Matwiyoff N A, Gasparovic C, Mazurchuk R, Matwiyoff G
Center for Non-Invasive Diagnosis, University of New Mexico School of Medicine, Albuquerque 87131.
Magn Reson Imaging. 1990;8(3):295-301. doi: 10.1016/0730-725x(90)90102-8.
The 300 MHz (7 T) water proton resonances of suspensions of red blood cells containing paramagnetic deoxyhemoglobin or methemoglobin can be resolved into two broad lines assignable to intra- and extracellular water which undergoes rapid T2 relaxation by diffusion in magnetic field gradients induced by the intracellular paramagnets. The width of the resolved lines allowed an estimate of the maximum contribution that diffusion makes to T2 relaxation at 7 T. The dependence of the diffusion contribution on the square of the strength of the static magnetic field suggest that diffusion makes a small contribution to water proton T2 relaxation at 1.5 T compared to 7 T, and a negligible one at 0.5 T in early and intermediate hematomas containing deoxyhemoglobin or methemoglobin in intact red blood cells. At the lower field strengths, water proton T2 relaxation is apparently dominated by the rapid chemical exchange (mean lifetime tau = 10 msec) between the intra- and extracellular environments.
含有顺磁性脱氧血红蛋白或高铁血红蛋白的红细胞悬液的300兆赫（7特斯拉）水质子共振可分解为两条宽线，分别对应细胞内和细胞外水，它们在细胞内顺磁体诱导的磁场梯度中通过扩散经历快速的T2弛豫。分辨线的宽度使得能够估计扩散对7特斯拉下T2弛豫的最大贡献。扩散贡献对静磁场强度平方的依赖性表明，与7特斯拉相比，扩散对1.5特斯拉下水质子T2弛豫的贡献较小，而在含有完整红细胞中脱氧血红蛋白或高铁血红蛋白的早期和中期血肿中，扩散对0.5特斯拉下水质子T2弛豫的贡献可忽略不计。在较低场强下，水质子T2弛豫显然由细胞内和细胞外环境之间的快速化学交换（平均寿命τ = 10毫秒）主导。
