大脳白質を見る：MRI

Cerebral White Matter Lesions: Differential Diagnosis on Magnetic Resonance Imaging

大脳白質病変のMRI画像における鑑別診断は難しいことが多いが，詳細な読影により特徴的な画像所見を拾い上げることで鑑別できる場合もある。鑑別可能な疾患を見逃さないことが重要である。本稿では鑑別のポイントとして，①皮質直下の白質優位の疾患，②両側側頭葉尖端部の皮質下白質に高信号を示す疾患，③mass effectを呈する疾患，④拡散強調画像やT₂^*強調画像での所見が特徴的な疾患を提示する。

Abstract

It is often difficult to make a differential diagnosis of cerebral white-matter lesions on magnetic resonance images (MRI), because imaging findings are non-specific. However, it is possible to make a correct diagnosis of some kinds of cerebral white-matter lesions upon a detailed analysis of MRI. In analyzing MRI of cerebral white matter lesions, the localization and shape of white-matter lesions are important factors to make a differential diagnosis. Other images such as diffusion-weighted or T2-star weighted images are sometimes also useful for making such a diagnosis. In this manuscript, I describe how to read MRI of cerebral white-matter lesions, and present some educational cases.