  MR findings of demyelination include white matter (WM) T2 hyperintensity anywhere in the brain including the corpus callosum (CC) with minimal surrounding edema and mass effect, nodular, patchy, incomplete ring and arc patterns of contrast enhancement on post-contrast T1 weighted imaging (T1WI). 脱髓鞘的MRI表现包括：脑白质T2高信号，还会累及大脑皮质，外周微水肿，占位效应也不明显。T1增强呈结节样、斑块样、不完整环状或弧形强化。 However, contrary to popular belief, tumefactive demyelinating lesion can be associated with mass effect and edema. Diffusion restriction could be subtle but not common and usually indicates acute lesions. Low relative blood volume and flow on perfusion studies have been reported in demyelination. 但是，和普遍认知矛盾的是，肿瘤样脱髓鞘可伴占位效应和水肿。可有轻微弥散首先，但不常见，通常提示急性病变。脱髓鞘灌注成像显示血流量减低。 The definition of “tumefactive demyelination” is not consistent in the literature and may refer to various combinations of the following: white matter location, large size (>2 cm), little mass effect or edema, and/or typical enhancement patterns (nodular, patchy, thin open or incomplete ring, or heterogeneous). 关于“瘤样脱髓鞘”的定义在不同文献中也不太统一，大致为以下几种组合：病灶位于脑白质、病灶较大（大于2cm）、占位效应和水肿不明显、和/或典型强化方式（结节样、斑块样、开放薄层或不完整环状、不均匀强化） Notes: 1. Tumefactive demyelinating lesion 肿瘤样脱髓鞘性病变 2. edema [ɪ'di:mə] n. 水肿 来源：每天朗读一段医学影像学英语文章 圈主 深圳市人民医院放射科副主任医师杨敏洁 |
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