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Hemorrhagic transformation is caused by extravasation of blood products from vessels after acute ischemic stroke. It is an undesirable and potentially devastating complication, which occurs in 10%-40% of clinical cases. Hemorrhagic transformation is classified into four subtypes based on European cooperative acute stroke study II. Predicting hemorrhagic complications at presentation can be useful life saving/altering decisions for the patient. Also, understanding the mechanisms of hemorrhagic transformation can lead to new treatments and intervention measures. We highlighted various imaging techniques that have been used to predict hemorrhagic transformation. Specifically, we looked at the usefulness of perfusion and permeability imaging for hemorrhagic transformation. Use of imaging to predict hemorrhagic transformation could change patient management that may lead to the prevention of hemorrhagic transformation before it occurs. We concluded that the current evidence is not strong enough to rely on these imaging parameters for predicting hemorrhagic transformation and more studies are required.

Purpose:Contrast-enhanced magnetic resonance imaging (CEMRI) of the head is frequently employed in investigations of sensorineural hearing loss (SNHL). The yield of these studies is perceptibly low and seemingly at odds with the aims of wise resource allocation and risk reduction within the Canadian healthcare system. The purpose of our study was to audit the use and diagnostic yield of CEMRI for the clinical indication of SNHL in our institution and to identify characteristics that may be leveraged to improve yield and optimize resource utilization.Materials and methods:The charts of 500 consecutive patients who underwent CEMRI of internal auditory canal for SNHL were categorized as cases with relevant positive findings on CEMRI and those without relevant findings. Demographics, presenting symptoms, interventions and responses, ordering physicians, and investigations performed prior to CEMRI testing were recorded. Chi-squared test and t-test were used to compare proportions and means, respectively.Results:CEMRI studies revealed relevant findings in 20 (6.2%) of 324 subjects meeting the inclusion criteria. Pre-CEMRI testing beyond audiometry was conducted in 35% of those with relevant positive findings compared to 7.3% of those without (p < 0.001). Auditory brainstem response/vestibular-evoked myogenic potentials were abnormal in 35% of those with relevant CEMRI findings compared to 6.3% of those without (p < 0.001).Conclusion:CEMRI is a valuable tool for assessing potential causes of SNHL, but small diagnostic yield at present needs justification for contrast injection for this indication. Our findings suggest preferred referral from otolaryngologists exclusively, and implementation of a non-contrast MRI for SNHL may be a better diagnostic tool.

Background:Collateral status is an indicator of a favorable outcome in stroke. Leptomeningeal collaterals provide alternative routes for brain perfusion following an arterial occlusion or flow-limiting stenosis. Using a large cohort of ischemic stroke patients, we examined the relative contribution of various demographic, laboratory, and clinical variables in explaining variability in collateral status.Methods:Patients with acute ischemic stroke in the anterior circulation were enrolled in a multi-center hospital-based observational study. Intracranial occlusions and collateral status were identified and graded using multiphase computed tomography angiography. Based on the percentage of affected territory filled by collateral supply, collaterals were graded as either poor (0–49%), good (50–99%), or optimal (100%). Between-group differences in demographic, laboratory, and clinical factors were explored using ordinal regression models. Further, we explored the contribution of measured variables in explaining variance in collateral status.Results:386 patients with collateral status classified as poor (n = 64), good (n = 125), and optimal (n = 197) were included. Median time from symptom onset to CT was 120 (IQR: 78–246) minutes. In final multivariable model, male sex (OR 1.9, 95% CIs [1.2, 2.9], p = 0.005) and leukocytosis (OR 1.1, 95% CIs [1.1, 1.2], p = 0.001) were associated with poor collaterals. Measured variables only explained 44.8–53.0% of the observed between-patient variance in collaterals.Conclusion:Male sex and leukocytosis are associated with poorer collaterals. Nearly half of the variance in collateral flow remains unexplained and could be in part due to genetic differences.

Endovascular thrombectomy (EVT) has revolutionized the care of patients with acute ischemic stroke. The efficacy of EVT is dependent on the optimal setup of a stroke system. Extrapolating the results of clinical trials to any individual stroke center should be done with caution. This is more important for centers with suboptimal stroke systems of care. The Canadian registry has helped highlight the suboptimal outcome post EVT in Manitoba. This could potentially be optimized with the addition of an acute stroke unit in the near future. Our study will serve as a baseline for future improvement in acute stroke care.

Background:The T2 hypointensity has been suggested to be associated with intracranial metastatic adenocarcinomas (IMA). The purpose of our study was to determine the association of T2 hypointensity with IMA.Methods:All patients with pathologically confirmed metastatic brain tumors who had a magnetic resonance imaging (MRI) at our institution in the last 10 years were retrospectively assessed. Qualitative assessment of the lesions on MRI was done by two separate readers who were blinded to the pathological diagnosis. For qualitative assessment, the T2 hypointensity in the lesion was compared with the contralateral normal appearing white matter. Odds ratio, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.Results:Of 107 patients with intracranial metastasis, only 73 (40 females; 33 males; mean age 61 years) had MRI available for review. Of these, only 46 (25 females; 21 males; mean age 61 years) had pathologically proven IMA. T2 hypointensity was seen in 20% of IMA. The odds ratio of T2 hypointensity in IMA was 3 compared to nonadenocarcinomas but was not statistically significant (p = 0.16). Intralesional hemorrhage was seen in 20. When controlled for hemorrhage, the odds ratio for T2 hypointensity in IMA was 4.7. The specificity, sensitivity, PPV, and NPV for T2 hypointensity to diagnose IMA were 92%, 19%, 81%, and 40%, respectively.Conclusion:T2 hypointensity was seen only in 20% of IMA with an odds ratio of 4.7. T2 hypointensity showed a high specificity and PPV for diagnosis of IMA.

Transorbital penetration accounts for one-quarter of the penetrating head injuries (PHIs) in adults and half of those in children. Injuries that traverse (with complete penetration of) the brainstem are often fatal, with survivors rarely seen in clinical practice. Here, the authors describe the case of a 16-year-old male who suffered and recovered from an accidental transorbital PHI traversing the brainstem—the first case of complete neurological recovery following such injury. Neuroimaging captured the trajectory of the initial injury. A delayed-onset carotid cavernous fistula and the subsequent development of internal carotid artery pseudoaneurysms were managed by endovascular embolization.The authors also review the relevant literature. Sixteen cases of imaging-confirmed PHI traversing the brainstem have been reported, 14 involving the pons and 12 penetrating via the transorbital route. Management and outcome of PHI are informed by object velocity, material, entry point, trajectory, relationship to neurovascular structures, and the presence of a retained foreign body. Trauma resuscitation is followed by a careful neurological examination and appropriate neuroimaging. Ophthalmological examination is performed if transorbital penetration is suspected, as injuries may be occult; the potential for neurovascular complications highlights the value of angiography. The featured case shows that complete recovery is possible following injury that traverses the brainstem.

Endovascular thrombectomy (EVT) is efficacious for ischemic stroke caused by proximal intracranial large-vessel occlusion involving the anterior cerebral circulation. However, evidence of its cost-effectiveness, especially in a real-world setting, is limited. We assessed whether EVT ± tissue plasminogen activator (tPA) was cost-effective when compared with standard care ± tPA at our center.We identified patients treated with EVT ± tPA after the Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing computed tomography to recanalization times trial from our prospective stroke registry from February 1, 2013 to January 31, 2017. Patients admitted before February 2013 and treated with standard care ± tPA constitute the controls. The sample size was 88. Cost-effectiveness was assessed using the net monetary benefit (NMB). Differences in average costs and quality-adjusted life years (QALYs) were estimated using the augmented inverse probability weighted estimator. We accounted for sampling and methodological uncertainty in sensitivity analyses.Patients treated with EVT ± tPA had a net gain of 2.89 [95% confidence interval (CI): 0.93-4.99] QALYs at an additional cost of $22,200 (95% CI: -28,902-78,244) per patient compared with the standard care ± tPA group. The NMB was $122,300 (95% CI: -4777-253,133) with a 0.85 probability of being cost-effective. The expected savings to the healthcare system would amount to $321,334 per year.EVT ± tPA had higher costs and higher QALYs compared with the control, and is likely to be cost-effective at a willingness-to-pay threshold of $50,000 per QALY.Analyse coût-efficacité de la thrombectomie endovasculaire dans un contexte réel. Objectif : La thrombectomie endovasculaire (TE) est efficace dans le cas d’accidents ischémiques cérébraux (AIC) causés par une occlusion proximale de l’artère cérébrale antérieure. Toutefois, les preuves d’un bon rapport coût-efficacité, particulièrement dans le cadre d’une pratique réelle, demeurent limitées. Nous avons ainsi évalué au sein de notre établissement dans quelle mesure la thrombectomie endovasculaire jumelée à un traitement au moyen d’un activateur tissulaire du plasminogène (t-PA) étaient davantage rentables en comparaison avec des soins usuels également jumelés à un traitement de t-PA. Méthodes : En consultant nos registres prospectifs, nous avons identifié des patients traités par une thrombectomie endovasculaire jumelée à un traitement de t-PA après avoir subi, du 1er février 2013 au 31 janvier 2017, un traitement endovasculaire destiné à un petit AVC central et ischémique à occlusion proximale avec un accent mis sur la minimisation du temps de recanalisation par tomodensitométrie. Les patients hospitalisés avant février 2013 et auxquels des soins usuels avaient été prodigués de concert avec l’administration d’un t-PA ont fait partie de notre groupe témoin. Au total, notre échantillon était formé de 88 patients. Nous avons évalué le rapport coût-efficacité au moyen du concept d’avantage monétaire net (AMN). Nous avons également estimé les différences en ce qui concerne les coûts moyens et l’indicateur QALY (quality-adjusted life years) en faisant appel à un estimateur pondéré par l’inverse de la probabilité inverse (augmented inverse probability weighted estimator). Enfin, nous avons tenu compte de l’incertitude de notre échantillonnage et de nos choix méthodologiques dans nos analyses de sensibilité. Résultats : Les patients traités par thrombectomie endovasculaire et l’administration d’un t-PA ont donné à voir un gain net de 2,89 années selon l’indicateur QALY (IC 95 % : 0,93 – 4,99) pour un coût additionnel de 22 200 $ (IC 95 % : −28,902 – 78,244) par patient si on les compare à notre groupe témoin. L’AMN s’est quant à lui élevé à 122 300 $ (IC 95 % : −4 777 – 253 133), sa probabilité d’être rentable atteignant 0,85. À cet égard, les économies annuelles pour le système de soins de santé pourraient atteindre les 321 334 $. Conclusion : Il appert que la thrombectomie endovasculaire jumelée à un traitement de t-PA entraînent des coûts plus élevés et un meilleur indicateur QALY en comparaison avec notre groupe témoin. Il est probable qu’une telle approche soit rentable en vertu d’un seuil de disposition à payer (willingness-to-pay threshold) avoisinant les 50 000 $ par année selon le QALY.

Clinical trials with percutaneous vertebral augmentation (PVA) for intractable pain from vertebral compression fractures (VCF) have shown variable results. Variation in the outcomes may be related to poor patient selection on imaging.To assess if PVA augmentation for osteoporotic VCF results in better improvement in pain when patients were selected based on clinical examination plus imaging vs clinical examination only.A systematic review and meta-analysis were performed. PubMed, Embase and Cochrane Library databases were searched from 2000 to May 2018. Two reviewers independently screened and extracted data to identify randomised control trials (RCTs) on PVA for osteoporotic VCF and assessed the risk of bias. Standard systematic review and meta-analysis methods were advocated by the Cochrane Collaboration and PRISMA Statement. A total of 12 RCTs with 1110 participants met the inclusion criteria. Eight of the 10 studies (938 participants) that used imaging to confirm oedema in the target vertebral bodies showed PVA (compared to nonsurgical treatment) was effective in reducing pain (immediate term: mean difference (MD) of -1.89; 95% confidence interval -1.93 to -1.85, p0.001; short term: MD of -1.68; 95% CI -1.82 to -1.54, p0.001; intermediate term: MD of -2.04; 95% CI -2.15 to -1.94, p0.001 and long term: MD of -1.88; 95% CI -1.95 to -1.80, p0.001).RCTs using imaging to confirm marrow oedema in the index vertebra showed an improved size effect compared to RCTs using no imaging. This benefit was observed in the immediate, short, intermediate and long term.Améliorer l’efficacité de la vertébroplastie au moyen de l’imagerie médicale : une revue systématique et une méta-analyse.Contexte: Des essais cliniques au cours desquels on a fait appel aux techniques percutanées de la vertébroplastie (vertebral augmentation) pour soulager des douleurs réfractaires produites par des fractures vertébrales par compression (FVC) ont donné à voir des résultats variables. Cette variabilité pourrait être liée à une mauvaise sélection des participants au moyen d’examens d’IRM. Objectif: Évaluer dans quelle mesure la vertébroplastie entraîne un soulagement accru de la douleur dans le cas de patients aux prises avec des FVC d’origine ostéoporotique. On a ainsi voulu comparer des patients choisis en fonction d’un examen clinique et d’un examen d’IRM avec d’autres patients choisis en fonction d’un seul examen clinique. Résultats: Nous avons mené une revue systématique ainsi qu’une méta-analyse. Pour ce faire, nous avons effectué des recherches dans les bases de données suivantes : PubMed, Embase et Cochrane, et ce, de l’année 2000 au mois de mai 2018. Deux examinateurs indépendants ont ensuite extrait et passé au crible des données afin d’identifier les essais cliniques randomisés (ECR) portant sur la vertébroplastie dans le cas de FVC d’origine ostéoporotique et d’évaluer les risques de biais. À noter que notre revue systématique et notre méta-analyse ont été effectuées en tenant compte des méthodes recommandées par Cochrane et PRISMA. Au total, douze ECR incluant 1110 participants ont satisfait à nos critères de sélection. Sur 10 ECR (938 participants) dans lesquels on a recouru à un examen d’IRM pour confirmer la présence d’un œdème dans les corps vertébraux ciblés, 8 d’entre eux ont révélé que le recours à la vertébroplastie était plus efficace qu’un traitement non-chirurgical dans le soulagement de la douleur (sur le champ : écart moyen de -1,89 ; IC 95 % -1,93 à -1,85 ; p0,001 ; à court terme : écart moyen de -1,68 ; IC 95 % -1,82 à -1,54 ; p0,001 ; à moyen terme : écart moyen de -2,04 ; IC 95 % -2,15 à -1,94 ; p0,001 ; et à long terme : écart moyen de -1,88 ; IC 95% -1,95 à -1,80 ; p0,001). Conclusions: En somme, les ECR utilisant des examens d’IRM pour confirmer la présence d’œdèmes de la moelle épinière dans une vertèbre de référence (index vertebra) ont révélé une taille d’effet améliorée si on les compare à des ECR n’utilisant pas ces examens. Cet avantage a été observé sur le champ mais aussi à court, moyen et long terme.

KEY POINTS • Computed tomographic perfusion (CTP) is increasingly being used in the characterization of brain ischemia.• Variations in post-processing protocols continue to be a challenge, resulting in a slight variation of CTP results.• We need to adopt a universal acquisition protocol to help optimize output of CTP.

IntroductionSevere traumatic brain injury (TBI) is a catastrophic neurological condition with significant economic burden. Early in-hospital mortality (Methods and analysisThe Early Diagnosis of Mortality using Admission CT Perfusion in Severe Traumatic Brain Injury Patients study, is a prospective cohort study in patients with severe TBI funded by a grant from the Canadian Institute of Health Research. Adults aged 18 or older, with evidence of a severe TBI (Glasgow Coma Scale score ≤8 before initial resuscitation) and, on mechanical ventilation at the time of imaging are eligible. Patients will undergo CTP at the time of first imaging on their hospital admission. Admission CTP compares with the reference standard of an accepted bedside clinical assessment for brainstem function. Deferred consent will be used. The primary outcome is a binary outcome of mortality (dead) or survival (not dead) in the first 48 hours of admission. The planned sample size for achieving a sensitivity of 75% and a specificity of 95% with a CI of ±5% is 200 patients.Ethics and disseminationThis study has been approved by the University of Manitoba Health Research Ethics Board. The findings from our study will be disseminated through peer-reviewed journals and presentations at local rounds, national and international conferences. The public will be informed through forums at the end of the study.Trial registration numberNCT04318665

BackgroundThe effectiveness and safety of endovascular thrombectomy (EVT) for medium vessel occlusions (MeVO) in the anterior intracranial circulation for patients with acute ischemic stroke (AIS) has yet to be definitively established. We compared outcomes in patients undergoing EVT for large vessel occlusion (LVO) versus those with MeVO.MethodsThis retrospective cohort study, using an intention to treat design, compared the 90-day modified Rankin Scale (mRS) score between 43 patients with MeVO and 199 with LVO in the anterior intracranial circulation. Secondary outcome measures included vessel recanalization using the Thrombolysis in Cerebral Infarction (TICI) score, procedural complications, post-EVT intracranial hemorrhage (ICH), and infarct size.ResultsThe rate of good functional outcome (90-day mRS 0–2) was higher in patients with LVO than in those with MeVO (32.9% vs 27%), but this was not statistically significant (p=0.19). The rate of EVT procedural complications was also not significantly different between the groups (p=0.10), nor was the rate of ICH (p=0.30). There was also no significant difference in TICI scores between groups (p=0.12). Infarct size was larger in the LVO group (pConclusionThe 90-day mRS and rate of periprocedural complications were not significantly different between patients treated for LVO and those treated for MeVO with EVT. Older age, not receiving r-tPA, and larger infarct size were independent predictors of poor outcome at 90 days.

Purpose:Endovascular thrombectomy (EVT) significantly improves outcomes for acute ischemic stroke patients with large vessel occlusion (LVO) who present in a time sensitive manner. Prolonged EVT access times may reduce benefits for eligible patients. We evaluated the efficiency of EVT services including EVT rates, onset-to-CTA time and onset-to-groin puncture time in our province.Materials and methods:Three areas were defined: zone I- urban region, zone II-areas within 1 h drive distance from the Comprehensive Stroke Center (CSC); and zone III-areas more than 1hr drive distance from the CSC. In this retrospective cohort study, EVT rate, onset-to-groin puncture time and onset-to-CTA time were compared among the three groups using Krustal–Wallis and Wilcoxon tests.Results:The EVT rate per 100,000 inhabitants for urban zone I was 8.6 as compared to 5.1 in zone II, and 7.5 in zone III. Compared to zone I (114 min; 95% CI (96, 132); n = 128), mean onset-to-CTA time was 19 min longer in zone II (133 min; 95% CI (77, 189); n = 23; p = 0.0459) and 103 min longer in zone III (217 min, 95% CI (162, 272); n = 44; p < 0.0001). Compared to zone I (209 min, 95% CI (181, 238)), mean onset-to-groin puncture time was 22 min longer in zone II (231 min, 95% CI (174, 288); p = 0.046) but 163 min longer in zone III (372 min, 95% CI (312, 432); p < 0.0001).Conclusion:EVT access in rural areas is considerably reduced with significantly longer onset-to-groin puncture times and onset-to-CTA times when compared to our urban area. This may help in modifying the patient transfer policy for EVT referral.

Background:Venolymphatic malformations are rare benign vascular lesions of the head and neck. Sclerotherapy has become the first-line therapy of these lesions with bleomycin being a sclerosing agent commonly used.Purpose:To perform a systematic review of the published literature to synthesize evidence on the safety and efficacy of bleomycin for the treatment of head and neck venolymphatic malformations.Data sources:A systematic review of the literature (January 1995–May 2019) was performed in PubMed, Embase, and Cochrane Library databases to identify studies on sclerotherapy of venolymphatic malformations of the head and neck.Study selection:A total of 32 studies with participants met the inclusion criteria among which 1121 patients were included in the systematic review.Data analysis:Two reviewers independently screened and extracted data and assessed the risk of bias. The primary outcome was the subjective or objective reduction of lesion size as well as minor and major complications.Data synthesis:The bleomycin/pingyangmycin sclerotherapy achieved subjective or objective lesion size reduction in 96.3% (95% CI 94.1%–98.5%) of patients. Minor complications were observed in 16.2% and major complications in 1.1%.Conclusion:Bleomycin is a highly effective treatment of venolymphatic malformations of the head and neck with a low rate of major adverse events. This study represents an update on the “available” evidence, but only low-to-moderate quality studies were available.Limitations:This study reviewed 32 studies performed in different parts of the world, but there was heterogeneity of the study designs and interventions.

BackgroundSimulation training has been used in the aviation industry and surgical specialties for many years, but integration into neurointerventional practice is lagging behind.ObjectiveTo investigate how neurointerventionalists perceive the usefulness and limitations of simulation tools for the treatment of unruptured intracranial aneurysms (UIAs), and to identify simulation applications that were perceived to be most valuable for endovascular UIA treatment.MethodsA web-based international multidisciplinary survey was conducted among neurointerventionalists. Participants were asked for their perceptions on the usefulness of current simulation tools and the potential impact of future simulation tools in endovascular UIA treatment. They identified simulation applications that could add most value to endovascular UIA treatment and help to specifically reduce endovascular UIA treatment complications.Results233 neurointerventionalists from 38 countries completed the survey, most of whom (157/233 (67.4%)) had access to a simulator as a trainee, but only 15.3% used it frequently. Most participants (117/233 (50.2%)) considered currently available simulation tools relatively useful for endovascular UIA treatment, with greater value for trainees than for staff. Simulation of new devices (147/233 (63.1%)) and virtual practice runs in individual patient anatomy (119/233 (51.1%)) were considered most valuable for reducing endovascular UIA treatment complications.ConclusionAlthough neurointerventionalists perceived currently available simulation tools relatively useful, they did not use them regularly during their training. A priori testing of new devices and practice runs in individual patient anatomy in a virtual environment were thought to have the greatest potential for reducing endovascular UIA treatment complications.

Spontaneous intracranial hypotension (SIH) is a significant cause of chronic, postural headaches. Spontaneous intracranial hypotension is generally believed to be associated with cerebrospinal fluid (CSF) leaks, and these leaks can be posttraumatic, iatrogenic, or idiopathic in origin. An integral part of the management of patients with this condition consists of localizing and stopping the leaks. Radiologists play a central role in the workup of this condition detecting leaks using computed tomography, magnetic resonance imaging, or nuclear imaging. In this article, we briefly review SIH and the various imaging modalities, which can be used to identify and localize a spontaneous CSF leak.

Purpose: Endovascular thrombectomy (EVT) treatment for acute ischemic stroke is now recommended as a standard of care. However, implementing EVT in routine clinical practice poses many challenges, even in countries with advanced health-care systems. The aim of the current study is to delineate if EVT at our institution is an effective treatment for acute ischemic stroke. Methods: All patients who underwent EVT at our institution between December 2011 and July 2017 were retrospectively assessed from our prospective registry. Clinical and imaging (including the Alberta Stroke Program Early CT [ASPECT] score, single-phase computed tomography angiography, and computed tomography perfusion) criteria were utilized to determine EVT suitability. Primary outcomes included modified Rankin score (mRS) at 90 days and recanalization determined by the modified Treatment in Cerebral Infarction score. Effectiveness was assessed by comparing our cohort with patients receiving EVT in the ESCAPE (Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke) trial. Results: Eighty-eight patients presented to our hospital after a median of 87 minutes last seen normal. Of these, median ASPECT score was 9. A majority (72%) also received intravenous alteplase. Successful recanalization (≥TICI 2b) was achieved in 79%. At 90 days, 48% (36/75) were functionally independent (mRS score of 0-2) and 28% (21/75) were disabled (mRS score of 3-5); 24% (18/75) died (mRS of 6) within 90 days. Conclusions: An audit of our initial experience with EVT for the treatment of acute ischemic stroke in a small tertiary care center yielded similar results compared to the ESCAPE trial, which is encouraging for implementing this treatment in routine clinical practice.

BackgroundThe efficacy of SILK flow diverters (SFD) in the management of cerebral aneurysms has been established. However, the risk of complications with parent artery occlusion (PAO) remains to be fully elucidated. The purpose of our study was to analyze intracranial aneurysms treated with SFDs and assess for occurrences and potential risk factors for PAO.Materials and methodsBetween September 2010 and September 2017, 34 patients were treated for intracranial aneurysms using SFDs at a Canadian institution. This database was retrospectively analyzed for frequency of PAOs and statistical analysis performed for potential contributing factors.ResultsFollowing treatment with SFDs, average clinical and imaging follow-ups were 31 and 22 months, respectively. PAOs were identified in 21% (7/34) of patients and occurred between 8 days and 1.5 years from intervention but only in 11.8% in those compliant to anti-platelet medications. These were all associated with anterior circulation aneurysms (P=0.131) and had no associated neurological deficits. Of these, 57% (4/7) had a fusiform morphology compared with only 19% (5/27) in non-occluded patients (P=0.039). The presence of clinical symptoms at the time of initial SFD intervention was significantly associated with PAO (P=0.021).ConclusionDelayed PAO is not an uncommon outcome of flow diverter deployment and could be seen up to 1.5 years after treatment with no associated neurological deficits. Anti-platelet non-adherence remains a risk factor for PAO. Fusiform morphology of the aneurysm and symptoms at the time of intervention were associated with subsequent occlusion.

Stroke is the second leading cause of mortality and the third leading cause of disability-adjusted life-years worldwide. For each minute of an ischemic stroke, an estimated 1.9 million brain cells die. The year 2015 saw the unprecedented publication of 5 multicentre, randomized, controlled trials. These studies showed that patients with acute ischemic stroke caused by large-vessel thrombus occlusion of the proximal anterior circulation had significantly reduced disability at 90 days when treated with endovascular thrombectomy and usual stroke care compared to usual stroke care alone. As a result, endovascular thrombectomy is now the new North American and European standard of care for suitable patients with acute ischemic stroke caused by large-vessel proximal anterior circulation occlusion. We review key take-home messages in this paradigm shift for radiologists, including the importance of time and workflow efficiency, what currently constitutes appropriate preimaging patient selection and imaging criteria, the use of newer generation thrombectomy devices, safety outcomes, as well as further areas still in need of elucidation.

Diffusion-weighted imaging provides image contrast that is different from that provided by conventional magnetic resonance imaging techniques. It is highly sensitive for detection of cytotoxic oedema, and as such has gained favor in the detection of acute infarcts. However, diffusion-weighted imaging is underrepresented in the characterisation of many other disease processes. Our objective is to differentiate diseases that manifest with various neurological disorders, based on diffusion contrast and apparent diffusion coefficient values and review of hyper- and hypointense lesions on diffusion-weighted imaging.

Radiologists may be the first to suggest the diagnosis of posterior reversible encephalopathy syndrome (PRES). PRES is associated with many diverse clinical entities, the most common of which are eclampsia, hypertension, and immunosuppressive treatment. Radiologists should be aware of the spectrum of imaging findings in PRES. When promptly recognized and treated, the symptoms and radiological abnormalities can be completely reversed. When unrecognized, patients can progress to ischemia, massive infarction, and death. In this review, we present an overview of the unique signs observed on computed tomography and magnetic resonance images in PRES that can help in the early diagnosis and treatment that is highly effective in this syndrome.

Although the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke caused by intracranial anterior circulation large vessel occlusion (LVO) is proven, demonstration of local effectiveness is critical for health system planning and resource allocation because of the complexity and cost of this treatment.Using our prospective registry, we identified all patients who underwent EVT for out-of-hospital LVO stroke from February 1, 2013 through January 31, 2017 (n = 44), and matched them 1:1 in a hierarchical fashion with control patients not treated with EVT based on age (±5 years), prehospital functional status, stroke syndrome, severity, and thrombolysis administration. Demographics, in-hospital mortality, discharge disposition from acute care, length of hospitalization, and functional status at discharge from acute care and at follow-up were compared between cases and controls.For EVT-treated patients (median age 66, 50% women), the median onset-to-recanalization interval was 247 min, and successful recanalization was achieved in 30/44 (91%). Alteplase was administered in 75% of cases and 57% of controls (p = 0.07). In-hospital mortality was 11% among the cases and 36% in the control group (p = 0.006); this survival benefit persisted during follow-up (p = 0.014). More EVT patients were discharged home from acute care (50% vs. 18%, p = 0.002). Among survivors, there were nonsignificant trends in favor of EVT for median length of hospitalization (14 vs. 41 days, p = 0.11) and functional independence at follow-up (51% vs. 32%, p = 0.079).EVT improved survival and decreased disability. This demonstration of single-center effectiveness may help facilitate expansion of EVT services in similar health-care jurisdictions.Étude cas-témoin portant sur la thrombectomie endovasculaire dans un centre canadien de prise en charge des AVC. Contexte : Bien qu’on ait prouvé l’efficacité de la thrombectomie endovasculaire dans le cas d’accidents ischémiques cérébraux aigus causés par l’occlusion de grosses artères affectant la circulation antérieure intracrânienne, la démonstration de son efficacité sur le terrain est essentielle à la planification du réseau la santé et à l’allocation des ressources en raison de la complexité de ce traitement et des coûts qui y sont associés. Méthodes : À l’aide d’un registre prospectif, nous avons identifié tous les patients ayant bénéficié (n = 44), du 1er février 2013 au 31 janvier 2017, d’une thrombectomie endovasculaire à la suite d’un AVC survenu en dehors d’un établissement de la santé, AVC causé par l’occlusion de grosses artères. De manière hiérarchique, nous avons fait correspondre nos patients dans un rapport de 1 à 1 à nos témoins non traités par thrombectomie endovasculaire, et ce, en nous basant sur leur âge (± 5 ans), sur leur situation fonctionnelle avant d’être admis, sur les signes cliniques et la gravité de leur AVC, et sur l’administration d’un traitement thrombolytique. Nous avons également comparé leurs caractéristiques démographiques, leur taux de mortalité hospitalière, les modalités d’obtention d’un congé des soins intensifs, la durée de leur hospitalisation et leur situation fonctionnelle au moment de quitter les soins intensifs et à l’occasion d’un suivi. Résultats : Dans le cas de nos patients traités par thrombectomie endovasculaire (âge médian : 66 ans ; 50 % de femmes), l’intervalle médian entre les premiers signes d’un AVC et la recanalisation a été de 247 minutes. Fait à souligner, une recanalisation réussie a été accomplie dans 30 cas sur 44 (91 %). L’altéplase a été administré dans 75 % des cas et chez 57 % des témoins (p = 0,07). En ce qui concerne le taux de mortalité hospitalière, il a été de 11 % parmi tous nos cas et de 36 % chez nos témoins (p = 0,006) ; À noter que cet avantage en termes de survie a persisté au moment des suivis (p = 0,014). Plus de patients traités par thrombectomie endovasculaire ont obtenu leur congé des soins intensifs et sont revenus à la maison (50 % contre 18 % ; p = 0,002). Parmi les survivants à ces AVC, on a noté des tendances non significatives en faveur des patients traités par thrombectomie endovasculaire pour ce qui est de la durée médiane d’hospitalisation (14 jours contre 41 jours ; p = 0,11) et de l’autonomie fonctionnelle au moment des suivis (51 % contre 32 % ; p = 0,079). Conclusion : En somme, la thrombectomie endovasculaire a permis d’améliorer le taux de survie des patients ainsi que leur niveau d’autonomie fonctionnelle. Effectuée dans un seul établissement hospitalier, cette démonstration de l’efficacité de ce traitement pourrait contribuer à faciliter l’essor des traitements de thrombectomie endovasculaire dans d’autres systèmes de santé similaires.

Objective Whether transverse venous sinus stenosis (TVSS) causes idiopathic intracranial hypertension (IIH) or is an effect of the increased intracranial pressures is controversial. The purpose of this study was to assess the feasibility of serial imaging in patients with IIH on medical management. Design and Participants Patients found to have IIH and TVSS on contrast-enhanced magnetic resonance venography (CEMRV) were recruited in a prospective cohort study. Patients were medically managed and followed with a CEMRV immediately after lumbar puncture, 3–6 months after diagnosis with resolution of IIH symptoms, and 1 year after diagnosis. Ophthalmological data were collected at the time of diagnosis, 3–6 months after diagnosis, and 1 year after diagnosis. Feasibility data, including patient recruitment rate, barriers, and logistical issues, were recorded. Results Twenty patients with suspected IIH were screened, and 5 of 7 (71.4%; 95% confidence interval: 36.21–100) eligible patients were enrolled in 1 year, at completion. All recruited patients had clinical resolution of their IIH on medical therapy, and none of them had any obvious change in their TVSS. Conclusions Prospective examination of TVSS with serial magnetic resonance imaging in patients with IIH is feasible. TVSS in patients with IIH did not show any change, despite clinical improvement on medical management in all participants.

IntroductionIndirect carotid cavernous fistulas are treated with coil embolization when they present with orbital/visual symptoms or if there is cortical venous reflux. Most of the time, the treatment is done by non-specifically packing the whole cavernous sinus with coils. The purpose of this case series was to examine whether DSA-Dynavision before embolization would improve treatment by shortening the procedure time, requiring fewer coils, or reducing the complication rate.Materials and method8 patients with 9 fistula sites were retrospectively identified. DSA-Dynavision and non-DSA-Dynavision patients were compared in a retrospective cohort study.ResultsMean total coil length was significantly shorter for the group who had DSA-Dynavision than for those who had non-DSA-Dynavision (130.5 cm vs 190 cm, p=0.034) and mean procedural time was significantly shorter for the DSA-Dynavision group (171.1 min vs 280.3 min, p=0.025). A transient neurological complication was seen in only one patient.ConclusionsThe use of DSA-Dynavision in pre-procedural planning facilitates selective coil embolization of the foot of the vein.

IntroductionStents reduce the rate of angiographic recurrence of intracranial aneurysms. The newest stent for intracranial use is the Low-profile Visible Intraluminal Support device (LVIS Jr).ObjectiveTo assess the efficacy of the new stent in a multicenter retrospective registry.Materials and methodCenters across Canada using LVIS Jr were contacted and asked to participate in a retrospective registry of consecutive patients treated with LVIS Jr for intracranial aneurysms between January 2013 and July 2015.ResultsA total of 102 patients, with saccular aneurysms in 100 patients (72 women; age range 21–78 years; mean 56.0 years; median 57.5 years) were treated with a LVIS Jr stent. The mean maximum diameter of the dome and neck of the aneurysm and dome to neck ratios were 8.3 mm±7.7 mm, 4.4 mm±1.9 mm, and 1.86±1.22, respectively. Angiographic complications arose in 23 patients, clinical complications in 9 patients, and only 3% of permanent neurological deficits occurred. Death occurred in 1 patient, unrelated to the stent. The ruptured status of the aneurysms (OR=3.29; p=0.046) and use of LVIS Jr for bailout (OR=2.54; p=0.053) showed a trend towards significant association with higher angiographic complications. At the last available follow-up, 68 class I, 20 class II, and 12 class III results were seen.ConclusionsThe LVIS Jr stent is a safe and effective device for stent-assisted coiling, with 3% permanent neurological complications. Stent-assisted coiling continues to be technically challenging in cases of ruptured aneurysms and bailout situations.

A radiopaque temporary liquid embolic agent was synthesized from polyphosphate (PP) coacervates and optimized using a design of experiments approach. Variables studied were: strontium substitution (0–15 mol%), barium substitution (0–15 mol%), PP concentration and degree of polymerization of the polyphosphate (Dp). The viscosity, radiopacity and cell viability of the resulting coacervates were measured for 60 formulations and response surface modeling was used to determine the optimum coacervate that maximized radiopacity and cell viability. The optimum coacervate made from PP with a large Dp (9.5 g NaPP/100 mL, 2.2 mol% Sr, 9 mol% Ba and 3.8 mol% Ca) was taken forward to a pilot animal trial. In this rabbit model, PP embolic agent successfully occluded the central auricular artery with promising biocompatibility. Further study is required to optimize the cohesiveness and clinical effectiveness of PP as an in situ setting temporary embolic agent. Statement of significance This article describes the development of a new radiopaque temporary liquid embolic agent from the optimization using design of experiments to a pilot animal study. Embolization is a minimally invasive interventional radiology procedure used to block blood flow in a targeted blood vessel. This procedure is used to treat many conditions including: tumors, aneurysms and arteriovenous malformations. Currently, no inherent radiopaque embolic agents are available in the clinic, which would allow for direct imaging of the material during the procedure and follow up treatment.

Purpose The purpose of this article is to prospectively test the hypothesis that time-resolved CT angiography (TRCTA) on a Toshiba 320-slice CT scanner enables the same characterization of cerebral vascular malformation (CVM) including arteriovenous malformation (AVM), dural arteriovenous fistula (DAVF), pial arteriovenous fistula (PAVF) and developmental venous anomaly (DVA) compared to digital subtraction angiography (DSA). Materials and methods Eighteen (eight males, 10 females) consecutive patients (11 AVM, four DAVF, one PAVF, and two DVA) underwent 19 TRCTA (Aquillion one, Toshiba) for suspected CVM diagnosed on routine CT or MRI. One patient with a dural AVF underwent TRCTA and DSA twice before and after treatment. Of the 18 patients, 13 were followed with DSA (Artis, Siemens) within two months of TRCTA. Twenty-three sequential volume acquisitions of the whole head were acquired after injection of 50 ml contrast at the rate of 4 ml/sec. Two patients with DVA did not undergo DSA. Two TRCTA were not assessed because of technical problems. TRCTAs were independently reviewed by two neuroradiologists and DSA by two other neuroradiologists and graded according to the Spetzler-Martin classification, Borden classification, overall diagnostic quality, and level of confidence. Weighted kappa coefficients ( k) were calculated to compare reader’s assessment of DSA vs TRCTA. Results There was excellent ( k = 0.83 and 1) to good ( k = 0.56, 0.61, 0.65 and 0.67) agreement between the different possible pairs of neuroradiologists for the assessment of vascular malformations. Conclusion TRCTA may be a sufficient noninvasive substitute for conventional DSA in certain clinical situations.

IntroductionThe SILK flow diverter (SFD) is used for the treatment of complex intracranial aneurysms. Small case series have been reported in the literature but few studies with a large number of patients have been published. We present our experience with the SFD for the treatment of intracranial aneurysms in Canada.MethodsCenters across Canada using SFDs were contacted to fill out a case report form for patients treated with an SFD in their center. Individual centers were responsible for approval from their ethics committee. Image analysis was performed by individual operators. The case report forms were collected and the final analysis was performed.ResultsA total of 92 patients were treated with SFDs in eight centers in Canada between January 2009 and August 2013. The aneurysms were located in the posterior circulation in 16 patients and in the anterior circulation in 76 patients. Most aneurysms (75%) were saccular in shape; 22% were fusiform and 3% were blister aneurysms. The size of the aneurysms varied from 2 to 60 mm with the neck varying from 2 to 60 mm. Perioperative morbidity and mortality were 8.7% and 2.2%, respectively. At the last available follow-up, 83.1% of the aneurysms were either completely or near-completely occluded. The rate of complications was higher for fusiform aneurysms (pConclusionsThe SFD appears to be an important tool for the treatment of complex intracranial aneurysms. Treatment outcomes and complication rates remain a problem, but should be considered in the context of available alternative interventions. Ongoing analysis of flow-diverting stents for radiographic and clinical performance is required.

Purpose: To compare patient effective dose resulting from two alternative imaging protocols for pre-coiling assessment of intracranial aneurysms: a series of 2D Digital Subtraction Angiography (DSA) projections, and a 3D rotational angiography (RA) acquisition. Methods: In a retrospective analysis, we investigated 44 patients who underwent endovascular coiling in our institution. Images were acquired on a biplane Image Intensifier system not equipped with dose-area product (DAP) meter. Conventional 2D DSA images were simulated with an anthropomorphic skull phantom. Entrance skin dose was measured with a 60 cc ion chamber, and the PCXMC Monte Carlo based software was used to calculate patient effective dose. For the RA protocol, a 16 cm computed tomography (CT) dosimetry phantom and a 100 mm pencil ion chamber were employed to measure the CT dose index. Patient effective dose was calculated with the ImPACT calculator. An unpaired two-tailed t-test was used to determine the significance of differences between patient doses in each group. Results: Sixteen patients underwent the 2D DSA protocol with multiple projections; their mean number of cine runs was 5.1; the mean effective dose was 2.11 millisievert (mSv) (range 1.69–3.43 mSv). Twenty eight patients were assessed using the 3D RA protocol with the effective dose of 1.29 mSv. The difference between the means of two dose distributions was statistically significant (p=0.00028). Conclusion: Our study demonstrated that the patient effective dose was significantly lower from the 3D RA protocol than that from the 2D DSA protocol used in the planning of coiling of intracranial aneurysm.

BackgroundTandem occlusions of the extracranial carotid and intracranial carotid or middle cerebral artery have a particularly poor prognosis without treatment. Several management strategies have been used with no clear consensus recommendations. We examined subjects with tandem occlusions enrolled in the ESCAPE trial and their outcomes.MethodsData are from the ESCAPE trial. Additional data were sought on interventions for each subject.ResultsThere were 54 (17%) subjects with tandem extracranial and intracranial occlusions. Patients in the endovascular treatment arm (n=30) were more likely to be younger (median age 66 years, pConclusionsTandem occlusions occurred in one-sixth of patients and were treated highly variably within the ESCAPE trial. While outcomes were similar, the best method to treat the carotid artery in patients with tandem occlusion awaits further randomized data.Trial registration numberNCT01778335.

Objectives: To compare growth patterns of nonfunctioning and prolactin-producing pituitary macroadenomas, and to find whether their specific growth patterns are associated with clinically significant effects on vision. Materials and Methods: From our comprehensive provincial neuropituitary registry, we retrospectively identified 35 randomly selected patients each with nonfunctioning adenomas and prolactinomas >10 mm in any dimension. MRI scans were analyzed to determine the superior and inferior growth, volume, and maximum craniocaudal height of the adenomas. Patients underwent visual field testing at diagnosis. Continuous variables were compared using Student’s t test, the Mann–Whitney U test, and ANOVA. Categorical variables were compared using the chi-square test. Results: The mean height of prolactinomas (23.2±11.3 mm) was similar to nonfunctioning adenomas (22.3±9.3 mm, p=0.8), and so were mean tumor volumes (prolactinoma=5.9±8 ml vs. nonfunctioning adenoma=4.8±5 ml, p=0.47). However, the mean suprasellar growth for prolactinomas was 2.9±5.3 mm and 7.3±4.7 mm for nonfunctioning adenomas (pp=0.04). The inferior growth pattern of prolactinomas was associated with a significantly lower likelihood of having visual field abnormalities (11.4 vs. 57.1%, pConclusions: Prolactinomas have predominantly inferior growth compared to nonfunctioning adenomas and are less likely to cause vision changes.

Object The pathophysiology of spinal dural arteriovenous fistulas (SDAVFs) results in perimedullary venous congestion and in turn central cord congestion. Clinically, this presents with progressive neurological dysfunctions that, if diagnosed in a timely fashion, can be at least halted and in part reversed. In SDAVFs, imaging features on MRI and digital subtraction angiography (DSA) have not been studied in conjunction with clinical findings. The primary purpose of the present study was to test if severity of clinical presentation varies in relation to imaging. Methods This retrospective cohort study identified 12 patients treated for SDAVF at the authors' institution. The extent of venous congestion and cord edema was quantified by the number of vertebral levels shown to be affected on DSA and MRI. A modified Aminoff-Logue Scale (ALS) score was assigned at the time of diagnosis and again after definitive therapy. The patients were divided into one of two groups: those with venous congestion < 7 and ≥ 7 vertebral levels seen on DSA and MRI and with central cord edema < 6 and ≥ 6 levels. A t-test was used to assess for a difference in the presenting ALS score between the groups. Results Patients with ≥ 7 levels of venous congestion reported greater functional disability (DSA: p ≤ 0.001, Cohen's d = 0.509; and MRI: p ≤ 0.001, d = 0.632). Patients with a greater extent of cord edema also reported worse functional disability (p ≤ 0.001, d = 2.31). There was a strong linear correlation between the post- and pretreatment ALS scores (R2 = 0.86) for those with successful interventions (n = 9). Conclusions In patients with an SDAVF, the severity of the neurological dysfunction may be predicted by the extent of DSA- and MRI-documented venous congestion and cord edema. There was a strong positive relationship between initial and posttreatment neurological dysfunction.

Introduction Migrainous infarction accounts for 12.8% of ischemic strokes of unusual etiology. Case report A 59-year-old woman with longstanding migraine with aura experienced what appeared to be migrainous infarction characterized by dysmetropsia and transient Cotard’s syndrome. Imaging demonstrated right temporal-parietal-occipital changes with apparent cortical laminar necrosis. Conclusion The spectrum of the pathophysiology of migrainous infarction has not been established; however, cortical spreading depression may explain the appearance of imaging findings that do not obey a vascular territory.

Differentiation of grade 3 astrocytoma from glioblastoma multiforme can be difficult with conventional structural imaging but is important for prognosis. The purpose of this study was to assess perfusion CT in differentiating high-grade gliomas (HGGs) and their role in prognosis in the care of patients with HGG.Twenty patients with previously untreated HGG underwent prospective evaluation with perfusion CT. Permeability surface area product (PS) and cerebral blood volume (CBV) were calculated by the deconvolution method and were compared between HGGs with Student two-sample t tests. Receiver operating characteristic curves were generated for PS, CBV, and the conjoint factor PS + CBV. Cox regression analysis was used to correlate these parameters with patient survival over a follow-up period. Hazard ratios were calculated, and Kaplan-Meier survival curves were drawn.There was a significant difference between grade 3 and grade 4 gliomas for PS (p = 0.022) and PS + CBV (p = 0.019) but not for CBV alone (p = 0.411). Receiver operating characteristic analyses showed that PS (area under the curve [AUC], 0.72) and CBV + PS (AUC, 0.73) can be used to differentiate grade 3 from grade 4 gliomas but that CBV alone cannot be so used (AUC, 0.54). There was a significant relation between patient outcome and age (p = 0.034) and CBV + PS (p = 0.048). Patients with HGG and a CBV + PS greater than 9 had a poor outcome (hazard ratio, 6.00).PS and CBV + PS can be used to differentiate grade 3 from grade 4 gliomas. The outcome of patients with HGG depends on age and CBV + PS.

Background The flow diverting stent is a new and expansive tool in the endovascular therapy of complex intracranial aneurysms. We present our experience using SILK flow diverter (SFD) in patients with complex intracranial aneurysms, and a cost analysis. Methods Between September 2010 and May 2012, 19 consecutive patients with 29 complex intracranial aneurysms were treated with SFD without the adjunctive use of coils. We retrospectively evaluated the technical aspects, thromboembolic events, adjunctive therapies, and short term results in patients with complex intracranial aneurysms treated with SFD. A cost analysis of patients who were treated with SFD was performed and compared with similar sized aneurysms coiled with stent assisted coiling. Results The primary technical success rate was 100%. An adjunctive device was required in two of our patients. The technique related complication rate and the 30 day mortality and morbidity rates were 5% (1/20) and 10% (2/20), respectively. We had a total of 263 patient months of clinical and 166 patient months of imaging follow-up. Follow-up imaging revealed two asymptomatic occlusions of the parent artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 59% of patients where follow-up images were available. The cost analysis showed that the mean cost of treatment with SFD was significantly cheaper compared with the presumed cost of stent assisted coiling (p Conclusions The SFD provides a very feasible, efficient, relatively safe, and cost effective method to treat complex intracranial aneurysms without the use of adjunct coiling.

With increasing application of endovascular therapies worldwide, the management of procedure-related complications has become increasingly important. Of particular interest is the surgical management of complications refractory to endovascular recanalization. Here, we present the unique surgical management of an inadvertent intracranial glue embolus following urgent glue embolization of a maxillofacial arteriovenous malformation. This is the first report to document management of this complication. An arteriotomy was performed and the glue, despite being adhered to the vessel intima, was retrieved in its entirety from the middle cerebral artery (MCA). Following the procedure, the patient developed a new thrombus at the previous glue site, likely related to endothelial injury. With post-operative heparin therapy, the patient recovered to baseline neurological state. This report demonstrates that microsurgical arteriotomy and glue embolectomy of the MCA is feasible, safe and may be useful in the management of complications of inadvertent intracranial glue embolization.

Synchronous multiplicity of cranial and spinal dural arteriovenous fistulas (DAVFs) is known but uncommon. The authors report on a patient with the unusual finding of multiple cranial and multiple separate spinal DAVFs. The patient initially presented with vague visual symptoms in 2004. A cranial DAVF was identified along the left transverse sinus with cortical venous reflux and another DAVF was identified along the posterior part of the superior sagittal sinus with no cortical venous reflux. The first DAVF was treated both endovascularly and surgically and the second was left untreated. The follow-up angiogram showed multiple spinal DAVFs at the levels of C-1, C-2, and C-6 on the left side and at the C-3 level on the right side along with another cranial DAVF along the anterior part of the superior sagittal sinus with cortical venous reflux. A retrospective analysis of the digital subtraction angiogram and MR images suggested that the cervical spinal DAVFs were already present in 2004 (6 years previously). Multiple DAVFs, although rare, do exist and it is important to look for any evidence of their presence when evaluating patients with symptoms suggestive of arteriovenous fistulas.

OBJECTIVE. The purpose of this study was to investigate whether perfusion CT values obtained with a reduced-dose imaging protocol on a 320-MDCT scanner are similar to those obtained with a standard protocol.CONCLUSION. Similar perfusion values at one-half the radiation dose can be obtained with the alternative algorithm used in this study.

Background: EVT is now recommended as standard of care for stroke in Canada, but its implementation still poses challenges. We studied the delivery of EVT in our hospital, a participanting site in the ESCAPE trial, which serves the province of Nova Scotia. Methods: Patients who underwent EVT December 2011 – December 2016 were identified prospectively. Demographics, process measures, imaging characteristics (Alberta Stroke Program Early CT Score [ASPECTS], collateral score, Thrombolysis in Cerebral Infarction [TICI] score), and outcomes, including modified Rankin score [mRS] ~ 90 days post-EVT, were collected retrospectively. Effectiveness was assessed by comparison with outcomes in the ESCAPE trial. Results: 91 patients (M:F= 48:43; mean age 64 years) presented to hospital after 194 min ± 230 min from last seen normal. In 58%, the ASPECTS was >7. 80% had good/intermediate collaterals. Alteplase was administered to 72% (75% in ESCAPE, p=0.97). EVT mean duration was 70 min ± 62 min. Successful recanalization (≥TICI 2b) was achieved in 76% (vs 72.4% in ESCAPE, p= 0.97). Among the 54 patients recanalized, mRS scores of 0-2, 3-5 and 6 were seen in 57.4, 24.1 and 14.8% respectively; ESCAPE comparators 53, 37 and 10%, p=0.96, 0.86 and 0.91. Conclusions: EVT at our hospital yielded results similar to the ESCAPE trial.

Background: Glioblastoma multiforme (GBM) is known to have poor prognosis, with no available imaging marker that can predict survival at the time of diagnosis. Diffusion weighted images are used in characterisation of cellularity and necrosis of GBM. The purpose of this study was to assess whether pattern or degree of diffusion restriction could help in the prognostication of patients with GBM. Material and Methods: We retrospectively analyzed 84 consecutive patients with confirmed GBM on biopsy or resection. The study was approved by the institutional ethics committee. The total volume of the tumor and total volume of tumor showing restricted diffusion were calculated. The lowest Apparent Diffusion Coefficient (ADC) in the region of the tumor and in the contralateral Normal Appearing White Matter were calculated in order to calculate the nADC. Treatment and follow-up data in these patients were recorded. Multivariate analsysis was completed to determine significant correlations between different variables and the survival of these patients. Results: Patient survival was significantly related to the age of the patient (pConclusion: The survival of patients with GBM had small, but significant, correlations with the patient’s age and nADC within the tumor.

Background: Computed tomography perfusion (CTP) is increasingly being used in the setting of acute ischemic stroke (AIS). The aim of the current study was to compare the prognostic utility of, and inter-observer variation between, baseline appearances on non-contrast CT (using Alberta Stroke Program Early CT score(ASPECTS)) and on CTP for predicting final infarct volume. We also assessed impact of training on interpretation of these images. Methods: Retrospectively, plain head computed tomography (CT) and CTP images at presentation and CT or diffusion imaging on follow up of patients with AIS were analyzed. The lesion volume on different CTP parameters was then correlated with the final infarct volume. This analysis was done by a Neuroradiologist, a stroke Neurologist and a medical student. Kappa statistics and Intra-class correlation coefficients were used for agreement between readers. Pearson correlation coefficients were used.Results: Thirty eight patients with AIS met all inclusion criteria. There was very good agreement among all readers for the CTP parameters. There was only fair agreement for ASPECT score. Correlation coefficient (r-square) between CTP parameters and final infarct volume showed that cerebral blood volume was the best parameter to predict the final infarct volume followed by cerebral blood flow and time to peak. The best reader to predict the final infarct volume on the initial CT perfusion study was the neuroradiologist followed by medical student and stroke neurologist. Conclusions: Cerebral blood volume defect correlated the best with the final infarct volume. There was a very good inter-observer agreement for all the CTP maps in predicting the final infarct volume despite the wide variation in the experience of the readers.

Purpose: Computed tomography perfusion (CTP) has been performed to predict which patients with aneurysmal subarachnoid hemorrhage are at risk of developing delayed cerebral ischemia (DCI). Patients with severe arterial narrowing may have significant reduction in perfusion. However, many patients have less severe arterial narrowing. There is a paucity of literature evaluating perfusion changes which occur with mild to moderate narrowing. The purpose of our study was to investigate serial whole-brain CTP/computed tomography angiography in aneurysm-related subarachnoid hemorrhage (aSAH) patients with mild to moderate angiographic narrowing. Methods: We retrospectively studied 18 aSAH patients who had baseline and follow-up whole-brain CTP/computed tomography angiography. Thirty-one regions of interest/hemisphere at six levels were grouped by vascular territory. Arterial diameters were measured at the circle of Willis. The correlation between arterial diameter and change in CTP values, change in CTP in with and without DCI, and response to intra-arterial vasodilator therapy in DCI patients was evaluated. Results: There was correlation among the overall average cerebral blood flow (CBF; R=0.49, pConclusions: Our preliminary study demonstrates there is a correlation between mild to moderate angiographic narrowing and serial changes in perfusion in patients with aSAH. Patients developing DCI tended to have progressively worsening CBF compared with those not developing DCI.

Wide-necked bifurcation intracranial aneurysms have traditionally not been amenable to coil embolization with the use of a single stent due to the high risk of coil prolapse. Y-configuration double stent-assisted coil embolization (‘Y-stenting’) of this aneurysm type has been shown to have generally good clinical outcomes, although the technique is complex with various challenges described in the literature. The compliant and flexible closed-cell design of braided stents such as the LVIS Jr allows for the creation of a ‘shelf’ across the aneurysm neck sufficient to prevent coil prolapse. We describe this novel ‘shelf’ technique and present a small case series of LVIS Jr stent-assisted wide-necked bifurcation intracranial aneurysm coiling in eight patients. Our small, albeit important, case series demonstrates that the ‘shelf’ technique is feasible and safe with very good short-term clinical and angiographic outcomes, and may obviate the need for Y-stenting.

Background Coiling of small aneurysms can be technically challenging. These aspects of coiling tend to be less problematic in medium to large aneurysms as they are more accommodating of microcatheters and coils. When physicians are asked their opinion regarding aneurysm coilability in small aneurysms, the decision often lies in the operator9s feeling that they could reasonably exclude the aneurysm with a complication rate similar to larger aneurysms. The purpose of our study was to investigate the feasibility, intraprocedural rupture rates and long term durability of endovascular coiling for small (≤4 mm) aneurysms compared with non-small (>4 mm) aneurysms. To control for factors such as vessel tortuosity and aneurysm location, a control group was chosen matched to the study group both in age and aneurysm location. Materials and methods A retrospective review of 360 intracranial aneurysms coiled at our institution between 2003 and 2008 was performed. For the control group, intracranial aneurysms coiled in the same period matched to location and age were chosen. Results The frequency of intraprocedural perforations was 4/34 (0.12) and 3/68 (0.04) for the small and non-small cohort, respectively (p=0.22). All patients who had a perforation in the small aneurysm groups had a good clinical outcome compared with 1/3 in the non-small group (two mortalities). The frequency of recanalization for the small and non-small groups was 3/34 (0.09) and 23/68 (0.33), respectively (p=0.006). There was no retreatments in the small aneurysm group and five (0.07) in the non-small group (p=0.116). Conclusion Coiling of small (≤4 mm) aneurysms is feasible with a reasonable complication rate. There is a non-significant increase in frequency of intraprocedural rupture with coiling of small aneurysms compared with controls matched to aneurysm location and age but this is not associated with increased morbidity. Coiling of small aneurysms leads to durable results at long term follow-up.