Haruhiko Hoshino

Effect of Extracranial Carotid Artery Stenosis and Other Risk Factors for Stroke on Periventricular Hyperintensity

BACKGROUND AND PURPOSE The pathogenesis of periventricular hyperintensity (PVH) is still uncertain. We investigated the relationship between PVH and risk factors for cerebrovascular diseases, especially extracranial carotid artery stenosis (ECAS). METHODS We studied PVH and ECAS in 323 subjects between 1991 and 1994. Using 1.5-T MRI scan images, we measured PVH quantitatively at eight points and evaluated cerebral infarction. Duplex carotid sonography was performed on the carotid arteries bilaterally and used to divide the severity of ECAS into five grades. Risk factors for cerebrovascular diseases and atherosclerotic complications were assessed from the clinical history. RESULTS Age was significantly correlated with the size of frontal and whole PVH (P < .01). Frontal PVH was significantly more severe in subjects with hypertension (P < .05). Frontal, occipital, and whole PVH were significantly more severe in subjects with a history of cerebrovascular accident (P < .01). Other risk factors and atherosclerotic complications were not correlated with PVH. There were no significant differences in the severity of PVH among the five groups of ECAS. The severity of PVH in each region was not related to ECAS. There was no significant difference in the age of patients in relation to the five grades of ECAS. However, PVH was significantly more severe in subjects with lacunar infarction or infarction of the deep border zone (P < .05). There was no relationship between PVH and cortical infarction or infarction of the cortical border zone. CONCLUSIONS PVH correlated with age, hypertension, and past history of cerebrovascular disease but not with ECAS. PVH was significantly more severe in lacunar infarction and infarction of the deep border zone. These results suggest that small-vessel disease may underlie the pathogenesis and development of PVH.

Recanalization of intracranial carotid occlusion detected by duplex carotid sonography.

We studied three patients with internal carotid artery occlusion at the siphon who had recanalization during 1 month of close observation. Angiography and duplex carotid sonography (DCS) were repeated serially in each patient. Blood flow patterns detected by DCS were classified into three patterns by specific angiographic changes. The distal occlusive flow pattern on DCS corresponds to internal carotid artery occlusion at the siphon angiographically, the median flow pattern on DCS corresponds to partial recanalization, and a normal flow pattern on DCS indicates almost complete recanalization. Since DCS can be easily repeated, the exact time of recanalization can be determined noninvasively. In all three patients, hemorrhagic infarction observed on computed tomograms occurred at the time of recanalization detected by DCS. DCS demonstrates that recanalization is one of the mechanisms of hemorrhagic infarction.

Visual field defects in lateral geniculate body infarction.

比較的稀である外側膝状体梗塞の1例を報告した.症例は77歳男性, 高血圧, 糖尿病あり, 右視野が見えないと訴え来院.MRIで左外側膝状体 (LGB) に限局したラクナ梗塞と診断した.視野は黄斑回避なく, 非合同性の右下楔型部分盲であった.従来LGB梗塞は閉塞血管により水平線に沿って扇状に欠損あるいは残存する合同性の部分盲を呈するとされるが, 本症例の視野はそれらとは異なっていた.その理由としてLGB表面上における前脈絡叢動脈と外側後脈絡叢動脈の間の血管吻合の個体差や, そこからLGB内へ分岐する穿通動脈間の個体差が大きいためと考えられた.