Experimental hypoxemic hypoxia: effects of variation in hematocrit on magnetic resonance T2*-weighted brain images.
Experimental hypoxemic hypoxia: effects of variation in hematocrit on magnetic resonance T2*-weighted brain images.
复制标题
实验性低氧性缺氧：血细胞比容变化对磁共振 T2* 加权脑图像的影响。
DOI：
10.1097/00004647-199809000-00011
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Powers,WJ
中科院分区：
文献类型：
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作者：
Lin,W;Paczynski,RP;Celik,A;Hsu,CY;Powers,WJ
动态获取大鼠脑T2加权梯度回波磁共振图像，探讨脑血氧饱和度(ΔYb)、血细胞比容(Hct)与R2*(ΔR2*)的关系。将Hct正常的低氧大鼠(42.8%±2.33%；n=12)与轻度Hct降低(33.4%±1.88%；n=8)或中度Hct降低(27.14%±2.7%；n=10)大鼠的图像进行比较。三组ΔYb与ΔR2*均呈线性关系。然而，线性回归的斜率彼此之间存在统计学差异(P<；0.001)，回归直线的斜率与Hct成反比；即Hct正常的斜率小于轻度Hct降低的斜率，小于中度Hct降低的斜率。这些数据表明，对于任何给定的脑血氧饱和度降低，当血红蛋白浓度降低时，ΔR2*将具有较小的幅度；这些数据与现有的T2*加权磁共振成像中脱氧血红蛋白含量依赖效应的理论模型一致。
T2*-weighted gradient echo magnetic resonance images of rat brain were obtained dynamically during acute hypoxemic hypoxia to investigate the relations between changes in cerebral blood oxygen saturation(ΔYb), blood hematocrit (Hct), and R2* (ΔR2*). Images from hypoxemic rats with normal Hct (42.8% ± 2.33%; n = 12) were compared with those from hypoxemic rats with mild (33.4% ± 1.88%; n = 8) or moderate (27.14% ± 2.7%; n = 10) reduction of Hct. A linear relation between ΔYb and ΔR2* was obtained for all three groups. However, the slopes of the linear regressions were statistically different from one another (P< 0.001), with the slopes of the regression lines increasing inversely with Hct; that is, the slope for normal Hct is less than the slope for mildly reduced Hct, which is less than the slope for moderately reduced Hct. These data suggest that for any given reduction in the oxygen saturation of cerebral blood, the ΔR2* will be of a lesser magnitude when the hemoglobin concentration is reduced; the data are consistent with existing theoretical models of deoxyhemoglobin content-dependent effects in T2*-weighted magnetic resonance imaging.