Hardy P A, Henkelman R M
Department of Medical Biophysics, University of Toronto, Canada.
Magn Reson Imaging. 1989 May-Jun;7(3):265-75. doi: 10.1016/0730-725x(89)90549-3.
Magnetic particulates have been shown to be powerful transverse relaxation enhancers and are under consideration as an MR contrast agent for the detection of liver and spleen lesions. This work describes the magnetic properties of a commercially available magnetic particulate and a Monte Carlo simulation of the effect of these particles on the transverse relaxation rates of water protons for spin-echo experiments. From the simultations, empirical relations were developed to describe the dependence of the enhancement of particle size, and concentration as well as the diffusion constant of water and the pulse spacing of a Carr-Purcell-Meiboom-Gill pulse sequence used to measure the transverse relaxation time. The simulations are shown to agree with measurements of relaxation rates in agar samples containing the magnetic particulates.
磁性微粒已被证明是强大的横向弛豫增强剂，正在考虑将其作为检测肝脏和脾脏病变的磁共振造影剂。这项工作描述了一种市售磁性微粒的磁性，以及对这些微粒在自旋回波实验中对水质子横向弛豫率影响的蒙特卡罗模拟。通过模拟，建立了经验关系来描述增强与粒径、浓度、水的扩散常数以及用于测量横向弛豫时间的Carr-Purcell-Meiboom-Gill脉冲序列的脉冲间隔之间的依赖关系。模拟结果与含有磁性微粒的琼脂样品的弛豫率测量结果一致。
