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Background and Purpose-The aim of this study was to evaluate the sensitivity and specificity of MR angiography (MRA) in the diagnosis of ruptured and unruptured intracranial aneurysms. Methods-A systematic search was performed on 4 electronic databases on relevant articles that were published from January 1998 to October 2013. Inclusion criteria were met by 12 studies that compared MRA with digital subtraction angiography as reference standard. Two independent reviewers evaluated the methodological quality of the studies. Data from eligible studies were extracted and used to construct 2×2 contingency tables on a per-aneurysm level. Pooled estimates of sensitivity and specificity were calculated for all studies and subgroups of studies. Heterogeneity was tested, and risk for publication bias was assessed. Results-Included studies were of high methodological quality. Studies with larger sample size tended to have higher diagnostic performance. Most studies used time-of-flight MRA technique. Among the 960 patients assessed, 772 aneurysms were present. Heterogeneity with reference to sensitivity and specificity was moderate to high. Pooled sensitivity of MRA was 95% (95% confidence interval, 89%-98%), and pooled specificity was 89% (95% confidence interval, 80%-95%). False-negative and false-positive aneurysms detected on MRA were mainly located at the skull base and middle cerebral artery. Freehand 3-dimensional reconstructions performed by the radiologist significantly increased diagnostic performance. Studies performed on 3 Tesla showed a trend toward higher performance (P=0.054). Conclusions-Studies

Background Medical treatment of initially uncomplicated acute Stanford type-B aortic dissection is associated with a high rate of late adverse events. Identification of individuals who potentially benefit from preventive endografting is highly desirable. Methods and Results The association of CT imaging features with late adverse events was retrospectively assessed in 83 patients with acute uncomplicated Stanford type-B aortic dissection, followed over a median of 850 (IQR 247–1824) days. Adverse events were defined as fatal or non-fatal aortic rupture, rapid aortic growth (>10 mm/year), aneurysm formation (≥6 cm), organ or limb ischemia, or new uncontrollable hypertension or pain. Five significant predictors were identified using multivariable Cox regression analysis: connective tissue disease (HR 2.94, 95%CI: 1.29–6.72, p=0.01), circumferential extent of false lumen in angular degrees (HR 1.03 per degree, 95%CI: 1.01–1.04, p=0.003), maximum aortic diameter (HR 1.10 per mm, 95%CI: 1.02–1.18, p=0.015), false lumen outflow (HR 0.999 per mL, 95%CI: 0.998–1.000, p=0.055), and number of intercostal arteries (HR 0.89 per n, 95%CI: 0.80–0.98, p=0.024). A prediction model constructed to calculate patient specific risk at 1, 2 and 5 years and to stratify patients into high, intermediate, and low risk groups. The model was internally validated by bootstrapping and showed good discriminatory ability with an optimism-corrected c-statistic of 70.1%. Conclusions CT imaging-based morphologic features combined into a prediction model may be able to identify patients at high risk for late adverse events after an initially uncomplicated type B aortic dissection.