Acute subarachnoid hemorrhage: in vitro comparison of magnetic resonance and computed tomography.
Acute subarachnoid hemorrhage: in vitro comparison of magnetic resonance and computed tomography.
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急性蛛网膜下腔出血：磁共振和计算机断层扫描的体外比较。
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
R. N. Bryan
中科院分区：
文献类型：
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作者：
D. Chakeres;R. N. Bryan
对模拟急性蛛网膜下腔出血的CT衰减值和MR信号强度进行了系统比较。体外MR和CT测量(T1、T2和Hounsfield单位)由正常人脑脊液(CSF)和正常肝素化血液的混合物组成，体积从0%到100%不等。混合物在有机玻璃体模和西门子DR3 CT扫描仪的衰减测量(Hounsfield单位)中测量，并在贝勒·布鲁克仪器质子扫描仪(6-MHz)中使用反转恢复和自旋回波脉冲序列技术测量T1和T2计算的驰豫时间。用Praxis II(10.7 MHz永磁体)非显像仪独立测量脑脊液/血液混合物的松弛时间作为对照。层状混合物最致密部分的Hounsfield测量结果显示，随着出血量的增加(0%血，0H；100%血，66H)，Hounsfield值呈非线性增加。混合液的T1时间随出血量的增加而减小，100%脑脊液和100%血液的T1时间分别为2200~500毫秒。T1松弛时间的倒数与血液百分比成正比。混合物的T2数据在性质上与T1弛豫时间相似，只是在血液浓度较高时T2时间较短。结论：MRI根据松弛时间区分不同的血液/脑脊液混合物优于以Hounsfield单位为基础的CT。CT仍然具有成像优势，因为高浓度出血与正常脑明显不同，而浓缩的急性蛛网膜下腔血的松弛时间与正常脑相似，在MRI上几乎等信号。
The computed tomographic (CT) attenuation values and magnetic resonance (MR) signal intensities of simulated acute subarachnoid hemorrhage were compared systematically. In vitro MR and CT measurements (T1, T2, and Hounsfield units) were made of mixtures of normal human cerebrospinal fluid (CSF) and normal heparinized blood, ranging from 0% to 100% by volume. The mixtures were measured in a plexiglass phantom with a Siemens DR3 CT scanner for attenuation measurements (Hounsfield units) and in the Baylor Bruker Instruments Proton Scanner (6-MHz) using inversion-recovery and spin-echo pulse sequence techniques for T1- and T2-calculated relaxation times. A PRAXIS II (10.7 MHz permanent magnet) nonimaging unit was used to measure the relaxation times of the CSF/blood mixtures independently for comparison. The Hounsfield measurements of the densest parts of the layered mixtures showed increasing values with increasing amounts of hemorrhage (0% blood, 0 H; 100% blood, 66 H) in a nonlinear pattern. The T1 times of the mixtures decreased with increasing amounts of blood, ranging from 2200 msec to 500 msec for 100% CSF and 100% blood, respectively. The inverse of the T1 relaxation times was proportional to the percentage of blood. The T2 data for the mixtures were similar in character to the T1 relaxation times, except for shorter T2 times at high concentrations of blood. It was concluded the MRI distinguishes varying blood/CSF mixtures on the basis of relaxation times better than does CT on the basis of Hounsfield units. CT still has an imaging advantage, since high-concentration hemorrhage is clearly different from normal brain, while concentrated acute subarachnoid blood has relaxation times similar to normal brain and is nearly isointense on MRI.