Implementation of a Survey Spine MR Imaging Protocol for Cord Compression in the Emergency Department: Experience at a Level 1 Trauma Center.

BACKGROUND AND PURPOSE: Imaging stewardship in the emergency department (ED) is vital in ensuring patients receive optimized care. While suspected cord compression (CC) is a frequent indication for total spine MR imaging in the ED, the incidence of CC is low. Recently, our level 1 trauma center introduced a survey spine MR imaging protocol to evaluate for suspected CC while reducing examination time to avoid imaging overutilization. This study aims to evaluate the time savings, frequency of ordering patterns of the survey, and the symptoms and outcomes of patients undergoing the survey. MATERIALS AND METHODS: This retrospective study examined patients who received a survey spine MR imaging in the ED at our institution between 2018 and 2022. All examinations were performed on a 1.5T GE Healthcare scanner by using our institutional CC survey protocol, which includes sagittal T2WI and STIR sequences through the cervical, thoracic, and lumbar spine. Examinations were read by a blinded, board-certified neuroradiologist. RESULTS: A total of 2002 patients received a survey spine MR imaging protocol during the study period. Of these patients, 845 (42.2%, mean age 57 ± 19 years, 45% women) received survey spine MR imaging examinations for the suspicion of CC, and 120 patients (14.2% positivity rate) had radiographic CC. The survey spine MR imaging averaged 5 minutes and 50 seconds (79% faster than routine MR imaging). On multivariate analysis, trauma, back pain, lower extremity weakness, urinary or bowel incontinence, numbness, ataxia, and hyperreflexia were each independently associated with CC. Of the 120 patients with CC, 71 underwent emergent surgery, 20 underwent nonemergent surgery, and 29 were managed medically. CONCLUSIONS: The survey spine protocol was positive for CC in 14% of patients in our cohort and acquired at a 79% faster rate compared with routine total spine. Understanding the positivity rate of CC, the clinical symptoms that are most associated with CC, and the subsequent care management for patients presenting with suspected cord compression who received the survey spine MR imaging may better inform the broad adoption and subsequent utilization of survey imaging protocols in emergency settings to increase throughput, improve allocation of resources, and provide efficient care for patients with suspected CC.

Symmetric collateral pattern on CTA predicts favorable outcomes after endovascular thrombectomy for large vessel occlusion stroke.

Endovascular thrombectomy (EVT) has revolutionized large vessel occlusion (LVO) stroke management, but often requires advanced imaging. The collateral pattern on CT angiograms may be an alternative because a symmetric collateral pattern correlates with a slowly growing, small ischemic core. We tested the hypothesis that such patients will have favorable outcomes after EVT. Consecutive patients (n = 74) with anterior LVOs who underwent EVT were retrospectively analyzed. Inclusion criteria were available CTA and 90-day modified Rankin Scale (mRS). CTA collateral patterns were symmetric in 36%, malignant in 24%, or other in 39%. Median NIHSS was 11 for symmetric, 18 for malignant, and 19 for other (p = 0.02). Ninety-day mRS ≤2, indicating independent living, was achieved in 67% of symmetric, 17% of malignant, and 38% of other patterns (p = 0.003). A symmetric collateral pattern was a significant determinant of 90-day mRS ≤2 (aOR = 6.62, 95%CI = 2.24,19.53; p = 0.001) in a multivariable model that included age, NIHSS, baseline mRS, thrombolysis, LVO location, and successful reperfusion. We conclude that a symmetric collateral pattern predicts favorable outcomes after EVT for LVO stroke. Because the pattern also marks slow ischemic core growth, patients with symmetric collaterals may be suitable for transfer for thrombectomy. A malignant collateral pattern is associated with poor clinical outcomes.

Aluminum Thin Film Nanostructure Traces in Pediatric EEG Net for MRI and CT Artifact Reduction.

Magnetic resonance imaging (MRI) and continuous electroencephalogram (EEG) monitoring are essential in the clinical management of neonatal seizures. EEG electrodes, however, can significantly degrade the image quality of both MRI and CT due to substantial metallic artifacts and distortions. Thus, we developed a novel thin film trace EEG net ("NeoNet") for improved MRI and CT image quality without compromising the EEG signal quality. The aluminum thin film traces were fabricated with an ultra-high-aspect ratio (up to 17,000:1, with dimensions 30 nm × 50.8 cm × 100 µm), resulting in a low density for reducing CT artifacts and a low conductivity for reducing MRI artifacts. We also used numerical simulation to investigate the effects of EEG nets on the B1 transmit field distortion in 3 T MRI. Specifically, the simulations predicted a 65% and 138% B1 transmit field distortion higher for the commercially available copper-based EEG net ("CuNet", with and without current limiting resistors, respectively) than with NeoNet. Additionally, two board-certified neuroradiologists, blinded to the presence or absence of NeoNet, compared the image quality of MRI images obtained in an adult and two children with and without the NeoNet device and found no significant difference in the degree of artifact or image distortion. Additionally, the use of NeoNet did not cause either: (i) CT scan artifacts or (ii) impact the quality of EEG recording. Finally, MRI safety testing confirmed a maximum temperature rise associated with the NeoNet device in a child head-phantom to be 0.84 °C after 30 min of high-power scanning, which is within the acceptance criteria for the temperature for 1 h of normal operating mode scanning as per the FDA guidelines. Therefore, the proposed NeoNet device has the potential to allow for concurrent EEG acquisition and MRI or CT scanning without significant image artifacts, facilitating clinical care and EEG/fMRI pediatric research.

Assessing the Relationship Between Race, Language, and Surgical Admissions in the Emergency Department.

INTRODUCTION: English proficiency and race are both independently known to affect surgical access and quality, but relatively little is known about the impact of race and limited English proficiency (LEP) on admission for emergency surgery from the emergency department (ED). Our objective was to examine the influence of race and English proficiency on admission for emergency surgery from the ED. METHODS: We conducted a retrospective observational cohort study from January 1-December 31, 2019 at a large, quaternary-care urban, academic medical center with a 66-bed ED Level I trauma and burn center. We included ED patients of all self-reported races reporting a preferred language other than English and requiring an interpreter or declaring English as their preferred language (control group). A multivariable logistic regression was fit to assess the association of LEP status, race, age, gender, method of arrival to the ED, insurance status, and the interaction between LEP status and race with admission for surgery from the ED. RESULTS: A total of 85,899 patients (48.1% female) were included in this analysis, of whom 3,179 (3.7%) were admitted for emergent surgery. Regardless of LEP status, patients identifying as Black (odds ratio [OR] 0.456, 95% CI 0.388-0.533; P<0.005), Asian [OR 0.759, 95% CI 0.612-0.929]; P=0.009), or female [OR 0.926, 95% CI 0.862-0.996]; P=0.04) had significantly lower odds for admission for surgery from the ED compared to White patients. Compared to individuals on Medicare, those with private insurance [OR 1.25, 95% CI 1.13-1.39; P <0.005) were significantly more likely to be admitted for emergent surgery, whereas those without insurance [OR 0.581, 95% CI 0.323-0.958; P=0.05) were significantly less likely to be admitted for emergent surgery. There was no significant difference in odds of admission for surgery between LEP vs non-LEP patients. CONCLUSION: Individuals without health insurance and those identifying as female, Black, or Asian had significantly lower odds of admission for surgery from the ED compared to those with health insurance, males, and those self-identifying as White, respectively. Future studies should assess the reasons underpinning this finding to elucidate impact on patient outcomes.

Trends in oncological imaging during the COVID-19 pandemic through the vaccination era.

BACKGROUND: This study examines the impact that the COVID-19 pandemic has had on computed tomography (CT)-based oncologic imaging utilization. METHODS: We retrospectively analyzed cancer-related CT scans during four time periods: pre-COVID (1/5/20-3/14/20), COVID peak (3/15/20-5/2/20), post-COVID peak (5/3/20-12/19/20), and vaccination period (12/20/20-10/30/21). We analyzed CTs by imaging indication, setting, and hospital type. Using percentage decrease computation and Student's t-test, we calculated the change in mean number of weekly cancer-related CTs for all periods compared to the baseline pre-COVID period. This study was performed at a single academic medical center and three affiliated hospitals. RESULTS: During the COVID peak, mean CTs decreased (-43.0%, p < 0.001), with CTs for (1) cancer screening, (2) initial workup, (3) cancer follow-up, and (4) scheduled surveillance of previously treated cancer dropping by 81.8%, 56.3%, 31.7%, and 45.8%, respectively (p < 0.001). During the post-COVID peak period, cancer screenings and initial workup CTs did not return to prepandemic imaging volumes (-11.4%, p = 0.028; -20.9%, p = 0.024). The ED saw increases in weekly CTs compared to prepandemic levels (+31.9%, p = 0.008), driven by increases in cancer follow-up CTs (+56.3%, p < 0.001). In the vaccination period, cancer screening CTs did not recover to baseline (-13.5%, p = 0.002) and initial cancer workup CTs doubled (+100.0%, p < 0.001). The ED experienced increased cancer-related CTs (+75.9%, p < 0.001), driven by cancer follow-up CTs (+143.2%, p < 0.001) and initial workups (+46.9%, p = 0.007). CONCLUSIONS AND RELEVANCE: The pandemic continues to impact cancer care. We observed significant declines in cancer screening CTs through the end of 2021. Concurrently, we observed a 2× increase in initial cancer workup CTs and a 2.4× increase in cancer follow-up CTs in the ED during the vaccination period, suggesting a boom of new cancers and more cancer examinations associated with emergency level acute care.

Percent Insular Ribbon Infarction for Predicting Infarct Growth Rate and 90-Day Outcomes in Large-Vessel Occlusive Stroke: Secondary Analysis of Prospective Clinical Trial Data.

BACKGROUND. Insight into the natural history of infarct growth could help identify patients with slowly progressing stroke who may benefit from delayed endovascular thrombectomy (EVT). OBJECTIVE. The purpose of this article is to evaluate associations of percent insular ribbon infarction (PIRI) with infarct growth rate (IGR) and 90-day outcomes in patients with large-vessel occlusive stroke. METHODS. This retrospective study was a secondary analysis of a prior clinical trial that enrolled patients with acute stroke not treated with reperfusion therapies from January 2007 to June 2009. The present analysis evaluated 31 trial patients (median age, 71 years; 12 women, 19 men) with anterior-circulation large-vessel occlusion who underwent serial MRI examinations. Two neuroradiologists independently scored PIRI on presentation MRI examinations on the basis of the ratio of the length of the portion of the insula showing restricted diffusion to the insula's total length using a previously described 0-4 scale; scores were categorized (mild [0-1], moderate [2], or severe [3-4]), and discrepancies were resolved by consensus. The 90-day modified Rankin Scale (mRS) was obtained. As part of earlier clinical trial analyses, collateral pattern on CTA was classified as symmetric, malignant, or other, and infarct volumes were measured on DWI during the initial 48 hours after presentation and on FLAIR at 90 days. RESULTS. Interrater agreement for PIRI category was strong (κ = 0.89). PIRI was mild in 10, moderate in four, and severe in 17 patients. For mild, moderate, and severe PIRI, median IGR from onset to presentation was 1.6 cm3/h, 8.5 cm3/h, and 17.5 cm3/h (p < .001); median IGR from presentation to 48 hours was 0.3 cm3/h, 0.2 cm3/h, and 1.2 cm3/h (p = .005); median 90-day infarct volume was 9.4 cm3, 39.8 cm3, and 108.6 cm3 (p = .01); and 90-day mRS of 2 or less occurred in 78%, 67%, and 6% of patients (p = .001). In multivariable models controlling for age, internal carotid artery occlusion, and collateral pattern, PIRI category independently predicted onset-to-presentation IGR (ß = 1.5), presentation-to-48-hour IGR (ß = 1.3), and 90-day mRS of 2 or less (OR = 0.2). For predicting 90-day mRS of 2 or less, mild-to-moderate PIRI had sensitivity of 90.0% and specificity of 84.2%; symmetric collateral pattern had sensitivity of 70.0% and specificity of 73.7%. CONCLUSION. PIRI was independently associated with IGR and 90-day outcome. CLINICAL IMPACT. PIRI may help identify patients who could benefit from late-window EVT when requiring transfer to EVT-capable centers.

Head CT deep learning model is highly accurate for early infarct estimation.

Non-contrast head CT (NCCT) is extremely insensitive for early (< 3-6 h) acute infarct identification. We developed a deep learning model that detects and delineates suspected early acute infarcts on NCCT, using diffusion MRI as ground truth (3566 NCCT/MRI training patient pairs). The model substantially outperformed 3 expert neuroradiologists on a test set of 150 CT scans of patients who were potential candidates for thrombectomy (60 stroke-negative, 90 stroke-positive middle cerebral artery territory only infarcts), with sensitivity 96% (specificity 72%) for the model versus 61-66% (specificity 90-92%) for the experts; model infarct volume estimates also strongly correlated with those of diffusion MRI (r2 > 0.98). When this 150 CT test set was expanded to include a total of 364 CT scans with a more heterogeneous distribution of infarct locations (94 stroke-negative, 270 stroke-positive mixed territory infarcts), model sensitivity was 97%, specificity 99%, for detection of infarcts larger than the 70 mL volume threshold used for patient selection in several major randomized controlled trials of thrombectomy treatment.

Symmetric CTA Collaterals Identify Patients with Slow-progressing Stroke Likely to Benefit from Late Thrombectomy.

Background Understanding ischemic core growth rate (IGR) is key in identifying patients with slow-progressing large vessel occlusion (LVO) stroke who may benefit from delayed endovascular thrombectomy (EVT). Purpose To evaluate whether symmetric collateral pattern at CT angiography (CTA) can help to identify patients with low IGR and small 24-hour diffusion-weighted MRI ischemic core volume in patients with LVO not treated with reperfusion therapies. Materials and Methods In this secondary analysis of clinical trial data from before EVT became standard of care from January 2007 to June 2009, patients with anterior proximal LVO not treated with reperfusion therapies were evaluated. All patients underwent admission CTA and at least three MRI examinations at four time points over 48 hours. Arterial phase CTA collaterals at presentation were categorized as symmetric, malignant, or other. Diffusion-weighted MRI ischemic core volume and IGR at multiple time points were determined. The IGR at presentation was defined as follows: (ischemic core volume in cubic centimeters)/(time since stroke symptom onset in hours). Multivariable analyses and receiver operator characteristic analyses were used. Results This study evaluated 31 patients (median age, 71 years; interquartile range, 61-81 years; 19 men) with median National Institutes of Health Stroke Scale (NIHSS) score of 13. Collaterals were symmetric (45%; 14 of 31), malignant (13%; four of 31), or other (42%; 13 of 31). Median ischemic core volume was different between collateral patterns at all time points. Presentation was as follows: symmetric, 16 cm3; other, 69 cm3; and malignant, 104 cm3 (P < .001). At 24 hours, median ischemic core volumes were as follows: symmetric, 28 cm3; other, 156 cm3; and malignant, 176 cm3 (P < .001). Median IGR was also different, and most pronounced at presentation: symmetric, 4 cm3 per hour; other, 17 cm3 per hour; and malignant, 20 cm3 per hour (P < .001). After multivariable adjustment, independent determinants of higher presentation IGR included only higher NIHSS (parameter estimate [ß = 0.20; 95% CI: 0.05, 0.36; P = .008) and worse collaterals (ß = -2.90; 95% CI: -4.31, -1.50; P < .001). The only independent determinant of 24-hour IGR was worse collaterals (ß = -2.03; 95% CI: -3.28, -0.78; P = .001). Symmetric collaterals had sensitivity of 87% (13 of 15) and specificity of 94% (15 of 16) for 24-hour ischemic core volume less than 50 cm3 (area under the receiver operating characteristic curve, 0.92; 95% CI: 0.81, 1.00; P < .001). Conclusion In patients with large vessel occlusion not treated with reperfusion therapies, symmetric collateral pattern at CT angiography was common and highly specific for low ischemic core growth rate and small 24-hour ischemic core volume as assessed at diffusion-weighted MRI. After further outcome studies, collateral status at presentation may prove useful in triage for endovascular thrombectomy, especially when MRI and CT perfusion are unavailable. Clinical trial registration no. NCT00414726. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Messina in this issue.

Trends in cancer imaging by indication, care setting, and hospital type during the COVID-19 pandemic and recovery at four hospitals in Massachusetts.

BACKGROUND: We aimed to investigate the effects of COVID-19 on computed tomography (CT) imaging of cancer. METHODS: Cancer-related CTs performed at one academic hospital and three affiliated community hospitals in Massachusetts were retrospectively analyzed. Three periods of 2020 were considered as follows: pre-COVID-19 (1/5/20-3/14/20), COVID-19 peak (3/15/20-5/2/20), and post-COVID-19 peak (5/3/20-11/14/20). 15 March 2020 was the day a state of emergency was declared in MA; 3 May 2020 was the day our hospitals resumed to non-urgent imaging. The volumes were assessed by (1) Imaging indication: cancer screening, initial workup, active cancer, and surveillance; (2) Care setting: outpatient and inpatient, ED; (3) Hospital type: quaternary academic center (QAC), university-affiliated community hospital (UACH), and sole community hospitals (SCHs). RESULTS: During the COVID-19 peak, a significant drop in CT volumes was observed (-42.2%, p < 0.0001), with cancer screening, initial workup, active cancer, and cancer surveillance declining by 81.7%, 54.8%, 30.7%, and 44.7%, respectively (p < 0.0001). In the post-COVID-19 peak period, cancer screening and initial workup CTs did not recover (-11.7%, p = 0.037; -20.0%, p = 0.031), especially in the outpatient setting. CT volumes for active cancer recovered, but inconsistently across hospital types: the QAC experienced a 9.4% decline (p = 0.022) and the UACH a 41.5% increase (p < 0.001). Outpatient CTs recovered after the COVID-19 peak, but with a shift in utilization away from the QAC (-8.7%, p = 0.020) toward the UACH (+13.3%, p = 0.013). Inpatient and ED-based oncologic CTs increased post-peak (+20.0%, p = 0.004 and +33.2%, p = 0.009, respectively). CONCLUSIONS: Cancer imaging was severely impacted during the COVID-19 pandemic. CTs for cancer screening and initial workup did not recover to pre-COVID-19 levels well into 2020, a finding that suggests more patients with advanced cancers may present in the future. A redistribution of imaging utilization away from the QAC and outpatient settings, toward the community hospitals and inpatient setting/ED was observed.

Toward a more inclusive paradigm: thrombectomy for stroke patients with pre-existing disabilities.

BACKGROUND: Persons with pre-existing disabilities represent over one-third of acute stroke presentations, but account for a far smaller proportion of those receiving endovascular thrombectomy (EVT) and thrombolysis. This is despite existing ethical, economic, legal, and social directives to maximize equity for this vulnerable population. We sought to determine associations between baseline modified Rankin Scale (mRS) and outcomes after EVT. METHODS: Individuals who underwent EVT were identified from a prospectively maintained database. Demographics, medical history, presentations, treatments, and outcomes were recorded. Baseline disability was defined as baseline mRS≥2. Accumulated disability was defined as the delta between baseline mRS and absolute 90-day mRS. RESULTS: Of 381 individuals, 49 had baseline disability (five with mRS=4, 23 mRS=3, 21 mRS=2). Those with baseline disability were older (81 vs 68 years, P<0.0001), more likely female (65% vs 49%, P=0.032), had more coronary disease (39% vs 20%, P=0.006), stroke/TIA history (35% vs 15%, P=0.002), and higher NIH Stroke Scale (19 vs 16, P=0.001). Baseline mRS was associated with absolute 90-day mRS ≤2 (OR=0.509, 95%CI=0.370-0.700). However, baseline mRS bore no association with accumulated disability by delta mRS ≤0 (ie, return to baseline, OR=1.247, 95%CI=0.943-1.648), delta mRS ≤1 (OR=1.149, 95%CI=0.906-1.458), delta mRS ≤2 (OR 1.097, 95% CI 0.869-1.386), TICI 2b-3 reperfusion (OR=0.914, 95%CI=0.712-1.173), final infarct size (P=0.853, ß=-0.014), or intracerebral hemorrhage (OR=0.521, 95%CI=0.244-1.112). CONCLUSIONS: While baseline mRS was associated with absolute 90-day disability, there was no association with accumulated disability or other outcomes. Patients with baseline disability should not be routinely excluded from EVT based on baseline mRS alone.

Turning around cancer: Oncology imaging and implications for emergency department radiology workflow.

PURPOSE: Oncologic imaging in the emergency department (ED) is frequently encountered, including non-acute scans known as "metastatic workups" or "staging" (referred to as "cancer staging computed tomography (CT) exams"). This study examines the impact of oncologic staging CT exams on ED imaging turnaround time (TAT), defined as the time from the end of the CT exam to a final signed radiologist report, as well as order to scan completion time. METHODS: A retrospective review was conducted of all adult patients presenting to an urban, quaternary academic medical center ED from February 2016 to September 2017, who had CT imaging ordered, performed, and interpreted in the ED imaging department. CT exams containing institution-specific cancer descriptors were included. After excluding all acute exams, cancer staging CT exams were compared to a matched cohort of non-oncologic ED CT exams to evaluate median TAT and order to scan completion time using a log transformed multivariable linear regression. RESULTS: Adjusting for age and CT body part, cancer staging CT exams were associated with an independently statistically significant increased median log TAT compared to non-oncologic ED CT exams (114.5 min [IQR 112] versus 69 min [IQR 67], respectively, p < .0001) and an independently statistically significant increased median log initial order to scan completion time (166 min [IQR: 89] vs 119 min [IQR: 93], p < .0001). CONCLUSION: Oncology patients receiving non-acute metastatic workup scans in the ED have a significantly longer TAT compared to non-oncologic ED CT exams as well as longer order to scan completion times.

Nivolumab-induced small bowel obstruction and perforation: a rare but life-threatening side effect of immunotherapy.

We present a case of a 58-year-old female with anti-PD-1 immunotherapy-related small bowel perforation. The patient was on long-term therapy with nivolumab for metastatic non-small cell lung cancer. She presented to the emergency department with acute abdominal pain, in which the CT revealed a short segment of dilated distal ileum proximal to a very short segment of bowel with mural thickening and a perforation near the transition point. The patient underwent subsequent laparotomy, which confirmed the CT findings and revealed a short-segment of friable and dilated loop of distal ileum proximal to a stricture and a small perforation at the transition point. Pathological analysis revealed mural thickening at the site of stricture without evidence of malignancy with focal necrosis and perforation at the transition point. Bowel perforation in the setting of anti-PD-1 immunotherapy is rare, but life-threatening complication, and should be considered in oncology patients on immunotherapy presenting with severe abdominal pain.

Nontraumatic Head and Neck Emergencies.

Head and neck imaging is an intimidating subject for many radiologists because of the complex anatomy and potentially serious consequences of delayed or improper diagnosis of the diverse abnormalities involving this region. The purpose of this article is to help radiologists to understand the intricate anatomy of the head and neck and to review the imaging appearances of a variety of nontraumatic head and neck conditions that bring patients to the emergency department, including acute infectious and inflammatory diseases and acute complications of head and neck neoplasms. These conditions are presented in five sections on the basis of their primary location of involvement: the oral cavity and pharynx, neck, sinonasal tract, orbits, and ears. Important anatomic landmarks are reviewed briefly in each related section.Online supplemental material is available for this article.©RSNA, 2019.

MR Imaging Selection of Acute Stroke Patients with Emergent Large Vessel Occlusions for Thrombectomy.

Acute stroke caused by large vessel occlusions (LVOs) are common. The time window to treat is up to 24 hours, and the most important factor is the size of the ischemic core. If the core is small (<70-100 mL), the penumbra must be large; penumbral imaging is unnecessary. MR imaging is precise in measuring the core, and superior to alternatives. The necessary sequences are obtainable rapidly, comparable to computed tomography scans. Available evidence suggests that most patients with LVOs are slow progressors defined as having a small core 6 hours or more after ictus onset.

Combined Evaluation of Noncontrast CT ASPECTS and CT Angiography Collaterals Improves Detection of Large Infarcts in Proximal Artery Occlusive Stroke.

BACKGROUND AND PURPOSE: Imaging may identify patients with very large infarcts who are unlikely to benefit from intra-arterial therapy. Although computed tomography (CT) is widely used, it suffers from poor sensitivity. We sought to evaluate whether combined evaluation of noncontrast CT (NCCT) and CT angiography (CTA) collaterals would improve the detection of large infarcts. METHODS: All patients with anterior circulation proximal artery occlusion and baseline CT, CTA, and magnetic resonance imaging (MRI) performed were identified. NCCT ASPECTS, CTA collateral score (CS), and diffusion-weighted imaging (DWI) lesion volume were determined. Receiver-operating characteristic analyses were performed to test the discrimination of NCCT ASPECTS 0-4, CTA malignant collaterals (CS = 0: absent collaterals in >50% of M2 territory), and the combination for DWI volume > 100 mL. RESULTS: Among 54 patients, mean age was 67 years; median NIHSS was 14. Occlusion locations were ICA terminus (18 [33%]), MCA M1 (20 [37%]), and M2 (16 [30%]). Median NCCT ASPECTS was 8; 8 (15%) had ASPECTS 0-4. Median CTA CS was 2; 9 (17%) were categorized as malignant. Median DWI lesion volume was 25 mL; 12 (22%) had lesions >100 mL. Individually, the CTA malignant collateral profile (98%) and NCCT ASPECTS 0-4 (100%) demonstrated high specificity for DWI lesion volume >100 mL, but had suboptimal sensitivity (both 67%). In the combined approach (CTA CS = 0 and/or NCCT ASPECTS ≤4), the sensitivity improved significantly to 92%, while maintaining high specificity (98%). CONCLUSIONS: Combined evaluation of NCCT ASPECTS and CTA collaterals identifies patients with infarcts >100 mL with high accuracy, and can improve patient selection using current CT techniques.

A Programme for Risk Assessment and Minimisation of Progressive Multifocal Leukoencephalopathy Developed for Vedolizumab Clinical Trials.

INTRODUCTION: Over the past decade, the potential for drug-associated progressive multifocal leukoencephalopathy (PML) has become an increasingly important consideration in certain drug development programmes, particularly those of immunomodulatory biologics. Whether the risk of PML with an investigational agent is proven (e.g. extrapolated from relevant experience, such as a class effect) or merely theoretical, the serious consequences of acquiring PML require careful risk minimisation and assessment. No single standard for such risk minimisation exists. Vedolizumab is a recently developed monoclonal antibody to α4ß7 integrin. Its clinical development necessitated a dedicated PML risk minimisation assessment as part of a global preapproval regulatory requirement. OBJECTIVE: The aim of this study was to describe the multiple risk minimisation elements that were incorporated in vedolizumab clinical trials in inflammatory bowel disease patients as part of the risk assessment and minimisation of PML programme for vedolizumab. METHODS: A case evaluation algorithm was developed for sequential screening and diagnostic evaluation of subjects who met criteria that indicated a clinical suspicion of PML. An Independent Adjudication Committee provided an independent, unbiased opinion regarding the likelihood of PML. RESULTS: Although no cases were detected, all suspected PML events were thoroughly reviewed and successfully adjudicated, making it unlikely that cases were missed. CONCLUSION: We suggest that this programme could serve as a model for pragmatic screening for PML during the clinical development of new drugs.

Thrombectomy versus medical management for large vessel occlusion strokes with minimal symptoms: an analysis from STOPStroke and GESTOR cohorts.

INTRODUCTION: It remains unclear whether patients presenting with large vessel occlusion strokes and mild symptoms benefit from thrombectomy. OBJECTIVE: To compare outcomes of endovascular therapy versus medical management in patients with large vessel occlusion strokes and National Institute of Health Stroke Scale (NIHSS) score ≤5. METHODS: This was a retrospective analysis combining two large prospectively collected datasets including patients with (1) admission NIHSS score ≤5, (2) premorbid modified Rankin Scale (mRS) score 0-2, and (3) middle cerebral-M1/M2, intracranial carotid, anterior cerebral or basilar artery occlusions. Groups receiving (1) endovascular treatment and (2) medical management were compared. The primary and secondary outcome measures were NIHSS shift (discharge NIHSS minus admission NIHSS) and the rates of mRS 0-2 at discharge and 3-6 months, respectively. Univariate, multivariate, and matched analyses were performed. RESULTS: Eighty-eight patients received medical management and 30 thrombectomy. Multivariable analysis indicated thrombectomy was the only predictor of favorable NIHSS shift (ß -3.7, 95% CI -6.0 to -1.5, p=0.02), as well as independence at discharge (ß -21.995% CI -41.4to -20.8, p<0.01) and 3-6-month follow-up (ß -21.1, 95% CI -39.1 to -19.7, p<0.01). A matched analysis (based on age, baseline NIHSS and intravenous tissue plasminogen activator use) produced 26 pairs. Endovascular therapy was statistically associated with lower NIHSS at discharge (p=0.04), favorable NIHSS shift (p=0.03), and increased independence rates at discharge (p=0.03) and 3-6-month follow-up (p=0.04). CONCLUSION: In patients presenting with minimal stroke symptoms (NIHSS score ≤5) and large vessel occlusion strokes, mechanical thrombectomy appears to be associated with a favorable shift of NIHSS at discharge, as well as higher rates of independence at discharge and long-term follow-up. Confirmatory prospective studies are warranted.

Clinical diffusion mismatch better discriminates infarct growth than mean transit time-diffusion weighted imaging mismatch in patients with middle cerebral artery-M1 occlusion and limited infarct core.

BACKGROUND AND PURPOSE: Our purpose was to compare clinical diffusion mismatch (CDM) and mean transit time (MTT)-diffusion mismatch as predictors of infarct growth in patients with proximal middle cerebral artery (MCA) occlusion and small infarct core on presentation. METHODS: Retrospective analysis of consecutive stroke patients with: (1) MCA-M1 occlusion; (2) MRI performed ≤10 h from symptoms onset; and (3) baseline MRI-diffusion weighted imaging (DWI) volume ≤25 mL. Definitions included: CDM=baseline National Institutes of Health Stroke Scale (NIHSS) score ≥8 and DWI volume ≤25 mL; MTT-DWI mismatch=visually assessed unthresholded MTT lesion ((MTT-DWI))/DWI) ≥20% and ≥10 mL larger than the DWI lesion; and significant infarct growth (>20% (≥5 mL) increase in infarct volume on follow-up). Uni-/multivariate analyses were performed to define the predictors of infarct growth. RESULTS: 63 stroke patients with MCA-M1 occlusions and MRI within 10 h of onset were evaluated. 20 patients were excluded on the basis of DWI volume >25 mL leaving 43 patients (mean age 75.8 years; median NIHSS=13) in the study cohort. On univariate analysis, larger admission DWI volume (p<0.0001), baseline NIHSS score ≥8 (p=0.001), lack of IV and/or endovascular treatment (p=0.021), glucose levels >125 mg/dL (p=0.024), poor CT angiography collaterals (p=0.046), and lower admission Alberta Stroke Program Early CT score (ASPECTS) (p=0.049) predicted infarct growth. Baseline NIHSS score ≥8 was the only independent predictor of stroke growth in the multivariate analysis (p=0.001). All patients had MTT-DWI mismatch >20%. There was no significant association between the amount of MTT-DWI mismatch and infarct growth (p=0.33). CONCLUSIONS: CDM is the most powerful predictor of infarct growth in patients with MCA-M1 occlusion and small infarct core. Most of these patients will have a significant oligemic MTT lesion regardless of admission NIHSS score.

The peer review process: a primer for JNIS readers.

Peer review of scientific articles submitted for publication has been such an integral component of innovation in science and medicine that participants (be they readers, reviewers, or editors) seldom consider its complexity. Not surprisingly, much has been written about scientific peer review. The aim of this report is to share some of the elements of that discourse with readers of the Journal of NeuroInterventional Surgery (JNIS).