同名性暗点を認めた前脈絡叢動脈領域梗塞の1例

A Case of Brain Infarction in the Anterior Choroidal Artery Territory with Homonymous Scotomas

はじめに

　前脈絡叢動脈は内包後脚の後2/3の血流支配を行う^1）とともに，外側膝状体の内側部，外側部の血流も支配している^2－4）。外側膝状体の障害では特徴的な視野欠損を生じることが知られており，視野欠損の症状から梗塞部位を推定することができる。われわれは一過性の視野欠損を呈し，Goldmann視野検査で同名性暗点を認めた前脈絡叢動脈領域梗塞の1例を報告し，外側膝状体の機能局在と血流支配について考察を加える。

Abstract

　We report a case of brain infarction in the anterior choroidal artery territory accompanied homonymous scotomas.　A 59-year-old man with diabetes mellitus felt weakness in his left upper and lower extremities.　He was admitted to our hospital with mild hemiparesis on his left side.　He noticed a small black spot in the left inferior portion of his visual field; however, this disappeared within one minute.　He had no visual defects as assessed by a confrontation test, but a Goldmann visual field test revealed that there were homonymous scotomas in the left inferior portion of the visual field.　Brain MRI showed hyperintense signals on diffusion-weighted images in the territory of the right anterior choroidal artery.　He was diagnosed as having a brain infarction.　The anterior choroidal artery penetrates the lateral geniculate nucleus from the front, and branches of the artery usually supply the medial and lateral parts of the lateral geniculate nucleus.　Occlusion of these branches causes the loss of the upper and lower homonymous sectors in the visual field.　The present case exhibited homonymous scotomas.　We assumed that our patient's homonymous scotomas were a variant form of wedge-shaped visual field deficits often seen in anterior choroidal artery syndrome.　On the basis the experience gained in this case, we consider that patients with brain infarction in the anterior choroidal artery territory should undergo ophthalmological examination, even when no visual defects are detected by a confrontation test.

(Received: November 21,2008,Accepted: March 18,2009)