Bass J, Sostman H D, Boyko O, Koepke J A
School of Medicine, Duke University Medical Center, Durham, North Carolina 27710.
Invest Radiol. 1990 Nov;25(11):1232-7. doi: 10.1097/00004424-199011000-00015.
The magnetic resonance imaging (MRI) characteristics of hemorrhage and clotted blood change with age. The effects of methemoglobin and cell membrane lysis, factors which in part may underlie this evolution of imaging characteristics, were studied using clotted and heparinized dog blood at various methemoglobin concentrations. Cell lysis did not alter the longitudinal relaxation rate (1/T1) in clotted or unclotted samples. Membrane lysis altered significantly the transverse relaxation rate (1/T2) in both clotted and unclotted samples. Lysed samples of oxygenated blood at 0% methemoglobin had significantly higher T2 values than intact samples. At 0% methemoglobin, clotted samples had slightly but significantly shorter relaxation times than unclotted samples. Within the samples studied, large changes in the state of oxygenation and methemoglobin content were observed in less than 24 h. Such changes necessitate frequent monitoring of these parameters if serial studies are to be done.
出血和凝血块的磁共振成像（MRI）特征会随年龄变化。使用不同高铁血红蛋白浓度的凝血和肝素化犬血，研究了高铁血红蛋白和细胞膜溶解的影响，这两个因素可能部分解释了成像特征的这种演变。细胞溶解并未改变凝血或未凝血样本的纵向弛豫率（1/T1）。膜溶解显著改变了凝血和未凝血样本的横向弛豫率（1/T2）。高铁血红蛋白含量为0%的含氧血液的裂解样本的T2值显著高于完整样本。在高铁血红蛋白含量为0%时，凝血样本的弛豫时间略短但显著短于未凝血样本。在所研究的样本中，在不到24小时内观察到氧合状态和高铁血红蛋白含量的巨大变化。如果要进行系列研究，这些变化需要对这些参数进行频繁监测。
