Diffusion tensor imaging may help the determination of time at onset in cerebral ischaemia
Diffusion tensor imaging may help the determination of time at onset in cerebral ischaemia
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DOI：
10.1136/jnnp.2008.163584
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发表时间：
2009-09-01
影响因子：
11
通讯作者：
Nishimura, T.
中科院分区：
文献类型：
--
作者：
Sakai, K.;Yamada, K.;Nishimura, T.
背景和目的：缺血组织的表观扩散系数（ADC）和各向异性（例如，分数各向异性（FA））随着时间的推移而变化。扩散率的降低（即λ（2）和λ（3））是表征超急性期梗死的重要标志，因为这些参数可以反映轴突膜状态。本研究探讨是否横向扩散可能是有用的评估白色物质梗死的各种age.Methods：扩散张量成像数据从44例成人患者（34名男性，10名女性，年龄46至89岁，平均= 70.3）急性白色物质梗死（1-168小时）的内囊进行了分析。相对本征值计算为：（lambda（ipsi）- lambda（contra））/lambda（contra）。根据扩散率随时间的理论预期演变，将病变分类如下：I期，FA高于对侧病变感兴趣区（ROI）; II期，所有特征值的扩散率低于对侧病变; III期，两个横向特征值之一结果：I期梗死（n = 5）主要发生在症状发作后24 h内，1例发生在第3天。II期梗死最常见于24 h内（n = 18），24 h后较少。第一天后，III期梗死的比例显著增加。因此，基于弥散度的分类白色物质梗死似乎表现出时间trends.Conclusions：弥散各向异性可能是有用的定义的生物组织时钟的白色物质梗死。
Background and aim: The apparent diffusion coefficient (ADC) and anisotropy (eg, fractional anisotropy (FA)) of ischaemic tissue evolve over time. A reduction in diffusivity (ie, lambda(2) and lambda(3)) is an important marker for characterising hyperacute-stage infarction, as these parameters may reflect axonal membrane status. The study examines whether transverse diffusivity could be useful in assessing white matter infarcts of various ages.Methods: Diffusion tensor imaging data from 44 adult patients (34 men, 10 women, aged 46 to 89 years, mean = 70.3) with acute white matter infarction (1-168 h) of the internal capsule were analysed. Relative eigenvalues were calculated as: (lambda(ipsi) - lambda(contra))/lambda(contra). Lesions were classified based on theoretically expected evolution of diffusivity over time as follows: stage I, FA higher than the contralesional region of interest (ROI); stage II, diffusivity lower than the contralesional side for all eigenvalues; stage III, one of two transverse eigenvalues (lambda(2) or lambda(3)) higher than the contralesional ROI.Results: Stage I infarcts (n = 5) were found primarily within 24 h of the onset of symptoms, with one case found on the third day. Stage II infarcts were found most commonly within 24 h (n = 18), and fewer after 24 h. After the first day, the ratio of stage III infarcts increased significantly. Thus, diffusivity-based classification of white matter infarcts seems to show a chronological trend.Conclusions: Diffusion anisotropy may be useful for defining the biological tissue clock of white matter infarctions.