磁共振成像造影剂在弛豫增强中扩散与交换作用的评估。

An evaluation of the contributions of diffusion and exchange in relaxation enhancement by MRI contrast agents.

作者信息

Gossuin Yves, Roch Alain, Muller Robert N, Gillis Pierre

机构信息

Biological Physics Department, University of Mons-Hainaut, Mons B-7000, Belgium.

出版信息

J Magn Reson. 2002 Sep-Oct;158(1-2):36-42. doi: 10.1016/s1090-7807(02)00057-5.

DOI:10.1016/s1090-7807(02)00057-5

PMID:12419669

Abstract

Magnetic compounds are known to enhance water proton relaxation, either by diffusion or by proton exchange. An experimental procedure to distinguish both mechanisms is proposed and validated by relaxation measurements made in water-methanol solutions of Dy(3+), Ni(2+), Gd(3+), Tempo, and AMI-25. The test discriminates according to the character of the transverse relaxation in water-methanol solutions: a mono-exponential decay corresponds to diffusion, while a bi-exponential decay indicates the contribution of a proton exchange. The study of ferritin and akaganeite particle solutions confirms the occurrence of a proton exchange between protons belonging to hydroxyl groups of the particle surface and free water protons.

摘要

已知磁性化合物可通过扩散或质子交换增强水质子弛豫。本文提出了一种区分这两种机制的实验方法，并通过在Dy(3+)、Ni(2+)、Gd(3+)、Tempo和AMI-25的水-甲醇溶液中进行的弛豫测量进行了验证。该测试根据水-甲醇溶液中横向弛豫的特征进行区分：单指数衰减对应于扩散，而双指数衰减表明存在质子交换。对铁蛋白和赤铁矿颗粒溶液的研究证实了颗粒表面羟基上的质子与游离水质子之间发生了质子交换。