ACR Appropriateness Criteria\u3csup\u3e®\u3c/sup\u3e on Cerebrovascular Disease

Stroke is the sudden onset of focal neurologic symptoms due to ischemia or hemorrhage in the brain. Current FDA-approved clinical treatment of acute ischemic stroke involves the use of the intravenous thrombolytic agent recombinant tissue plasminogen activator given \u3e3 hours after symptom onset, following the exclusion of intracerebral hemorrhage by a noncontrast CT scan. Advanced MRI, CT, and other techniques may confirm the stroke diagnosis and subtype, demonstrate lesion location, identify vascular occlusion, and guide other management decisions but, within the first 3 hours after ictus, should not delay or be used to withhold recombinant tissue plasminogen activator therapy after the exclusion of acute hemorrhage on noncontrast CT scans. MR diffusionweighted imaging is highly sensitive and specific for acute cerebral ischemia and, when combined with perfusionweighted imaging, may be used to identify potentially salvageable ischemic tissue, especially in the period \u3e3 hours after symptom onset. Advanced CT perfusion methods improve sensitivity to acute ischemia and are increasingly used with CT angiography to evaluate acute stroke as a supplement to noncontrast CT. The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment

The four categories of circle of Willis variations used in this study.

<p>Classical circle of Willis was defined as A1, P1 and PcomA diameters >0.8 mm, with no asymmetric A1s and no fetal posterior circulation. A1 asymmetry was defined as a difference in diameter of the A1 segments of >33%. Incomplete PcomA was defined as a uni- or bilateral PcomA diameter <0.8 mm. Finally, fetal posterior circulation was defined as a PcomA diameter >10% larger than the P1 diameter on the same side. A1 = proximal segment of anterior cerebral artery; P1 = proximal segment of posterior cerebral artery; PcomA = posterior communicating artery.</p

Sample calculation of concordance proportions for index and comparison family units.

<p>Sample calculation of concordance proportions for index and comparison family units.</p

Prevalence of circle of Willis variations in probands and FDRs.

<p>Prevalence of circle of Willis variations in probands and FDRs.</p

Concordance proportions in index and comparison families and odds ratios for group 1, group 2 and meta-analysis.

<p>Concordance proportions in index and comparison families and odds ratios for group 1, group 2 and meta-analysis.</p

Genome-Wide Association Study of Intracranial Aneurysm Identifies a New Association on Chromosome 7

BACKGROUND AND PURPOSE: Common variants have been identified using genome-wide association studies which contribute to intracranial aneurysms (IA) susceptibility. However, it is clear that the variants identified to date do not account for the estimated genetic contribution to disease risk. METHODS: Initial analysis was performed in a discovery sample of 2617 IA cases and 2548 controls of white ancestry. Novel chromosomal regions meeting genome-wide significance were further tested for association in 2 independent replication samples: Dutch (717 cases; 3004 controls) and Finnish (799 cases; 2317 controls). A meta-analysis was performed to combine the results from the 3 studies for key chromosomal regions of interest. RESULTS: Genome-wide evidence of association was detected in the discovery sample on chromosome 9 (CDKN2BAS; rs10733376: P<1.0×10(-11)), in a gene previously associated with IA. A novel region on chromosome 7, near HDAC9, was associated with IA (rs10230207; P=4.14×10(-8)). This association replicated in the Dutch sample (P=0.01) but failed to show association in the Finnish sample (P=0.25). Meta-analysis results of the 3 cohorts reached statistical significant (P=9.91×10(-10)). CONCLUSIONS: We detected a novel region associated with IA susceptibility that was replicated in an independent Dutch sample. This region on chromosome 7 has been previously associated with ischemic stroke and the large vessel stroke occlusive subtype (including HDAC9), suggesting a possible genetic link between this stroke subtype and IA