Complete Non-visualization Of Basilar Artery On MR Angiography In Patients With Posterior Circulation Ischemia: Reports 89 Cases

Objective: To identify clinical or radiological measures in patients with posterior circulation ischemia characterized by basilar artery absent on magnetic resonance angiography(MRA) so as to that could assist in predicting their clinical outcome.Materials and method: All 89 patients with posterior circulation ischemia whose basilar arteries completely non-visualized on MRA were collected in the department of neurology in The General Hospital of Shenyang Military Command from March 2012 to September 2014 Clinical outcomes were classified as favorable(modified Rankin Scale(m RS) = 0-3 points) and poor(m RS = 4-6 points). The extents of ischemic damage were assessed on DWI according to infarction scoring systems suggested by Renard et al and Cho et al. The FLAIR-hyperintense basilar artery(FHBA) scores were used to evaluate the condition of the basilar artery, and the potential feeding artery score(PFAS) was adopted to evaluate the potential feeding supplies to the basilar artery through reviewing the MRA data. The impacting factors on prognosis of baseline clinical or radiologic data included age, National Institutes of Health Stroke Scale(NIHSS) score, Glasgow Coma Scale(GCS), Renard score, Cho score and so on. Logistic regression was then performed to select the most important variables independently affecting prognosis.Result: Eighty-nine patients were collected in this work. The clinical outcomes at discharge were favorable in 16 cases(18%) and poor in 73 cases(82%). In the univariate analysis, variables associated with poor outcome were: baseline NIHSS, GCS score, Renard score, Cho score and PFA score. Multivariate analysis showed that the NIHSS, Renard score and PFA score were the independent predictors for clinical outcome. The CT angiography examination was simultaneously performed on seven patients with the basilar artery non-visualization on MRA, confirming the basilar artery occlusion in three cases, the severe stenosis on intersection of vertebral artery and basilar artery in two case, the severe stenosis of bilateral vertebral artery and basilar artery in one case, and the occlusion of only both vertebral arteries while basilar artery well in one case.Conclusion: 1. The patients with posterior circulation ischemia characterized by complete non-visualization of the basilar artery on MR angiography have multiple territory infarctions and rather than 80% poor prognosis. 2. In multivariate analysis, NIHSS, Renard score and Cho score were significantly associated with clinical short-outcome. 3. The CTA confirmed the existence of a varying degree of stenosis or occlusion in the basilar artery and/or both vertebral arteries in the case of complete non-visualization of basilar artery on MR Angiography.