Abstract T P43: Hyperdense Basilar Artery (HDBA) Sign: Its Association With Clinical Signs, Symptoms And Outcome Of Posterior Circulation Ischemic Stroke

Abstract

Background and purpose: Posterior circulation ischemic stroke is a clinical syndrome associated with ischemia related to stenosis, in situ thrombosis, or embolic occlusion of the posterior circulation arteries - the vertebral arteries, basilar, posterior cerebral arteries, and their branches. In order to reach the definite diagnosis, different imaging methods can be used, such as CT (computed tomography) and MRI (magnetic resonance imaging), or by conventional angiography. Hyperdense Basilar artery (HDBA) is a radiologic sign seen on unenhanced computed tomography scan suggestive of an early ischemic stroke. In a hospital facility that lacks advancement in neuroimaging, evaluating HDBA sign on unenhanced cranial CT scan can help clinicians in the diagnosis of posterior circulation ischemic stroke. Methods: A total of 67 subjects were included in the study. Medical records and neuroimaging of patients with a final diagnosis of posterior circulation ischemic stroke were retrieved. The radiologist who read the Cranial CT Scan was blinded as to the clinical signs, symptoms, and outcome of our subjects. All neuroimaging were reviewed as to location of the posterior circulation infarction, and for presence or absence of HDBA sign. Results: There were higher proportions with cerebellar signs and quadriplegia among those with positive HDBA sign, and a higher proportion with ocular signs among those with negative HDBA sign. However, we found no significant statistical difference (P=0.185). Location of infarction (P=0.363), baseline NIHSS (p=0.307), MRS on discharge (P=0.938), and timing of neuroimaging (P=0.227) were also not statistically significant. A positive HDBA sign had low sensitivity (54%), specificity (43%) and positive predictive value (16%). However, it had a high negative predictive value which means that among those found without an HDBA sign, 83% are likely to survive. Conclusion: There is no significant association between HDBA sign and clinical findings among patients with a posterior circulation ischemic stroke. Among those found with a positive HDBA sign, there is high likelihood for the presence of infarction and for those with a negative HDBA sign, a higher likelihood for survival.