Vieira Karuta Simone Carreiro, Raskin Salmo, de Carvalho Neto Arnolfo, Gasparetto Emerson Leandro, Doring Thomas, Teive Helio Afonso Ghizoni
Federal University of Parana, Hospital de Clinicas, Brazil.
Pontificia Universidade Catolica do Parana, Genetika Laboratorio: Rua Saldanha Marinho, 1782, Bigorrilho, Curitiba, Parana 80730-180, Brazil.
Parkinsonism Relat Disord. 2015 May;21(5):504-8. doi: 10.1016/j.parkreldis.2015.02.021. Epub 2015 Mar 11.
Friedreich's ataxia (FRDA) is the most common hereditary ataxia and thinning of the cervical spinal cord is a consistent observation in Magnetic resonance imaging (MRI), although neuropathological examination in FRDA reveals neuronal loss in gray matter (GM) nuclei and degeneration of white matter (WM) tracts in the spinal cord, brainstem and cerebellum. Using diffusion-tensor (DTI) imaging and tract-based spatial statistics (TBSS) we tested the hypothesis that WM damage in FRDA is more extensive than previously described and probably involves normal-appearing WM.
This transversal study included 21 genetically confirmed FRDA patients and seventeen healthy controls that underwent structural MRI of the brain on a 1.5 T scanner. We quantify the severity of ataxia using SARA scale. DTI was performed and diffusion data were analyzed using FMRIB's Diffusion Toolbox in FSL 4.1 in order to identify Fractional anisotropy (FA) decreases in specific brain regions and also the mean, radial and axial diffusivities (MD, RD, AD).
The greatest decreases in FA were in the left superior cerebellar peduncle, left posterior thalamic radiation, major forceps, left inferior fronto-occipital fasciculus and corpus callosum and had a significance level of p < 0.01. No significant correlation between FA, AD, MD and RD values and the clinical findings, SARA scores and genetic expansion was found.
DTI and TBSS techniques clearly demonstrate the extensive cerebral and cerebellar involvement in FRDA, partially explaining the clinical phenotype of the disease. Further studies are needed with larger samples to correlate clinical, genetic findings and ataxia scores.
弗里德赖希共济失调（FRDA）是最常见的遗传性共济失调，磁共振成像（MRI）显示颈髓萎缩是其一致表现，尽管FRDA的神经病理学检查显示脊髓、脑干和小脑的灰质（GM）核团存在神经元丢失以及白质（WM）束变性。我们使用扩散张量成像（DTI）和基于束的空间统计学（TBSS）来检验这一假设，即FRDA中的WM损伤比先前描述的更为广泛，并且可能涉及外观正常的WM。
这项横断面研究纳入了21例经基因确诊的FRDA患者和17名健康对照者，他们在1.5T扫描仪上接受了脑部结构MRI检查。我们使用SARA量表对共济失调的严重程度进行量化。进行DTI检查，并使用FSL 4.1中的FMRIB扩散工具箱分析扩散数据，以确定特定脑区的分数各向异性（FA）降低情况，以及平均、径向和轴向扩散率（MD、RD、AD）。
FA降低最明显的部位是左侧小脑上脚、左侧丘脑后辐射、主要钳状束、左侧额枕下束和胼胝体，显著性水平为p < 0.01。未发现FA、AD、MD和RD值与临床发现、SARA评分和基因扩增之间存在显著相关性。
DTI和TBSS技术清楚地表明FRDA存在广泛的大脑和小脑受累，部分解释了该疾病的临床表型。需要更大样本量的进一步研究来关联临床、基因发现和共济失调评分。
