Rostrocaudal Thickness on Sagittal Diffusion-weighted Imaging as a Predictor of Motor Deficits in an Acute Isolated Pontine Infarction

Abstract

The relationship between infarct dimensions and neurologic severity in patients with acute pontine infarctions remains unclear. This study aimed to clarify the morphometric predictive value of magnetic resonance imaging for motor deficits in pontine infarction. Nineteen patients with an acute pontine infarction (12 males and 7 females, 70.6 ± 13.5 years [mean age ± SD]) had ventrodorsal length and rostrocaudal thickness and width retrospectively measured as parameters of infarct size on axial and sagittal diffusion-weighted imaging (DWI). Each patient's functional score (FS) based on Brunnstrom scale (upper limb, hand, and lower limb) was assessed. The functional score of bulbar symptoms was coded as follows: 2, none; 1, dysarthria or dysphasia; and 0, both. The mean FS was compared with each infarct size parameter and the patients' clinical features. Rostrocaudal thickness on sagittal DWI was the parameter most closely correlated with FS (Spearman rank correlation coefficient (rs) = -.474, P = .040). However, there is apparently no association between FS and infarct size with correction for age. FS was most severe in patients with an atherothrombotic infarction; it was mildest in patients with a lacunar infarction (value of K [Kruskal-Wallis] = 9.0, P = .015). The branch orifices of the pontine paramedian arteries could be narrowed by atheromatous plaques within the basilar artery. These atheromatous lesions involving multiple branching paramedian arteries probably cause rostrocaudally thick infarctions. A pontine infarction extending rostrocaudally along the corticospinal tract may cause severe motor impairments.