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Background and Purpose: Distal medium vessel occlusions (DMVOs) are a significant contributor to acute ischemic stroke (AIS), with collateral status (CS) playing a pivotal role in modulating ischemic damage progression. We aimed to explore baseline characteristics associated with CS in AIS‐DMVO. Methods: This retrospective analysis of a prospectively collected database enrolled 130 AIS‐DMVO patients from two comprehensive stroke centers. Baseline characteristics, including patient demographics, admission National Institutes of Health Stroke Scale (NIHSS) score, admission Los Angeles Motor Scale (LAMS) score, and co‐morbidities, including hypertension, hyperlipidemia, diabetes, coronary artery disease, atrial fibrillation, and history of transient ischemic attack or stroke, were collected. The analysis was dichotomized to good CS, reflected by hypoperfusion index ratio (HIR) <.3, versus poor CS, reflected by HIR ≥.3. Results: Good CS was observed in 34% of the patients. As to the occluded location, 43.8% occurred in proximal M2, 16.9% in mid M2, 35.4% in more distal middle cerebral artery, and 3.8% in distal anterior cerebral artery. In multivariate logistic analysis, a lower NIHSS score and a lower LAMS score were both independently associated with a good CS (odds ratio [OR]: 0.88, 95% confidence interval [CI]: 0.82‐0.95, p <.001 and OR: 0.77, 95% CI: 0.62‐0.96, p =.018, respectively). Patients with poor CS were more likely to manifest as moderate to severe stroke (29.1% vs. 4.5%, p <.001), while patients with good CS had a significantly higher chance of having a minor stroke clinically (40.9% vs. 12.8%, p <.001). Conclusions: CS remains an important determinant in the severity of AIS‐DMVO. Collateral enhancement strategies may be a worthwhile pursuit in AIS‐DMVO patients with more severe initial stroke presentation, which can be swiftly identified by the concise LAMS and serves as a proxy for underlying poor CS. [ABSTRACT FROM AUTHOR]

Background and Purpose: In large vessel occlusion (LVO) stroke patients, relative cerebral blood flow (rCBF)<30% volume thresholds are commonly used in treatment decisions. In the early time window, nearly infarcted but salvageable tissue volumes may lead to pretreatment overestimates of infarct volume, and thus potentially exclude patients who may otherwise benefit from intervention. Our multisite analysis aims to explore the strength of relationships between widely used pretreatment CT parameters and clinical outcomes for early window stroke patients. Methods: Patients from two sites in a prospective registry were analyzed. Patients with LVOs, presenting within 3 hours of last known well, and who were successfully reperfused were included. Primary short‐term neurological outcome was percent National Institutes of Health Stroke Scale (NIHSS) change from admission to discharge. Secondary long‐term outcome was 90‐day modified Rankin score. Spearman's correlations were performed. Significance was attributed to p‐value ≤.05. Results: Among 73 patients, median age was 66 (interquartile range 54‐76) years. Among all pretreatment imaging parameters, rCBF<30%, rCBF<34%, and rCBF<38% volumes were significantly, inversely correlated with percentage NIHSS change (p<.048). No other parameters significantly correlated with outcomes. Conclusions: Our multisite analysis shows that favorable short‐term neurological recovery was significantly correlated with rCBF volumes in the early time window. However, modest strength of correlations provides supportive evidence that the applicability of general ischemic core estimate thresholds in this subpopulation is limited. Our results support future larger‐scale efforts to liberalize or reevaluate current rCBF parameter thresholds guiding treatment decisions for early time window stroke patients. [ABSTRACT FROM AUTHOR]

Background and Purpose: Acute ischemic stroke due to large vessel occlusion (AIS‐LVO) is a major cause of functional dependence. Collateral status (CS) is an important determinant of functional outcomes. Pretreatment CT perfusion (CTP) parameters serve as reliable surrogates of CS. Penumbra Salvage Index (PSI) is another parameter predictive of functional outcomes in AIS‐LVO. The aim of this study is to assess the relationship of pretreatment CTP parameters with PSI. Methods: In this prospectively collected, retrospectively reviewed multicenter analysis, inclusion criteria were as follows: (1) CT angiography confirmed middle cerebral artery (MCA) M1‐segment and proximal M2‐segment occlusion from 9/1/2017 to 9/22/2022; (2) diagnostic CTP; and (3) available diagnostic Magnetic resonance Imaging (MRI) diffusion‐weighted images. Pearson correlation analysis was performed to assess the association between cerebral blood volume (CBV) index and hypoperfusion intensity ratio (HIR) with PSI. p value ≤.05 was considered statistically significant. Results: In total, 131 patients (n = 86, M1 and n = 45, proximal M2 occlusion) met our inclusion criteria. CBV index showed a modest positive correlation with PSI (r = 0.34, p<.001) in patients with proximal MCA occlusion. Similar trends were noted in subgroup analysis of patients with M1 occlusion, and proximal M2 occlusion. Whereas, HIR did not have a strong trend or correlation with PSI. Conclusion: CBV index correlates with PSI, whereas HIR does not. Future studies are needed to expand our understanding of the adjunct role of CBV index with other similar pretreatment CTP‐based markers in clinical evaluation and decision‐making in patients with MCA occlusion. [ABSTRACT FROM AUTHOR]

Background and Purpose: Quantitative CT perfusion (CTP) thresholds for assessing the extent of ischemia in patients with acute ischemic stroke (AIS) have been established; relative cerebral blood flow (rCBF) <30% is typically used for estimating estimated ischemic core volume and Tmax (time to maximum) >6 seconds for critical hypoperfused volume in AIS patients with large vessel occlusion (LVO). In this study, we aimed to identify the optimal threshold values for patients presenting with AIS secondary to distal medium vessel occlusions (DMVOs). Methods: In this retrospective study, consecutive AIS patients with anterior circulation DMVO who underwent pretreatment CTP and follow‐up MRI/CT were included. The CTP data were processed by RAPID (iSchemaView, Menlo Park, CA) to generate estimated ischemic core volumes using rCBF <20%, <30%, <34%, and <38% and critical hypoperfused volumes using Tmax (seconds) >4, >6, >8, and >10. Final infarct volumes (FIVs) were obtained from follow‐up MRI/CT within 5 days of symptom onset. Diagnostic performance between CTP thresholds and FIV was assessed in the successfully and unsuccessfully recanalized groups. Results: Fifty‐five patients met our inclusion criteria (32 female [58.2%], 68.0 ± 12.1 years old [mean ± SD]). Recanalization was attempted with intravenous tissue‐type plasminogen activator and mechanical thrombectomy in 27.7% and 38.1% of patients, respectively. Twenty‐five patients (45.4%) were successfully recanalized. In the successfully recanalized patients, no CTP threshold significantly outperformed what is used in LVO setting (rCBF < 30%). All rCBF CTP thresholds demonstrated fair diagnostic performances for predicting FIV. In unsuccessfully recanalized patients, all Tmax CTP thresholds strongly predicted FIV with relative superiority of Tmax >10 seconds (area under the receiver operating characteristic curve =.875, p =.001). Conclusion: In AIS patients with DMVOs, longer Tmax delays than Tmax > 6 seconds, most notably, Tmax > 10 seconds, best predict FIV in unsuccessfully recanalized patients. No CTP threshold reliably predicts FIV in the successfully recanalized group nor significantly outperformed rCBF < 30%. [ABSTRACT FROM AUTHOR]

Background and purpose: Mechanical thrombectomy (MT) has proven to be the standard of care for patients with acute ischemic stroke due to large vessel occlusion (AIS‐LVO). However, high revascularization rates do not necessarily result in favorable functional outcomes. We aimed to investigate imaging biomarkers associated with futile recanalization, defined as unfavorable functional outcome despite successful recanalization in AIS‐LVO patients. Methods: A retrospective multicenter cohort study was made of AIS‐LVO patients treated by MT. Successful recanalization was defined as modified Thrombolysis in Cerebral Infarction score of 2b–3. A modified Rankin Scale score of 3–6 at 90 days was defined as unfavorable functional outcome. Cortical Vein Opacification Score (COVES) was used to assess venous outflow (VO), and the Tan scale was utilized to determine pial arterial collaterals on admission computed tomography angiography (CTA). Unfavorable VO was defined as COVES ≤ 2. Multivariable regression analysis was performed to investigate vascular imaging factors associated with futile recanalization. Results: Among 539 patients in whom successful recanalization was achieved, unfavorable functional outcome was observed in 59% of patients. Fifty‐eight percent of patients had unfavorable VO, and 31% exhibited poor pial arterial collaterals. In multivariable regression, unfavorable VO was a strong predictor (adjusted odds ratio = 4.79, 95% confidence interval = 2.48–9.23) of unfavorable functional outcome despite successful recanalization. Conclusions: We observe that unfavorable VO on admission CTA is a strong predictor of unfavorable functional outcomes despite successful vessel recanalization in AIS‐LVO patients. Assessment of VO profiles could help as a pretreatment imaging biomarker to determine patients at risk for futile recanalization. [ABSTRACT FROM AUTHOR]

Objective: Patients with acute ischemic stroke harboring a large vessel occlusion who present to primary stroke centers often require inter‐hospital transfer for thrombectomy. We aimed to determine clinical and imaging factors independently associated with fast infarct growth (IG) during inter‐hospital transfer. Methods: We retrospectively analyzed data from acute stroke patients with a large vessel occlusion transferred for thrombectomy from a primary stroke center to one of three French comprehensive stroke centers, with an MRI obtained at both the primary and comprehensive center before thrombectomy. Inter‐hospital IG rate was defined as the difference in infarct volumes on diffusion‐weighted imaging between the primary and comprehensive center, divided by the delay between the two MRI scans. The primary outcome was identification of fast progressors, defined as IG rate ≥5 mL/hour. The hypoperfusion intensity ratio (HIR), a surrogate marker of collateral blood flow, was automatically measured on perfusion imaging. Results: A total of 233 patients were included, of whom 27% patients were fast progressors. The percentage of fast progressors was 3% among patients with HIR < 0.40 and 71% among those with HIR ≥ 0.40. In multivariable analysis, fast progression was independently associated with HIR, intracranial carotid artery occlusion, and exclusively deep infarct location at the primary center (C‐statistic = 0.95; 95% confidence interval [CI], 0.93–0.98). IG rate was independently associated with good functional outcome (adjusted OR = 0.91; 95% CI, 0.83–0.99; P = 0.037). Interpretation: Our findings show that a HIR > 0.40 is a powerful indicator of fast inter‐hospital IG. These results have implication for neuroprotection trial design, as well as informing triage decisions at primary stroke centers. ANN NEUROL 2023;93:1117–1129 [ABSTRACT FROM AUTHOR]

Purpose: Baseline variables could be used to guide the administration of additional intravenous alteplase (IVT) before mechanical thrombectomy (MT). The aim of this study was to determine how baseline imaging and demographic parameters modify the effect of IVT on clinical outcomes in patients with ischemic stroke due to large vessel occlusion.Methods: Multicenter retrospective cohort study of ischemic stroke patients triaged by multimodal-CT undergoing MT treatment after direct admission to an MT-eligible center. Inverse-probability weighting analysis (IPW) was used to assess the treatment effect of IVT adjusted for baseline variables. Multivariable logistic regression analysis with IPW-weighting and interaction terms for IVT was performed to predict functional independence (mRS 0-2 at 90-days).Results: 720 patients were included, of which 366 (51%) received IVT. In IPW, the treatment effect of IVT on outcome (mRS 0-2) distinctively varied according to the ASPECTS subgroup (ASPECTS 9-10: +15%, ASPECTS 6-8: +7%, ASPECTS <6: -11%). In multivariable logistic regression analysis, IVT was independently associated with functional independence (aOR: 1.57, 95% CI: 1.16-2.14, p = 0.003) and the interaction term was significant for ASPECTS and IVT revealing that IVT was only significantly associated with better outcomes in patients with higher ASPECTS. No other significant baseline variable interaction terms were identified.Interpretation: ASPECTS was the only baseline variable that showed a significant interaction with IVT for outcome prediction. Use of IVT prior to MT in patients with an ASPECTS of <6 was not associated with a treatment benefit and should be considered carefully. ANN NEUROL 2022;92:588-595. [ABSTRACT FROM AUTHOR]

Objective: Perfusion imaging identifies anterior circulation stroke patients who respond favorably to endovascular thrombectomy (ET), but its role in basilar artery occlusion (BAO) is unknown. We hypothesized that BAO patients with limited regions of severe hypoperfusion (time to reach maximum concentration in seconds [Tmax] > 10) would have a favorable response to ET compared to patients with more extensive regions involved. Methods: We performed a multicenter retrospective cohort study of BAO patients with perfusion imaging prior to ET. We prespecified a Critical Area Perfusion Score (CAPS; 0–6 points), which quantified severe hypoperfusion (Tmax > 10) in cerebellum (1 point/hemisphere), pons (2 points), and midbrain and/or thalamus (2 points). Patients were dichotomized into favorable (CAPS ≤ 3) and unfavorable (CAPS > 3) groups. The primary outcome was a favorable functional outcome 90 days after ET (modified Rankin Scale = 0–3). Results: One hundred three patients were included. CAPS ≤ 3 patients (87%) had a lower median National Institutes of Health Stroke Scale score (NIHSS; 12.5, interquartile range [IQR] = 7–22) compared to CAPS > 3 patients (13%; 23, IQR = 19–36; p = 0.01). Reperfusion was achieved in 84% of all patients, with no difference between CAPS groups (p = 0.42). Sixty‐four percent of reperfused CAPS ≤ 3 patients had a favorable outcome compared to 8% of nonreperfused CAPS ≤ 3 patients (odds ratio [OR] = 21.0, 95% confidence interval [CI] = 2.6–170; p < 0.001). No CAPS > 3 patients had a favorable outcome, regardless of reperfusion. In a multivariate regression analysis, CAPS ≤ 3 was a robust independent predictor of favorable outcome after adjustment for reperfusion, age, and pre‐ET NIHSS (OR = 39.25, 95% CI = 1.34–>999, p = 0.04). Interpretation: BAO patients with limited regions of severe hypoperfusion had a favorable response to reperfusion following ET. However, patients with more extensive regions of hypoperfusion in critical brain regions did not benefit from endovascular reperfusion. ANN NEUROL 2022;91:23–32 [ABSTRACT FROM AUTHOR]

Background and purpose: Arterial clot localization affects collateral flow to ischemic brain in patients with acute ischemic stroke due to large vessel occlusion (AIS‐LVO). We determined the association between vessel occlusion locations, tissue‐level collaterals (TLC), and venous outflow (VO) profiles and their impact on good functional outcomes. Methods: We conducted a multicenter retrospective cohort study of consecutive AIS‐LVO patients who underwent thrombectomy triage. Baseline computed tomographic angiography (CTA) was used to localize vessel occlusion, which was dichotomized into proximal vessel occlusion (PVO; internal carotid artery and proximal first segment of the middle cerebral artery [M1]) and distal vessel occlusion (DVO; distal M1 and M2), and to assess collateral scores. TLC were assessed on computed tomographic perfusion data using the hypoperfusion intensity ratio. VO was determined on baseline CTA by the cortical vein opacification score. Primary outcomes were favorable VO and TLC; secondary outcome was the modified Rankin Scale after 90 days. Results: A total of 649 patients met inclusion criteria. Of these, 376 patients (58%) had a PVO and 273 patients (42%) had a DVO. Multivariate ordinal logistic regression showed that DVO predicted favorable TLC (odds ratio [OR] = 1.77, 95% confidence interval [CI] = 1.24–2.52, p = 0.002) and favorable VO (OR = 7.2, 95% CI = 5.2–11.9, p < 0.001). DVO (OR = 3.4, 95% CI = 2.1–5.6, p < 0.001), favorable VO (OR = 6.4, 95% CI = 3.8–10.6, p < 0.001), and favorable TLC (OR = 3.2, 95% CI = 2–5.3, p < 0.001), but not CTA collaterals (OR = 1.07, 95% CI = 0.60–1.91, p = 0.813), were predictors of good functional outcome. Conclusions: DVO in AIS‐LVO patients correlates with favorable TLC and VO profiles, which are associated with good functional outcome. [ABSTRACT FROM AUTHOR]

Background and Purpose: Patients with acute ischemic stroke due to a large vessel occlusion (AIS‐LVO) undergo emergent neuroimaging triage for thrombectomy treatment. MRI is often utilized for this evaluation, and cerebral magnetic resonance perfusion (MRP) imaging is used to identify the presence of the salvageable penumbra. To determine if dose reduction is feasible, we assessed whether a half‐dose reduction in gadobenate provided sufficient MRP quality in AIS‐LVO patients. Methods: A prospective observational study of all patients presenting to our neurovascular referral center with AIS‐LVO was performed. MRP was done with a half‐dose of gadolinium (0.1 ml/kg body weight) over a period of 10 months. MRP images were compared to a consecutive historical cohort of full‐dose gadolinium (0.2 ml/kg body weight) MRP studies and rated for image quality (poor, borderline, or good) that determined thrombectomy eligibility. Results: Fifty‐four half‐dose and 127 full‐dose patients were included. No differences in patient demographics or stroke presentation details were identified. MRP quality differed between half‐ and full‐dose scans (p < 0.001), which were rated as poor (40.7% vs. 6.3%), borderline (18.5% vs. 26.8%), and good quality (40.7% vs. 66.9%), respectively. MRP image quality was then dichotomized into poor and sufficient (borderline and good) quality groups; half‐dose studies were more likely to have poor quality compared to full‐dose studies (40.7% vs. 6.3%; p < 0.001). Conclusions: Half‐dose gadolinium administration for MRP in AIS‐LVO patients results in poor image quality in a substantial number of studies. MR cerebral perfusion performed with half‐dose gadolinium may adversely affect stroke patient triage for thrombectomy. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Intracranial pressure (ICP) monitoring is recommended in severe traumatic brain injury (sTBI), yet invasive monitoring has risks, and many patients do not develop elevated ICP. Tools to identify patients at risk for ICP elevation are limited. We aimed to identify early radiologic biomarkers of ICP elevation. METHODS: In this retrospective study, we analyzed a prospectively enrolled cohort of patients with a sTBI at an academic level 1 trauma center. Inclusion criteria were nonpenetrating TBI, age ≥16 years, Glasgow Coma Scale (GCS) score ≤8, and presence of an ICP monitor. Two independent reviewers manually evaluated 30 prespecified features on serial head computed tomography (CTs). Patient characteristics and radiologic features were correlated with elevated ICP. The primary outcome was clinically relevant ICP elevation, defined as ICP ≥ 20 mm Hg on at least 5 or more hourly recordings during postinjury days 0‐7 with concurrent administration of an ICP‐lowering treatment. RESULTS: Among 111 sTBI patients, the median GCS was 6 (interquartile range 3‐8), and 45% had elevated ICP. Features associated with elevated ICP were younger age (every 10‐year decrease, odds ratio [OR] 1.4), modified Fisher scale (mFS) score at 0‐4 hours postinjury (every 1 point, OR 1.8), and combined volume of contusional hemorrhage and peri‐hematoma edema (10 ml, OR 1.2) at 4‐18 hours postinjury. CONCLUSIONS: Younger age, mFS score, and volume of contusion are associated with ICP elevation in patients with a sTBI. Imaging features may stratify patients by their risk of subsequent ICP elevation. [ABSTRACT FROM AUTHOR]

We hypothesized that automated assessment of collaterals on computed tomography perfusion can predict the rate of infarct growth during transfer from a primary to a comprehensive stroke center for endovascular stroke treatment. We identified consecutive patients (N = 28) and assessed their collaterals based on the hypoperfusion intensity ratio (HIR) prior to transfer. Infarct growth rate was strongly correlated with HIR (r = 0.78, p < 0.001). Receiver operating characteristic analysis identified HIR ≥ 0.5 as optimal for predicting infarct growth. Patients with HIR ≥ 0.5 had a median infarct growth rate of 10.1ml/h (interquartile range [IQR] = 6.4-18.4) compared with 0.9ml/h (IQR = 0-2.8; p < 0.001) in patients with HIR < 0.5. Patients with HIR ≥ 0.5 had an 83% probability of significant core growth, whereas patients with HIR < 0.5 had an 88% probability of core stability. These preliminary data have the potential to guide decision making regarding whether repeat brain imaging should be performed after transfer to a comprehensive stroke center. Ann Neurol 2018;84:616-620. [ABSTRACT FROM AUTHOR]

Background and Purpose: Transitional venous anomalies (TVAs) are rare cerebrovascular lesions that resemble developmental venous anomalies (DVAs), but demonstrate early arteriovenous shunting on digital subtraction angiography (DSA) without the parenchymal nidus of arteriovenous malformations (AVMs). We investigate whether arterial spin labeling (ASL) magnetic resonance imaging (MRI) can distinguish brain TVAs from DVAs and guide their clinical management.Methods: We conducted a single-center retrospective review of patients with brain parenchymal DVA-like lesions with increased ASL signal on MRI. Clinical histories and follow-up information were obtained. Two readers assessed ASL signal location relative to the vascular lesion on MRI and, if available, the presence of arteriovenous shunting on DSA.Results: Thirty patients with DVA-like lesions with increased ASL signal were identified. Clinical symptoms prompted MRI evaluation in 83%. Symptoms did not localize to the venous anomaly in 90%. Ten percent presented with acute symptoms, only one of whom presented with hemorrhage. ASL signal in relation to the venous anomaly was identified in: 50% in the adjacent parenchyma, 33% in the lesion, 7% in a distal draining vein/sinus, and 10% in at least two of these sites. Follow-up DSA confirmed arteriovenous shunting in 71% of ASL-positive venous anomalies. Interrater agreement was very good (κ = .81-1.0, P < .001).Conclusion: A DVA-like lesion with increased ASL signal likely represents a TVA with arteriovenous shunting. Our study indicates that these lesions are usually incidentally detected and have a lower risk of hemorrhage than AVMs. ASL-MRI may be a useful tool to identify TVAs and guide further management of patients with TVAs. [ABSTRACT FROM AUTHOR]

The aim of the study by Dr Cereda et al was to determine whether perfusion imaging could identify BSO patients who respond favorably to thrombectomy, developing what was deemed the Critical Area Perfusion Score (CAPS) for this analysis. The authors found that BSO patients with a favorable CAPS and successful reperfusion after thrombectomy achieved better functional outcomes than patients with a favorable CAPS who were not successfully reperfused. When anticipating the future of thrombectomy for patients presenting with acute BSO, Dr Heit emphasized that even within a "favorable perfusion profile", there may be some patients who benefit more than others. [Extracted from the article]

The article discusses calcineurin and Nuclear Factor of Activated T-cells (NFAT) signaling in pancreatic β-cell, in relation to diabetes treatment. Calcineurin activates insulin expression in response to a Ca2+ stimulus. Studies indicate that the NFATc and TORC protein families mediate calcineurin-dependent insulin transcription. The calcineurin/NFAT signaling pathway is important in pancreatic β-cell function and growth.

Transplantation of functional islets of Langerhans may emerge as a useful therapy for some patients with type 1 diabetes mellitus (DM), but donor islet shortages motivate the search for new sources of transptantable islets. Pluripotent embryonic stem (ES) cells are expandable in culture and have the potential to give rise to all cell types in the body. The recent isolation of pluripotent ES cells from humans has generated excitement over the possibility of engineering glucoseresponsive islet replacement tissue from these cells in large quantities. In this study, we review the recent advances in generating insulin-producing cells (IPC) from mouse and human ES (hES) cells. [ABSTRACT FROM AUTHOR]

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. Student t test, Mann-Whitney U test, and χ 2 test were used in the univariate data analysis. Spearman's rank correlation analysis was used to assess correlations. Outcome measure was dichotomized into good functional outcome (90-day modified Rankin Scale score, 0-2) and poor functional outcome (90-day modified Rankin Scale score, 3-6) for logistic regression and receiver operating characteristic analysis. P ≤0.05 was considered significant. In total, 229 patients met our inclusion criteria. The majority of the patients (n=161) in our cohort had M1 occlusion. All the rCBV thresholds were significantly higher in patients with poor 90-day functional outcomes and were independently associated with the outcome. Spearman's rank correlation analysis revealed a slightly stronger correlation of rCBV <42% (ρ=0.27, P <0.001), as compared with rCBV <38% (ρ=0.25, P <0.001) and rCBV <34% (ρ=0.24, P <0.001) with functional outcome. Receiver operating characteristic analysis revealed that rCBV <42% (area under the curve, 0.67 [95% CI, 0.60-0.74]; P <0.001) performed marginally better than rCBV <38% (area under the curve, 0.66 [95% CI, 0.59-0.73]; P <0.001), and rCBV <34% (area under the curve, 0.65 [95% CI, 0.58-0.72]; P <0.001)., Conclusions: All the rCBV thresholds were independently associated with poor 90-day functional outcome; however, the rCBV <42% marginally outperformed rCBV <38% and rCBV <34% lesion volumes.