Extracranial and Intracranial Ultrasonographic Findings in Posterior Circulation Infarction

Patients with posterior circulation infarction are at higher risk of early recurrent stroke, especially those with vertebrobasilar stenosis or hypoplasia. The clinical presentations of this condition vary over a broad range, making diagnosis and treatment a challenge. Hemodynamic changes and stenosis detected by ultrasonography (US) are sensitive and important indicators for further evaluation. In this study, we correlated extracranial and intracranial US characteristics with brain magnetic resonance imaging (MRI) in patients with posterior circulation infarction.

Inpatients with acute ischemic stroke who received both MRI and US were enrolled. Baseline characters, underlying disorders, the ischemic territory, and vascular stenosis on MRI were recorded. Series of US data, including flow volume, diameter, mean velocity, and pulsatility index, were analyzed. Patients with new infarction over the medulla, pons, midbrain, or cerebellum were enrolled as the posterior circulation infarction group. Patients with pure anterior circulation infarction were also enrolled.

A total of 210 patients with anterior circulation infarction (mean age ± SD, 66.24 ± 12.88 years) and 143 with posterior circulation infarction (mean age, 65.82 ± 11.39 years) were enrolled. Significant higher frequencies of vertebral artery hypoplasia and decreased intracranial vertebrobasilar velocity in the posterior circulation infarction group (44.75% and 64.33%, respectively) were documented (P < .0001; P = .035). Ischemic lesion distributions were correlated with vertebral artery hypoplasia (55.56 %) and low vertebral and basilar artery velocities (44.44% and 25.53%), as documented by US. A low vertebrobasilar velocity was highly correlated with MRI-documented vascular stenosis (53.06%).

Vertebral artery hypoplasia and a low velocity in the intracranial vertebrobasilar system on US might change the treatment of patients with posterior circulation infarction for primary and secondary prevention.