Barkovich A James, Deon Sean
Neuroradiology Section, Department of Radiology and Biomedical Imaging, UCSF-Benioff Children's Hospital, San Francisco, Q6 CA, United States.
University of Colorado Medical Center and Prof. Petra Pouwels, University of Amsterdam.
Neurobiol Dis. 2016 Mar;87:50-8. doi: 10.1016/j.nbd.2015.10.015. Epub 2015 Oct 22.
In recent years, the concept of hypomyelinating disorders has been proposed as a group of disorders with varying systemic manifestations that are identified by MR findings of absence or near absence of the T2 hypointensity that develops in white matter as a result of myelination. Initially proposed as a separate group because they were the largest single category of undiagnosed leukodystrophies, their separation as a distinct group that can be recognized by looking for a specific MRI feature has resulted in a marked increase in their diagnosis and a better understanding of the different causes of hypomyelination. This review will discuss the clinical presentations, imaging findings on standard MRI, and new MRI-related techniques that allow a better understanding of these disorders and proposed methods for quantifying the myelination as a potential means of assessing disease course and the effects of proposed treatments. Disorders with hypomyelination of white matter, or hypomyelinating disorders (HMDs), represent the single largest category among undiagnosed genetic leukoencephalopathies (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010). This group of inborn errors of metabolism is characterized by a magnetic resonance imaging (MRI) appearance of reduced or absent myelin development: delay in the development of T2 hypointensity and, often, T1 hyperintensity in the white matter of the brain. The concept of hypomyelination was first conceptualized by (Schiffmann and van der Knaap, 2009; Steenweg et al., 2010; Schiffmann et al., 1994) in a series of papers that showed that these MRI characteristics were easily recognized, were different from the MRI characteristics of dysmyelinating and demyelinating disorders, and that the combination of these imaging findings with specific other clinical and imaging features could be used to make diagnoses with some confidence. In this manuscript, we will discuss the physiologic and genetic bases of hypomyelinating disorders, as well as their classification, clinical manifestations and imaging characteristics.
近年来，低髓鞘形成障碍的概念被提出，它是一组具有不同全身表现的疾病，通过磁共振成像（MR）发现白质中因髓鞘形成而出现的T2低信号缺失或几乎缺失来确定。最初因其是未确诊的脑白质营养不良中最大的单一类别而被提议作为一个独立的组，将其作为一个可通过寻找特定MRI特征来识别的独特组进行区分，使得它们的诊断显著增加，并且对低髓鞘形成的不同原因有了更好的理解。本综述将讨论临床表现、标准MRI上的影像学表现以及新的MRI相关技术，这些技术有助于更好地理解这些疾病，并提出了量化髓鞘形成的方法，作为评估疾病进程和所提议治疗效果的潜在手段。白质低髓鞘形成的疾病，即低髓鞘形成障碍（HMDs），是未确诊的遗传性脑白质病中最大的单一类别（希夫曼和范德克纳普，2009年；斯滕韦格等人，2010年）。这组先天性代谢缺陷的特征是磁共振成像（MRI）显示髓鞘发育减少或缺失：脑白质中T2低信号发育延迟，且通常T1高信号。低髓鞘形成的概念最初由（希夫曼和范德克纳普，2009年；斯滕韦格等人，2010年；希夫曼等人，1994年）在一系列论文中提出，这些论文表明这些MRI特征易于识别，与脱髓鞘和髓鞘形成异常疾病的MRI特征不同，并且这些影像学表现与特定的其他临床和影像学特征相结合可用于有一定把握地做出诊断。在本手稿中，我们将讨论低髓鞘形成障碍的生理和遗传基础，以及它们的分类、临床表现和影像学特征。
