Anterior Circulation Territory Research Articles

Intra-arterial contrast administration: a confounding appearance on stroke CT imaging.

A female patient in her 70s presented with mild slurred speech. Clinical assessment revealed only minor dysarthria. A stroke protocol CT study was performed comprising a non-contrast CT head, CT angiogram (CTA) and CT perfusion (CTP) imaging. Despite a normal non-contrast CT head, CTP imaging demonstrated a large left anterior circulation territory abnormality compatible with core infarct. The CTA displayed absent left middle cerebral artery opacification and an abnormal pattern of thalamic and posterior fossa structure enhancement. Following a neuroradiology review, it was identified that the contrast bolus had been administered into the right brachial artery causing direct arterial opacification of the right vertebral/carotid arteries and their distal branches. No contrast was present in the left carotids or distal left intracranial anterior circulation giving the false impression of a large vessel occlusion. The patient was subsequently discharged without receiving inappropriate reperfusion therapy. This case highlights the role of technical factors influencing CT interpretation, particularly when performed by artificial intelligence/automated analysis.

Territory-Related Functional Connectivity Changes Associated with Verbal Memory Decline in Patients with Unilateral Asymptomatic Internal Carotid Stenosis.

Verbal memory decline is a common complaint of patients with severe asymptomatic stenosis of the internal carotid artery (aICS). Previous publications explored the associations between verbal memory decline and altered functional connectivity (FC) after aICS. Patients with severe aICS may show reduced perfusion in the ipsilateral territory and redistribution of cerebral blood flow to compensate for the deficient regions, including expansion of the posterior and contralateral ICA territories via the circle of Willis. However, aICS-related FC changes in anterior and posterior territories and the impact of the sides of stenosis were less explored. This study aims to investigate the altered FC in anterior and posterior circulation territories of patients with left or right unilateral aICS and its association with verbal memory decline. We enrolled 15 healthy controls (HCs), 22 patients with left aICS (aICSL), and 33 patients with right aICS (aICSR) to receive fMRI, Mini-Mental State Examination (MMSE), the Digit Span Test (DST), and the 12-item Chinese version of Verbal Learning Tests. We selected brain regions associated with verbal memory within anterior and posterior circulation territories. Territory-related FC alterations and verbal memory decline were identified by comparing the aICSL and aICSR groups with HC groups (P < .05, corrected for multiple comparisons), respectively. Furthermore, the association between altered FC and verbal memory decline was tested with the Pearson correlation analysis. Compared with HCs, patients with aICSL or aICSR had significant impairment in delayed recall of verbal memory. Decline in delayed recall of verbal memory was significantly associated with altered FC between the right cerebellum and right middle temporal pole in the posterior circulation territory (r = 0.40, P = .03) in the aICSR group and was significantly associated with altered FC between the right superior medial frontal gyrus and left lingual gyrus in the anterior circulation territory (r = 0.56, P = .01) in the aICSL group. Patients with aICSL and aICSR showed different patterns of FC alterations in both anterior and posterior circulation territories, which suggests that the side of aICS influences the compensatory mechanism for decline in delayed recall of verbal memory.

Characteristics and risk of stroke in emergency department patients with acute dizziness

BackgroundAcute dizziness is a common symptom in the emergency department (ED), with strokes accounting for 3 %–5 % of cases. We investigated the risk of stroke in ED patients with acute dizziness and compared stroke characteristics diagnosed during and after the ED visit. MethodsWe identified adult patients with acute dizziness, vertigo, or imbalance using a hospital research-based database. Patients with abdominal or flank pain were used as the comparison group. Patients with dizziness were 1:1 matched to comparison patients. Each patient was traced for up to one year until being hospitalized for a stroke. ResultsOut of the 24,266 eligible patients, 589 (2.4 %) were hospitalized for stroke during the ED visit. For the remaining 23,677 patients, the risk of stroke at 7, 30, 90, and 365 days after ED discharge was 0.40 %, 0.52 %, 0.71 %, and 1.25 % respectively. Patients with dizziness had a higher risk of stroke compared to the comparison group at 7, 30, 90, and 365 days. The risk ratios decreased from 5.69 (95 % confidence interval [CI], 3.34–9.68) to 2.03 (95 % CI, 1.65–2.49). Compared to patients hospitalized for stroke during the ED visit, those hospitalized for stroke after the ED visit had greater stroke severity despite a lower initial triage acuity. Patients with early stroke (≤7 days) after ED discharge were less likely to have hypertension, diabetes, hyperlipidemia, and atrial fibrillation. They mostly experienced posterior circulation stroke. Patients with late stroke (>7 days) were older and less likely to have hypertension and hyperlipidemia but more likely to have a history of prior stroke and ischemic heart disease. Their strokes were mainly located in the anterior circulation territory. ConclusionsThe risk of stroke after ED discharge was higher in patients with dizziness than in the comparison group, with gradually decreasing risk ratios in the following year. Patients hospitalized for stroke during and after the ED visit had different profiles of vascular risk factors and clinical characteristics.

Radiomics-Based Prediction of Collateral Status from CT Angiography of Patients Following a Large Vessel Occlusion Stroke.

A major driver of individual variation in long-term outcomes following a large vessel occlusion (LVO) stroke is the degree of collateral arterial circulation. We aimed to develop and evaluate machine-learning models that quantify LVO collateral status using admission computed tomography angiography (CTA) radiomics. We extracted 1116 radiomic features from the anterior circulation territories from admission CTAs of 600 patients experiencing an acute LVO stroke. We trained and validated multiple machine-learning models for the prediction of collateral status based on consensus from two neuroradiologists as ground truth. Models were first trained to predict (1) good vs. intermediate or poor, or (2) good vs. intermediate or poor collateral status. Then, model predictions were combined to determine a three-tier collateral score (good, intermediate, or poor). We used the receiver operating characteristics area under the curve (AUC) to evaluate prediction accuracy. We included 499 patients in training and 101 in an independent test cohort. The best-performing models achieved an averaged cross-validation AUC of 0.80 ± 0.05 for poor vs. intermediate/good collateral and 0.69 ± 0.05 for good vs. intermediate/poor, and AUC = 0.77 (0.67-0.87) and AUC = 0.78 (0.70-0.90) in the independent test cohort, respectively. The collateral scores predicted by the radiomics model were correlated with (rho = 0.45, p = 0.002) and were independent predictors of 3-month clinical outcome (p = 0.018) in the independent test cohort. Automated tools for the assessment of collateral status from admission CTA-such as the radiomics models described here-can generate clinically relevant and reproducible collateral scores to facilitate a timely treatment triage in patients experiencing an acute LVO stroke.

Abstract TMP69: Impaired Cognitive Function and Cerebral Hemodynamics Associated With APOE4 in Asymptomatic Carotid Artery Stenosis/Occlusion

Introduction: Cerebral hypoperfusion even in asymptomatic CASO may cause cognitive impairment. We reported APOE4 induces neurovascular dysfunction and cognitive impairment in a mouse model of CASO. However, it has not been clinically investigated in patients with asymptomatic CASO. Methods: A cross-sectional observational study was conducted between January 2017 and March 2022. In a primary analysis, 91 patients with asymptomatic moderate or severe CASO who underwent cognitive tests, including the Alzheimer’s Disease Assessment Scale-Cognitive Subscale 13 (ADAS-Cog), and 15 O-gas positron-emission tomography (PET) were included to examine associations of cognitive impairment and cerebral hemodynamic disruption with APOE4 . To investigate hemodynamic disruption, a sensitivity analysis in 70 additional patients who underwent only 15 O-gas PET was performed. Results: Among the 91 patients with asymptomatic moderate or severe CASO, 20 (22.0%) were APOE4 carriers. In a multivariable linear regression analysis, APOE4 was an independent risk factor for a worse ADAS-Cog delayed word recall score, indicating short-term memory impairment (β = 0.21, 95% confidence interval (CI) 0.026–2.30, p = 0.045). The 15 O-gas PET showed that APOE4 was an independent risk factor for lower cerebral blood flow (CBF) in the anterior circulation territory (β = –0.31, 95%CI –0.091 to –0.015, p = 0.007), without changes in cerebral metabolic rate of oxygen (CMRO 2 ) or oxygen extraction fraction. Of 161 patients in the sensitivity analysis, 31 (19.3%) carried APOE4 , which was an independent predictor of lower CBF (β = –0.23, 95%CI –0.072 to –0.014, p = 0.004) in the anterior circulation territory. Conclusions: APOE4 may confer an increased risk of memory impairment accompanied by cerebral hemodynamic disruption in asymptomatic CASO. The present study indicated that identifying APOE4 in such patients may be useful in early detection of disease severity.

Acute ischemic STROKE - from laboratory to the Patient's BED (STROKELABED): A translational approach to reperfusion injury. Study Protocol.

Cerebral edema (CE) and hemorrhagic transformation (HT) are frequent and unpredictable events in patients with acute ischemic stroke (AIS), even when an effective vessel recanalization has been achieved. These complications, related to blood-brain barrier (BBB) disruption, remain difficult to prevent or treat and may offset the beneficial effect of recanalization, and lead to poor outcomes. The aim of this translational study is to evaluate the association of circulating and imaging biomarkers with subsequent CE and HT in stroke patients with the dual purpose of investigating possible predictors as well as molecular dynamics underpinning those events and functional outcomes. Concurrently, the preclinical study will develop a new mouse model of middle cerebral artery (MCA) occlusion and recanalization to explore BBB alterations and their potentially harmful effects on tissue. The clinical section of the study is based on a single-center observational design enrolling consecutive patients with AIS in the anterior circulation territory, treated with recanalization therapies from October 1, 2015 to May 31, 2020. The study will employ an innovative evaluation of routine CT scans: in fact, we will assess and quantify the presence of CE and HT after stroke in CT scans at 24 h, through the quantification of anatomical distortion (AD), a measure of CE and HT. We will investigate the relationship of AD and several blood biomarkers of inflammation and extracellular matrix, with functional outcomes at 3 months. In parallel, we will employ a newly developed mouse model of stroke and recanalization, to investigate the emergence of BBB changes 24 h after the stroke onset. The close interaction between clinical and preclinical research can enhance our understanding of findings from each branch of research, enabling a deeper interpretation of the underlying mechanisms of reperfusion injury following recanalization treatment for AIS.

Usefulness of automated tractography for outcome prediction in patients with recurrent stroke.

[Purpose] To examine the usefulness of automated tractography for predicting outcomes in patients with recurrent stroke. [Participants and Methods] Diffusion tensor imaging was performed in the second week after stroke, and fractional anisotropy was calculated using automated tractography. Three patients with recurrent strokes were included in this study. [Results] Initial computed tomography findings of a 62-year-old man with stuttering speech revealed a hemorrhage in the left thalamus. Fractional anisotropy indicated slight neural damage in the association fibers of both hemispheres. The patient returned to work with mild attention deficit and aphasia. Initial diffusion-weighted imaging of a 75-year-old man with right upper extremity paresis showed high-intensity areas in the left corona radiata. Fractional anisotropy indicated bilateral neural damage to the corticospinal tract. The patient was discharged with severe right upper extremity impairment and a modified gait. Initial diffusion-weighted imaging of a 60-year-old woman with moyamoya disease who experienced a sudden loss of consciousness showed high-intensity areas in the left anterior circulation territories. Fractional anisotropy indicated severe damage to the right hemisphere, the corticospinal tract, and the superior longitudinal fasciculus of the left hemisphere. She was transferred to a nursing home and remained bedridden. [Conclusion] The symptoms identified in this study agreed with automated tractography findings, which suggests that this methodology is useful for predicting recurrent stroke outcomes.

The ivy sign as a radiological marker for follow-up of postoperative cerebral perfusion status in adult moyamoya disease.

Little is known about the relationship between postoperative changes in cerebral perfusion and the ivy sign representing leptomeningeal collateral burden in moyamoya disease (MMD). This study aimed to investigate the usefulness of the ivy sign in evaluating cerebral perfusion status following bypass surgery in patients with adult MMD. Two hundred thirty-three hemispheres in 192 patients with adult MMD undergoing combined bypass between 2010 and 2018 were retrospectively enrolled. The ivy sign was represented as the ivy score on FLAIR MRI in each territory of the anterior, middle, and posterior cerebral arteries. Ivy scores, as well as clinical and hemodynamic states on SPECT, were semiquantitatively compared both preoperatively and at 6 months after surgery. Clinical status improved at 6 months after surgery (p < 0.01). On average, ivy scores in whole and individual territories were decreased at 6 months (all p values < 0.01). Cerebral blood flow (CBF) postoperatively improved in three individual vascular territories (all p values ≤ 0.03) except for the posterior cerebral artery territory (PCAt), and cerebrovascular reserve (CVR) improved in those areas (all p values ≤ 0.04) except for the PCAt. Postoperative changes in ivy scores and CBF were inversely correlated in all territories (p ≤ 0.02), except for the PCAt. Furthermore, changes in ivy scores and CVR were only correlated in the posterior half of the middle cerebral artery territory (p = 0.01). The ivy sign was significantly decreased after bypass surgery, which was well correlated with postoperative hemodynamic improvement in the anterior circulation territories. The ivy sign is believed to be a useful radiological marker for postoperative follow-up of cerebral perfusion status.

Enlarged left atrium may be associated with laterality of anterior circulation cardioembolic stroke

BackgroundPropensity for lesion lateralization in atrial fibrillation-related cardiac embolic stroke (AF-stroke) remains controversial. In this study, we compared the hemispheric differences among patients with AF-stroke and identified factors associated with lesion laterality. MethodsWe retrospectively reviewed patients with acute AF-stroke admitted from January, 2017 to March, 2022. Patients were grouped based on whether lesions were right or left hemispheric in the anterior circulation territory, based on diffusion-weighted imaging. Factors associated with right-side propensity were analyzed. ResultsAmong 385 patients, the mean age was 74±11 years and 52.5 % were male. Right and left hemispheric lesions were observed in 189 (49.1 %) and 196 (50.9%) patients, respectively. In the multivariate analysis, enlarged left atrium (LA) (adjusted odds ratio [aOR]=1.03, 95% confidential interval [CI], 1.007–1.061; p=0.013) and single confluent lesion pattern (aOR= 1.55, 95% CI, 1.012–2.381; p=0.044) were associated with right hemispheric lesions. ConclusionsEnlarged LA and single confluent lesion pattern were strongly related to right-sided propensity in patients with AF-stroke.

The optimum anticoagulation time after endovascular thrombectomy for atrial fibrillation-related large vessel occlusion stroke: a real-world study

ObjectivesTo investigate the relationship between the initiation time of anticoagulation after endovascular treatment (EVT) and the outcomes in atrial fibrillation (AF)-related acute ischemic stroke (AIS) patients.MethodsIn this prospective registry study, from March 2013 to June 2022, patients with anterior circulation territories AF-related AIS who underwent EVT within 24 h were included. The primary outcome was favorable [modified Rankin Scale (mRS) 0–1) at ninety days and the secondary outcome was hemorrhage events after anticoagulants. Factors affecting the outcomes were pooled into multivariate regression and ROC curve analysis.ResultsOf 234 eligible patients, there were 63 (26.9%) patients achieved a favorable outcome. The symptomatic intracranial hemorrhage (sICH), ICH, and systemic hemorrhage events after anticoagulants occurred in 8 (3.4%), 28 (12.0%), and 39 (16.7%) patients, severally. A longer EVT to anticoagulation time (p = 0.033) was associated with an unfavorable outcome (mRS 3–6). An earlier EVT to anticoagulation time was the independent risk factor of sICH (p = 0.043), ICH (p = 0.005), and systemic hemorrhage (p = 0.005). There was no significant difference in recurrent AIS/ transient ischemic attack (TIA) or mortality among patients who started anticoagulation at ≤ 4 days, ≥ 15 days, or 4 to 15 days. The optimum cut-off for initiating anticoagulants to predict a favorable outcome and hemorrhage events was 4.5 days and 3.5 days after EVT, respectively.ConclusionsIn AF-related AIS, the time of EVT to anticoagulation is an independent factor of the functional outcome and hemorrhage events after anticoagulation. The optimal initiate time of anticoagulant after EVT is 4.5 days.ClinicalTrialRegisterNCT03754738.

Evaluation of the association between the internal carotid artery and vertebral artery tortuosity and acute ischemic stroke using tortuosity index.

To determine the association between the tortuosity of the internal carotid artery and vertebral artery and the occurrence of acute ischemic stroke based on a new quantitative method. This retrospective case-control study was conducted on 63 patients diagnosed with acute ischemic stroke in the case group and 52 patients in the control group. All the participants underwent neck Computed Tomography Angiography. The images were retrospectively reviewed and the tortuosity index was measured for internal carotid and vertebral artery. Then, a multivariable binary logistic regression model adjusted for the potential confounders was performed to assess the independent effect of internal carotid/vertebral artery tortuosity on acute ischemic stroke. Analysis of the logistic regression model revealed a significant effect of the internal carotid artery tortuosity index on anterior territory infarction (odds ratio = 1.04, p = 0.01) as well as a significant effect of the vertebral artery tortuosity index on posterior territory infarction (odds ratio = 1.14, p < 0.001). The optimal cut-off points for the internal carotid and vertebral artery tortuosity were 16.91 and 22.96, respectively. This study showed that tortuosity of extracranial portions of the internal carotid and vertebral artery could be an independent imaging predictor of acute ischemic stroke in anterior and posterior circulation territories, respectively.

Moyamoya syndrome and stroke among pediatric sickle cell disease patients in Sudan: A cross-sectional study

BackgroundSickle cell disease (SCD) is autosomal recessive hemolytic anemia due to hemoglobinopathy commonly in Sub-Saharan Africa, and particularly in Sudan. The disease induces a pro-inflammatory cascade in the intimal layer that leads to hyperplasia and progressive stenosis in the major vessel of the circle of Willis. This is associated with the development of Moyamoya collaterals. The aim of this study is to highlight the frequency of Moyamoya syndrome in Sudanese pediatric patients with sickle cell disease presenting with stroke. Materials and methodsA descriptive cross-sectional hospital-based study was conducted in the Department of Hematology at Gaafar Ibnauf Pediatric Tertiary Hospital in Khartoum state in Sudan, in the period between March 2021 and August 2021. Secondary data has been collected from the medical record after ethical approval and informed consent. ResultsA total of 104 patients were included in the study. The males were the majority, about 60 (57.7) compared to 44 (42.3%) females. More than half of our study population was in the school-age 54 compared to 42 adolescents and only 8 patients of preschool age. Only 50 out of 104 patients had diagnostic MRA which revealed features of Moyamoya syndrome in 48 (96%) patients. Motor weakness (100%), aphasia (52.9%), and facial palsy (35%) were the major stroke presentations. The left anterior circulation territory was the most common site of moyamoya features involvement in 31 patients out of 48. ConclusionStroke is a common problem in Sudanese pediatric patients with sickle cell disease, with a very high frequency of Moyamoya vasculopathy among patients with stroke presentation. The burden of Moyamoya syndrome in Sudanese pediatric patients with sickle cell disease is underestimated due to the cost of the available screening and diagnostic tools.

Cerebral Augmentation Effect Induced by External Counterpulsation Is Not Related to Impaired Dynamic Cerebral Autoregulation in Ischemic Stroke.

Background and PurposeDynamic cerebral autoregulation is impaired after ischemic stroke. External counterpulsation (ECP) augments the cerebral blood flow of patients with ischemic stroke by elevation of blood pressure (BP). We aimed to investigate if cerebral augmentation effects during ECP were associated with impaired dynamic cerebral autoregulation in patients after acute ischemic stroke.MethodsForty patients with unilateral ischemic stroke and large artery atherosclerosis in the anterior circulation territory within 7 days from symptom onset and eighteen healthy controls were recruited. We monitored changes in mean flow velocity over both middle cerebral arteries (MCA) by transcranial Doppler (TCD) before, during, and immediately after ECP. Cerebral augmentation index was MCA mean flow velocity increase in percentage during ECP compared with baseline to evaluate the augmentation effects of ECP. Spontaneous arterial BP and cerebral blood flow velocity in both bilateral MCAs were recorded using a servo-controlled plethysmograph and TCD, respectively. Transfer function analysis was used to derive the autoregulatory parameters, including phase difference (PD), and gain.ResultsThe cerebral augmentation index in patients with stroke was significantly higher on both the ipsilateral and contralateral sides than that in controls, while the PD in patients with stroke was significantly lower on both sides than those in controls (all P < 0.05). The cerebral augmentation index did not correlate with PD and gain on either the ipsilateral or contralateral side of patients with stroke or in controls (all P > 0.05). The cerebral augmentation index of patients with stroke was significantly related to mean BP change on the ipsilateral side (R2 = 0.108, P = 0.038).ConclusionThe degree of ECP-induced cerebral augmentation effects as measured by the cerebral augmentation index did not correlate with the magnitude of impaired dynamic cerebral autoregulation.

Angiography suite cone-beam CT perfusion for selection of thrombectomy patients: A pilot study.

Background and PurposeThe availability of cone‐beam CT perfusion (CBCTP) in angiography suites may improve large‐vessel occlusion (LVO) triage and reduce reperfusion times for patients presenting during extended time window. We aim to evaluate the perfusion maps correlation and agreement between multidetector CT perfusion (MDCTP) and CBCTP when obtained sequentially in patients undergoing endovascular therapy.MethodsThis is a prospective, pilot, single‐arm interventional cohort study of consecutive patients with anterior circulation LVO. All patients underwent MDCTP and CBCTP prior to endovascular therapy, generating cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time‐to‐maximum/time to peak contrast concentration maps. We compared the two imaging modalities using three different methods: (1) six regions of interest (ROIs) placed in the anterior circulation territory; (2) ROIs placed in all 10 Alberta Stroke Program Early CT Score regions; and (3) ROI drawn around the entire ischemic area. ROI ratios (unaffected/affected area) were compared for all sequences in each method. We used the intraclass correlation coefficient to calculate the correlation between the studies. Bland‐Altman plots were also created to measure the degree of agreement. Finally, a sensitivity analysis was done comparing both modalities in patients with low infarct growth rate.ResultsFourteen patients were included (median age 81 years [74‐87], 50% males, median National Institutes of Health Stroke Scale 19 [14‐22]). Median time between studies was 42 minutes (interquartile range 29‐61). Independently of the method used, we found moderate to excellent correlation in CBF, CBV, and MTT between modalities. CBF correlation further improved in patients with low infarct growth.ConclusionThese results demonstrate promising accuracy of CBCTP in evaluating ischemic tissue in patients presenting with LVO ischemic stroke.

Predictive value of Tmax perfusion maps on final core in acute ischemic stroke: an observational single-center study.

To assess utility of computed tomography perfusion (CTP) protocols for selection of patients with acute ischemic stroke (AIS) for reperfusive treatments and compare the diagnostic accuracy (ACC) in predicting follow-up infarction, using time-to-maximum (Tmax) maps. We retrospectively reviewed consecutive AIS patients evaluated for reperfusive treatments at comprehensive stroke center, employing a multimodal computed tomography. To assess prognostic accuracy of CTP summary maps in predicting final infarct area (FIA) in AIS patients, we assumed the best correlation between non-viable tissue (NVT) and FIA in early and fully recanalized patients and/or in patients with favorable clinical response (FCR). On the other hand, the tissue at risk (TAR) should better correlate with FIA in untreated patients and in treatment failure. We enrolled 158 patients, for which CTP maps with Tmax thresholds of 9.5s and 16s, presented sensitivity of 82.5%, specificity of 74.6%, and ACC of 75.9%. In patients selected for perfusion deficit in anterior circulation territory, CTP-Tmax > 16s has proven relatively reliable to identify NVT in FCR patients, with a tendency to overestimate NVT. Similarly, CTP-Tmax > 9.5s was reliable for TAR, but it was overestimated comparing to FIA, in patients with unfavorable outcomes. In our experience, Tmax thresholds have proven sufficiently reliable to identify global hypoperfusion, with tendency to overestimate both NVT and TAR, not yielding satisfactory differentiation between true penumbra and benign oligoemia. In particular, the overestimation of NVT could have serious consequences in not selecting potential candidates for a reperfusion treatment.

Penumbra Detection With Oxygen Extraction Fraction Using Magnetic Susceptibility in Patients With Acute Ischemic Stroke.

BackgroundThe oxygen extraction fraction (OEF) has been applied to identify ischemic penumbral tissue, but is difficult to use in an urgent care setting. This study aimed to investigate whether an OEF map generated via magnetic resonance quantitative susceptibility mapping (QSM) could help identify the ischemic penumbra in patients with acute ischemic stroke.Materials and MethodsThis prospective imaging study included 21 patients with large anterior circulation vessel occlusion who were admitted <24 h after stroke onset and 21 age-matched healthy controls. We identified the ischemic penumbra as the region with a Tmax of >6 s during dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI) and calculated the perfusion-core mismatch ratio between the ischemic penumbra and infarct core volumes. The OEF values were measured based on magnetic susceptibility differences between the venous structures and brain tissues using rapid QSM acquisition. Volumes with increased OEF values were compared to the ischemic penumbra volumes using an anatomical template.ResultsEleven patients had a perfusion-core mismatch ratio of ≥1.8, and reperfusion therapy was recommended. In these patients, the volumes with increased OEF values of >51.5%, which was defined using the anterior circulation territory OEF values from the 21 healthy controls, were positively correlated with the ischemic penumbra volumes (r = 0.636, 95% CI: 0.059 to 0.895, P = 0.035) and inversely correlated with the 30-day change in the National Institutes of Health Stroke Scale scores (r = −0.624, 95% CI: −0.891 to −0.039, P = 0.041).ConclusionTissue volumes with increased OEF values could predict ischemic penumbra volumes based on DSC-MRI, highlighting the potential of the QSM-derived OEF map as a penumbra biomarker to guide treatment selection in patients with acute ischemic stroke.

CT angiographic radiomics signature for risk stratification in anterior large vessel occlusion stroke

Background and PurposeAs “time is brain” in acute stroke triage, the need for automated prognostication tools continues to increase, particularly in rapidly expanding tele-stroke settings. We aimed to create an automated prognostication tool for anterior circulation large vessel occlusion (LVO) stroke based on admission CTA radiomics. MethodsWe automatically extracted 1116 radiomics features from the anterior circulation territory on admission CTAs of 829 acute LVO stroke patients who underwent mechanical thrombectomy in two academic centers. We trained, optimized, validated, and compared different machine-learning models to predict favorable outcome (modified Rankin Scale ≤ 2) at discharge and 3-month follow-up using four different input sets: “Radiomics”, “Radiomics + Treatment” (radiomics, post-thrombectomy reperfusion grade, and intravenous thrombolysis), “Clinical + Treatment” (baseline clinical variables and treatment), and “Combined” (radiomics, treatment, and baseline clinical variables). ResultsFor discharge outcome prediction, models were optimized/trained on n = 494 and tested on an independent cohort of n = 100 patients from Yale. Receiver operating characteristic analysis of the independent cohort showed no significant difference between best-performing Combined input models (area under the curve, AUC = 0.77) versus Radiomics + Treatment (AUC = 0.78, p = 0.78), Radiomics (AUC = 0.78, p = 0.55), or Clinical + Treatment (AUC = 0.77, p = 0.87) models. For 3-month outcome prediction, models were optimized/trained on n = 373 and tested on an independent cohort from Yale (n = 72), and an external cohort from Geisinger Medical Center (n = 232). In the independent cohort, there was no significant difference between Combined input models (AUC = 0.76) versus Radiomics + Treatment (AUC = 0.72, p = 0.39), Radiomics (AUC = 0.72, p = 0.39), or Clinical + Treatment (AUC = 76, p = 0.90) models; however, in the external cohort, the Combined model (AUC = 0.74) outperformed Radiomics + Treatment (AUC = 0.66, p < 0.001) and Radiomics (AUC = 0.68, p = 0.005) models for 3-month prediction. ConclusionMachine-learning signatures of admission CTA radiomics can provide prognostic information in acute LVO stroke candidates for mechanical thrombectomy. Such objective and time-sensitive risk stratification can guide treatment decisions and facilitate tele-stroke assessment of patients. Particularly in the absence of reliable clinical information at the time of admission, models solely using radiomics features can provide a useful prognostication tool.

Effectiveness of Continuous Hypertonic Saline in Acute Ischemic Infarcts: A Radiographic and Clinical Evaluation

The role of continuous hypertonic saline (HS) infusion in the management of malignant cerebral edema is controversial. We evaluated patients presenting with large anterior circulation territory infarcts and compared radiographic and clinical outcomes to evaluate the effects of continuous HS. This was a retrospective review of patients with malignant ischemic strokes who were initially managed with continuous HS versus routine medical management. Radiographic parameters of cerebral edema and clinical parameters were collected at different time intervals after admission. Rates and timing of surgery, mortality, and complications were also collected. The study included 43 patients: 26 in group 1 (HS) and 17 in group 2 (no HS). Both cohorts had comparable baseline clinical and radiographic parameters. There was no difference between rates and timing of surgery, complications, and mortality. Mean midline shift was significantly greater in the HS group at interval 1 (12-36 hours, P= 0.003) and interval 2 (36-60 hours, P= 0.030), and mean change in midline shift from initial interval to interval 1 was significantly greater in the HS group (P= 0.019). Despite the widespread use of continuous HS in acute ischemic infarcts, only a limited number of studies have evaluated its efficacy, and virtually no studies have studied its effect on radiographic progression and rates of decompressive surgery. Results of this study indicate that there is no benefit of continuous HS. In fact, there may be worsening of cerebral edema with administration of continuous HS. In addition, there are no differences in prevention or delay of decompressive surgery or in overall mortality.

Diagnostic and prognostic computed tomography imaging markers in basilar artery occlusion (Review).

Acute ischemic stroke treatment has been revolutionized by the addition of mechanical and aspiration thrombectomy. Randomized controlled trials have proven beyond doubt, the substantial clinical impact of endovascular interventions in anterior circulation territory strokes. Unfortunately, patients with vertebrobasilar ischemic stroke could not be included in these early trials due to inherent clinical, radiological, and prognostic particularities of posterior circulation ischemia; thus, indications for the treatment of posterior fossa strokes and basilar artery occlusion (BAO) are mainly based on retrospective studies and registries. BAO carries high morbidity and mortality, despite the new improvements in endovascular therapy. Identifying patients who will likely benefit from invasive treatment and have a good clinical outcome resides in discovering clinical, biological, or imaging markers, that have prognostic implications. Such imaging markers have been described, especially in the last decade. Hyperdense Basilar Artery Sign (HDBA), Posterior Circulations-Alberta Stroke Program Early CT Score (pc-ASPECTS), Pons-Midbrain Index (PMI), Posterior Circulation Collateral Score (pc-CS), Posterior Circulation CT Angiography Score (pc-CTA), and Basilar Artery on CT Prognostic Score (BATMAN), are computed tomography (CT) markers with properties that can aid the diagnosis of BAO and can independently predict clinical outcome. This paper aims to present a comprehensive review of these imaging signs to have a thorough understanding of their diagnostic and prognostic attributes.

Abstract P568: Incidence and Progression of Posterior Circulation Involvement in Moyamoya Disease

Introduction: The incidence and natural history of posterior circulation moyamoya disease (PCMMD) is not well-characterized. Methods: Consecutive patients with moyamoya disease prospectively treated at our institution from 2015-2018 were reviewed. Results: 262 consecutive patients with moyamoya disease undergoing 370 revascularization procedures were enrolled. Concurrent PCMMD was identified in 68 (26%) patients – all of which were confined to the anterior circulation. There were no differences in age, sex, race, or rates of diabetes, hypertension, smoking, or symptoms upon presentation between patients with or without PCMMD. Patients with PCMMD were more likely to present with bilateral disease (p&lt;0.001), higher Suzuki grade (p=0.001), more extensive collateral angiopathy (p&lt;0.001), and pial-pial collaterals from the PCA territory (p=0.03). Patients with PCMMD were more likely to suffer from ischemic peri-operative complications in both the anterior (p=0.03) and posterior (p&lt;0.001) circulation territories after anterior circulation revascularization. No differences were observed for hemorrhagic complications (p=1.0). Over a mean follow-up of 1.91±1.5 years, 19 (7.3%) developed new or progressive PCMMD. Patients with PCMMD progression had an Asian predilection and were less likely to present with sentinel symptoms such as headaches (p=0.05 and 0.01 respectively). Patients with bilateral disease (p=0.02), higher Suzuki (p&lt;0.001) and collateral angiopathy grades (p=0.002), and more extensive external carotid artery supply (p=0.03) were also more likely to experience PCMMD progression. There was no association between PCMMD progression and delayed neurological events or functional outcomes, but patients with concurrent PCMMD upon presentation were associated with poor functional outcome (mRS &gt;2) at last follow-up (p=0.02). Conclusions: Posterior circulation disease involvement often presents in the later stages of moyamoya and is associated with higher rates of ischemic peri-operative complications and poor functional outcomes likely due to reduced collateral flow. Progression of PCMMD is not uncommon. Future studies are needed to assess the impact of PCMMD progression on long-term outcomes.