Leptomeningeal Collaterals Research Articles

Arterial transit artifacts on arterial spin labeling MRI can predict cerebral hyperperfusion after carotid endarterectomy: an initial study

To investigate whether preoperative arterial spin labeling (ASL) MRI can predict cerebral hyperperfusion after carotid endarterectomy (CEA) in patients with carotid stenosis. Consecutive patients with carotid stenosis who underwent CEA between May 2015 and July 2021 were included. For each patient, a cerebral blood flow ratio (rCBF) map was obtained by dividing postoperative CBF with preoperative CBF images from two pseudo-continuous ASL scans. Hyperperfusion regions with rCBF > 2 were extracted and weighted with rCBF to calculate the hyperperfusion index. According to the distribution of the hyperperfusion index, patients were divided into hyperperfusion and non-hyperperfusion groups. Preoperative ASL images were scored based on the presence of arterial transit artifacts (ATAs) in 10 regions of interest corresponding to the Alberta Stroke Programme Early Computed Tomography Score methodology. The degree of stenosis and primary and secondary collaterals were evaluated to correlate with the ASL score. Logistic regression and receiver operating characteristic curve analyses were performed to assess the predictive ability of the ASL score for cerebral hyperperfusion. Of 86 patients included, cerebral hyperperfusion was present in 17 (19.8%) patients. Carotid near occlusion, opening of posterior communicating arteries with incomplete anterior semicircle, and leptomeningeal collaterals were associated with lower ASL scores (p < 0.05). The preoperative ASL score was an independent predictor of cerebral hyperperfusion (OR = 0.48 [95% CI [0.33-0.71]], p < 0.001) with the optimal cutoff value of 25 points (AUC = 0.98, 94.1% sensitivity, 88.4% specificity). Based on the presence of ATAs, ASL can non-invasively predict cerebral hyperperfusion after CEA in patients with carotid stenosis. • Carotid near occlusion, opening of posterior communicating arteries with incomplete anterior semicircle, and leptomeningeal collaterals were associated with lower ASL scores. • The ASL score performed better than the degree of stenosis, type of CoW, and leptomeningeal collaterals, as well as the combination of the three factors for the prediction of cerebral hyperperfusion. • For patients with carotid stenosis, preoperative ASL can non-invasively identify patients at high risk of cerebral hyperperfusion after carotid endarterectomy without complex post-processing steps.

Small vessel disease and collaterals in ischemic stroke patients treated with thrombectomy.

To determine the influence of the cerebral small vessel disease (SVD) burden on collateral recruitment in patients treated with mechanical thrombectomy (MT) for anterior circulation acute ischemic stroke (AIS). Patients with AIS due to large vessel occlusion (LVO) from the Thrombectomie des Artères Cérébrales (THRACE) trial and prospective cohorts from 2 academic comprehensive stroke centers treated with MT were pooled and retrospectively analyzed. Collaterals' adequacy was assessed using the American Society of Interventional and Therapeutic Radiology/Society of Interventional Radiology (ASITN/SIR) score on initial digital subtraction angiography and dichotomized as good (3,4) versus poor (0-2) collaterals. The SVD burden was rated with the global SVD score on MRI. Multivariable logistic regression analyses were used to determine relationships between SVD and ASITN/SIR scores. A total of 312 participants were included (53.2% males, mean age 67.8 ± 14.9years). Two hundred and seven patients had poor collaterals (66.4%), and 133 (42.6%) presented with any SVD signature. In multivariable analysis, patients demonstrated worse leptomeningeal collaterality with increasing SVD burden before and after adjustment for SVD risk factors (adjusted odds ratio [aOR] 0.69; 95%CI [0.52-0.89] and aOR 0.66; 95%CI [0.5-0.88], respectively). Using individual SVD markers, poor collaterals were significantly associated with the presence of lacunes (aOR 0.40, 95% CI [0.20-0.79]). Our study provides evidence that in patients with AIS due to LVO treated with MT, the burden of SVD assessed by pre-treatment MRI is associated with poorer recruitment of leptomeningeal collaterals.

Clinical and radiological factors predicting stroke outcome after successful mechanical intervention in anterior circulation.

The recanalization effect of large-vessel occlusion (LVO) in anterior circulation is well documented but only some patients benefit from endovascular treatment. We analysed clinical and radiological factors determining clinical outcome after successful mechanical intervention. We included 146 patients from the Prague 16 study enrolled from September 2012 to December 2020, who had initial CT/CTA examination and achieved good recanalization status after mechanical intervention (TICI 2b-3). One hundred and six (73%) patients achieved a good clinical outcome (modified Rankin Scale 0–2 in 3 months). It was associated with age, leptomeningeal collaterals (LC), onset to intervention time, ASPECTS, initial NIHSS, and leukoaraiosis (LA) in univariate analysis. The regression model identified good collateral status [odds ratio (OR) 5.00, 95% confidence interval (CI) 1.91–13.08], late thrombectomy (OR 0.24, 95% CI 0.09–0.65), LA (OR 0.44, 95% CI 0.19–1.00), ASPECTS (OR 1.45, 95% CI 1.08–1.95), and NIHSS score (OR 0.86, 95% CI 0.78–0.95) as independent outcome determinants. In the late thrombectomy subgroup, 14 out of 33 patients (42%) achieved a favourable clinical outcome, none of whom with poor collateral status. The presence of LC and absence of LA predicts a good outcome in acute stroke patients after successful recanalization of LVO in anterior circulation. Late thrombectomy was associated with higher rate of unfavourable clinical outcome. Nevertheless, collateral status in this subgroup was validated as a reliable selection criterion.

Transcranial Doppler After Endovascular Treatment to Evaluate Collateral Status and Outcomes in Patients With Large‐Vessel Occlusion

Background Recent advances in endovascular therapy (EVT) have led to significant improvements in functional outcomes of patients with stroke. However, early neurological deterioration after EVT has remained a concerning issue. This cohort study was designed to assess the feasibility of early transcranial Doppler (TCD) after EVT and to identify associations between TCD findings and early neurological deterioration. Methods Between October 16, 2020, and March 28, 2021, we recruited 20 patients with acute ischemic stroke with large‐vessel occlusion who underwent EVT. Five patients were excluded because of a poor temporal window; 2 had an unsuccessful intervention. Using TCD, we measured peak systolic velocity, end‐diastolic velocity, mean flow velocity, and pulsatility index for all selected arteries before and within 60 minutes after EVT. We also examined the association between active leptomeningeal collateral flow after EVT and early neurological deterioration. Patients were followed for 3 months, and disability was measured using the modified Rankin scale. Results Two patients had early neurological deterioration with elevated blood pressure and active leptomeningeal flow despite successful EVT. Most patients with poststroke disability (modified Rankin scale&gt;2) had either flow diversion or active leptomeningeal collateral flow in the presence of elevated blood pressure (≥170/93 mm Hg). In cases without early neurological deterioration and in those with a modified Rankin scale&lt;2, we did not observe any flow diversion or active leptomeningeal collateral. They also had a blood pressure of ≤155/85 mm Hg after EVT. All patients with hemorrhagic transformation had evidence of hyperemia on TCD. Conclusions Early TCD is a feasible and safe approach to evaluate cerebral blood flow before and after EVT and identify those at risk of early neurological deterioration. For the next phase of this study, we plan to manage blood pressures based on individualized cerebral flow and the presence of active collateral arteries after EVT.

The Hyperdense middle cerebral artery sign is associated with poor leptomeningeal collaterals in acute ischemic stroke: a retrospective study

BackgroundThe hyperdense middle cerebral artery sign (HMCAS) is an early radiological marker to provide an early diagnosis and to identify ischemia. As reported, HMCAS is associated with heavy clot burden. Moreover, a heavy clot burden may cause obstruction of the orifices of arteries for leptomeningeal collateral flows and can lead to severe clinical conditions. However, the direct relationship between HMCAS and collateral flows remains unclear. Therefore, we explored the association between HMCAS and leptomeningeal collaterals in patients with acute ischemic stroke.MethodsConsecutive ischemic stroke patients were enrolled from January 2015 to April 2021. HMCAS appearance and collateral status were detected by multimodal computed tomography at admission. Logistic regression analyses helped to identify the association between HMCAS, collateral flows and stroke severity.ResultsIn 494 included patients, 180 (36.4%) presented with HMCAS. Ipsilateral collaterals were not seen or less prominent in patients with HMCAS (P < 0.001). The HMCAS appearance was significantly associated with less collaterals (odds ratio 5.17, 95% confidence interval 3.27-8.18, P < 0.001), internal carotid artery + M1/M1 occlusion, the initial stroke severity and follow-up outcomes. Subgroup analyses further confirmed HMCAS as an indicator of poor collaterals in ischemic stroke (all P values < 0.05).ConclusionsHMCAS is associated with poor leptomeningeal collaterals, the stroke severity and a poor neurological outcome. Therefore, the HMCAS appearance can act as an early warning sign for healthcare professionals to be alert for poor collateral flows and poor neurological outcomes in ischemic stroke patients with middle cerebral artery occlusion.

Abstract WMP116: Age-related Dysfunction In Leptomeningeal Collateral Remodeling After Ischemic Stroke

Introduction: The leptomeningeal collaterals (LMCs) are specialized brain surface arterioles that interconnect the major cerebral artery territories. Good outcome following ischemic stroke is highly correlated with high collateral number and function. Unfortunately, with aging and disease, the LMCs demonstrate impaired dilatory capacity, reduced vessel diameter, and even complete vessel loss (rarefaction). The present study examined the chronic remodeling capacity of LMCs following permanent stroke in young and aged mice. Methods: Young and aged C57BL6 mice (5 and 20 months) were subjected to permanent distal middle cerebral artery occlusion (pdMCAO). At 2 weeks or 3 months, LMCs were evaluated for inner diameter and VWF expression (% LMC coverage). We compared the LMCs feeding the occluded MCA territory (LMC ipsi) to the contralateral equivalent vessels (LMC contra). Diameter change is reported as fold change relative to the distal-most arteriole (DMA) associated with each LMC. Results: Young male mice demonstrated increased diameter of LMC ipsi relative to DMA at both 2 weeks (1.36 ± 0.075; n=24 vessels/4 mice, P&lt;0.01) and 3 months after stroke (1.27 ± 0.073, n=19 vessels/2 mice, P&lt;0.01). LMC contra were 0.901 ± 0.064 and 1.01 ± 0.053 for the same time points (n=19 and 10 vessels, P=NS). VWF expression was significantly increased in LMC ipsi at 2 weeks (ipsi 10.9 ± 2.87 vs. contra 2.91 ± 0.82, P&lt;0.05) and neared significance at 3 months (ipsi 6.45 ± 1.54 vs. contra 2.06 ± 0.264, P=0.051). Aged mice demonstrated increased diameter of LMC ipsi relative to DMA at 2 weeks (1.24 ± 0.052, n=25 vessels from 3 mice, P&lt;0.01), but not at 3 months (1.08 ± 0.044, n=14 from 2 mice, P=NS). Notably, the 3 month LMC ipsi vessels demonstrated irregular diameter and characteristics of rarefaction. LMC contra were 0.897 ± 0.032 and 0.967 ± 0.092 for the same time points (n=17 and 8 vessels, P=NS). VWF expression was significantly elevated in LMC ipsi vs. LMC contra at 2 weeks (6.74 ± 1.33 vs. 1.87 ± 0.361, P&lt;0.01), but not at 3 months (2.27 ± 0.387 vs. 1.81 ± 0.398, P=NS). Conclusions: Our data show lasting LMC remodeling in young stroke brain, consisting of increased LMC diameter and expression of VWF. With aging, LMC remodeling is transient and evidence of LMC rarefaction is apparent by 3 months.

Abstract WP8: Blood Pressure And EVT Outcomes By The Baseline Perfusion And Recanalization Timing

Introduction: Leptomeningeal collaterals help maintain cerebral perfusion after the large vessel occlusion (LVO), potentially regulated by systemic blood pressure (BP). We hypothesized that the association between BP and endovascular treatment (EVT) outcomes would differ by the baseline perfusions status and before and after recanalization. Method: From a prospective registry, we identified anterior circulation LVO patients who received EVT ≤24 hours after their onset, had baseline perfusion, and achieved post-EVT mTICI ≥2b. BPs were measured from arrival at 5-minute intervals in the ER and during the procedure. Systolic BPs (SBP) up to 24 hours after EVT were summarized as dropmax (the maximal decrement over two consecutive measurements), incmax (the maximal increment), mean, coefficient of variation, and standard deviation. Baseline perfusion images were quantified using Olea Sphere. Infarct proportion was defined as the volume of final infarct on DWI within the volume of Tmax&gt;6 sec. Significant hemorrhage included PH2 or HBC class 3. 3-month mRS was prospectively collected. Result: A total of 388 LVO patients were included. Mean SBP at arrival was 153 ± 42 mm Hg; the average count of BP measurements was 47 ± 17 per patient.In the adequate baseline perfusion group, i.e., hypoperfusion intensity ratio (HIR) &lt;0.5, SBP parameters were better associated with infarct proportion and functional outcome before the recanalization period; weaker associations were noted after recanalization. In the poor baseline perfusion group, i.e., HIR ≥0.5, SBP parameters before recanalization were partially associated with the infarct proportion but not functional status. No association between SBP parameters and significant hemorrhage was noted. (estimates in Table) Conclusion: Association between BP and patient outcomes differs by baseline perfusion status and before and after recanalization. BP management during the peri-EVT period may therefore need to be individualized.

Abstract WP120: Can Early Transcranial Doppler Ultrasound Predict Early Neurological Deterioration And Risk Of Hemorrhagic Transformation After Endovascular Treatment?

Background: Recent advances in endovascular therapy (EVT) have led to a significant improvement in functional outcomes of patients with stroke. However, early neurological deterioration (END) after EVT has still remained a concerning issue. Reasons for END include reocclusion, hyperperfusion after recanalization, and hemorrhagic transformation. The current study was designed to assess the feasibility of early transcranial Doppler (TCD) after EVT, to identify association between TCD findings and END. Methods: This is a pilot study to assess the feasibility of TCD prior and early (within 60 minutes) after EVT. For all selected arteries, we measured peak systolic velocity, end diastolic velocity, mean flow velocity and pulsatility index. Patients were followed for three months after the intervention and disability was measured using modified Rankin scale (mRS). We examined the possible association between active leptomeningeal collateral flow after EVT and END. Results: Between October 16, 2020, and March 28, 2021, we recruited 20 acute ischemic stroke patients with large vessel occlusion who underwent EVT. Five patients were excluded because of a poor temporal window; two had an unsuccessful intervention. Four patients had END and all of them had active leptomeningeal flow with elevated blood pressure after EVT. In cases without END, we did not observe any flow diversion or active leptomeningeal collateral after EVT.In those without significant post-stroke disability (mRS&lt;2), we did not observe any active leptomeningeal flow or flow diversion with blood pressure of ≤ 155/85. Most patients with post-stroke disability (mRS ≥ 2) had either flow diversion or active leptomeningeal flow in the presence of blood pressure ≥ 170/93. Hyperemia was associated with hemorrhagic transformation, particularly in the presence of elevated blood pressure. All cases with symptomatic hemorrhagic transformation had hyperemia. Conclusion: TCD is a feasible approach early after EVT. It has clinical implications in identifying those with END and risk for sICH. Early TCD after EVT may provide personalized BP management based on individualized cerebral flow and the presence of active collateral flow after EVT. Studies with larger sample size are warranted.

Clinical Implications of Prominent Cortical Vessels on Susceptibility-Weighted Imaging in Acute Ischemic Stroke Patients Treated with Recanalization Therapy.

Prominent cortical vessels on susceptibility-weighted imaging (PCV–SWI) correlate with poor leptomeningeal collaterals. However, little is known about PCV–SWI in recanalization therapy-treated patients with anterior circulation large vessel occlusions (LVO). We investigated PCV–SWI-based assessment of leptomeningeal collaterals and outcome predictions in 100 such patients in an observational study. We assessed PCV–SWI using the Alberta Stroke Program Early CT Score and evaluated leptomeningeal collaterals on multiphase CT angiography (mCTA). Predictive abilities were analyzed using multivariable logistic regression and area of receiver operating curves (AUCs). The extent of PCV–SWI correlated with leptomeningeal collaterals on mCTA (Spearman test, r = 0.77; p < 0.001); their presence was associated with worse functional outcomes and a lower successful recanalization rate (adjusted odds ratios = 0.24 and 0.23, 95% CIs = 0.08–0.65 and 0.08–0.65, respectively). The presence of PCV–SWI predicted outcomes better than good collaterals on mCTA did (C-statistic = 0.84 vs. 0.80; 3-month modified Rankin Scale (mRS) 0–2 = 0.75 vs. 0.67 for successful recanalization). Comparison of AUCs showed that they had similar abilities for predicting outcomes (p = 0.68 for 3-month mRS 0–2; p = 0.23 for successful recanalization). These results suggest that PCV–SWI is a useful feature for assessing leptomeningeal collaterals in acute ischemic stroke patients with anterior circulation LVO and predicting outcomes after recanalization therapy.

Assessment of Collaterals Using Multiphasic CT Angiography in Acute Stroke

The aim of the research was to compare the efficiency of multiphase and single-phase computed tomography (CT) angiography in assessing the leptomeningeal collaterals and in predicting the long-term clinical outcome as well as the risk of hemorrhagic transformation. A prospective study was conducted from October 2016 to May 2018 in consecutive patients who presented within 8 hours of the onset of acute anterior circulation ischemic strokes, with NIHSS (National Institutes of Health Stroke Scale) scores ≥5. They underwent triple-phase cerebral CT angiography, and the collaterals were assessed separately using both single-phase and multiphase techniques. The ability of the collaterals to predict the 24-hour CT ASPECTS (Alberta Stroke Program Early CT score), risk of cerebral hemorrhagic transformation, and 90-day clinical outcome was assessed. Fifty-six patients, which included 42 with an involvement of the middle cerebral artery and 14 with mixed occlusions, were assessed. In the multivariate logistic analysis, multiphase CT angiography collateral grading is one of the independent predictors of favorable outcomes. Area under the curve (AUC) was 0.853 (95% confidence interval [CI; 0.73, 0.97]) for multiphase CT collateral scoring in predicting the long-term functional independence, whereas single-phase CT (sCT) scoring displayed an AUC value of only 0.609 (95% CI [0.43, 0.78]). Eighty-two percent of the patients with good multiphase CT collaterals were functionally independent. CT ASPECTS at 24 hours was significantly better in patients with a good multiphase CT collateral score than in those with a good single-phase score. None of the patients with good collaterals in multiphase CT angiography had a significant hemorrhagic transformation. Good multiphase CT collaterals demonstrated 78% sensitivity, 81% specificity, and 80% accuracy in predicting the functional outcome. Multiphase CT collateral system was superior to single-phase angiography in predicting the long-term functional outcomes. Prediction of the hemorrhagic transformation risk was also observed to be better for multiphase CT.

Abstract 1122‐000005: Plasminogen Activator Inhibitor‐1 5G/5G Polymorphism – Do We Know All About It?

Introduction : The etiology of ischemic stroke is heterogeneous, and it has been proposed that different stroke subtypes might have different genetic architecture 1,2. The plasminogen activator inhibitor‐1 (PAI‐1) has been of particular interest due to its role in thrombotic diseases. Several polymorphisms have been found for this gene, with some having protective effect while others increase the risk of ischemic and hemorrhagic strokes 3,4. The protective role appears to be due to the role of PAI‐1 in fibrinolytic cascade and that PAI‐1 also inhibit plasmin‐dependent metalloproteinases activation. We hereby, present a case of ischemic stroke in young adult and its association with our gene of interest. Methods : Case: We present a case of 43‐year‐old woman with past medical history significant for Acetylcholine Receptor (AChR) antibody positive Myasthenia Gravis diagnosed in 1993 status post thymectomy (1994), currently on prednisone and intravenous immunoglobulin every two weeks (failed cyclosporine and mycophenolate mofetil). She had two events in 2018 where she reported episodic right sided numbness and weakness that lasted for few hours. Stroke workup was done, and she was found to have focal moderate to severe stenosis of the left middle cerebral artery (MCA) on CT angiography (figure 1) with very subtle left hypoperfusion in the MCA on the brain single‐photon emission computerized tomography scan. She underwent catheter angiogram (figure 1) showing severe stenosis involving the mid and distal M1 segment of the left MCA and nondominant proximal A1 segment left anterior cerebral artery (ACA). There were robust leptomeningeal collaterals from the left anterior and left posterior cerebral arteries. She also reported history of two miscarriages in the first trimester. Hypercoagulable workup was done and all of those were negative including: SLE profile, Lupus anticoagulant, ANA comprehensive panel, Cryoglobulin, Anticardiolipin antibody, Antithrombin III, Antithrombin antigen, protein C, protein S, Factor VIII activity, Factor V Leiden. She also had rheumatoid arthritis factor, Homocysteine, sedimentation rate, and C‐reactive protein done which were unremarkable. Genetic workup showed that she is PAI‐1 5G/5G homozygous. She has been stable since 2018 without new focal neurological events and is on Aspirin monotherapy and Statin. Results : The genetics for stroke disease are very complicated and yet to be discovered fully. The association between PA‐1 5G/5G and intracranial stenosis has not been reported previously. New genetic associations will need to be increasingly considered as we assess our cerebrovascular diseases and stroke patients Conclusions : • With the current knowledge, ischemic stroke have polygenic basis but no single common “stroke gene” has been identified yet. • Here we present a case suggesting that PAI‐1 5G/5G genotype is may be associated with an independent risk of intracranial atherosclerosis.

Hemodynamics of Leptomeningeal Collaterals after Large Vessel Occlusion and Blood Pressure Management with Endovascular Treatment.

Endovascular therapy (EVT) is an effective treatment for ischemic stroke due to large vessel occlusion (LVO). Unlike intravenous thrombolysis, EVT enables visualization of the restoration of blood flow, also known as successful reperfusion in real time. However, until successful reperfusion is achieved, the survival of the ischemic brain is mainly dependent on blood flow from the leptomeningeal collaterals (LMC). It plays a critical role in maintaining tissue perfusion after LVO via pre-existing channels between the arborizing pial small arteries or arterioles overlying the cerebral hemispheres. In the ischemic territory where the physiologic cerebral autoregulation is impaired and the pial arteries are maximally dilated within their capacity, the direction and amount of LMC perfusion rely on the systemic perfusion, which can be estimated by measuring blood pressure (BP). After the EVT procedure, treatment focuses on mitigating the risk of hemorrhagic transformation, potentially via BP reduction. Thus, BP management may be a key component of acute care for patients with LVO stroke. However, the guidelines on BP management during and after EVT are limited, mostly due to the scarcity of high-level evidence on this issue. In this review, we aim to summarize the anatomical and physiological characteristics of LMC to maintain cerebral perfusion after acute LVO, along with a landscape summary of the literature on BP management in endovascular treatment. The objective of this review is to describe the mechanistic association between systemic BP and collateral perfusion after LVO and thus provide clinical and research perspectives on this topic.

White Matter Hyperintensity Burden and Collateral Circulation in Large Vessel Occlusion Stroke.

White matter hyperintensity (WMH), a marker of chronic cerebral small vessel disease, might impact the recruitment of leptomeningeal collaterals. We aimed to assess whether the WMH burden is associated with collateral circulation in patients treated by endovascular thrombectomy for anterior circulation acute ischemic stroke. Consecutive acute ischemic stroke due to anterior circulation large vessel occlusion and treated with endovascular thrombectomy from January 2015 to December 2017 were included. WMH volumes (periventricular, deep, and total) were assessed by a semiautomated volumetric analysis on fluid-attenuated inversion recovery-magnetic resonance imaging. Collateral status was graded on baseline catheter angiography using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology grading system (good when ≥3). We investigated associations of WMH burden with collateral status. A total of 302 patients were included (mean age, 69.1±19.4 years; women, 55.6%). Poor collaterals were observed in 49.3% of patients. Median total WMH volume was 3.76 cm3 (interquartile range, 1.09-11.81 cm3). The regression analyses showed no apparent relationship between WMH burden and the collateral status measured at baseline angiography (adjusted odds ratio, 0.987 [95% CI, 0.971-1.003]; P=0.12). WMH burden exhibits no overt association with collaterals in large vessel occlusive stroke.

A-60 Case of Moyamoya Syndrome in Haitian Female without Known Risk Factors

Abstract Objective Moyamoya is a rare, progressive cerebrovascular disorder characterized by carotid artery stenosis or occlusion. Tiny “moyamoya” blood vessels open at the brain base to compensate, often resulting in large vessel ischemic strokes or from hemorrhage of moyamoya vessels. Peak incidence in adults is 30 to 50 years old and 30% progress bilaterally. 54 year-old right-handed Black Haitian female with 13 years of education presented with new stroke, now diagnosed with bilateral moyamoya syndrome. Premorbid history includes hypertension, Type II Diabetes Mellitus, patent foramen ovale, and malignant phyllodes breast tumor treated by resection and local radiation. Presents with no traditional risk factors for moyamoya (e.g., brain radiation, sickle cell disease, neurofibromatosis). Method Five years previously patient experienced multi-focal embolic MCA strokes from left internal carotid occlusion attributed to hypercoagulability of malignancy, returning to previous activities except driving. Present perfusion CT showed complete occlusion of bilateral cavernous carotid arteries. Diagnostic angiogram showed collateral system via PCA-MCA pial-pial collaterals in parieto-occipital-temporal regions, and leptomeningeal collaterals to ACA territory. She underwent bilateral STA-MCA direct bypass. Results Acute neuropsychological testing conducted in Haitian Creole by native-speaking trainee showed expressive aphasia, orientation to person and situation, ability to follow 1-step commands, moderately impaired naming of familiar objects, reduced sustained attention. Also left hemiparesis, right gaze preference, and left homonymous hemianopsia. Conclusions The present case study delineates development of secondary moyamoya in a Black Haitian woman without known risk factors, resulting in significant cognitive-linguistic deficits consistent with brain findings. Limitations include lack of validated measures in Haitian Creole.

Leptomeningeal collateral activation indicates severely impaired cerebrovascular reserve capacity in patients with symptomatic unilateral carotid artery occlusion

For patients with symptomatic unilateral internal carotid artery (ICA) occlusion, impaired cerebrovascular reactivity (CVR) indicates increased stroke risk. Here, the role of collateral activation remains a matter of debate, whereas angio-anatomical collateral abundancy does not necessarily imply sufficient compensatory flow provided. We aimed to further elucidate the role of collateral activation in the presence of impaired CVR. From a prospective database, 62 patients with symptomatic unilateral ICA occlusion underwent blood oxygenation-level dependent (BOLD) fMRI CVR imaging and a transcranial Doppler (TCD) investigation for primary and secondary collateral activation. Descriptive statistic and multivariate analysis were used to evaluate the relationship between BOLD-CVR values and collateral activation. Patients with activated secondary collaterals exhibited more impaired BOLD-CVR values of the ipsilateral hemisphere (p = 0.02). Specifically, activation of leptomeningeal collaterals showed severely impaired ipsilateral hemisphere BOLD-CVR values when compared to activation of ophthalmic collaterals (0.05 ± 0.09 vs. 0.12 ± 0.04, p = 0.005). Moreover, the prediction analysis showed leptomeningeal collateral activation as a strong independent predictor for ipsilateral hemispheric BOLD-CVR. In our study, ipsilateral leptomeningeal collateral activation is the sole collateral pathway associated with severely impaired BOLD-CVR in patients with symptomatic unilateral ICA occlusion.

Assessment of cerebrovascular insufficiency with MR-ASL perfusion in patients with moyamoya angiopathy

Purpose. To develop a methodology for assessing the degree of cerebrovascular insufficiency in patients with moyamoya angiopathy (AMM) based on measurement of cerebral blood flow (CBF) and determination the presence of arterial transit artifact (ATA) using MR method of arterial spin labeling (ASL).Materials and methods. The study included 47 patients with AMM who underwent 148 MR studies in PCASL mode (296 hemispheres), of which 47 (94 hemispheres) were done before surgical treatment. On received perfusion maps 7 areas of interest (ROI) were manually set in the gray and white matter of the brain using “Fusion” technique outside the ATA zones. The CBF values at the central point of the ATA were estimated. In the preoperative stage, 47 patients underwent direct angiography to assess the stage of the disease according to Suzuki, the presence and severity of leptomeningeal and transdural collaterals and MR angiography to assess the stage of the disease according to Houkin and the level of ICA stenosis. Statistical processing included univariate analysis of variance (ANOVA) and chi-square test (IBM SPSS Statistics 23).Results. ATA was detected in 77% of studies (69% of hemispheres). The average minimum CBF in ATA was 120.2 ± 21.1 ml/min/ 100 g at the lower bound of the confidence interval of 117.43 ml/min / 100 g. The average maximum CBF in ATA was 234.9. Depending on the CBF values in the MCA territory and the presence of ATA, 4 degrees of perfusion deficiency were identified: degree 0 (CBF = 64.5 ± 16.2 ml/min / 100 g, without ATA) corresponded to the stage of “compensation” of cerebral blood flow, degree 1 (CBF = 61.5 ± 16.6 ml/min/ 100 g, with ATA) – “subcompensation”, degree 2 (CBF = 26.5 ± 7.2 ml/min/100 g, with ATA) – “initial decompensation”, degree 3 (CBF = 16.0 ± 4.7 ml/min / 100 g, without ATA) – “decompensation”. The highlighted degrees statistically significantly differed among themselves in all ROIs (p &lt; 0.0001). More severe perfusion deficiency corresponded to the more developed stages of AMM according to Suzuki and Houkin, proximal stenosis of the ICA (p &lt; 0.0001), and more severe neurological deficit (p &lt; 0.02). The occurrence of ATA reliably reflected the presence of leptomeningeal collaterals (p &lt; 0.001).Conclusions. The proposed method for assessing patterns of ASL perfusion has a good agreement with the stage of the disease, the presence of sources of collateral circulation, the severity of neurological deficit and can be used to assess cerebrovascular insufficiency in patients with AMM.

Susceptibility-diffusion mismatch correlated with leptomeningeal collateralization in large vessel occlusion stroke.

ObjectiveTo investigate the relationship between asymmetric prominent hypointense vessels (prominent vessel sign, PVS) on susceptibility-weighted imaging (SWI) and leptomeningeal collateralization in patients with acute ischemic stroke due to large vessel occlusion.MethodsWe retrospectively enrolled patients with M1 segment occlusion of the middle cerebral artery who underwent emergency magnetic resonance imaging and digital subtraction angiography within 24 hours from stroke onset. The extent of PVS on SWI was assessed using the Alberta Stroke Program Early CT Score (ASPECTS). Leptomeningeal collateralization on digital subtraction angiography images was assessed using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Spearman’s rank correlation test was performed to explore the correlation of ASITN/SIR scores with SWI-ASPECTS and SWI-diffusion-weighted imaging (DWI) mismatch scores.ResultsThirty-five patients were enrolled. There was no significant correlation between SWI-ASPECTS and ASITN/SIR scores. However, SWI-DWI mismatch scores were positively correlated with ASITN/SIR scores.ConclusionThe range of PVS on SWI did not closely reflect the collateral status, while the range of SWI-DWI mismatch was significantly correlated with the leptomeningeal collateralization. In patients with acute anterior circulation stroke due to large vessel occlusion, larger SWI-DWI mismatch was associated with better leptomeningeal collaterals.

Quantitative collateral assessment evaluated by cerebral blood volume measured by CT perfusion in patients with acute ischemic stroke

ObjectivesCollateral status (CS) is considered a predictor of clinical outcome after reperfusion therapy (RT) in patients with acute ischemic stroke (AIS). We proposed a quantitative assessment of CS using cerebral blood volume (CBV) measured by computed tomography perfusion (CTP) imaging. Materials and MethodsThis retrospective study was approved by the Institutional Review Board. Between February 2019 and September 2020, 60 patients with anterior circulation large-vessel occlusion who presented to our institution within 8 h after stroke onset were included. The ratio of the average CBV values in the affected middle cerebral artery (MCA) territories to the unaffected side was defined as the CBV ratio. CS was assessed by scores from previously reported qualitative scoring systems (Tan & regional leptomeningeal collateral (rLMC) scores). ResultsThe CBV ratio was an independent factor contributing to a good functional outcome (P<0.01) and was significantly correlated with the Tan score (ρ=0.73, P<0.01) and the rLMC score (ρ=0.77, P<0.01). Among the patients with recanalization, the CBV ratio was a useful parameter that predicted both a good functional outcome (area under the receiver operating characteristic curve (AUC-ROC), 0.76; 95% CI, 0.55–0.89) and a good radiological outcome (AUC-ROC, 0.90; 95% CI, 0.72–0.97), and it was an independent predictor for good radiological outcome (OR: 4.38; 95% CI:1.29–14.82; P<0.01) in multivariate models. ConclusionsThe CBV ratio is a suitable parameter for evaluating CS quantitatively for patients with AIS that can predict patient response to recanalization.

Ivy Sign in Moyamoya Disease: A Comparative Study of the FLAIR Vascular Hyperintensity Sign Against Contrast-Enhanced MRI.

The ability of the ivy sign on contrast-enhanced T1-weighted MR imaging (CEMR) to reflect cerebral perfusion and postoperative revascularization in Moyamoya disease remains largely unknown. We aimed to compare the capabilities of CEMR and FLAIR. CEMR, FLAIR, arterial spin-labeling, and DSA were performed in 44 patients with Moyamoya disease. The ivy sign was scored separately on CEMR and FLAIR using the Alberta Stroke Program Early CT Score. The status of leptomeningeal collaterals was scored on DSA. The postoperative Matsushima grade was evaluated at least 3 months after surgical revascularization. Scoring of the ivy sign on CEMR showed excellent interrater reliability, and FLAIR vascular hyperintensity showed moderate interrater reliability. Correlation analyses revealed that DSA scores were more consistent with the CEMR-based ivy sign score (r = 0.25, P = .03) than with FLAIR vascular hyperintensity (r = 0.05, P = .65). The CEMR-based ivy sign score was significantly correlated with CBF in late-Suzuki stage Moyamoya disease (t = -2.64, P = .02). The CEMR-based ivy sign score at baseline was significantly correlated with the postoperative Matsushima grade (r = 0.48, P = .03). In this study, CEMR outperformed FLAIR in capturing the ivy sign in Moyamoya disease. In addition, the CEMR-based ivy sign score provided adequate information on hemodynamic status and postoperative neovascularization. The current study suggested that CEMR could be considered as an alternative to FLAIR in future studies investigating leptomeningeal collaterals in Moyamoya disease.

Abstract P769: Remodeling of the Leptomeningeal Collaterals Following Stroke Involves Selective Upregulation of Von Willebrand Factor (VWF)

Introduction: The leptomeningeal collaterals (LMCs) are arterial anastomoses that interconnect the distal branches of the major cerebral arteries. They distribute blood flow from adequately to poorly perfused vascular territories when needed. In normal conditions, the LMCs experience little net flow. However, during ischemic stroke, the LMCs are recruited to provide rescue flow to the ischemic territory. During prolonged or permanent stroke, the LMCs can rapidly remodel to provide increased perfusion capacity. Von Willebrand factor (VWF) is a secreted protein expressed in cerebral endothelium and has recently been implicated in angiogenesis. We sought to determine if VWF expression was increased in remodeling LMCs in the post-stroke brain. Methods: C57BL6 mice were subjected to permanent distal middle cerebral artery occlusion (pdMCAO). At 3 days after pdMCAO, mice were perfused with fluorescent tomato lectin to label vascular endothelium. The cortical surface was “planed off” by vibratome to provide largely contiguous cortical surface vessel preparations containing distalmost arterioles (DMAs) and the connected LMCs. VWF immunofluorescence intensity was measured in LMCs and the connecting DMAs of hemispheres ipsilateral and contralateral to the stroke. Inner diameter of the LMCs and DMAs were measured with Image J. Results: At 3 days post-stroke, LMCs of the stroke hemisphere demonstrated significant outward remodeling. Mean inner diameter of the ipsilateral versus contralateral LMCs were 44.5 ± 5.9 um versus 28.2 ± 1.2 um, respectively (p&lt;0.02, 7-8 vessels from 3 mice). In contrast, the DMAs were unaltered in diameter, 35.2 ± 4.0 and 35.7 ± 3.1 um, respectively. VWF expression was significantly increased in the ipsilateral LMCs versus contralateral LMCs (2.8 fold, p&lt;0.05) and versus ipsilateral DMAs (3.7 fold, p&lt;0.02). The DMAs showed significantly lower VWF expression, which was unchanged between ipsilateral and contralateral hemispheres. Conclusions: We demonstrate that VWF is highly expressed in the remodeling LMCs (but not connecting DMAs) of the post-stroke brain. These findings suggest a novel and selective role for endothelial VWF in the LMC response to prolonged recruitment during ischemic stroke.