Abstract W P114: Pure Pontine versus Pontine Plus Infarction Assessed by Diffusion Weighted MRI: Etiological and Clinical Differences

Abstract

Pontine infarction is often associated with extrapontine infarcts. We aimed to elucidate differences in clinical characteristics and stroke mechanisms between the isolated pontine (IP) and pontine plus (PP) infarcts. We studied consecutively admitted patients with acute ischemic stroke (< 7 days after the symptom) occurring in the pons between 2004 and 2013. All patients were assessed by diffusion weighted MRI (DWI) and MR angiography. According to DWI findings, we divided the patients into the IP and PP groups. In addition, pontine lesions were categorized as upper, middle and low according the previous report (Kim JS et al. Stroke 1995). Lesions were also categorized as focal vs. extensive and unilateral vs. bilateral. Functional outcome was measured by modified Rankin scale (mRS) at discharge. There were 834 (504 male) patients, 675 in the IP group and 159 in the PP group. The most commonly involved extrapontine territory was the posterior inferior cerebellar artery territory (54.1%) followed by superior cerebellar artery territory (42.1%) and occipital lobe (35.2%). As compared to the IP group, the pontine lesions in the PP group were more often located in the rostral (upper (67.3%), middle (61.6%), upper plus middle (40.3%)) level (p < 0.001). Lesions involving more than 2 levels (40.3% vs. 10.5% p<0.001), extensive (20.8% vs. 2.7%, <0.001) and bilateral (37.1%, vs. 2.8%, p<0.001) infarcts were more frequent in the PP group. The PP group had a higher prevalence of symptomatic stenosis (26.7% vs. 72.2%, p<0.001), large artery disease (60.5% vs 25.9%) and cardioembolism (16.0% vs. 2.1%, <0.001) than the IP group. In multivariable analysis, atrial fibrillation (OR: 3.87, 95% CI: 2.16-7.08) was significantly associated with PP. mRS at discharge was higher in the PP than IP group (median 3 (IQR 2-5) vs. 2 (IQR 1-3), <0.001). PP groups have more extensive and rostral pontine lesions, and are more often associated with large artery artherosclerosis, cardioembolism, and worse functional outcome. Prevention and therapeutic strategies should differ between the two groups.