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OBJECTIVE: 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 unfavorable 90-day functional outcomes despite successful reperfusion. This study investigates the association between PVT and percent change on the National Institutes of Health Stroke Scale (NIHSS) among AIS-LVO patients who have undergone successful reperfusion. METHODS: We performed a retrospective analysis of prospectively collected data from consecutive adult AIS-LVO patients with successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/2c/3). PVT+ was defined as Tmax ≥10 s in the superior sagittal sinus, torcula, or both. The primary outcome was continuous NIHSS percent change and dichotomous NIHSS percent change ≥70%. Regression analyses were performed to assess the effect of PVT on NIHSS percent change. RESULTS: In 119 patients of median (IQR) age 71 (63-81) years, the admission and discharge NIHSS scores were significantly higher in PVT+ patients compared to PVT- patients (17 [14-23.5] vs. 13 [9.5-19], p = 0.011, and 7.5 [4-12] vs. 3 [1-7], p 6 s volume, and hemorrhagic transformation, PVT+ was significantly associated with lower NIHSS percent change (B = -0.163, 95%CI -0.326 to -0.001, p = 0.049) and was less likely to achieve higher than 70% NIHSS improvement (OR = 0.331, 95% CI 0.127-0.863, p = 0.024). INTERPRETATION: PVT+ was significantly associated with reduced neurological improvement despite successful reperfusion in AIS-LVO patients, highlighting the critical role of VO impairment in short-term functional outcomes. These findings further validate PVT as a valuable adjunct imaging biomarker derived from CTP for assessing VO profiles in AIS-LVO.

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. Patients were divided into two groups based on BUN/Cr ratio: ≤20 (n=205) and >20 (n=93). Primary outcomes included 90-day mortality and unfavourable functional outcomes, defined as a modified Rankin Scale score of 3-6. Secondary outcomes included the successful reperfusion, haemorrhagic transformation and National Institutes of Health Stroke Scale score at discharge. RESULTS: Patients with a BUN/Cr ratio >20 had significantly higher 90-day mortality (35% vs 13%, p

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]

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. In this narrative review, we will highlight the different parameters and modalities used to assess the VOP in acute ischemia., Vo Assessment With Different Modalities: CT parameters include cortical vein opacification score, interhemispheric difference of composite scores of the draining veins classifications on single-phase CT angiography (CTA), as well as the extent and velocity of optimal cortical venous filling on multiphase CTA. Differences in contrast administration and acquisition time render the single-phase CTA parameters less reliable. Perfusion parameters are semiautomated, thus offering greater reproducibility. These include time to peak and prolonged venous transit. Finally, the venous transit time is an MRI parameter., Associations and Prognostic Implications: VOP parameters' significance lies in their potential to predict tissue fate and, subsequently, clinical outcomes. Recent studies indicate that favorable VOP is independently associated with slower rates of infarct edema progression, smaller infarct volumes, and higher rates of functional independence after 90 days. Moreover, it is considered a predictor of recanalization success and the first-pass effect during mechanical thrombectomy. Conversely, an unfavorable VOP predicts futile recanalization and indicates a higher risk of reperfusion hemorrhage. Our aim is to explore these prognostic implications and their relevance in determining the utility of intracranial intervention., (© 2025 American Society of Neuroimaging.)

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., Methods: We conducted a retrospective analysis of prospectively maintained stroke databases, comprising AIS cases with MeVO in the anterior circulation, assessed by adequate CT perfusion (CTP). Baseline and clinical data were obtained from electronic health records. Alberta Stroke Program Early CT Scores (ASPECTS) were calculated from non-contrast head CT. The perfusion mismatch volume (time to maximum > 6 s minus relative cerebral blood flow <30%) volume was reported from CTP. Multiple regression was employed to examine the relationship between baseline parameters and hospital LOS., Results: A total of 133 patients (median age 71 [interquartile range 63-80] years, 59.4% females) were included in the study cohort. The perfusion mismatch volume significantly positively correlated with LOS (r = 0.264, p = 0.004). After adjusting for age, sex, hypertension, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, Tan score, intravenous thrombolysis, mechanical thrombectomy (MT), and hemorrhagic transformation, a larger mismatch volume remained independently associated with longer hospital stays (β = 0.209, 95% confidence interval [CI] 0.006-0.412, p = 0.045). Additional significant determinants of longer hospital stay included admission NIHSS (β = 0.250, 95% CI: 0.060-0.440, p = 0.010) and MT (β = 0.208, 95% CI: 0.006-0.410, p = 0.044). Among patients who underwent MT (n = 83), multiple regression analysis incorporating both perfusion mismatch volume and admission NIHSS revealed that perfusion mismatch volume remained independently associated with LOS (β = 0.248, 95% CI: 0.019-0.471, p = 0.033), while admission NIHSS did not retain significance (β = 0.208, 95% CI: 0.019-0.433, p = 0.071)., Conclusions: In our cohort of AIS patients with MeVO in the anterior circulation, and particularly in those who underwent MT, the perfusion mismatch volume serves as an independent predictor of LOS. These findings offer critical valuable insights in clinical assessments and decision-making protocols of MT in AIS-MeVO., (© 2025 American Society of Neuroimaging.)

Background and Purpose: Acute ischemic strokes caused by distal medium vessel occlusions (DMVO) represent a significant proportion of all stroke cases, yet the predictors of excellent functional outcomes in these patients remain poorly understood. This study aims to identify pretreatment computed tomography perfusion (CTP) parameters associated with excellent functional outcomes, defined as a modified Rankin Scale (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 three stroke centers within the Johns Hopkins Medical Enterprise. Baseline demographic, clinical, and imaging data were collected, with CTP parameters analyzed using RAPIDAI software. Univariable and multivariable logistic regression models were used to identify predictors of excellent outcomes. Receiver operating characteristic (ROC) curves were constructed to assess the predictive accuracy of CTP parameters., Results: Among the 82 patients (median age, 71 years; 57% female), occlusions were located in the M2 segment in 89%, M3 in 8.5%, and A2 in 2.4%. IVT was administered to 37% of patients, and EVT was attempted in 59%. Excellent outcomes at 90 days were achieved in 45% of patients. In univariate analysis, white race (OR, 4.14; 95% CI, 1.66-10.9; P=0.003), higher CBV index (OR per 0.1-unit change, 1.45; 95% CI, 1.08-2.05; P=0.022), and lower relative cerebral blood flow (rCBF < 20%) volumes (OR, 0.91; 95% CI, 0.81-0.98; P=0.038) were significantly associated with excellent outcomes. In multivariate analysis adjusting for age, sex, race, IVT administration, EVT attempted, dyslipidemia, and premorbid mRS, higher CBV index remained a significant independent predictor (OR per 0.1-unit change, 1.72; 95% CI, 1.14-2.81; P=0.017), and lower rCBF < 20% volume was associated with better outcomes (OR, 0.91; 95% CI, 0.80-0.98; P=0.05). The multivariate model demonstrated good predictive performance (area under the ROC curve, 80%; 95% CI, 70%-90%; P < 0.001)., Conclusions: In patients with anterior circulation DMVO, a higher CBV index on pretreatment CTP is an independent predictor of excellent functional outcomes at 90 days. These findings suggest that CTP parameters, particularly the CBV index, may be useful in prognostic assessment for this stroke population. Further studies are needed to validate these results and optimize therapeutic approaches., Abbreviations: ABC＝ definition; XYZ＝ definition., (© 2024 by American Journal of Neuroradiology.)

Background and Purpose: Ischemic strokes due to isolated posterior cerebral artery (PCA) occlusions represent 5% of all strokes but have significant impacts on patients' quality of life, primarily due to visual deficits and thalamic involvement. Current guidelines for acute PCA occlusion management are sparse, and the prognostic value of perfusion imaging parameters remains underexplored., Methods: We conducted a retrospective analysis of 32 patients with isolated PCA occlusions treated at Johns Hopkins Medical Institutions between January 2017 and March 2023. Patients underwent pretreatment perfusion imaging, with perfusion parameters analyzed using RAPID software. The primary outcome was short-term clinical outcome as measured by the National Institutes of Health Stroke Scale (NIHSS) at discharge., Results: The median age of the cohort was 70 years, with 34% female and 66% male. Significant correlations were found between NIHSS at discharge and various perfusion parameters, including time-to-maximum (Tmax) >6 seconds (ρ = .55, p = .004), Tmax >8 seconds (ρ = .59, p = .002), Tmax >10 seconds (ρ = .6, p = .001), mismatch volume (ρ = .51, p = .008), and cerebral blood volume (CBV) < 34% (ρ = .59, p = .002)., Conclusions: Tmax and CBV volumes significantly correlated with discharge NIHSS with marginal superiority of Tmax >10 seconds and CBV <42% volumes. These findings suggest that CT and MR perfusion imaging can play a crucial role in the acute management of PCA strokes, though larger, standardized studies are needed to validate these results and refine imaging thresholds specific to posterior circulation infarcts., (© 2024 American Society of Neuroimaging.)

Background: Recent large core trials have highlighted the effectiveness of mechanical thrombectomy (MT) in acute ischemic stroke with large vessel occlusion. Variable perfusion-imaging thresholds and poor Alberta Stroke Program Early Computed Tomography Score reliability underline the need for more standardized, quantitative ischemia measures for MT patient selection. We aimed to identify the computed tomography perfusion parameter most strongly associated with poor outcomes in patients with acute ischemic stroke-large vessel occlusion with significant ischemic cores., Methods: In this study from 2 comprehensive stroke centers from 2 comprehensive stroke centers within the Johns Hopkins Medical Enterprise (Johns Hopkins Hospita-East Baltimore and Bayview Medical Campus) from July 29, 2019 to January 29, 2023 in a continuously maintained database, we included patients with acute ischemic stroke-large vessel occlusion with ischemic core volumes defined as relative cerebral blood flow <30% and ≥50 mL on computed tomography perfusion or Alberta Stroke Program Early Computed Tomography Score <6. We used receiver operating characteristics to find the optimal cutoff for parameters like cerebral blood volume (CBV) <34%, 38%, 42%, and relative cerebral blood flow >20%, 30%, 34%, 38%, and time-to-maximum >4, 6, 8, and 10 seconds. The primary outcome was unfavorable outcomes (90-day modified Rankin Scale score 4-6). Multivariable models were adjusted for age, sex, diabetes, baseline National Institutes of Health Stroke Scale, intravenous thrombolysis, and MT., Results: We identified 59 patients with large ischemic cores. A receiver operating characteristic curve analysis showed that CBV<42% ≥68 mL is associated with unfavorable outcomes (90-day modified Rankin Scale score 4-6) with an area under the curve of 0.90 (95% CI, 0.82-0.99) in the total and MT-only cohorts. Dichotomizing at this CBV threshold, patients in the ≥68 mL group exhibited significantly higher relative cerebral blood flow, time-to-maximum >8 and 10 seconds volumes, higher CBV volumes, higher HIR, and lower CBV index. The multivariable model incorporating CBV<42% ≥68 mL predicted poor outcomes robustly in both cohorts (area under the curve for MT-only subgroup was 0.87 [95% CI, 0.75-1.00])., Conclusions: CBV<42% ≥68 mL most effectively forecasts poor outcomes in patients with large-core stroke, confirming its value alongside other parameters like time-to-maximum in managing acute ischemic stroke-large vessel occlusion., Competing Interests: Dr Yedavalli reports compensation from IschemaView (RAPID AI) for consultant services and compensation from MRIOnline for consultant services. Dr Guenego reports compensation from Acandis for consultant services; compensation from Rapid Medical Ltd for consultant services; and compensation from phenox, Inc, for consultant services. Dr Heit reports compensation from iSchemaView for consultant services; compensation from Medtronic for consultant services; and compensation from MicroVention Inc for consultant services. Dr Albers reports compensation from iSchemaView for consultant services; compensation from Genentech for consultant services; and stock holdings in iSchemaView. Dr Urrutia reports grants from Genentech and employment by Johns Hopkins University School of Medicine. Dr Nael reports compensation from BRAINOMIX LIMITED for consultant services and compensation from Olea Medical for consultant services. Dr Hillis reports compensation from American Heart Association for other services; compensation from Elsevier Publishing for other services; employment by Johns Hopkins University School of Medicine; compensation from National Institute on Deafness and Other Communication Disorders for other services; and grants from National Institute on Deafness and Other Communication Disorders. The other authors report no conflicts.