Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore, Karnataka, India.
Parkinsonism Relat Disord. 2011 Aug;17(7):521-7. doi: 10.1016/j.parkreldis.2011.04.008. Epub 2011 May 20.
Spinocerebellar ataxias (SCA) are a group of autosomal dominant ataxias with varied clinical phenotypes. However there are no unique distinguishing features on routine neuroimaging among the various genetically defined SCAs. Voxel-based morphometry (VBM) provides an automated unbiased analysis of structural MRI scans and gives a comprehensive assessment of anatomical differences throughout the brain.
The aims of this study were to (i) characterize the patterns of atrophy in SCA1, SCA2 and SCA3 using optimized VBM, (ii) demonstrate the characteristic anatomical differences in these genetically distinct SCA subtypes, and (iii) assess the relationship between morphometric measures and the CAG repeat lengths and other attributes of the disease.
Thirty-one genetically confirmed patients suffering from SCA (SCA1 - 12, SCA2 - 9, and SCA3 - 10) were studied. High resolution T1-weighted 3-Dimensional Magnetic Resonance Images of 31 patients were analyzed using the optimized VBM procedure.
In all the three SCAs there was a significant loss of gray matter in both cerebellar hemispheres and vermis. Vermian atrophy was more pronounced in SCA3, while SCA1 and SCA2 had significant white matter atrophy. Pontine white matter atrophy was more pronounced in SCA2. In SCA1, the severity of ataxia strongly correlated with the degree of gray matter atrophy in cerebellar hemispheres. The duration of symptoms and lengths of CAG repeats had no correlation with the degree of atrophy.
This study showed that the different subtypes of SCAs may have morphometric differences in the cerebellum, brainstem and the supratentorial structures.
脊髓小脑共济失调（SCA）是一组常染色体显性共济失调，具有不同的临床表型。然而，在各种遗传定义的 SCA 中，常规神经影像学检查没有独特的鉴别特征。体素形态计量学（VBM）提供了对结构 MRI 扫描的自动无偏分析，并对整个大脑的解剖差异进行了全面评估。
本研究的目的是：（i）使用优化的 VBM 来描述 SCA1、SCA2 和 SCA3 的萎缩模式，（ii）证明这些遗传上不同的 SCA 亚型的特征性解剖差异，（iii）评估形态计量测量与 CAG 重复长度和疾病其他特征之间的关系。
研究了 31 名经基因证实患有 SCA 的患者（SCA1-12、SCA2-9 和 SCA3-10）。使用优化的 VBM 程序对 31 名患者的高分辨率 T1 加权三维磁共振图像进行了分析。
在所有三种 SCA 中，小脑半球和蚓部均有明显的灰质丢失。SCA3 的蚓部萎缩更为明显，而 SCA1 和 SCA2 有明显的白质萎缩。SCA2 的脑桥白质萎缩更为明显。在 SCA1 中，共济失调的严重程度与小脑半球灰质萎缩的程度强烈相关。症状持续时间和 CAG 重复长度与萎缩程度无相关性。
本研究表明，不同亚型的 SCA 可能在小脑、脑干和大脑半球结构中存在形态计量差异。
