Differential effects of radiation and age on diffusion tensor imaging in rats.
Differential effects of radiation and age on diffusion tensor imaging in rats.
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DOI：
10.1016/j.brainres.2010.06.049
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发表时间：
2010-09-10
期刊：
影响因子：
2.9
通讯作者：
Brunso-Bechtold, Judy K.
中科院分区：
文献类型：
--
作者：
Peiffer, Ann M.;Shi, Lei;Olson, John;Brunso-Bechtold, Judy K.
分割部分或全脑放疗后存活超过 6 个月的超过 50% 的成人和约 100% 的儿童会出现认知障碍。需要非侵入性方法来检测和跟踪与这些损伤相关的辐射引起的脑损伤。使用磁共振成像，我们试图在分次全脑照射（fWBI）引起的认知障碍的啮齿动物模型中检测与脑损伤相关的结构变化，并将这些变化与衰老过程中发生的变化进行比较。中年大鼠接受临床相关剂量的 fWBI（40 Gy：每周两次 5 Gy 剂量，持续 4 周），并在照射后约一年进行扫描，以获得全脑 T2 和扩散张量图像 (DTI)；还扫描了假照射的年龄匹配的对照组和年轻大鼠。 T2 结构图像中没有明显的总体结构变化，并且在重髓鞘白质（胼胝体、扣带回和深层皮质白质）中未发现可检测到的 fWBI 诱导的 DTI 分数各向异性 (FA) 变化。然而，由于 fWBI 诱导的顶叶皮质更前层的 FA 下降，浅层顶叶皮质中存在显着的 fWBI 诱导的 FA 分布变异。与两组老年大鼠相比，年轻大鼠的 FA 值显着降低，但仅限于胼胝体内。这些发现表明，该模型中 fWBI 诱导变化的目标可能是少髓鞘或无髓鞘轴突、细胞外基质或突触区，而不是重髓鞘束。
Greater than 50% of adults and ∼100% of children who survive >6 months after fractionated partial or whole-brain radiotherapy develop cognitive impairments. Noninvasive methods are needed for detecting and tracking the radiation-induced brain injury associated with these impairments. Using magnetic resonance imaging, we sought to detect structural changes associated with brain injury in our rodent model of fractionated whole-brain irradiation (fWBI) induced cognitive impairment and to compare those changes with alterations that occur during the aging process. Middle aged rats were given a clinically relevant dose of fWBI (40 Gy: two 5 Gy fractions/wk for 4 wk) and scanned approximately one year post-irradiation to obtain whole-brain T2 and diffusion tensor images (DTI); control groups of sham-irradiated age-matched and young rats were also scanned. No gross structural changes were evident in the T2 structural images, and no detectable fWBI-induced DTI changes in fractional anisotropy (FA) were found in heavily myelinated white matter (corpus callosum, cingulum, and deep cortical white matter). However, significant fWBI-induced variability in FA distribution was present in the superficial parietal cortex due to an fWBI-induced decline in FA in the more anterior slices through parietal cortex. Young rats had significantly lower FA values relative to both groups of older rats, but only within the corpus callosum. These findings suggest that targets of the fWBI-induced change in this model may be the less myelinated or unmyelinated axons, extracellular matrix, or synaptic fields rather than heavily myelinated tracts.
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影响因子：
254.7
作者：
Jemal, Ahmedin;Siegel, Rebecca;Thun, Michael J.
通讯作者：
Thun, Michael J.
DOI：
10.1016/0360-3016(89)90518-x
发表时间：
1989-12-01
影响因子：
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作者：
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作者：
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影响因子：
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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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