Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, Scientific Institute and University Hospital San Raffaele, Via Olgettina 60, 20132 Milan, Italy.
Radiology. 2010 Jun;255(3):882-9. doi: 10.1148/radiol.10091742.
To investigate in vivo severity and topographic distribution of brain white matter (WM) fiber bundle atrophy in patients with Friedreich ataxia, a condition characterized by an uneven involvement of brain WM, and to correlate such findings with the clinical status of the patients.
The study was conducted with institutional review board approval. Written informed consent was obtained from each participant. Sixteen patients with Friedreich ataxia and 15 healthy control subjects were studied by using a 1.5-T magnetic resonance (MR) imager and 3-mm-thick diffusion-tensor images with 15 noncollinear directions. The size of WM fiber bundles was examined at a voxel level by using a recently developed method, which relies on production of anisotropy maps and nonlinear registration. Data were analyzed by using statistical parametric mapping software and an analysis of covariance model adjusted for age and sex.
Compared with control subjects, patients with Friedreich ataxia had WM atrophy in (a) the central portion of the medulla oblongata, (b) the dorsal upper pons, (c) the superior cerebellar peduncles, (d) the central portion of the midbrain, (e) the medial portion of the right cerebral peduncle, (f) the peridentate region, bilaterally, and (g) the optic chiasm. The severity of the neurologic deficits correlated significantly with atrophy of the peridentate WM, bilaterally, and that of the superior cerebellar peduncle decussation.
Findings of this study show that it is feasible to obtain in vivo atrophy estimates of specific brain WM fiber bundles in patients with Friedreich ataxia and that such estimates correlate with patients' clinical status. This approach has the potential to provide new information that is likely to improve the understanding of the pathophysiology of inherited ataxias.
研究弗里德赖希共济失调患者脑白质（WM）纤维束萎缩的严重程度和局灶分布，该病的脑 WM 受累程度不均一，并将这些发现与患者的临床状况相关联。
本研究经机构审查委员会批准进行，每位参与者均签署了书面知情同意书。使用 1.5-T 磁共振（MR）成像仪和 3-mm 厚的扩散张量图像（具有 15 个非共线方向）对 16 例弗里德赖希共济失调患者和 15 例健康对照者进行了研究。通过最近开发的一种方法在体素水平上检查 WM 纤维束的大小，该方法依赖于各向异性图的产生和非线性配准。使用统计参数映射软件和协方差模型分析数据，协方差模型调整了年龄和性别因素。
与对照组相比，弗里德赖希共济失调患者的 WM 萎缩位于（a）延髓中央部分，（b）上脑桥背侧上部，（c）小脑上脚，（d）中脑中央部分，（e）右侧大脑脚内侧部分，（f）双侧齿状核区，以及（g）视交叉。神经缺损的严重程度与双侧齿状核 WM 萎缩以及小脑上脚交叉的萎缩显著相关。
本研究结果表明，对弗里德赖希共济失调患者特定脑 WM 纤维束的进行体萎缩估计是可行的，并且这些估计与患者的临床状况相关。这种方法有可能提供新的信息，这可能有助于加深对遗传性共济失调的病理生理学的理解。
