The effects of changing water content, relaxation times, and tissue contrast on tissue segmentation and measures of cortical anatomy in MR images.
The effects of changing water content, relaxation times, and tissue contrast on tissue segmentation and measures of cortical anatomy in MR images.
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DOI：
10.1016/j.mri.2013.07.017
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发表时间：
2013-12
影响因子：
2.5
通讯作者：
Peterson, Bradley S.
中科院分区：
文献类型：
--
作者：
Bansal, Ravi;Hao, Xuejun;Liu, Feng;Xu, Dongrong;Liu, Jun;Peterson, Bradley S.
含水量是大脑中的主要化合物，并且是磁共振（MR）图像中组织对比度的主要决定因素。水含量在个体之间变化很大，并且随着时间的推移，从出生到人类寿命的衰老，它会发生巨大的变化。我们假设，个体和年龄相关的水含量的变化对MR图像中大脑对比度的影响也对基于MRI的局部脑体积的体内测量具有重要的系统性影响。我们还假设，随着时间的推移，水含量和组织对比度的变化可能会导致区域体积的年龄相关变化，并且不同神经精神病诊断之间的水含量或组织对比度差异可能会导致诊断组之间区域体积的差异。我们以几种互补的方式证明了不同年龄和不同组织间含水量的细微变化会改变组织对比度，而组织对比度的变化反过来又会改变皮质套的厚度和体积的测量：（1）我们推导了描述组织弛豫时间的年龄相关变化如何产生组织灰度强度值和组织对比度的年龄相关变化的解析关系;（2）我们改变计算机生成图像中的组织对比度，以评估其对组织分割以及灰质和白色物质体积的影响;（3）我们使用来自精神分裂症或双相情感障碍成年人的真实世界成像数据，以及年龄和性别，匹配的健康成年人，以评估不同诊断的组织对比度变化影响组织分割和相关的组间差异的方式。卷我们的结论是，在体内MRI为基础的形态测量的大脑，包括区域体积和皮质厚度的措施，是一个产品，或至少是混淆，在组织对比度的差异，在个人，年龄和诊断组，而组织对比度的差异反过来可能来自相应的差异，在不同的个人，年龄和诊断组的脑含水量。
Water content is the dominant chemical compound in the brain and it is the primary determinant of tissue contrast in magnetic resonance (MR) images. Water content varies greatly between individuals, and it changes dramatically over time from birth through senescence of the human life span. We hypothesize that the effects that individual- and age-related variations in water content have on contrast of the brain in MR images also has important, systematic effects on in vivo, MRI-based measures of regional brain volumes. We also hypothesize that changes in water content and tissue contrast across time may account for age-related changes in regional volumes, and that differences in water content or tissue contrast across differing neuropsychiatric diagnoses may account for differences in regional volumes across diagnostic groups. We demonstrate in several complementary ways that subtle variations in water content across age and tissue compartments alter tissue contrast, and that changing tissue contrast in turn alters measures of the thickness and volume of the cortical mantle: (1) We derive analytic relations describing how age-related changes in tissue relaxation times produce age-related changes in tissue gray-scale intensity values and tissue contrast; (2) We vary tissue contrast in computer-generated images to assess its effects on tissue segmentation and volumes of gray matter and white matter; and (3) We use real-world imaging data from adults with either Schizophrenia or Bipolar Disorder and age- and sex-matched healthy adults to assess the ways in which variations in tissue contrast across diagnoses affects group differences in tissue segmentation and associated volumes. We conclude that in vivo MRI-based morphological measures of the brain, including regional volumes and measures of cortical thickness, are a product of, or at least are confounded by, differences in tissue contrast across individuals, ages, and diagnostic groups, and that differences in tissue contrast in turn likely derive from corresponding differences in water content of the brain across individuals, ages, and diagnostic groups.
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影响因子：
5.7
作者：
Fischl, B;Sereno, MI;Dale, AM
通讯作者：
Dale, AM
DOI：
10.1109/4233.992165
发表时间：
2002-03-01
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
1.3
作者：
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通讯作者：
Hill, DLG