Background and Purpose To provide the first correlative study of the hyperdense MCA sign (HMCAS) and gradient-echo (GRE) MRI blooming artifact (BA) with pathology of retrieved thrombi in acute ischemic stroke. Methods Noncontrast CT and GRE MRI studies prior to mechanical thrombectomy in 50 consecutive cases of acute MCA ischemic stroke were reviewed, blinded to clinical and pathology data. Occlusions retrieved by thrombectomy underwent histopathologic analysis, including automated quantitative and qualitative rating of proportion composed of red blood cells (RBC), white blood cells (WBC), and fibrin on microscopy of sectioned thrombi. Results Among 50 patients, mean age was 66 years and 48% were female. Mean (SD) proportion was 61% (±21) fibrin, 34% (±21) RBC, and 4% (±2) WBC. Of retrieved clots, 22 (44%) were fibrin-dominant, 13 (26%) RBC-dominant and 15 (30%) mixed. HMCAS was identified in 10/20 MCA stroke cases with CT, with mean Hounsfield Unit (HU) density of 61 (SD±8). BA occurred in 17/32 with GRE MRI. HMCAS was more commonly seen with RBC-dominant and mixed than fibrin-dominant clots (100% vs. 67% vs. 20%, p=0.016). Mean percent RBC composition was higher in clots associated with HMCAS (47% vs. 22%, p=0.016). BA was more common in RBC-dominant and mixed clots compared to fibrin-dominant clots (100% vs. 63% vs. 25%, p=0.002). Mean percent RBC was greater with BA (42% vs. 23%, p=0.011). Conclusions CT HMCAS and GRE MRI BA reflect pathology of occlusive thrombus. RBC content determines appearance of HMCAS and BA, whereas absence of HMCAS or BA may indicate fibrin-predominant occlusive thrombi.

Campbell, B. C.V. et al. (2019) Penumbral imaging and functional outcome in patients with anterior circulation ischaemic stroke treated with endovascular thrombectomy versus medical therapy: a meta-analysis of individual patient-level data.ABSTRACT Background: CT-perfusion (CTP) and MRI may assist patient selection for endovascular thrombectomy. We aimed to establish whether imaging assessments of ischaemic core and penumbra volumes were associated with functional outcomes and treatment effect.

Campbell, B. C. V. et al. (2018) Effect of general anaesthesia on functional outcome in patients with anterior circulation ischaemic stroke having endovascular thrombectomy versus standard care: a meta-analysis of individual patient data. Lancet Neurology, 17(1), pp. 47-53. (doi:10.1016/S1474-4422(17)30407-6) This is the author's final accepted version.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.http://eprints.gla.ac.uk/149670/ variables. An alternative approach using propensity-score stratification was also used. To account for between-trial variance we used mixed-effects modeling with a random effect for trial incorporated in all models. Bias was assessed using the Cochrane tool.Findings: Of 1764 patients in 7 trials, 871 were allocated to endovascular thrombectomy. After exclusion of 74 patients (72 who did not undergo the procedure and 2 with missing data on anaesthetic strategy), 236/797 (30%) of endovascular patients were treated under GA. At baseline, GA patients were younger and had shorter time to randomisation but similar pre-treatment clinical severity compared to non-GA. Endovascular thrombectomy improved functional outcome at 3 months versus standard care in both GA (adjusted common odds ratio (cOR) 1·52, 95%CI 1·09-2·11, p=0·014) and non-GA (adjusted cOR 2·33, 95%CI 1·75-3·10, p<0·001) patients. However, outcomes were significantly better for those treated under non-GA versus GA (covariate-adjusted cOR 1·53, 95%CI 1·14-2·04, p=0·004; propensitystratified cOR 1·44 95%CI 1·08-1·92, p=0·012). The risk of bias and variability among studies was assessed to be low.Interpretation: Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons. Funding:The HERMES collaboration was funded by an unrestricted grant from Medtronic to the University of Calgary. Research in contextEvidence before this study between abolition of the thrombectomy treatment effect in MR CLEAN and no effect in THRACE. Three single-centre randomised trials of general anaesthesia versus conscious sedation found either no difference in functional outcome between groups or a slight benefit of general anaesthesia. Added value of this studyThese data from contemporary, high quality randomised trials form the largest study to date of the association between general anesthesia and the benefit of endovascular thrombectomy versus standard care. We used two different approaches to adjust for baseline imbalances (multivariable logistic regression and propensity-score stratification). We found that GA for endovascular thrombectomy, as practiced in contemporary clinical care across a wide range of expert centres during the rand...

Purpose:To characterize the relationship between aneurysm size and epidemiologic risk factors with growth and rupture by using computed tomographic (CT) angiography. Materials and Methods:In this HIPAA-compliant, institutional review board approved study, patients with known asymptomatic unruptured intracerebral aneurysms were followed up longitudinally with CT angiographic examinations. Growth was defined as an increase in one or more dimensions above the measurement error, and at least 5% volume by using the ABC/2 method. Associations of epidemiologic factors with aneurysm growth and rupture were analyzed by using logistic regression analysis. Intra-and interobserver agreement coefficients for dimension, volume, and growth were evaluated by using the Pearson correlation coefficient and difference of means with 95% confidence intervals, the agreement statistic, and the McNemar x 2 . Results:Patients (n = 165) with aneurysms (n = 258) had a mean follow-up time of 2.24 years from time of diagnosis. Forty-six of 258 (18%) aneurysms in 38 patients grew larger. Spontaneous rupture occurred in four of 228 (1.8%) intradural aneurysms of average size (6.2 mm). Risk of aneurysm rupture per patient-year was 2.4% (95% CI: 0.5%, 7.12%) with growth and 0.2% (95% CI: 0.006%, 1.22%) without growth (P = .034). There was a 12-fold higher risk of rupture for growing aneurysms (P , .002), with high intra-and interobserver correlation coefficients for size, volume, and growth. Tobacco smoking (3.806, one degree of freedom; P , .015,) and initial size (5.895, two degrees of freedom; P , .051) were independent covariates, predicting 78.4% of growing aneurysms. Conclusion:These results support imaging follow-up of all patients with aneurysms, including those whose aneurysms are smaller than the current 7-mm treatment threshold. Aneurysm growth, size, and smoking were associated with increased rupture risk. Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. Patients underwent follow-up CT angiographic examinations (16-64 detectors) at intervals of approximately 6 or 12 months. The scan protocol was standardized with the following parameters: kVp, 120; mA, 250-300; section thickness, 0.6-1.0 mm; reconstruction interval, 0.5 mm; matrix size, 512 3 512; field of view, 180 mm; soft-tissue kernel; injection rate, 3 mL per second of iohexol (Omnipaque 350; GE Healthcare, Milwaukee, Wis) and bolus triggering software with a carotid artery threshold of 150 HU. Axial oblique two-dimensional multiplanar reformatted grayscale images (window width = 450 HU, window level = 150 HU) were analyzed to obtain the length 3 width 3 height of the aneurysm sac relative history of subarachnoid hemorrhage has not been clearly established.Many investigators believe that all patients with aneurysms should receive follow-up to monitor for the possibility of growth or other signs of impending rupture, such as a bleb (9). The tradit...

Background and Purpose— Acceleration of intra-aneurysmal clot organization and fibrosis may be a solution to preventing aneurysm recanalization after endovascular treatment. The purpose of this study was to evaluate the short-term efficacy and long-term safety of the new Matrix coil system. Methods— Matrix coils consist of thin platinum coils covered with a bioabsorbable, polymeric material (polyglycolic acid/lactide). Fifty-two experimental aneurysms were created in 26 swine. All of the aneurysms were tightly packed with Matrix or Guglielmi detachable coils (GDC). Comparative angiographic and histopathologic data were analyzed at 2 weeks (n=14), 3 months (n=6), and 6 months (n=6) after embolization. Results— Three aneurysms treated with GDC ruptured despite tight packing. No recanalization or rupturing was observed in the aneurysms embolized with Matrix coils. At 14 days after embolization, the aneurysms treated with Matrix coils exhibited a more extensive area of organized thrombus when compared with the aneurysms treated with GDC (87% versus 75%, P =0.008, n=11). At 3 months, both Matrix and GDC-treated aneurysms demonstrated complete clot organization. Neck tissue thickness was higher in Matrix-treated aneurysms at 14 days and 3 months, but not at 6 months. No untoward parent artery stenosis was observed in aneurysms treated with Matrix during follow-up. The angiographic cross-sectional area of the Matrix-treated aneurysms was smaller than those treated with GDC at the 3 months. Conclusion— Matrix accelerated aneurysm fibrosis and neointima formation without parent artery stenosis. The Matrix system might prevent aneurysmal recanalization after endovascular treatment of cerebral aneurysms.