A Simplified One-Size-Fits-All Approach to Carotid Stenting.

BACKGROUND: Carotid artery stenosis causes up to 20% of ischemic strokes. Stenting is used as an alternative to endarterectomy in symptomatic patients. Each commercially available stent offers numerous stent diameters/lengths. Most centers thus carefully match each individual stenosis to a specific stent length/diameter stent size. However, this process can be time-consuming and costly while the relative benefit of a custom stent sizing versus one-size-fits-all approach has not been well evaluated yet. We hypothesized that a 'one-size-fits-all' default approach to carotid stenting results in comparable results to a customized approach. METHODS: We conducted a descriptive retrospective cohort study on 154 patients who presented to our academic carotid revascularization clinic with symptomatic carotid artery stenosis who underwent carotid artery stenting for peri- and postprocedural carotid artery stenting complications. The primary outcomes were periprocedural (within 24 hours of the procedure) or postprocedural (within 30 days of the procedure) TIA, stroke, or death. The secondary outcome was the estimated degree of stenosis on follow-up ultrasound performed within 6 months of the procedure. RESULTS: The complication rate within the first 24 hours was 4.5% while that during the first 30 days postprocedure was 6.5%. Age over 80 and degree of stenosis on postprocedural cerebral angiogram were associated with an increased risk of complications. Severe restenosis was reported in 16.8% of patients within 6 months postprocedure. CONCLUSION: Our study suggests that using a simplified, one-size-fits-all, approach to carotid stenting results in safe and effective outcomes, suggesting an alternative to simplify a complex medical procedure.

Multiphase CT angiography perfusion maps for predicting target mismatch and ischemic lesion volumes.

The complexity of CT perfusion (CTP) acquisition protocols may limit the availability of target mismatch assessment at resource-limited hospitals. We compared CTP mismatch with a mismatch surrogate generated from a simplified dynamic imaging sequence comprising widely available non-contrast CT (NCCT) and multiphase CT angiography (mCTA). Consecutive patients with anterior circulation acute ischemic stroke who received NCCT, mCTA, and CTP were retrospectively included in this study. An mCTA-perfusion (mCTA-P) dynamic series was formed by co-registering NCCT and mCTA. We simulated an ideal mCTA-P study by down-sampling CTP (dCTP) dynamic images according to mCTA timing. Ischemic core and penumbra volumes were estimated by cerebral blood flow and Tmax thresholding, respectively, on perfusion maps calculated independently for CTP, dCTP, and mCTA-P by deconvolution. Concordance in target mismatch (core < 70 ml, penumbra ≥ 15 ml, mismatch ratio ≥ 1.8) determination by dCTP and mCTA-P versus CTP was assessed. Of sixty-one included patients, forty-six had a CTP target mismatch. Concordance with CTP profiles was 90% and 82% for dCTP and mCTA-P, respectively. Lower mCTA-P concordance was likely from differences in collimation width between NCCT and mCTA, which worsened perfusion map quality due to a CT number shift at mCTA. Moderate diagnostic agreement between CTP and mCTA-P was found and may improve with optimal mCTA scan parameter selection as simulated by dCTP. mCTA-P may be a pragmatic alternative where CTP is unavailable or the risks of additional radiation dose, contrast injections, and treatment delays outweigh the potential benefit of a separate CTP scan.

Deep learning prediction of stroke thrombus red blood cell content from multiparametric MRI.

BACKGROUND AND PURPOSE: Thrombus red blood cell (RBC) content has been shown to be a significant factor influencing the efficacy of acute ischemic stroke treatment. In this study, our objective was to evaluate the ability of convolutional neural networks (CNNs) to predict ischemic stroke thrombus RBC content using multiparametric MR images. MATERIALS AND METHODS: Retrieved stroke thrombi were scanned ex vivo using a three-dimensional multi-echo gradient echo sequence and histologically analyzed. 188 thrombus R2*, quantitative susceptibility mapping and late-echo GRE magnitude image slices were used to train and test a 3-layer CNN through cross-validation. Data augmentation techniques involving input equalization and random image transformation were employed to improve network performance. The network was assessed for its ability to quantitatively predict RBC content and to classify thrombi into RBC-rich and RBC-poor groups. RESULTS: The CNN predicted thrombus RBC content with an accuracy of 62% (95% CI 48-76%) when trained on the original dataset and improved to 72% (95% CI 60-84%) on the augmented dataset. The network classified thrombi as RBC-rich or poor with an accuracy of 71% (95% CI 58-84%) and an area under the curve of 0.72 (95% CI 0.57-0.87) when trained on the original dataset and improved to 80% (95% CI 69-91%) and 0.84 (95% CI 0.73-0.95), respectively, on the augmented dataset. CONCLUSIONS: The CNN was able to accurately predict thrombus RBC content using multiparametric MR images, and could provide a means to guide treatment strategy in acute ischemic stroke.

Feasibility of deconvolution-based multiphase CT angiography perfusion maps in acute ischemic stroke: Simulation and concordance with CT perfusion.

OBJECTIVES: Integration of CT perfusion (CTP) with requisite non-contrast CT and CT angiography (CTA) stroke imaging may allow efficient stroke lesion volume measurement. Using surrogate images from CTP, we simulated the feasibility of using multiphase CTA (mCTA) to generate perfusion maps and assess target mismatch profiles. MATERIALS AND METHODS: Patients with acute ischemic stroke who received admission CTP were included in this study. Four CTP images (surrogate mCTA, one pre-contrast and three post-contrast, starting at the arterial peak then at 8 s intervals) were selected according to the CTP arterial time-density curve to simulate non-contrast CT and mCTA images. Cerebral blood flow (CBF) and Tmax maps were calculated using the same model-based deconvolution algorithm for the standard CTP and surrogate mCTA studies. Infarct and penumbra were delineated with CBF < 20% and Tmax > 6 s threshold, respectively. Classification accuracy of surrogate mCTA target mismatch (infarct <70 ml; penumbra ≥15 ml; mismatch ratio ≥1.8) with respect to standard CTP was assessed. Agreement between infarct and penumbra volumes from standard CTP and surrogate mCTA maps were evaluated by Bland-Altman analysis. RESULTS: Of 34 included patients, 28 had target mismatch and 6 did not by standard CTP. Accuracy of classifying target mismatch profiles with surrogate mCTA was 79% with respect to that from standard CTP. Mean  ±  standard deviation of differences (standard CTP minus surrogate mCTA) of infarct and penumbra volumes were 9.8 ± 14.8 ml and 20.1 ± 45.4 ml, respectively. CONCLUSIONS: Surrogate mCTA ischemic lesion volumes agreed with those from standard CTP and may be an efficient alternative when CTP is not practical.

Ruptured intracranial infectious aneurysms: Single Canadian center experience.

Background: Ruptured intracranial infected aneurysms (IIAs) are relatively rare, but they portend high mortality. To the best of our knowledge, there is no Canadian case series on IIA, as well there is a relative paucity of international published experiences. Our purpose is to share the experience of a single Canadian tertiary center in managing ruptured IIA and to conduct a systematic review. Methods: We did a retrospective case review series of adult patients with ruptured IIA treated at our institution. Second, we conducted a systematic review of the literature on ruptured IIA between 2011 and 2021 inclusive. Results: At our institution, of a total eight cases with ruptured IIA, four were treated endovascularly and two by surgical bypass. For the systematic review, we included nine noncomparative studies with a total of 509 patients (318 males) and at least 437 ruptured IIA aneurysms. Favorable outcome was specified for 63.3% of patients (n = 57). Regarding ruptured IIA, favorable clinical outcome was described in 59.3% (n = 16). Conclusion: This study highlights a single Canadian tertiary center experience in the management of IIA and compares it to the global trends of the past 10 years in a systematic review.

Low-dose CT Perfusion with Sparse-view Filtered Back Projection in Acute Ischemic Stroke.

RATIONALE AND OBJECTIVES: Radiation dose associated with computed tomography (CT) perfusion (CTP) may discourage its use despite its added diagnostic benefit in quantifying ischemic lesion volume. Sparse-view CT reduces scan dose by acquiring fewer X-ray projections per gantry rotation but is contaminated by streaking artifacts using filtered back projection (FBP). We investigated the achievable dose reduction by sparse-view CTP with FBP without affecting CTP lesion volume estimations. MATERIALS AND METHODS: Thirty-eight consecutive patients with acute ischemic stroke and CTP were included in this simulation study. CTP projection data was simulated by forward projecting original reconstructions with 984 views and adding Gaussian noise. Full-view (984 views) and sparse-view (492, 328, 246, and 164 views) CTP studies were simulated by FBP of simulated projection data. Cerebral blood flow (CBF) and time-to-maximum of the impulse residue function (Tmax) maps were generated by deconvolution for each simulated CTP study. Ischemic volumes were measured by CBF<30% relative to the contralateral hemisphere and Tmax > 6 s. Volume accuracy was evaluated with respect to the full-view CTP study by the Friedman test with post hoc multiplicity-adjusted pairwise tests and Bland-Altman analysis. RESULTS: Friedman and multiplicity-adjusted pairwise tests indicated that 164-view CBF < 30%, 246- and 164-view Tmax > 6 s volumes were significantly different to full-view volumes (p < 0.001). Mean difference ± standard deviation (sparse minus full-view lesion volume) ranged from -1.0 ± 2.8 ml to -4.1 ± 11.7 ml for CBF < 30% and -2.9 ± 3.8 ml to -12.5 ± 19.9 ml for Tmax > 6 s from 492 to 164 views, respectively. CONCLUSION: By ischemic volume accuracy, our study indicates that sparse-view CTP may allow dose reduction by up to a factor of 3.

Acute ischaemic stroke associated with SARS-CoV-2 infection in North America.

BACKGROUND: To analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome. METHODS: Multicentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications. RESULTS: A total of 216 COVID-19 patients with AIS were included. 68.1% (147/216) were older than 60 years, while 31.9% (69/216) were younger. Median [IQR] National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.5 (15.8), and 44.2% (87/197) presented with large vessel occlusion (LVO). Approximately 51.3% (98/191) of the patients had poor outcomes with an observed mortality rate of 39.1% (81/207). Age >60 years (aOR: 5.11, 95% CI 2.08 to 12.56, p<0.001), diabetes mellitus (aOR: 2.66, 95% CI 1.16 to 6.09, p=0.021), higher NIHSS at admission (aOR: 1.08, 95% CI 1.02 to 1.14, p=0.006), LVO (aOR: 2.45, 95% CI 1.04 to 5.78, p=0.042), and higher NLR level (aOR: 1.06, 95% CI 1.01 to 1.11, p=0.028) were significantly associated with poor functional outcome. CONCLUSION: There is relationship between COVID-19-associated AIS and severe disability or death. We identified several factors which predict worse outcomes, and these outcomes were more frequent compared to global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-Dimer, predicted both morbidity and mortality.

Early Goal-directed Therapy During Endovascular Coiling Procedures Following Aneurysmal Subarachnoid Hemorrhage: A Pilot Prospective Randomized Controlled Study.

BACKGROUND: Maintenance of euvolemia and cerebral perfusion are recommended for the prevention of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH). We conducted a pilot randomized controlled study to assess the feasibility and efficacy of goal-directed therapy (GDT) to correct fluid and hemodynamic derangements during endovascular coiling in patients with aSAH. METHODS: This study was conducted between November 2015 and February 2019 at a single tertiary center in Canada. Adult patients with aSAH within 5 days of aneurysm rupture were randomly assigned to receive either GDT or standard therapy during endovascular coiling. The incidence of dehydration at presentation and the efficacy of GDT were evaluated. RESULTS: Forty patients were allocated to receive GDT (n=21) or standard therapy (n=19). Sixty percent of all patients were found to have dehydration before the coiling procedure commenced. Compared with standard therapy, GDT reduced the duration of intraoperative hypovolemia (mean difference 37.6 [95% confidence interval, 6.2-37.4] min, P=0.006) and low cardiac index (mean difference 30.7 [95% confidence interval, 9.5-56.9] min, P=0.035). There were no differences between the 2 treatment groups with respect to the incidence of vasospasm, stroke, death, and other complications up to postoperative day 90. CONCLUSIONS: A high proportion of aSAH patients presented at the coiling procedure with dehydration and a low cardiac output state; these derangements were more likely to be corrected if the GDT algorithm was used. Compared with standard therapy, use of the GDT algorithm resulted in earlier recognition and more consistent treatment of dehydration and hemodynamic derangement during endovascular coiling.

A Protocol for Carotid Artery Stenting in COVID Times. A Single Canadian Centre Experience.

OBJECTIVES: The COVID-19 pandemic has resulted in huge disruption to healthcare delivery worldwide. There is a need to balance the urgent needs of the neurovascular patient population with the desire to preserve critical inpatient hospital capacity. It is incumbent on neurointerventionalists to advocate for their patients to minimise future disability. Patients still require semiurgent carotid revascularisation after ischaemic embolic events. We present a review of a novel protocol for expediting patient flow through the carotid stenting process, in accordance with government directives to minimise nonessential inpatient admissions, ensure its efficacy, and evaluate its safety. We also evaluate the literature regarding complications with attention to the timing of these related to the procedure. METHODS: A retrospective review of 45 consecutive carotid stenting cases performed at London Health Sciences Centre between March 2020 and March 2021 for symptomatic extracranial internal carotid artery stenosis utilising a default same-day discharge policy was performed. Complications were plotted as a function of time. RESULTS: Twenty-four patients underwent carotid artery stenting with same-day discharge and 21 patients underwent stenting with an overnight inpatient stay. A single stent occlusion occurred 27 h post stenting. CONCLUSION: Simple modification of protocol for symptomatic carotid artery stenting during the COVID-19 outbreak with radial access as first approach appears to provide safe, efficacious care.

The first described case of Lodderomyces elongisporus meningitis.

We describe the first documented case of meningitis caused by Lodderomyces elongisporus. Identification of L. elongisporus was made on the basis of an arachnoid biopsy with pathology samples sent for fungal internal transcribed spacer sequencing after multiple central nervous system (CNS) fungal culture specimens were negative. After final diagnosis, treatment was transitioned from amphotericin to fluconazole, which, combined with insertion of lumbar drain followed by a permanent ventriculopleural shunt, resulted in significant clinical improvement. Our report reviews the literature of (1) cases of L. elongisporus, which almost exclusively describe fungemia or endocarditis; (2) CNS infections caused by Candida parapsilosis, an organism with which L. elongisporus was previously conflated; and (3) management of fungal meningitis-associated hydrocephalus.

Les chercheurs décrivent le premier cas répertorié de méningite causée par le Lodderomyces elongisporus. Ils ont dépisté le L. elongisporus après avoir effectué une biopsie de l'arachnoïde et envoyé les prélèvements pathologiques au séquençage de l'espaceur transcrit interne fongique après l'obtention de multiples cultures fongiques négatives. Après le diagnostic définitif, le traitement d'amphotéricine a été remplacé par du fluconazole qui, combiné à l'insertion d'un drain lombaire suivie par l'installation d'une dérivation ventriculopleurale permanente, a favorisé une amélioration clinique évidente. L'analyse bibliographique a permis d'extraire 1) des cas de L. elongisporus, qui ont été observés presque exclusivement dans des cas de fongémie auparavant, 2) des infections du système nerveux central causées par le Candida parapsilosis, un organisme avec lequel le L. elongisporus a déjà été confondu et 3) la prise en charge de l'hydrocéphalie associée à la méningite fongique.

Interventional Neuroradiology: A Review.

Interventional neuroradiology (INR) has evolved from a hybrid mixture of daring radiologists and iconoclastic neurosurgeons into a multidisciplinary specialty, which has become indispensable for cerebrovascular and neurological centers worldwide. This manuscript traces the origins of INR and describes its evolution to the present day. The focus will be on cerebrovascular disorders including aneurysms, stroke, brain arteriovenous malformations, dural arteriovenous fistulae, and atherosclerotic disease, both intra- and extracranial. Also discussed are cerebral vasospasm, venolymphatic malformations of the head and neck, tumor embolization, idiopathic intracranial hypertension, inferior petrosal venous sinus sampling for Cushing's disease, and spinal interventions. Pediatric INR has not been included and deserves a separate, dedicated review.

Cortically based cystic supratentorial RELA fusion-positive ependymoma: a case report with unusual presentation and appearance and review of literature.

Ependymomas are rare central nervous system tumors that can arise anywhere in the neuroaxis. Supratentorial and posterior fossa ependymomas were identified as distinct diseases after extensive molecular analysis. The 2016 World Health Organization update further introduced RELA fusion-positive ependymoma as a novel entity as a subset of supratentorial ependymomas indicating the presence of C11orf95-RELA fusion genes. RELA fusion-positive ependymomas are commonly intraventricular, though they may rarely manifest as extraventricular, cortically-based tumors. They are commonly large solid, mixed solid/cystic tumors or rarely cystic. In this paper, we report a case of RELA fusion positive cortically based-cystic ependymoma and review the existing literature. Our patient is a 9-year-old boy who presented with an unusual presentation of right facial droop. He underwent gross total resection of the ependymoma, following resection, his facial droop resolved and there was no neurologic deficit.

Impact and prevention of errors in endovascular treatment of unruptured intracranial aneurysms.

BACKGROUND: Preventing errors and complications in neurointervention is crucial, particularly in the treatment of unruptured intracranial aneurysms (UIAs), where the natural history is generally benign, and the margin of treatment benefit small. We aimed to investigate how neurointerventionalists perceive the importance and frequency of errors and the resulting complications in endovascular UIA treatment, and which steps could be taken to prevent them. METHODS: An international multidisciplinary survey was conducted among neurointerventionalists. Participants provided their demographic characteristics and neurointerventional treatment volume. They were asked about their perceptions on the importance and frequency of different errors in endovascular UIA treatment, and which solutions they thought to be most effective in preventing these errors. RESULTS: Two-hundred-thirty-three neurointerventionalists from 38 countries participated in the survey. Participants identified errors in technical execution as the most common source of complications in endovascular UIA treatment (40.4% thought these errors constituted a relatively or very large proportion of all complication sources), closely followed by errors in decision-making/indication (32.2%) and errors related to management of unexpected events (28.4%). Simulation training was thought to be most effective in reducing technical errors, while cognitive errors were believed to be best minimized by abandoning challenging procedures, more honest discussion of complications and better standardization of procedure steps. CONCLUSION: Neurointerventionalists perceived both technical and cognitive errors to be important sources of complications in endovascular UIA treatment. Simulation training, a cultural change, higher acceptance of bail-out strategies and better standardization of procedures were perceived to be most effective in preventing these.

Optic Nerve Atrophy in N-methyl-D-aspartate (NMDA) Encephalitis.

N-methyl-D-aspartate receptor (NMDA) encephalitis is a recently described autoimmune disease that typically presents with prodromal symptoms including upper respiratory tract infection, headache, fever, nausea, vomiting and diarrhea. Psychiatric symptoms follow within weeks, including anxiety, insomnia, mania, paranoia and grandiose delusions. The diagnosis is confirmed by the detection of NMDA antibodies in the serum or cerebrospinal fluid (CSF).1 Tumours, especially teratomas, are frequently associated with NMDA encephalitis; however, only 5% of male patients older than 18 years have been found to have an underlying tumour. Optic neuropathy associated with NMDA encephalitis is being increasingly recognised in the literature2-6 and was reviewed most recently by Mugavin et al.2 in 2017. In this report, we present a case of bilateral optic neuropathy in a young man diagnosed with NMDA receptor encephalitis.