Spinocerebellar ataxia type 3/Machado–Joseph disease (SCA3/MJD) is a progressive autosomal dominantly inherited cerebellar ataxia characterized by the aggregation of polyglutamine-expanded protein within neuronal nuclei in the brain, which can lead to brain damage that precedes the onset of clinical manifestations. Magnetic resonance imaging (MRI) techniques such as morphometric MRI, diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI), and magnetic resonance spectroscopy (MRS) have gained increasing attention as non-invasive and quantitative methods for the assessment of structural and functional alterations in clinical SCA3/MJD patients as well as preclinical carriers. Morphometric MRI has demonstrated typical patterns of atrophy or volume loss in the cerebellum and brainstem with extensive lesions in some supratentorial areas. DTI has detected widespread microstructural alterations in brain white matter, which indicate disrupted brain anatomical connectivity. Task-related fMRI has presented unusual brain activation patterns within the cerebellum and some extracerebellar tissue, reflecting the decreased functional connectivity of these brain regions in SCA3/MJD subjects. MRS has revealed abnormal neurochemical profiles, such as the levels or ratios of N-acetyl aspartate, choline, and creatine, in both clinical cases and preclinical cases before the alterations in brain anatomical structure. Moreover, a number of studies have reported correlations of MR imaging alterations with clinical and genetic features. The utility of these MR imaging techniques can help to identify preclinical SCA3/MJD carriers, monitor disease progression, evaluate response to therapeutic interventions, and illustrate the pathophysiological mechanisms underlying the occurrence, development, and prognosis of SCA3/MJD.

中文翻译：

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SCA3/MJD 的 MR 成像

脊髓小脑性共济失调 3 型/马查多-约瑟夫病 (SCA3/MJD) 是一种进行性常染色体显性遗传的小脑性共济失调，其特征在于大脑神经元核内聚谷氨酰胺扩增蛋白的聚集，这可导致在临床发作之前的脑损伤。表现。磁共振成像 (MRI) 技术，如形态测量 MRI、弥散张量成像 (DTI)、功能磁共振成像 (fMRI) 和磁共振波谱 (MRS)，作为用于评估结构的非侵入性和定量方法越来越受到关注。和临床 SCA3/MJD 患者以及临床前携带者的功能改变。形态测量 MRI 显示小脑和脑干的典型萎缩或体积减少模式，在某些幕上区域有广泛病变。DTI 检测到大脑白质中广泛的微观结构改变，这表明大脑解剖学连接被破坏。与任务相关的 fMRI 在小脑和一些小脑外组织中呈现出异常的大脑激活模式，反映了 SCA3/MJD 受试者这些大脑区域的功能连通性降低。MRS 已经揭示了异常的神经化学特征，例如 N-乙酰天冬氨酸、胆碱和肌酸的水平或比率，在脑解剖结构改变之前的临床病例和临床前病例中。此外，许多研究报告了 MR 成像改变与临床和遗传特征的相关性。