified Rankin Score (mRS) at 90 days post-thrombectomy. RESULTS: Fifty-one patients received endovascular treatment (mean age 65.1 years, median National Institutes of Health Stroke Scale (NIHSS) 18). Mean infarct volume was 43.7 mL. The baseline NIHSS, 24-hour NIHSS, and the DWI volume were lower for the mRS 0-2 group. Also, the thrombolysis in cerebral infarction (TICI) 2b/3 rate was higher in the mRS 0-2 group. No differences were found in terms of the occlusion level, reperfusion technique, or recombinant tissue plasminogen activator use. There was a significant association noted between average infarct volume and mRS at 90 days. On multivariable analysis, higher infarct volume was significantly associated with 90-day mRS 3-5 when adjusted to TICI scores and occlusion location (OR 1.01; CI 95% 1.001-1.03; p = 0.008). Area under curve analysis showed poor performance of DWI volume reader ability to qualitatively predict 90-day mRS. CONCLUSION: The subjective impression of DWI as a predictor of clinical outcome is poorly correlated when controlling for premorbid status and other confounders. Qualitative DWI by experienced readers both overestimated the severity of stroke for patients who achieved good recovery and underestimated the mRS for poor outcome patients. Infarct core quantitation was reliable.

Interrater and Intrarater Measurement Reliability of Noncontrast Computed Tomography Predictors of Intracerebral Hemorrhage Expansion.

Background and Purpose- Early hematoma expansion after intracerebral hemorrhage is a potentially modifiable predictor of outcome and a promising therapeutic target. Radiological markers seen on noncontrast computed tomography can help predict hematoma expansion and risk stratify patients presenting with intracerebral hemorrhage. Our objective was to assess the interrater and intrarater reliability of 5 commonly reported noncontrast computed tomographic markers of hematoma expansion. Methods- Four readers independently reviewed images from 40 patients from 2 intracerebral hemorrhage imaging databases (PREDICT Collaboration [Predicting Haematoma Growth and Outcome in Intracerebral Haemorrhage Using Contrast Bolus CT] and Massachusetts General Hospital). Readers were blind to all demographic and outcome data and used accepted definitions to establish the presence or absence of intrahematoma hypodensities, blend sign, fluid level, irregular hematoma morphology, and heterogeneous hematoma density. We calculated interrater and intrarater agreement and stratified kappas for the 5 imaging markers. Results- Interrater agreement was excellent for all 5 markers, ranging from 94% to 98%. Interrater kappas ranged from 0.67 to 0.91 (the lowest for fluid level). Interrater agreement had a similar pattern, ranging from 89% to 93%, with Kappas ranging from 0.60 to 0.89. Conclusions- We show that 5 commonly used noncontrast computed tomographic imaging findings all have good-to-excellent interrater and intrarater reliabilities, with the best kappa for blend sign, hypodensities, and heterogeneity.

BOLD-based cerebrovascular reactivity vascular transfer function isolates amplitude and timing responses to better characterize cerebral small vessel disease.

Cerebrovascular reactivity (CVR) is a dynamic measure of the cerebral blood vessel response to vasoactive stimulus. Conventional CVR measures amplitude changes in the blood-oxygenation-level-dependent (BOLD) signal per unit change in end-tidal CO2 (PET CO2 ), effectively discarding potential timing information. This study proposes a deconvolution procedure to characterize CVR responses based on a vascular transfer function (VTF) that separates amplitude and timing CVR effects. We implemented the CVR-VTF to primarily evaluate normal-appearing white matter (WM) responses in those with a range of small vessel disease. Comparisons between simulations of PET CO2 input models revealed that boxcar and ramp hypercapnia paradigms had the lowest relative deconvolution error. We used a T2 * BOLD-MRI sequence on a 3 T MRI scanner, with a boxcar delivery model of CO2 , to test the CVR-VTF approach in 18 healthy adults and three white matter hyperintensity (WMH) groups: 20 adults with moderate WMH, 12 adults with severe WMH, and 10 adults with genetic WMH (CADASIL). A subset of participants performed a second CVR session at a one-year follow-up. Conventional CVR, area under the curve of VTF (VTF-AUC), and VTF time-to-peak (VTF-TTP) were assessed in WM and grey matter (GM) at baseline and one-year follow-up. WMH groups had lower WM VTF-AUC compared with the healthy group (p < 0.0001), whereas GM CVR did not differ between groups (p > 0.1). WM VTF-TTP of the healthy group was less than that in the moderate WMH group (p = 0.016). Baseline VTF-AUC was lower than follow-up VTF-AUC in WM (p = 0.013) and GM (p = 0.026). The intraclass correlation for VTF-AUC in WM was 0.39 and coefficient of repeatability was 0.08 [%BOLD/mm Hg]. This study assessed CVR timing and amplitude information without applying model assumptions to the CVR response; this approach may be useful in the development of robust clinical biomarkers of CSVD.

Single-phase CT angiography: collateral grade is independent of scan weighting.

PURPOSE: Collateral grading may vary on single-phase CTA (sCTA) depending on whether the CTA is arterial (A), arteriovenous (AV), or venous (V) weighted. We studied the impact of sCTA weighting on collateral grading using the Tan, MAAS, and Menon methods, and their ability to predict infarct and clinical outcome hypothesizing that AV-weighted sCTA should better predict these outcomes. METHODS: Multicenter retrospective analysis of 212 patients undergoing baseline CTP/sCTA. sCTA weighting was determined by comparing ICA to torcula AV ratios with those from concomitant CTP time-density curves at peak arterial or venous contrast attenuation. A generalized linear mixed model investigated the predictive value for infarct volume or 90-day mRS of the three collateral scores stratified by sCTA weighting and adjusting for age, sex, clot burden score (CBS), and NIHSS. Bayesian information criterion (BIC) differences were calculated between the null and fitted models. RESULTS: Mean age, baseline median NIHSS, ASPECTS, and onset to treatment time were 69.89 ± 14.45, 13 (6-18), 10 (8-10), and 128 (66-181) minutes. sCTA scans were AV-weighted in 137/212 (65%) and A-weighted in 73 (34%). No association was demonstrated between sCTA weighting, hospital site, and sCTA technique. All collateral scores were related to infarct volume irrespective of sCTA weighting, with greatest fit with the regional leptomeningeal score (BIC 18.29, p = 0.0001). No association was shown between sCTA weighting, collateral grade, and clinical outcome. CONCLUSION: sCTA weighting did not significantly impact collateral grade using three common collateral scores or their ability to predict final infarct.