Background: Our prior six-year review (n=2165) revealed 24% of patients undergoing posterior decompression surgeries (laminectomy or discectomy) sought emergency department (ED) care within three months post-surgery. We established an integrated Spine Assessment Clinic (SAC) to enhance patient outcomes and minimize unnecessary ED visits through pre-operative education, targeted QI interventions, and early post-operative follow-up. Methods: We reviewed 13 months of posterior decompression data (n=205) following SAC implementation. These patients received individualized, comprehensive pre-operative education and follow-up phone calls within 7 days post-surgery. ED visits within 90 days post-surgery were tracked using provincial databases and compared to our pre-SAC implementation data. Results: Out of 205 patients, 24 (11.6%) accounted for 34 ED visits within 90 days post-op, showing a significant reduction in ED visits from 24% to 11.6%, and decreased overall ED utilization from 42.1% to 16.6% (when accounting for multiple visits by the same patient). Early interventions including wound monitoring, outpatient bloodwork, and prescription adjustments for pain management, helped mitigate ED visits. Patient satisfaction surveys (n=62) indicated 92% were “highly satisfied” and 100% would recommend the SAC. Conclusions: The SAC reduced ED visits after posterior decompression surgery by over 50%, with pre-operative education, focused QI initiatives, and its individualized, proactive approach.

Background: The WHO grade of meningioma was updated in 2021 to include homozygous deletions of CDKN2A/B and TERT promotor mutations. Previous work including the recent cIMPACT-NOW statement have discussed the potential value of including chromosomal copy number alterations to help refine the current grading system. Methods: Chromosomal copy number profiles were inferred from from 1964 meningiomas using DNA methylation. Regularized Cox regresssion was used to identify CNAs independenly associated with post-surgical and post-RT PFS. Outcomes were stratified by WHO grade and novel CNAs to assess their potential value in WHO critiera. Results: Patients with WHO grade 1 tumours and chromosome 1p loss had similar outcomes to those with WHO grade 2 tumours (median PFS 5.83 [95% CI 4.36-Inf] vs 4.48 [4.09-5.18] years). Those with chromosome 1p loss and 1q gain had similar outcomes to those with WHO grade 3 cases regardless of initial grade (median PFS 2.23 [1.28-Inf] years WHO grade 1, 1.90 [1.23-2.25] years WHO grade 2, compared to 2.27 [1.68-3.05] years in WHO grade 3 cases overall). Conclusions: We advocate for chromosome 1p loss being added as a criterion for a CNS WHO grade of 2 meningioma and addition of 1q gain as a criterion for a CNS WHO grade of 3.

Background: Transitioning from home to long-term care (LTC) is challenging for people with dementia and their caregivers. We aimed to elucidate factors predicting long-term care admission within two years of presentation to the Rural and Remote Memory Clinic (RRMC) in Western Canada. Methods: A total of 679 community-dwelling patients were seen at the RRMC in Saskatchewan between its establishment in March 2004 through June 2019. Data analysis included 635 patients (admitted to LTC within two years = 222, not admitted to LTC = 413). Each patient was assessed neuropsychologically and completed self-report questionnaires measuring several domains. Both groups were compared using logistic regression analyses. Results: Univariate logistic regressions showed that age (OR = 1.052, CI = 1.035-1.069), male sex (OR = 1.794, CI = 1.279-2.517), Functional Activities Questionnaire (OR = 1.085, CI = 1.057-1.114), MMSE (OR = 0.861, CI = 0.827-0.897), and Clinical Dementia Rating score (OR = 1.132, CI = 1.062-1.206) remained significant (p < .001). Preserved cognition, as measured by the MMSE, was protective. Conclusions: We found that being older, male, more dependent in activities of daily living, and having increased severity of dementia predicted LTC admission. This information may help in planning care for individuals with dementia.

Background: Plasma pTau217 is a robust biomarker for the diagnosis of Alzheimer’s disease (AD). However, most pTau217 assays are not widely available for clinical testing. We assessed the performance of two commercially available plasma pTau217 immunoassays in a clinical diagnostic laboratory for AD diagnosis. Methods: 219 plasma samples from healthy controls with negative amyloid PET, 115 plasma samples from pathology-confirmed and 263 samples with confirmed amyloid PET were selected. Plasma pTau217 levels were measured using the ALZpath pTau217 assay on the Quanterix HD-X Simoa platform and the Lumipulse pTau217 assay on the Lumipulse G1200 platform at and BC Neuroimmunology Lab and Neurocode USA. Results: For the ALZpath assay, the coefficients were 10.4%, 10.4%, and 9.9%, and for the Fujirebio assay, were 12.1%, 12.2%, and 5.3%, respectively. Sample stability and interference were similar between the two assays, although moderate heterophilic antibody interference and reduced frozen sample stability at -20˚C were observed for the Fujirebio assay. Both assays demonstrated similar clinical performance and differentiated individuals with AD (ALZpath AUC = 0.94; Fujirebio AUC = 0.90). Conclusions: The performance of the two pTau 217 assays was comparable. The clinical separation between the healthy controls and those with Amyloid pathology was nearly complete for both assays.

Background: Attitudes toward aging influence many health outcomes, yet their relationship with cognition and Alzheimer’s disease (AD) remains unknown. To better understand their impact on cognition and AD risk, we examined whether positive attitudes predict better cognition and diminished risk on AD biomarkers. Methods: A subsample of older adults with a family history of AD (n=54; women=39) from the McGill PREVENT-AD cohort participated in this study. Participants completed the Attitudes to Ageing Questionnaire (AAQ-24), providing three scores: psychosocial loss, psychological growth and physical change. Participants underwent cognitive testing (Rey Auditory Verbal Learning Test, RAVLT; Delis-Kaplan Executive Function System-Color Word Interference Test, D-KEFS-CWIT), and AD blood-based biomarker assessments (p-tau217, Aβ42/40). Regression models tested associations, adjusting for covariates (age, sex, education, depression, APOE4), and were Bonferroni corrected. Results: Positive attitudes were associated with better recall and recognition (RAVLT) and improved word reading, colour naming, switching, and inhibition (D-KEFS-CWIT) (p<0.00077), while negative attitudes showed the opposite pattern. Negative attitudes were correlated with lower Aβ42/40 ratios, while positive attitudes were linked to lower p-tau217 (p<0.0167). Conclusions: These findings demonstrate that positive attitudes predict better cognition and a lower risk profile for AD biomarkers, suggesting that life outlook may be an early disease feature or a risk factor.

Background: Lecanemab is the first anti-amyloid monoclonal antibody to receive full approval in the US for early Alzheimer’s Disease (AD). Methods: Using open administrative claims from the PurpleLab (6Jan2023–1Aug2024) database, patients receiving ≥1 lecanemab and with continuous clinical activity ≥6 months prior to the first lecanemab infusion were included. The follow-up period ran from the first lecanemab administration to the latest clinical activity. Treatment gap was calculated as the number of days without lecanemab supply between consecutive infusions. Results: A total of 2,840 patients were included. Mean observation period was 130.7 days. Mean age was 75.4 (SD 6.2) years, and 54.8% were female. Most prescribers were neurologists (82.0%). Within 30 days before lecanemab initiation, 77.0% of patients had AD diagnosis, and 32.1% had mild cognitive impairment diagnosis. During lecanemab treatment, 27.2% of patients received cholinesterase inhibitors and 15.5% memantine. Among patients with ≥2 lecanemab infusions, average number of administrations per month was 1.9 (SD 0.4), 17.2 (SD 7.9) days apart; 9.9% had a treatment gap of ≥90 days, including those who discontinued or continuing beyond the gap, and 2.5% of patients experienced a treatment interruption with ≥90 days gap. Conclusions: Real-world use of lecanemab appears to follow FDA-approved prescribing information with high adherence.

Background: The efficacy and safety of lecanemab have previously been evaluated in the Phase 3 randomized clinical trial, Clarity AD (NCT03887455). Methods: A Markov cohort model was developed to estimate the cost-effectiveness of lecanemab versus standard of care (SoC) in patients with mild cognitive impairment (MCI) or mild dementia due to Alzheimer’s disease (AD), with confirmed beta-amyloid (Aβ) pathology, from a Canadian societal perspective. Health states were determined by Clinical Dementia Rating-Sum of Boxes (CDR-SB) scores. Transitions between health states during month 0-18 were estimated from Clarity AD. Beyond month 18, relative efficacy for lecanemab in the form of the hazard ratio for time-to-worsening of CDR-SB was applied to literature-based transition probabilities. The model included the effects of lost productivity and impact on carer health-related quality of life. Results: The incremental cost-effectiveness ratio (ICER) for lecanemab vs SoC was estimated to be CAD 62,751 per QALY gained. The probability that lecanemab was cost-effective at a threshold of CAD 100,000 was estimated to be 88.5%. Conclusions: Lecanemab represents a cost-effective option for the treatment for early AD from the Canadian societal perspective. The results of this analysis can be used to inform clinical and economic decision making.

Background: Non-pharmacological interventions that promote self-management are crucial for individuals with mild cognitive impairment (MCI.) Mindfulness training has shown promise but is often not tailored to MCI. Methods: In 2021, the Neil and Susan Manning Cognitive Health Initiative (CHI) - a collaboration between the Vancouver Island Health Authority, Universities of BC and Victoria, and the Victoria Hospitals Foundation - partnered with the BC Association for Living Mindfully (BCALM) to develop a specialized mindfulness program for MCI, based on Mindfulness-Based Stress Reduction (MBSR). This multi-phase initiative aimed to enhance self-management, address the lack of outpatient services for MCI in Victoria, and contribute to the evidence base for mindfulness interventions. Results: Phase 1 assessed the BCALM program’s suitability for MCI; feedback included suggestions to simplify content and meditations. Phase 2 piloted an adapted version, with an 8-week program consisting of weekly sessions. Participants, recruited from the Seniors Outpatient Clinic in Victoria, completed pre- and post-program surveys; results showed over 90% of participants reported improved memory and coping, and 80% managed memory-related challenges better. Conclusions: Now in Phase 3, the MCI program is being transitioned into regular BCALM curriculum, with plans for a clinical trial comparing it to traditional psychoeducational approaches.

Background: Functional movement disorder (FMD), a subtype of functional neurological disorder, is a complex neuropsychiatric syndrome characterized by inconsistent and incongruent motor symptoms, such as tremor and gait disorder. Despite its prevalence and associated disability, FMD remains understudied. The multidisciplinary FMD Clinic in Calgary, Alberta offers an opportunity to describe characteristics of FMD, focusing on sex and gender differences, neuropsychiatric risk factors, healthcare utilization and motor phenotypes. Methods: This ongoing registry study evaluates adult FMD patients seen in the Calgary FMD Clinic by a movement disorders neurologist and neuropsychiatrist. Patients undergo detailed movement disorders and neuropsychiatric assessments, including identifying motor phenotypes, psychiatric comorbidities, and relevant psychological traits. Standardized scales evaluate symptom severity and impact. Descriptive statistics and measure of variance will be calculated for variables of interest. Results: The Calgary FMD Registry was approved in March 2024, with 53 participants currently enrolled. Data collection for this study is projected to conclude in March 2025. Conclusions: The Calgary FMD Registry is the first of its kind to systematically characterize FMD based on both movement disorders and neuropsychiatric variables. This study aims to improve our understanding of neuropsychiatric factors related to FMD. Future studies from this registry will examine short- and long-term outcomes.

Background: Experimental and clinical evidence suggest that Parkinson’s disease (PD) manifests differently between females and males, yet women have been underrepresented in PD clinical research, leading to a limited understanding of the sex- and gender-specific aspects of the disease. Understanding the needs of women with PD (WwPD) is critical Methods: Patient-centered outcomes-based mixed methods study. Phase 1: Qualitative focus groups, patient-centered discussions, led by female interviewers. Phase 2: Nationwide survey via the Qualtrics platform, informed by focus group findings. We report the Phase 1 preliminary results Results: We conducted 5 focus groups with 22 cisgender women. Mean age 60.5 (range: 44 -81) and disease duration of 6.82 years. Two main themes emerged: (1) Mental Health: participants reported significant emotional distress, altered self-image, and impacts on family, social, and professional life. (2) Physical Health and Health care: While some were satisfied with care, those with young-onset PD experienced misdiagnosis, dismissal, and inadequate information. Sexual health, and the overlap between menopause and PD symptoms, were highlighted. Most participants emphasized the benefits of physical activity, nutrition, and social support. Conclusions: Findings highlight significant health challenges in women, underscoring the need for gender-specific care and tailored support to improve healthcare outcomes

Background: The complement component C5 inhibitor, ravulizumab, is approved in Canada for the treatment of adults with AQP4-Ab+ NMOSD. Updated efficacy and safety results from the ongoing CHAMPION-NMOSD (NCT04201262) trial are reported. Methods: Participants received IV-administered, weight-based dosing of ravulizumab, with loading on day 1 and maintenance doses on day 15 and every 8 weeks thereafter. Following a primary treatment period (PTP; up to 2.5 years), patients could enter a long-term extension (LTE). Outcome measures included safety, time to first adjudicated on-trial relapse (OTR), risk reduction, and disability scores. Results: 56/41 patients entered/completed the LTE as of June 14, 2024. Median follow-up was 170.3 weeks (186.6 patient-years). No patients experienced an OTR. 94.8% (55/58 patients) had stable or improved Hauser Ambulation Index scores. 89.7% (52/58 patients) had no clinically important worsening in Expanded Disability Status Scale scores. Treatment-emergent adverse events (98.4%) were predominantly mild and unrelated to ravulizumab. Serious adverse events occurred in 25.9% of patients. Two cases of meningococcal infection occurred during the PTP, and none in the LTE. One unrelated death (cardiovascular) occurred during the LTE. Conclusions: Ravulizumab demonstrated long-term clinical benefit in AQP4-Ab+ NMOSD relapse prevention while maintaining or improving disability measures, with no new safety concerns.

Background: The increasing use of anti-B cell therapies in managing multiple sclerosis(MS) around the time of conception has raised important considerations for neonates exposed in utero. International recommendations suggest assessing neonatal B cell count in potentially exposed neonates. Practical implementation of cord blood collection at birth requires coordinated care across specialties, including paediatric haematology, neurology and obstetrics. Methods: This workshop, scheduled for 01/30/2025, will address clinical and logistical challenges of neonatal B cell assessments following in utero exposure to anti-B cell therapies. Presentations by MS pregnancy specialists from Toronto,Ontario, will be complemented by collaborative problem-solving among participants, including a paediatric haematologist, MS neurologists, obstetricians, paediatricians, and a quality specialist. A patient with lived experience will contribute to discussions. Results: The workshop will develop a care pathway for cord blood B cell testing, optimizing vaccine scheduling at London Health Sciences Center (LHSC) in London Ontario. Outcomes will include enhanced multidisciplinary collaboration, participant feedback, development of a practical clinical care plan for B cell collection and interpretation and measures of the pathway’s impact on patient satisfaction and clinical decisions. Conclusions: This initiative will improve care for mothers and neonates exposed to anti-B cell therapies, addressing critical gaps in clinical practice through collaboration and a standardized approach.

Background: This study explored whether Myelin Water imaging could detect myelin injury in Anti-NMDA receptor autoimmune encephalitis (NMDAr-AIE), where traditional neuroimaging is often normal. Myelin Water Fraction (MWF) quantifies myelin content by distinguishing myelin sheath water from other brain water compartments. Methods: Adult participants with confirmed NMDAr-AIE diagnoses and healthy controls (HC) underwent 3T brain MRI including MWF mapping. Participants were recruited after discharge from the hospital. Mean MWF was calculated for 4 white matter regions of interest (ROI). Patient demographics, clinical assessments, treatment, and outcomes were collected. Results: Five participants with NMDAr-AIE (4F/1M, mean age 30, SD 7) and four HC (3F/1M, mean age 36, SD 6) were included. All NMDAr-AIE participants had normal or non-specific T2 hyperintensities on initial imaging and had received immunotherapy. The mean Modified Rankin Score (MRS) on discharge was 2. MWF (mean ± SD) for normal-appearing white matter, corpus callosum, corticospinal tract, and superior longitudinal fasciculus were 0.10±0.02, 0.12±0.02, 0.15±0.03, 0.12±0.02, which were very similar to HC at 0.09±0.02, 0.11±0.01, 0.15±0.02, and 0.11±0.02, respectively. Conclusions: Myelin Water imaging showed no myelin pathology in five NMDAr-AIE patients, with MWF values comparable to HC. This suggests that myelin pathways are relatively preserved post-recovery from AIE.

Background: The COVID-19 pandemic posed significant challenges for people with multiple sclerosis (PwMS) in Oman, including heightened stress, treatment disruptions, and risks associated with immunosuppressive therapies. This study aimed to evaluate the pandemic’s impact on MS management, COVID-19 incidence and outcomes, psychosocial and mental health effects, and demographic and clinical predictors influencing these outcomes among Omani PwMS. Methods: In this cross-sectional study conducted from January to April 2021, 104 PwMS aged 18–60 participated in structured interviews and completed the Expanded Disability Status Scale (EDSS) and the World Health Organization Well-being Index (WHO-5). Clinical data on relapse rates, disease-modifying therapies (DMTs), and treatment adherence were analyzed using descriptive and inferential statistics. Results: Of the participants, 76 (73.1%) were female, and 23 (22.1%) reported contracting COVID-19, with fatigue being the most common symptom (87%). Female sex (p = 0.042), younger age (18–34 vs. 35–45 years; p = 0.014), COVID-19 diagnosis (p = 0.037), and lower mental well-being scores (p = 0.021) were strongly associated with COVID-19-related effects. Conclusions: Key predictors of self-reported COVID-19 effects in Omani PwMS were a confirmed diagnosis, female sex, younger age, and lower mental well-being. These findings highlight the need for exploration of mental resilience in this group and interventions during crises.

Background: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by acute attacks. High-dose steroids (HDS) are the primary treatment, with no significant differences between oral and intravenous (IV) routes. However, factors influencing route selection and attack characteristics leading to treatment remain unclear. This study assesses trends in oral vs. IV HDS use, factors affecting decisions, and clinical impact. Methods: We retrospectively analyzed data from the Multiple Sclerosis database (MuSicaL) using Natural Language Processing (NLP) from 2010–2022. We examined annual trends in HDS route, its relationship with attack type, and prescribing specialties. Statistical analyses were conducted using R-4.2.2. Results: Of 2,413 individuals meeting inclusion criteria, 1,086 had an attack, and 543 (50%) used HDS. Among 265 with a known route, oral HDS was most common, and HDS use declined after 2018. Attack type significantly influenced HDS route (p = 0.045), with IV use highest in multifocal subtype (50.9%) and lowest in myelitis (32.7%). Neurologists were the primary prescribers of IV HDS. Conclusions: Our results indicate a trend towards increased oral HDS use, with IV reserved for severe attacks like multifocal ones. Attack type influences treatment choices, and neurologists remain key prescribers of IV HDS, guiding future treatment strategies.

Background: Accurate aquaporin-4 (AQP4) and Myelin Oligodendrocyte Glycoprotein (MOG) assays are essential for effectively diagnosing neuromyelitis Optica spectrum disorder and MOG antibody-associated disease. The Live Cell-Based Assay (L-CBA) is the gold standard laboratory test for detecting these antibodies. We studied the profiles of these antibodies, in samples of patients with relevant neurological conditions. Methods: Between January 2021 and December 2024, a total of 6673 samples of serum and/ or CSF were tested at BC Neuroimmunology Lab, Vancouver. We performed in-house L-CBA for the AQP4 and MOG Abs identification. We analyzed the demographics and characteristics of the positive Abs results. Results: We identified 7.8% positive results for anti-MOG and 2.7% for anti-AQP4 antibodies. Both antibodies were more frequent in females (AQP4: 76.9%, MOG: 65.1%). The average age of patients was 49.2 ± 18.8 years, ranging from 9 to 88 years for AQP4 antibodies, and 40.9 ± 19.5 years, ranging from 10 months to 89 years for MOG antibodies. Conclusions: Both anti-MOG and anti-AQP4 Abs are prevalent in females. Moreover, anti-MOG Abs are present across a wider age range from infancy to the elderly, and anti-AQP4 Abs are typically found in later ages, between 10 and 90 years.

Background: Anti-CD20 monoclonal antibodies are highly effective for RMS treatment. Ocrelizumab (OCR) is standard, while Rituximab (RTX) is an alternative. The impact of anti-CD20 therapies on immune markers remains understudied, though deficiencies are frequently observed and have been associated with increased risk of infection. Our objective is to characterize and compare lymphocyte, neutrophil, and immunoglobulin levels in OCR- versus RTX-treated persons with RMS. Methods: This retrospective chart review included RMS patients on OCR or RTX (2017–2023). Pre- and post-treatment levels of lymphocytes, neutrophils, and immunoglobulins (IgG, IgA, IgM) were analyzed. Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models were used for survival analysis. Results: 350 patients (OCR=175, RTX=175) were included. The mean treatment length was 60.9 (SD 19.1) months for OCR and 42.7 (SD 19.5) months for RTX. RTX was associated with a significantly shorter time to IgM deficiency (29.6 vs. 40.0 months, p=0.02). Cox analysis confirmed RTX increased IgM deficiency risk (HR=1.54, 95% CI: 1.06-2.23, p=0.02). No differences were seen for lymphocytes, neutrophils, IgG, or IgA. Conclusions: RTX was associated with a shorter time to and increased risk of IgM hypogammaglobulinemia compared to OCR, highlighting the importance of long-term monitoring. Further research is needed to guide treatment decisions.

Background: Epstein-Barr virus (EBV) infection is believed to be a critical prerequisite for the development of multiple sclerosis (MS). This study aims to investigate whether anti-EBV titres are elevated before the onset of MS symptoms in people with radiologically isolated syndrome (pwRIS) and to evaluate their association with markers of adverse clinical outcomes. Methods: Epstein-Barr nuclear antigen 1 (EBNA1) and viral capsid antigen (VCA) titres were quantified in a cohort of 47 pwRIS and 24 healthy controls using Enzyme-Linked Immuno-Sorbent Assay. Plasma glial fibrillary acidic protein (GFAP) and neurofilament light protein (NfL) were measured using single-molecule array. MRI lesion metrics and the development of MS symptoms over time were also evaluated. Results: EBNA1 titres were higher pwRIS compared to healthy controls (p=0.038), while VCA titres were not (p=0.237). A positive correlation was observed between EBNA1 titres and plasma GFAP in pwRIS (p=0.005). Neither EBNA1 nor VCA titres correlated with NfL. MRI lesion measures and the development of MS symptoms did not show any significant relationship with EBNA1 or VCA titres. Conclusions: Eelevated EBNA1 titres are detectable prior to MS symptom onset and correlate with GFAP, a biomarker associated with worse clinical outcomes. However, their role in disease progression and clinical outcomes requires further investigation.

Background: Facial diplegia with paresthesias (FDP) is a rare Guillain-Barré Syndrome (GBS) variant, characterized by subacute onset of bilateral facial palsy with no other motor weakness, absent reflexes and distal paresthesias, that may be associated with anti-ganglioside autoantibodies. Methods: Patient chart, including medical notes, radiologic, electrophysiological and laboratory testing during the patient’s hospitalization in December 2024 were reviewed. Results: We report the case of a 24-year-old woman, who presented one-week post-partum with a history of tongue and progressive distal extremity paresthesias, headache and gait instability. During hospitalization patient progressively developed bilateral lower limbs areflexia and facial diplegia. Imaging was negative for a central cause but lumbar puncture and clinical examination guided the diagnosis of FDP. Patient responded to a course of intravenous immunoglobulins (IVIg) and was discharged home without any weakness. Conclusions: This case illustrates the rarer FDP presentation of GBS, which can be more frequent in the postpartum period, and explores the differential diagnosis of subacute facial diplegia.

Background: Vasospasm is an important complication of subarachnoid hemorrhage (SAH). Attempts to identify patients at highest risk of vasospasm have not led to practice change. We sought to identify patients at lowest risk of vasospasm by testing the prognostic utility of novel low risk criteria: mean MCA velocities on TCD that peaked and remained below 120 cm/s by the 7th day. Methods: Retrospective observational study of TCD values in patients admitted to The Ottawa Hospital with SAH 2018-2023. The primary outcome was presence of moderate to severe vasospasm (MCA mean velocity >160 cm/s) by day 21. Results: Data were collected on 211 patients, of whom 197 fulfilled inclusion criteria. Only 2 of 104 patients (2%) meeting our low-risk criteria developed the primary outcome, compared to 48 of 93 patients (52%) who did not meet criteria (RR 27). The Negative Predictive Value (NPV) for vasospasm in our low-risk group was 98%. Conclusions: Our low-risk criteria based on TCD patterns in the first 7 days after SAH can identify patients at very low risk of vasospasm with great accuracy. This could inform a future prospective study.