脊髄小脳変性症の画像診断におけるvoxel-based morphometryの有用性

The Utility of Voxel-based Morphometry in the Diagnosis of Spinocerebellar Degeneration

脊髄小脳変性症におけるvoxel-based morphometry（VBM）を用いた画像診断の有用性について検討した。多系統萎縮症小脳型（MSA-C）9例では，小脳半球・虫部に広範な灰白質萎縮を，中小脳脚・脳幹・小脳に著明な白質萎縮所見を認めた。SCA3 6例では灰白質の萎縮は目立たず，中小脳脚・脳幹・小脳の著明な白質萎縮を認めた。DRPLA 2例では脳幹，歯状核周辺の軽度白質萎縮所見を認め，小脳灰白質の萎縮は目立たなかった。SCA6 3例，SCA31 2例では小脳半球・虫部の灰白質萎縮が顕著であったが，中小脳脚・脳幹の白質萎縮は認められず，小脳半球歯状核近傍に対称性の白質萎縮を認めた。いずれの疾患についてもVBM所見は各疾患で知られている特徴的な病理学的な萎縮部位を反映すると考えられ，VBMは脊髄小脳変性症の診断に有用と考えられた。

Abstract

We evaluated atrophic sites in the brainstem and cerebellum in the patients with spinocerebellar degeneration by using voxel-based morphometry (VBM). Gray matter atrophy was found extensively in both the cerebellar hemispheres and vermis of subjects presenting the cerebellar variant of multiple system atrophy (MSA-C; n＝9). In addition, remarkable white matter atrophy was observed in the middle cerebellar peduncle, brainstem, and cerebellar hemispheres. In contrast, gray matter atrophy was not apparent in the cerebellar hemispheres or vermis of subjects in the SCA3 group (n＝6), whereas intense white matter atrophy was visible in the middle cerebellar peduncle, brainstem, and cerebellar hemispheres. White matter atrophy was also observed in the brainstem and surrounding the dentate nucleus in both cases of dentatorubral-pallidoluysian atrophy (DRPLA) (n＝2), whereas gray matter atrophy of the cerebellum was not remarkable. In both the SCA6 group (n＝3) and the SCA31 group (n＝2), gray matter atrophy was prominent in the cerebellar hemispheres and vermis; however, white matter atrophy was not found in the middle cerebellar peduncle and brainstem, whereas symmetric atrophy of white matter was found in the vicinity of the dentate nucleus. In each of these diseases, VBM findings were consistent with the pathological findings; therefore, VBM can be considered a useful tool for the diagnosis of spinocerebellar degeneration.

(Receieved July 24, 2013; Accepted October 25, 2013; Published June 1 2014)