Composite arterial and venous collateral score on single-phase CTA predicts 90-day outcomes in anterior circulation large-vessel occlusion stroke.

Background: Collateral circulation influences clinical outcomes in patients with acute ischemic stroke due to anterior circulation large-vessel occlusion (LVO). While both arterial and venous collateral assessments on single-phase computed tomography angiography (CTA) have prognostic value, they have traditionally been evaluated independently.

Purpose: We developed the CTA Collateral Impairment Score (CCIS), a composite measure incorporating arterial (Tan) and venous (Cortical Venous Opacification Score (COVES)) scores, and investigated its association with 90-day functional outcomes.

Interobserver and Intraobserver Variability in the Assessment of Prolonged Venous Transit in Anterior Circulation Large-Vessel Occlusion Ischemic Stroke.

Background And Purpose: Prolonged venous transit (PVT) on time-to-maximum (Tmax) perfusion maps has been associated with worse outcomes in patients with acute ischemic stroke due to anterior circulation large-vessel occlusion (AIS-LVO). The qualitative nature of PVT assessment introduces potential variability, and its reproducibility has not been systematically evaluated.

Materials And Methods: In a retrospective study of patients with confirmed AIS-LVO, 2 board-certified neuroradiologists independently reviewed pretreatment Tmax maps to assess PVT in the posterior superior sagittal sinus and torcula.

Oxygen Extraction Fraction on Baseline MRI Predicts Infarction Growth in Successfully Reperfused Patients.

Background: In patients with acute ischemic stroke, infarct growth occurs despite successful reperfusion. Oxygen extraction fraction (OEF) has shown promising results in evaluating ischemic tissue viability and can now be quantified from routinely performed dynamic susceptibility contrast perfusion. We aimed to determine the association of OEF alterations within the ischemic tissue on pretreatment magnetic resonance imaging and infarct growth in patients who underwent successful reperfusion.

Cerebral aneurysm hemodynamics indicative of instability are associated with heterogeneous wall motion measured by amplified MRI.

Background: The prediction of rupture in intracranial aneurysms is challenging. Aneurysm growth has been identified as a strong risk factor for rupture and aneurysm wall motion is a potential biomarker for growth, but visualizing aneurysm wall motion using conventional imaging techniques is difficult. Computational fluid dynamic simulations have been used to identify hemodynamic risk factors of intracranial aneurysm instability, but often lack observable and quantifiable biomechanical correlates that can be directly measured in vivo.

Integrating perfusion imaging derived venous outflow and tissue-level collateral parameters in a comprehensive clinical model enhances prognostication in large vessel occlusion stroke.

Arterial inflow restoration and collateral status have been significantly correlated with functional outcomes in AIS-LVO patients undergoing mechanical thrombectomy (MT). CT perfusion imaging biomarkers, including prolonged venous transit (PVT), cerebral blood volume (CBV) index, and hypoperfusion intensity ratio (HIR), have emerged as reliable pretreatment adjunct parameters of comprehensive flow assessment. However, their absolute and comparative effectiveness in improving prognostic prediction remains unclear when used in conjunction with clinical and arterial inflow parameters.

Perfusion imaging parameters predict long-term clinical outcome in isolated posterior cerebral artery occlusion stroke patients.

BackgroundIsolated posterior cerebral artery (PCA) occlusions, which account for 5% of ischemic strokes, significantly impact patient quality of life due to effects on the thalamus and visual cortex. Current guidelines for acute treatment and the prognostic utility of perfusion imaging in PCA strokes remain limited and underexplored.MethodsWe conducted a retrospective analysis of 21 patients with isolated PCA occlusions from January 2017 to March 2023 at two comprehensive medical institutions.

Automated Vessel Occlusion Software in Acute Ischemic Stroke: Pearls and Pitfalls.

Software programs leveraging artificial intelligence to detect vessel occlusions are now widely available to aid in stroke triage. Given their proprietary use, there is a surprising lack of information regarding how the software works, who is using the software, and their performance in an unbiased real-world setting. In this educational review of automated vessel occlusion software, we discuss emerging evidence of their utility, underlying algorithms, real-world diagnostic performance, and limitations.

The relative cerebral blood volume (rCBV) <42% is independently associated with prolonged hospitalization in anterior circulation large vessel occlusion.

BackgroundThe pretreatment rCBV <42% lesion volume on CT Perfusion (CTP) has recently been shown to predict 90-day functional outcomes in stroke patients. However, its association with length of stay (LOS) has not yet been explored. This study aims to assess the relationship between rCBV <42% and prolonged LOS, defined as 7 days or longer.

Simultaneous Multiparametric Estimation of Arteriovenous Malformations Hemodynamics Using MR Fingerprinting ASL (MRF-ASL).

Background And Purpose: Accurate hemodynamic characterization of cerebral AVMs is critical for treatment planning, risk stratification, and post-treatment monitoring but remains challenging due to their abnormal angioarchitecture. MR-fingerprinting (MRF) arterial-spin-labeling (ASL) is a novel, non-invasive technique that enables simultaneous quantification of cerebral blood flow (CBF), arterial cerebral blood volume (aCBV), and bolus arrival time (BAT) within a single 5-minute scan. This study evaluates the feasibility of MRF-ASL in assessing AVM hemodynamics and compares its sensitivity for AVM detection with CBF measurements obtained using single-delay pseudo-continuous ASL (pCASL).

Prolonged Venous Transit as a Superior Predictor of Functional Outcomes in Successfully Reperfused Large Vessel Occlusions: Comparative Analysis With Cerebral Blood Volume Index and Hypoperfusion Intensity Ratio.

Background: Collateral status plays a crucial role in outcomes after acute ischemic stroke due to large vessel occlusion. Tissue-level collaterals and venous outflow are key components following mechanical thrombectomy. This study evaluates the predictive performance of prolonged venous transit (PVT), cerebral blood volume index, and hypoperfusion intensity ratio in determining 90-day functional outcomes.

Prolonged Venous Transit Independently Predicts Worse Functional Outcomes at Discharge in Successfully Reperfused Patients with Large Vessel Occlusion Stroke.

Background And Purpose: Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with 90-day mortality despite successful reperfusion. This study investigates the association between PVT and modified Rankin Scale (mRS) score at discharge among AIS-LVO patients who have undergone successful reperfusion.

Volume contracted state, mortality and functional outcomes in patients with acute ischaemic stroke due to large vessel occlusion.

Background: Acute ischaemic stroke (AIS) is a leading cause of mortality and disability globally, with volume contracted state (VCS), as indicated by an elevated blood urea nitrogen to creatinine (BUN/Cr) ratio, potentially influencing outcomes. This study investigates the association between VCS and clinical outcomes in patients with AIS due to large vessel occlusion (LVO).

Methods: A retrospective cohort study was conducted involving 298 patients with LVO-AIS from two comprehensive stroke centres.

Larger Perfusion Mismatch Volume Is Associated With Longer Hospital Length of Stay in Medium Vessel Occlusion Stroke.

Background And Purpose: Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO.

Cerebral blood volume index in the era of thrombectomy-treated large and medium vessel ischemic strokes.

The cerebral blood volume index (CBV index) is a perfusion-based marker of collateral status. Several real-world data analyses from observational stroke cohorts have established relationships between this parameter and a range of favorable and unfavorable stroke outcomes. In this review, an overview is provided of the CBV index, within the context of thrombectomy-treated large vessel and medium vessel occlusion ischemic strokes.

Factors Associated With Prolonged Venous Transit in Large Vessel Occlusion Acute Ischemic Strokes.

Background And Purpose: Prolonged venous transit (PVT), derived from computed tomography perfusion (CTP) time-to-maximum (T) maps, reflects compromised venous outflow (VO) in acute ischemic stroke due to large vessel occlusion (AIS-LVO). Poor VO is associated with worse clinical outcomes, but pre-treatment markers predictive of PVT are not well described.

Methods: We conducted a retrospective analysis of 189 patients with anterior circulation AIS-LVO who underwent baseline CT evaluation, including non-contrast CT, CT angiography, and CTP.

Role and Prognostic Implications of Venous Outflow Assessment in Acute Ischemic Stroke.

Introduction: The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral evaluation systems, which often fail to consider impaired autoregulation and its impact on cerebral blood flow at the microcirculatory levels.

The relative cerebral blood volume (rCBV) < 42% is independently associated with hemorrhagic transformation in anterior circulation large vessel occlusion.

Background: Pretreatment CT perfusion (CTP) marker relative cerebral blood volume (rCBV) < 42% lesion volume has recently shown to predict poor collateral status and poor 90-day functional outcome. However, there is a paucity of studies assessing its association with hemorrhagic transformation (HT). Here, we aim to assess the relationship between rCBV < 42% lesion volume with HT.

Prolonged venous transit is associated with lower odds of excellent recovery after reperfusion in anterior large-vessel occlusion stroke.

Background And Purpose: Acute ischemic stroke due to anterior circulation large-vessel occlusion (AIS-LVO) remains a leading cause of disability despite successful reperfusion therapies. Prolonged venous transit (PVT) has emerged as a potential prognostic imaging biomarker in AIS-LVO. We aimed to investigate whether PVT is associated with a decreased likelihood of excellent functional outcome (modified Rankin Scale [mRS] score of 0-1 at 90 days) after successful reperfusion.

Prolonged Venous Transit on Perfusion Imaging Is Associated with Longer Lengths of Stay in Acute Large Vessel Occlusions.

Background And Purpose: Prolonged venous transit (PVT+) is a marker of venous outflow; it is defined as the presence or absence of time-to-maximum ≥10 seconds timing in either the superior sagittal sinus or torcula. This novel perfusion imaging-based metric has been associated with higher odds of mortality and lower odds of functional recovery. This study aims to assess the relationship between PVT on admission perfusion imaging and length of hospital stay in large vessel occlusion strokes successfully reperfused with mechanical thrombectomy.

The Los Angeles Motor Scale is independently associated with cerebral blood flow < 30% volume in large vessel occlusions.

Background and PurposeMechanical thrombectomy (MT) is the treatment standard for large vessel occlusion (LVO) stroke. Under current guidelines, only patients with smaller ischemic core volumes (ICV) are eligible for MT. Thus, it is of interest to quickly estimate ICV in stroke patients.

The Cortical Vein Opacification Score (COVES) Is Independently Associated with DSA ASITN Collateral Score.

Background And Purpose: Pretreatment CTA-based Cortical Vein Opacification Score (COVES) has been shown to predict good functional outcomes at 90 days in patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO). This is thought to be related to its ability to measure collateral status (CS). However, its association with the reference standard test, the DSA-based American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score, has yet to be established.

Perfusion-Based Relative Cerebral Blood Volume Is Associated With Functional Dependence in Large-Vessel Occlusion Ischemic Stroke.

Background: Pretreatment computed tomography perfusion parameter relative cerebral blood volume (rCBV) lesion volume has been shown to predict 90-day modified Rankin Scale score in small-core strokes with Alberta Stroke Program Early Computed Tomography Score ≥5, including those with medium-vessel occlusions (mid and distal M2 segment occlusions). Hence, in this study we aim to assess the performance of different rCBV lesion volume thresholds (rCBV <42%, rCBV <38%, and rCBV <34%) with 90-day modified Rankin Scale score including patients with large core (Alberta Stroke Program Early Computed Tomography Score <5) and strictly including only patients with anterior circulation large-vessel occlusion.

Methods And Results: In this retrospective evaluation of our prospectively collected database, inclusion criteria were (1) Computed tomographic angiography confirmed anterior circulation large-vessel occlusion from September 1, 2017, to October 1, 2023; and (2) diagnostic computed tomography perfusion.

Mismatch Vs No Mismatch in Large Core-A Matter of Definition.

Background: Endovascular thrombectomy (EVT) has shown promise in randomized controlled trials (RCTs) for large ischemic core stroke patients, yet variability in core definition and onset-to-imaging time creates heterogeneity in outcomes. This study aims to clarify the prevalence and implications of core-perfusion mismatch (MM) versus no mismatch (No MM) in such patients, utilizing established imaging criteria.

Methods: A retrospective cohort study was conducted including patients from 7/29/2019 to 1/29/2023, with data extracted from a continuously maintained database.

Association of Pretreatment Perfusion Imaging Parameters with 90-Day Excellent Functional Outcomes in Anterior Circulation Distal Medium Vessel Occlusion Stroke.

Background And Purpose: Acute ischemic strokes caused by distal medium vessel occlusions (DMVOs) represent a remarkable proportion of all stroke cases, yet the predictors of excellent functional outcomes in these patients remain poorly understood. This study aims to identify pretreatment CTP parameters associated with excellent functional outcomes, defined as an mRS score of 0-1 at 90 days, in patients with anterior circulation DMVO.

Materials And Methods: We conducted a retrospective multicenter study involving patients with anterior DMVO, from 2 stroke centers within the Johns Hopkins Medical Enterprise.