M1 Segment Of MCA Research Articles

Management of patients with diffusion-weighted imaging-negative acute ischemic stroke: Retrospective analysis of 47 consecutive patients

BackgroundFew studies with a limited number of patients focused on the outcomes of patients with diffusion-weighted imaging (DWI)-negative acute ischemic stroke (AIS) after intravenous thrombolysis (IVT) and/or endovascular treatment (EVT). MethodsThis retrospective observational, single-center study included all consecutive patients admitted for AIS involving the anterior circulation and treated with IVT and/or EVT between January 1, 2015 and December 31, 2023. The collected data were used to identify the characteristics of patients with negative DWI and to compare outcomes in patients with negative and positive DWI. ResultsAmong the 1210 patients included, 47 (3.9 %) had negative (DWI-negative group) and 1163 had increased DWI signal (DWI-positive group). In the DWI-negative group, the mean age was 69 years (SD=19.4), 55.3 % were men, and 27 (57.4 %) had a large vessel occlusion. Thirty eight (80.9 %) were treated with IVT alone, 7 (14.9 %) with EVT alone, and 2 (4.3 %) with both. Fluid attenuated inversion recovery (FLAIR) sequences were the most sensitive to detect predictive factors of cerebral ischemia, such as vessel thrombosis and the spaghetti sign that were found in 68.1 % and 83 %, of patients, respectively. Oxyhemoglobin-sensitive (T2*) and susceptibility-weighted angiography (SWAN) sequences were less sensitive: vessel thrombosis and the brush sign were detected in 55.3 % and 19.1 % of patients, respectively. Comparison of the two DWI groups showed that M2 occlusion was more frequent (31.9 % vs 13 %, p<0.001) and M1 occlusion rarer (19.1 % vs 36 %, p<0.02) in the DWI-negative than DWI-positive group. At admission, the median National Institutes of Health Stroke Scale score was lower in the DWI-negative than DWI-positive group (2 vs 6, p=0.0001), but the median symptom onset-to-MRI time was similar in both groups (108 vs 111 min, p=0.88). ConclusionsIn patients with DWI-negative AIS, symptoms are less severe. Large vessel occlusions, notably in the M2 segment, are more distal at the expense of the M1 segment of MCA. The spaghetti sign remains the most predictive feature of AIS that should be specifically searched in the absence of DWI lesions.

Ayurvedic management of Hemorrhagic Stroke : A Case Report

WHO defines stroke as a "neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours". There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Stroke is a major global public health problem. According to the Global Burden of Diseases (GBD) study in 1990, stroke was the second leading cause of death worldwide. Subsequent efforts to update the GBD study reported nearly 5.87 million stroke deaths globally in 2010.With the rising proportion of mortality, stroke still remains the second leading cause of death worldwide. The present study is a diagnosed case of ruptured right DACA aneurysm and unruptured right MCA M1 segment aneurysm and ICD (International classification of diseases) classification as Subarchnoid hemorrhage from middle cerebral artery. The patient presented with symptoms of loss of strength and weakness in left upper &amp; lower extremity with stiffness. The Ayurvedic diagnosis of Vama Pakshaghata was done and managed with Dhanyamla Seka, Abhyanga, Shastika Shali Pinda Sweda, Dhara and Matrabasti. Two assessments were made before and after treatment using the National Institute of Health Stroke Scale (NIH-SS). The patient got significant improvement in the signs and symptoms and improvement in movements within 45 days. The results were remarkably encouraging.

Image-based visualization of stents in mechanical thrombectomy for acute ischemic stroke: Preliminary findings from a series of cases.

Mechanical thrombectomy is the most effective treatment for great cerebral artery embolization within a set time window. Typically, an arteriogram does not show the localization of the stent after release and whether a thrombus is captured or not. Thus, improving the visualization of a stent in interventional therapy will be helpful for clinicians. To analyze stent imaging findings to enhance clinicians' understanding of a special circumstance, wherein a Solitaire AB retrievable stent was visible during the imaging of a thrombus capture that improved the success rate of stent-based mechanical thrombectomy. This was a retrospective study with four acute ischemic stroke (AIS) patients who underwent stent-based mechanical thrombectomy. Patient 1 was a 64-year-old man admitted after 5 h of confusion; angiography revealed basilar artery occlusion. We inserted a stent into the left posterior cerebral artery-P2 segment and visualized the expanded stent that successfully captured a thrombus. Patient 2 was a 74-year-old man admitted with confusion, which lasted approximately 3 h. Angiography revealed a left middle cerebral artery (MCA)-M1 segment occlusion. A stent was deployed in the distal M2 segment, and we could visualize the stent by capturing the thrombus. Patient 3 was a 74-year-old woman admitted after experiencing left hemiplegia for 3 h. We deployed a stent at the distal right MCA-M2 segment, and the developing stent captured a large thrombus. Patient 4 was an 82-year-old man who presented with confusion for 3 h. A developing stent was placed in the distal left MCA-M1 segment, which captured a large thrombus and several fragmented thrombi. To the best of our knowledge, this is the first report of stent imaging in patients with AIS. We demonstrated the usefulness and substantial potential of stent imaging in stent-based mechanical thrombectomy for AIS.

Abstract TP138: The Effect Of Dominant Division Catheterization In Mechanical Thrombectomy On First Pass Effect And Clinical Outcome

Introduction: The middle cerebral artery (MCA M1 segment) bifurcates into anterior and posterior divisions (M2 segments) in 78% of the population. When feasible, preferential catheterization of the dominant division is performed during endovascular thrombectomy (EVT) in patients with acute ischemic strokes (AIS). Our aim was to evaluate the association of dominant division catheterization in EVT with first pass effect and clinical outcome. Methods: Retrospective chart review of AIS patients presenting to our comprehensive stroke center with AIS secondary to MCA M1 and/or internal carotid artery (ICA) terminus occlusions who underwent standardized EVT defined as proximal flow arrest, distal aspiration, and stent retriever. Patients receiving intra-arterial thrombolytics and/or non-thrombolytics were excluded. Digital subtraction angiographic images were reviewed to determine if dominant M2 branch catheterization was performed on first pass. Modified Thrombolysis in Cerebral Infarction (mTICI) score and 90-day modified Rankin score (mRS) were evaluated. TICI score of 2B or greater was considered successful recanalization. mRS ≤ 2 was considered good clinical outcome. Social science statistics software was used for data analysis. Results: From June 2019 to November 2021, 126 patients with MCA M1 and/or ICA terminus occlusions who underwent standardized EVT, 76 met the inclusion criteria. Fifty were excluded as they had codominant M2 branches. Mean age was 72 (95% CI 68.69, 75.31) and median NIHSS was 18 (95% CI 16.16, 18.72). Thirty-eight percent (n=34) of subjects were male. Fifty-seven subjects underwent dominant division catheterization during first pass. First pass recanalization was significantly associated with catheterization of dominant branch (Fisher value: 0.0002). Catheterization of dominant branch during first pass was not associated with total number of passes (Fisher value: 0.17). Administration of IV thrombolytics prior to procedure (n=19) was not significantly associated with pre-procedure recanalization (Fisher value: 0.38). Conclusion: Our study suggests that catheterization of dominant branch during thrombectomy is associated with higher rates of first-pass successful recanalization.

Abstract TP13: Is Tenecteplase Associated Recanalization Dependent On Thrombus Length?

Introduction: Recent evidence supports that IV tenecteplase (TNK) is non-inferior to IV alteplase when administered to eligible patients with acute ischemic stroke (AIS). Studies suggest that alteplase does not effectively lyse clots ≥ 8mm. However, the neurovascular characteristics of TNK are rapidly evolving. The aim of this study was to evaluate the efficacy of TNK in clot lysis ≥ 8mm as measured by hyperdense sign on CT for internal carotid artery (ICA) and middle cerebral artery (MCA M1 and M2 segment) occlusion. Methods: We conducted a retrospective cohort study of prospectively collected AIS patients who presented to our comprehensive stroke center, received TNK, and had hyperdense sign on CT head. Hyperdense signs were detected using 0.625 mm slices in retrospective fashion, blinded to the clinical scenario with regards to laterality. Revascularization was defined as modified Thrombolysis in Cerebral Infarction (mTICI) score on first run of digital subtraction angiography prior to intervention, follow up CTA or MRA without large vessel occlusion (LVO), and/or with improved clinical symptoms that correlate with hyperdense sign. Social science statistics software was used for data analysis. Results: From October 2020 to June 2022, out of 77 AIS patients who received TNK, 25 subjects (≥ 8mm, n=19) had associated hyperdense signs. Mean age was 67.16 (95% CI 60.05, 74.27). Median NIHSS was 14 (95% CI 11.378, 19.50). Mean thrombus length was 17.64 mm (95% CI, 13.26, 22.02). Twenty-one percent (n=4) of 19 subjects with hyperdense signs ≥ 8mm recanalized post-TNK (n=3 angiography, n=1 MRA). Thirty-three percent (n=2) of 6 subjects with hyperdense signs &lt; 8mm recanalized post-TNK. There was not a statistically significant difference between recanalization rates in hyperdense signs ≥ 8mm or &lt; 8mm (Fisher exact test statistic=0.61). There was not a statistically significant difference between intracerebral hemorrhage rates in hyperdense signs ≥ 8mm or &lt; 8mm (Fisher exact test statistic=1). Conclusion: Our study suggests that tenecteplase may be associated with higher thrombolytic-related recanalization in thrombi measuring 8mm or greater as compared to historical alteplase experience. Larger, prospective studies are needed to corroborate our findings.

A Reliable Nonhuman Primate Model of Ischemic Stroke with Reproducible Infarct Size and Long-term Sensorimotor Deficits.

A nonhuman primate model of ischemic stroke is considered as an ideal preclinical model to replicate various aspects of human stroke because of their similarity to humans in genetics, neuroanatomy, physiology, and immunology. However, it remains challenging to produce a reliable and reproducible stroke model in nonhuman primates due to high mortality and variable outcomes. Here, we developed a focal cerebral ischemic model induced by topical application of 50% ferric chloride (FeCl3) onto the MCA-M1 segment through a cranial window in the cynomolgus monkeys. We found that FeCl3 rapidly produced a stable intraarterial thrombus that caused complete occlusion of the MCA, leading to the quick decrease of the regional cerebral blood flow in 10 min. A typical cortical infarct was detected 24 hours by magnetic resonance imaging (MRI) and was stable at least for 1 month after surgery. The sensorimotor deficit assessed by nonhuman primate stroke scale was observed at 1 day and up to 3 months after ischemic stroke. No spontaneous revascularization or autolysis of thrombus was observed, and vital signs were not affected. All operated cynomolgus monkeys survived. Our data suggested that FeCl3-induced stroke in nonhuman primates was a replicable and reliable model that is necessary for the correct prediction of the relevance of experimental therapeutic approaches in human beings.

RAPID CT Perfusion-Based Relative CBF Identifies Good Collateral Status Better Than Hypoperfusion Intensity Ratio, CBV-Index, and Time-to-Maximum in Anterior Circulation Stroke.

Information of collateral flow may help to determine eligibility for thrombectomy. Our aim was to identify CT perfusion-based surrogate parameters of good collateral status in acute anterior circulation ischemic stroke. In this retrospective study, we assessed the collateral status of 214 patients who presented with acute ischemic stroke due to occlusion of the MCA M1 segment or the carotid terminus. Collaterals were assessed on dynamic CTA images analogous to the multiphase CTA score by Menon et al. CT perfusion parameters (time-to-maximum, relative CBF, hypoperfusion intensity ratio, and CBV-index) were assessed with RAPID software. The Spearman rank correlation and receiver operating characteristic analyses were performed to identify the parameters that correlate with collateral scores and good collateral supply (defined as a collateral score of ≥4). The Spearman rank correlation was highest for a relative CBF < 38% volume (ρ = -0.66, P < .001), followed by the hypoperfusion intensity ratio (ρ = -0.49, P < .001), CBV-index (ρ = 0.51, P < .001), and time-to-maximum > 8 seconds (ρ = -0.54, P < .001). Good collateral status was better identified by a relative CBF < 38% at a lesion size <27 mL (sensitivity of 75%, specificity of 80%) compared with a hypoperfusion intensity ratio of <0.4 (sensitivity of 75%, specificity of 62%), CBV-index of >0.8 (sensitivity of 60%, specificity of 78%), and time-to-maximum > 8 seconds (sensitivity of 68%, specificity of 76%). Automated CT perfusion analysis allows accurate identification of collateral status in acute ischemic stroke. A relative CBF < 38% may be a better perfusion-based indicator of good collateral supply compared with time-to-maximum, the hypoperfusion intensity ratio, and the CBV-index.

A Case Report: A 37 Years-old Women with Takayasu Arteritis

Background: A rarity of form of vasculitis, also known as TAK, induces inflammation in the walls of the major arteries in the body: the aorta and its main branches. The disease results from a body attack and inflammation of the walls of the arteries caused by the body's own immune system.&#x0D; Case Presentation: A 37-years-old women had complaints of fever, giddiness, weakness of right upper limb and lower limb since1 day. After undergoing whole blood count, liver function examination, renal and MRI function checks, CT scan, angiography, etc. was studied. She was diagnosed with takayasu arteritis. She had past medical history of neck pain and numbness since January 2020. For these complaints her family members referred her in private hospital. There is no significant history of surgery in present, lower segment caesarean section and piles operation was done previously. Physical findings were normal except the Glasgow Coma Scale score was 11 that is, patient was semi-conscious, In General appearance patient activity was dull and weak due disease condition, Patient’s all routine investigations were normal except few like Total WBC count was increased (21,500cell /cm) due to increased infection, Granulocytes were increased that is 75 % due to infection and autoimmune disease, ESR was increased that is52mm/h. Angiography showed block in the right common carotid artery, MRI- showed Acute infract in left fronto temporo parietal region involving insular par ventricular white matter, absent flow in distal M1 segment of MCA.&#x0D; Conclusion: The most frequently involved arteries and the angiographic trends in this Takayasu Arteritis study were subclavian arteries and carotid arteries. The difference between angiographic characteristics may lead to clinical differences. Operations and surgery should be carried out at various points in the course of the disease.

Abstract 1122‐000009: Impact of RNF213 p.R4810K Variant on Endovascular Therapy Outcome for Acute Large Vessel Occlusion Stroke

Introduction : The ring finger protein 213 gene ( RNF213 ) has been identified as a susceptibility gene for moyamoya disease, and the p.R4810K polymorphism as a founder variant commonly found in East Asian patients. 1 A recent large case‐control study including over 46,958 Japanese subjects reported that the RNF213 p.R4810K variant was a strong risk factor for Japanese cerebral infarction: the variant was found in 5.2% of patients with non‐cardioembolic stroke and in 2.1% of healthy controls. 2 Mechanical thrombectomy (MT) is a standard treatment for acute ischemic stroke due to occlusion of the internal carotid artery and M1 segment of the middle cerebral artery, but in East Asians, about 15–25% of LVOs for which MT was performed were reportedly caused by intracranial atherosclerotic disease (ICAD). 3 RNF213 p.R4810K variant may be involved to some extent in ICAD‐related LVO of Asian patients undergoing MT. In this study, we aimed to investigate the impact of RNF213 p.R4810K variant on EVT for anterior circulation LVO stroke. Methods : Of the consecutive ischemic stroke patients from 2011 to 2021 seen in our institute, patients who underwent EVT for acute occlusion of the intracranial ICA or M1 segment of MCA and signed a consent form for RNF213 genotyping were included. Outcomes were instant re‐occlusion, final modified Thrombolysis in Cerebral Infarction (mTICI) ≥2b reperfusion, early re‐occlusion, and modified Rankin Scale (mRS) score 0–2 at 90 days. Instant re‐occlusion was defined as occurrence of re‐occlusion during the procedure, whereas early re‐occlusion as re‐occlusion detected on magnetic resonance angiography within 2 weeks after confirmation of successful reperfusion at the end of the procedure. 4 Results : Of the 277 patients (128 women [46.2%]; median age, 76 years) analyzed, 10 (3.6%) patients had the RNF213 p.R4810K variant. The variant carriers were younger (67 years vs. 76 years, P &lt;0.01), more frequently received angioplasty (40.0% vs. 12.0%, P &lt;0.01), and more frequently had intracranial atherosclerotic disease‐related LVO as a cause of acute LVO (70.0% vs. 8.6%, P &lt;0.01) than non‐carriers. The variant carriers showed higher rates of instant re‐occlusion (40.0% vs. 5.6%, P &lt;0.01), but there were no statistically significant inter‐group differences for the final mTICI ≥2b reperfusion rate between carriers and non‐carriers (100.0% vs. 81.6%, P = 0.22). Early re‐occlusion was more frequent in the variant carriers than non‐ carriers (60.0% vs. 0.4%, P&lt;0.01) with no intergroup difference in the rate of repeated EVT (67.7% vs. 100.0%, P = 0.71). There were no statistically significant inter‐group differences for achievement of mRS score 0–2 (60.0% vs. 51.7%, P = 0.75) Conclusions : Both instant and early re‐occlusion were more frequent in the RNF213 p.R4810K variant carriers who had received EVT for acute anterior circulation LVO than in the non‐carriers. Potential impact of RNF213 polymorphism status on EVT outcomes was clarified.

Abstract 1122‐000171: Unusual Multicompartmental Intracranial Hemorrhage After Tenecteplase Administration

Introduction : The 2019 AHA/ASA updated Guidelines for the Early Management of Patients with Acute Ischemic Stroke mention tenecteplase (TNK) as a reasonable therapy in patients without contraindications for IV fibrinolysis who are also eligible to undergo mechanical thrombectomy. We describe a case of acute left MCA ischemic stroke treated with IV TNK (IV bolus of 0.25 mg/kg) followed by mechanical thrombectomy with subsequent multicompartmental intracranial hemorrhages unrelated to area of infraction. Methods : A retrospective review at a single center university hospital was performed for all intravenous TNK administrations outside of a clinical trial setting from October 2020 to July 2021. Results : A 61‐year‐old male with history of HTN and cardiomyopathy (EF&lt;20%). Presented with sudden onset right sided weakness, aphasia and left gaze. Presenting NIHSS was 28. CT head with hyperdense left MCA sign and ASPECTS score of 10. CTA confirmed proximal left MCA M1 segment occlusion. IV TNK was given within 01:23 hours of symptoms onset. Subsequently, patient underwent emergent mechanical thrombectomy for disabling large vessel occlusion stroke. Spontaneous near complete recanalization of left MCA occlusion was noted on initial angiography run with small non flow limiting distal thrombi visualized in the distal MCA territories. Immediate post procedure CT head was negative for any intracranial hemorrhage. Patient’s exam was noted to improve to NIHSS of 2. Approximately 6 hours after the TNK administration, patient became acutely unresponsive with NIHSS of 26. With Glasgow Coma Scale 7 patient required emergent intubation. CT head revealed bilateral cerebellar intraparenchymal hemorrhages, extensive subarachnoid hemorrhage in basal cisterns and within the sulci in bilateral frontotemporal regions, as well as subdural hemorrhages along the falx and tentorial dural folds. Hypertonic saline was administered followed by emergent extraventricular drain placement. Tranexamic acid 1000 mg was given as emergent reversal, fibrinogen level was 155 mg/dL. Despite aggressive medical management and over following 24 hours, exam worsened with loss of pupillary reflexes. Patient was terminally extubated 2 days after initial presentation in accordance with his advance directives. Conclusions : Tenecteplase was a reasonable choice in this case given LVO and disabling stroke. The patient’s neurological exam improved significantly after TNK with evidence of spontaneous recanalization. However, patient’s multicompartmental intracranial hemorrhages unrelated to area of infraction were unusual in the absence of any vascular lesions to predispose hemorrhage based on CT and conventional angiography. Further observational studies are warranted to evaluate similar complications of Tenecteplase administration and their occurrence rates.

Blind exchange technique to facilitate large-bore aspiration catheter navigation during stroke thrombectomy

ObjectivesOptimizing mechanical thrombectomy (MT) techniques is an essential facet of our developing field. Herein, we describe the “Blind exchange” (BE) technique; an alternative fashion of efficiently performing stent-retriever (SR) coupled with contact aspiration thrombectomy (aspiration-retriever technique for stroke-ARTS). MethodsA prospectively collected MT database was reviewed from July 2018-February 2020. We included all consecutive patients with anterior circulation large vessel occlusions in whom BE technique was performed. According to the response of the retriever, the decision to add an aspiration catheter (AC) for ARTS was made. The microcatheter was then fully retracted and the AC tracked over the deployed SR wire in a BE fashion. The primary outcome was technical success and safety measures included procedural-related complications. ResultsOne hundred nineteen patients were identified, mean age was 66.7 ± 15.8 years and 57(47.9%) were males. Twenty-six patients (21.8%) had intracranial ICA occlusion and 93(78.2%) had MCA-M1 segment occlusion. The median ASPECTS was 7(IQR;8–9), baseline NIHSS score was 18(IQR;14–21), and procedure time was 36(IQR;25–57) minutes. IV-tPA was used in 26(21.8%) of cases. Successful reperfusion (eTICI2b-3) was achieved in 100% of cases including full reperfusion (eTICI3) in 67(56.3%) of cases. The AC was successfully navigated into the target lesion without any complications in all cases. Symptomatic intracranial hemorrhage occurred in 4.2% of patients. The rates of 90-day mRS0–2 and mortality were 44.3% and 12.5%, respectively. ConclusionBE is a safe and feasible alternative technique of navigating large bore AC into the intracranial vasculature while performing ARTS.

Widening the Indications for Intrasaccular Flow Disruption: WEB 17 in the Treatment of Aneurysm Locations Different from Those in the Good Clinical Practice Trials.

The safety and efficacy of the Woven EndoBridge (WEB) device has been shown in multiple good clinical practice trials, whereas aneurysm locations in these trials were restricted to bifurcation aneurysms located at the circle of Willis (MCA bifurcation, ICA bifurcation, anterior communicating artery, basilar artery tip). Our aim was to evaluate angiographic and clinical results with the WEB 17 in aneurysm locations that were excluded from the good clinical practice trials, assuming that the angiographic and clinical results are similar to those of the good clinical practice trials for aneurysms in traditional locations. We performed retrospective analysis of immediate and follow-up results of aneurysms in locations outside the good clinical practice trials in which the WEB 17 was used on an intention-to-treat approach. Between June 2017 and May 2020, forty-seven aneurysms in 44 patients met the inclusion criteria. Aneurysm locations were the ICA posterior communicating artery in 19 (40.3%), the ICA paraophthalmic or choroidal locations in 4 (8.6%), anterior cerebral artery A2 segment in 13 (27.7%), MCA M1 segment in 2 (4.3%), posterior cerebral artery P2 segment in 2 (4.3%), PICA in 3 (6.4%), and the superior cerebellar artery in 4 (8.4%) cases. The procedure-related morbidity and mortality rates in the entire series were 0.0%. The early and late (<12 and >12 months) complete occlusion rates were 63.9% (23/36) and 77.8% (14/18), respectively. The WEB 17 is safe and effective in aneurysm locations different from the traditional bifurcation aneurysms included in the good clinical practice trials. Further studies will help to define the entire spectrum of aneurysm morphologies and locations suitable for the WEB 17.

Abstract TP11: CTA Collateral Status and Final Infarct Distribution Following Thrombectomy in Stroke Patients With Large Vessel Occlusion

Aim: The angiographic collateral status is a major predictor of final infarct volume in patients with large vessel occlusion (LVO). In this study, we assessed the effects of collateral status on final infarct lesion distribution after thrombectomy. Methods: Acute ischemic stroke patients with occluded terminal ICA and/or MCA M1 segment who underwent thrombectomy and had a follow up MRI within a week were included. The angiographic collateral status was evaluated on pre-thrombectomy CTA and graded according to Miteff et al. (Brain 2009;132(8):2231-8). The final infarct lesion was segmented on DWI; and using voxel-wise general linear model, we determined the correlation of final infarct volume with post-thrombectomy TICI (thrombolysis in cerebral infarction) score, and collateral status - as a covariate. Results: Among 106 patients with terminal ICA and/or MCA M1 occlusion in analysis, final infarct volume had a significant correlation with TICI reperfusion score (rho=0.384, p&lt;0.001), CTA collaterals (rho=0.221, p=0.023), and TICIxCollaterals interaction term (rho=0.446, p&lt;0.001). Voxel-wise analysis (Figure) showed that better reperfusion after thrombectomy (i.e. higher TICI) was associated with preservation of MCA territory cortex and deep white matter (green). The voxel-wise interaction analysis of TICI and CTA collateral status showed that poor collateral status is associated with infarction of the MCA-PCA border zone (red). Alternatively, good collaterals may preserve the peripheral edges of the MCA territory and MCA-ACA border zone (blue). Conclusion: A successful thrombectomy in LVO stroke patients can preserve the cortical and deep white matter of MCA territory - including eloquent speech and motor regions - while CTA collateral status mainly determines the fate of the MCA-PCA border zone. On the other hand, lentiform nuclei tend to infarct despite successful reperfusion and good CTA collateral status.

Abstract WP61: Artificial Intelligence for Automated Detection of Large Vessel Occlusion Strokes

Introduction: Identification of Large Vessel Occlusion (LVO) in acute ischemic stroke (AIS) patients is critical for proper decision-making. Limited availability of trained experts and delays in LVO recognition can have a detrimental effect on outcomes. We sought to evaluate an artificial intelligence-based algorithm for LVO detection in AIS. Methods: A retrospective analysis of a prospectively-collected database of AIS patients admitted to a large volume stroke center between 2014-2018 was performed. Experienced vascular neurologists graded CTA for presence and site of LVO. Concurrently, studies were analyzed by the Viz-LVO Algorithm® version 1.4 (GA) - a convolutional neural network programmed to detect occlusions from the internal carotid artery terminus (ICA-T) to the sylvian fissure, which would include all MCA M1-segment and most M2-segment lesions. CTA readings were categorized as LVOs (ICA-T, MCA-M1, MCA-M2) versus non-LVOs/more distal occlusions. Comparisons between human and AI-based readings were done by accuracy analysis and calculating Cohen’s kappa. Results: A total of 610 CTAs were analyzed. The AI algorithm rejected 3.4% of the CTAs due to poor quality. Viz-LVO identified LVOs with an overall sensitivity of 81.3%, specificity of 87.8%, and accuracy of 83.2% (AUC 0.845 (95%CI:0.81-0.88, p&lt;0.001). Table 1 shows the results per occlusion site. Accuracy was higher for ICA-T and M1 occlusions as compared to M2 occlusions. The mean run time of the algorithm was 2.78±0.5minutes. Conclusion: Our study demonstrates that automated AI reading allows for fast and accurate identification of LVO strokes. Future efforts should be made to improve the detection of the more distal occlusions.

Visualization of Lenticulostriate Arteries on CT Angiography Using Ultra-High-Resolution CT Compared with Conventional-Detector CT.

The newly developed ultra-high-resolution CT is equipped with a 0.25-mm detector, which has one-half the conventional section thickness, one-half the in-plane detector element width, and one-half the reconstructed pixel width compared with conventional-detector CT. Thus, the ultra-high-resolution CT scanner should provide better image quality for microvasculature than the conventional-detector CT scanners. This study aimed to determine whether ultra-high-resolution CT produces superior-quality images of the lenticulostriate arteries compared with conventional-detector CT. From February 2017 to June 2017, thirteen patients with aneurysms (4 men, 9 women; mean age, 61.2 years) who underwent head CTA with both ultra-high-resolution CT and conventional-detector CT were enrolled. Two board-certified radiologists determined the number of all lenticulostriate arteries on the CTA coronal images of the MCA M1 segment reconstructed from 512 matrixes on conventional-detector CT and 1024 matrixes on ultra-high-resolution CT. There were statistically more lenticulostriate arteries identified on ultra-high-resolution CT (average, 2.85 ± 0.83; 95% CI, 2.509-3.183) than on conventional-detector CT (average, 2.17 ± 0.76; 95% CI, 1.866-2.480) (P = .009) in 16 of the total 26 MCA M1 segments. Improvements in lenticulostriate artery visualization were the result of the combined package of the ultra-high-resolution CT scanner plus the ultra-high-resolution scanning protocol, which includes higher radiation doses with lower than the national diagnostic reference levels and stronger adaptive iterative dose-reduction processing. This package for ultra-high-resolution CT is a simple, noninvasive, and easily accessible method to evaluate microvasculature such as the lenticulostriate arteries.

Visualization of large vessel occlusion, clot extent, and collateral supply using volume perfusion flat detector computed tomography in acute stroke patients.

Background Flat detector computed tomography angiography (FDCTA) can be reconstructed from volume perfusion flat detector computed tomography (VP-FDCT). Thus, CTA equivalent stroke imaging might be feasible within the angio suite. Purpose To evaluate the diagnostic accuracy of FDCTA in detecting large vessel occlusion (LVO) and collateral supply in acute stroke patients. Material and Methods Sixteen patients with LVO of the anterior circulation were analyzed retrospectively. Each patient underwent a multimodal CT stroke protocol, subsequent VP-FDCT, and digital subtraction angiography (DSA) for endovascular stroke therapy. Angiographic images reconstructed secondarily from VP-FDCT were evaluated with regard to visualization of LVO, Collateral Score (CS), Clot Burden Score (CBS), and image quality. Results Image quality of FDCTA was sufficient for diagnosis with a strong correlation between CTA and FDCTA (median score: CTA = 4 ± 0.447; FDCTA = 4 ± 0.5). Detection of LVO could be achieved with high sensitivity and specificity for FDCTA and CTA (97.9%, 95% confidence interval [CI] = 96.0–99.9; 92.6%, 95% CI = 84.3–100.0 vs. 96.8%, 95% CI = 93.2–100.0; 86.3%, 95% CI = 88.2–95.2). CBS and CS assessment showed no significant difference between FDCTA and CTA for both readers (reader1CBS: P = 0.751, reader1CS: P = 0.718; reader2CBS: P = 0.164; reader2CS: P = 0.582) and an excellent interrater agreement (CTACBSICC = 0.984, FDCTACBSICC = 0.951; CTACSICC = 0.754, FDCTACSICC = 0.789). Conclusion FDCTA, reconstructed from VP-FDCT data, allows reliable detection of ICA or MCA M1 segment occlusion comparable to CTA and may provide information concerning the clot extent with sufficient image quality.

Novel 4D-Flow MRI to Assess Quantitative Arterial Hemodynamic Response after Brain Stereotactic Radiosurgery (SRS) for Cerebral Arteriovenous Malformations (AVMs)

For unresectable cerebral AVMs, ablative SRS is standard of care. However, obliteration may take years, during which period risk of hemorrhage is uncertain. 4D-Flow MRI, a velocity-encoded phase-contrast MRI technique used to assess cardiac hemodynamics, has potential as an early marker of treatment response to SRS. Here, we assess changes in blood flow in AVM feeding arteries after brain SRS using 4D-Flow. Patients: Retrospective review of AVM patients treated with SRS at a single institution. Four patients were identified who underwent 4D-Flow MRI prior to or within 1 month of treatment (baseline) and at least one subsequent time point (first-follow up). Imaging: Imaging was performed on a 3T scanner with dedicated head coil. 4D-Flow sequences were based on a 3D spoiled gradient echo sequence with resolution 1.12 x 0.98 x 1.6-1.8 mm. Three directional velocity encoding gradients were used with Venc 100-200 cm/s. In addition, T1 post-contrast, T2, and 3D-Time of flight (TOF) angiography images were obtained to identify the AVM nidus and feeding arteries. Analysis: In each case a feeding artery was selected that could be traced distally to the AVM on both baseline and follow up images. Measurements were made in two locations within each feeding artery. A distal measurement was made as close to the AVM nidus as possible. A proximal measurement was made in the most proximal segment of the feeding artery (e.g. M1 segment of MCA). A control measurement was made in the corresponding contralateral proximal artery. Blood flow was measured using imaging software with FDA clearance for clinical 4D flow post-processing for cardiac MRI. Changes in blood flow were assessed for significance using two-tailed paired t-tests. Baseline AVM nidus volume ranged from 4.6-10.2mL. All AVMs were treated with single fraction SRS, prescription dose 16-20 Gy. Follow up time ranged from 3-17 months. Baseline and follow up blood flow measurements in L/min are displayed in table 1. In feeding arteries, blood flow decreased by a mean of 49% proximally and by 54% distally (both p<0.05). There was no detectable change in blood flow in control arteries (mean change 12%, p = 0.28). Blood flow through cerebral AVM feeding arteries decreases significantly after SRS by time of first follow up as assessed by 4D-Flow MRI. 4D-Flow is a promising early marker of AVM response to SRS. Future studies are needed to determine if this hemodynamic response correlates to decreased risk of hemorrhage prior to radiographic AVM obliteration.Abstract 232; Table 1PatientSpetzler-Martin GradeDistal BaselineDistal Follow UpProximal BaselineProximal Follow UpControl BaselineControl Follow Up130.120.040.500.210.230.24240.290.130.560.280.030.05340.160.070.410.180.080.07420.420.240.510.350.250.26meann/a0.250.120.490.250.150.16SDn/a0.130.080.070.070.100.10 Open table in a new tab

Cushing Reflex and Importance during Treatment of Cerebrovascular Diseases via Endovascular Route

Aim: Assessment of the Cushing reflex developing during mechanical thrombectomy in a case presenting with acute ischemic stroke.Case: A 59-year-old male patient had CT angio tests due to speaking disorder and right lateral weakness developing 5 hours earlier. Acute infarctus was observed in the left MCA irrigation area with M1 segment occlusion observed in the left MCA. The decision was made to treat the patient with mechanical thrombectomy and he was transferred to the interventional neuroradiology unit. Under general anesthesia during navigation of the thromboaspiration catheter to the clot localization as the procedure was technically advancing routinely, with sudden development of bradycardia and hypertension the neuroradiology team was warned, and 1 mg IV atropine was administered for bradycardia.Simultaneously contrast material injection through the guide catheter showed the MCA M1 segment had ruptured and extravasation had developed.Conclusion: The Cushing reflex is a situation characterized by bradycardia and hypertension in cerebrovascular events causing sudden intracranial pressure increases. The most common situations observed during treatment of cerebrovascular diseases via the endovascular route is intracranial hemorrhage linked to arterial rupture. Prevention of the mortality and morbidity linked to hemorrhagic complications developing during endovascular treatment is based on early awareness and rapid treatment. Additionally, as extravasation is commonly not observed radiologically, the anesthesia team should be on the alert for the Cushing reflex and when variations of hemodynamic parameters in accordance with the Cushing response are observed, informing the operation team immediately has vital importance.

Abstract TP31: Variability of Stroke Patients Meeting Endovascular Stroke Trial Criteria in a Non-clinical Trial Setting

Introduction: Five randomized trials proving the efficacy and safety of mechanical embolectomy for ischemic stroke patients used differing radiological methods to select patients for treatment. Hypothesis: The percentage of patients evaluated in a non-clinical trial setting that would meet radiological criteria to be included in the five trials will differ substantially. Methods: Retrospective study of consecutive ischemic stroke patients who were considered for endovascular stroke therapy based on confirmed intracranial large vessel occlusion (M1, M2, or carotid terminus) at an academic medical center from April 2010 - November 2014. All patients underwent CT perfusion and CT angiogram. Results: The table shows baseline characteristics of 119 patients. Median age was 69 years (IQR 57-79) and median NIHSS 18 (IQR 14-21). Most patients had ASPECTS score ≥ 6 (n=105, 88.2%). The M1 segment of MCA was the most common vessel occluded (n=81, 68%). All 119 patients (100%) met radiological criteria for MR CLEAN while 105 (88.2%) met criteria for SWIFT-PRIME, 96 (80.7%) for REVASCAT, 80/116 (69.0%) for EXTEND IA, and 74 (62.2%) for ESCAPE. IV TPA was given to 58 patients (48.7%) and acute endovascular stroke therapy attempted in 66 (55.5%). Any intracranial hemorrhage was more common in the patients treated with endovascular therapy than in those who were not (36% vs. 17%, p=0.025). The frequency of symptomatic ICH did not significantly differ between these two groups (6.1% vs 3.8%, p=0.691). Conclusions: The percentage of patients with acute stroke and large vessel occlusion that would qualify for endovascular stroke trials based on radiological criteria varies considerably (62%-100%) in a non-clinical trial cohort from an academic comprehensive stroke center. Additional individual patient characteristics influence treatment decisions in non-clinical trial settings.

Abstract W P3: Core Infarct Size Agreement Between NCCT And DWI: Implications For Patient Selection For IAT

Background: Pre-treatment infarct volume is an important determinant of outcome after intra-arterial therapy (IAT). Ongoing IAT trials are using MRI DWI and noncontrast CT (NCCT) to quantify core infarction on the Alberta Stroke Program Early CT Score (ASPECTS) for patient selection. However, the degree to which these imaging approaches agree remains uncertain. Methods: Consecutive acute ischemic stroke patients over a 2-year period were included in this analysis if they had occlusion of the intracranial ICA or MCA M1 segment and underwent CT and MRI within 1 hour of each other and within 8 hours of onset. Two raters independently scored ASPECTS on both NCCT and DWI in separate reading sessions. Modified DWI-ASPECTS (including only &gt;20% regional involvement) was also scored. Differences were resolved by consensus, and the consensus scores were compared across the three scales using Bland-Altman analysis. Agreement was also assessed based on a dichotomized ASPECTS threshold of 0-5 vs. 6-10 using the kappa statistic. Results: There were 74 patients with mean age 69.6 years and median NIHSS 17. Occlusions involved the ICA in 27 (36 %) patients. Mean interval between CT and MRI was 37±15 minutes. The median (IQR) ASPECTS scores were 7 (4-8) on NCCT, 5 (3-7) on DWI (P&lt;0.0001 vs. NCCT), and 7 (4-8) on modified DWI (P=0.42 vs. NCCT). In Bland-Altman analysis, NCCT ASPECTS was mean 1.4 points (95%CI: -1.9 to 4.7 points) higher than DWI ASPECTS, and was mean 0.2 points (95%CI: -3.4 to 3.9 points) higher than modified DWI ASPECTS. For NCCT, DWI, and modified DWI, ASPECTS 6-10 scores were seen in 69%, 41%, and 60% of patients, respectively. The inter-scale agreement for ASPECTS &gt;5 was only moderate between DWI and NCCT (kappa=0.47) and good between modified DWI and NCCT (kappa=0.68). However, differences between modified DWI and NCCT for dichotomized ASPECTS were found in 15% of patients. Conclusion: Using ASPECTS, modified DWI has better agreement with NCCT than standard DWI evaluation. However, there is a sizeable proportion of patients where dichotomized ASPECTS differs even with the use of modified DWI. This has important implications for patient selection in clinical trials.