水-有机溶剂混溶体系弛豫率的变化：金属离子之外的隐藏作用力

Changes in the relaxivity of water-organic solvent miscible systems: Hidden forces beyond metal ions.

作者信息

Wu Shiman, Wang Chaochao, Xia Junjie, Sun Dijia, Wu Pu-Yeh, Wu Yue, Yao Zhenwei, Ren Yan, Zhang Qi

机构信息

Department of Radiology, Huashan hospital, Fudan University, Shanghai, P.R. China.

Department of Medical Ultrasound, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Tongji University Cancer Center, Shanghai, P.R. China.

出版信息

Med Phys. 2025 Feb;52(2):1108-1118. doi: 10.1002/mp.17471. Epub 2024 Oct 29.

DOI:10.1002/mp.17471

PMID:39470256

Abstract

BACKGROUND

The relaxivity of magnetic resonance imaging (MRI) contrast agents is primarily attributed to metal ions such as gadolinium (Gd) and iron. However, the impact of organic solutes on relaxivity, particularly through alterations in water molecule dynamics, has not been thoroughly investigated. This research was aimed to explore how organic solutes affect the relaxivities of water and Gd-based contrast agents (GBCAs), potentially revealing new aspects for the development of contrast agents.

PURPOSE

To investigate the effects of different proportions of water-soluble organic solvents mixed with pure water and GBCA on T and T relaxivities.

METHODS

Ethanol, dimethyl sulfoxide (DMSO), 1,4-dioxane, glycerin, ethylene glycol, diethylene glycol, polyethylene glycol (PEG) 200, and PEG 400 were mixed with ultrapure water in various ratios (100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 0:100). GBCA was added to these mixtures at a concentration of 0.05 mmol/L. The mixtures underwent T and T mapping scans using a 3.0 Tesla MRI machine, and the relaxivities R (1/T) and R (1/T) were calculated and compared.

RESULTS

The relaxivity R of ethanol, 1,4-dioxane, and DMSO mixtures with water or GBCA, as well as R of DMSO mixtures with GBCA, initially increased and then decreased. Conversely, R and R increased significantly with higher proportions of diethylene glycol, PEG 200, and glycerin in the mixtures with GBCA. The increase in relaxivity R was correlated with greater viscosity. When the proportion of DMSO and diethylene glycol exceeded 20%, minimal variability in R was observed as the water content decreased.

CONCLUSIONS

Adding organic solvents to water and paramagnetic relaxation reagents could alter T and T relaxivities, suggesting potential new directions for modifying current contrast agents. Additionally, increasing the viscosity of the contrast agent was found to enhance the relaxivity.

摘要

背景

磁共振成像（MRI）造影剂的弛豫率主要归因于钆（Gd）和铁等金属离子。然而，有机溶质对弛豫率的影响，特别是通过改变水分子动力学的影响，尚未得到充分研究。本研究旨在探讨有机溶质如何影响水和基于钆的造影剂（GBCA）的弛豫率，可能为造影剂的开发揭示新的方面。

目的

研究不同比例的水溶性有机溶剂与纯水和GBCA混合对T1和T2弛豫率的影响。

方法

将乙醇、二甲基亚砜（DMSO）、1,4-二氧六环、甘油、乙二醇、二甘醇、聚乙二醇（PEG）200和PEG 400与超纯水按不同比例（100:0、90:10、80:20、70:30、60:40、50:50、40:60、30:70、20:80、10:90、0:100）混合。将GBCA以0.05 mmol/L的浓度添加到这些混合物中。使用3.0特斯拉MRI机器对混合物进行T1和T2映射扫描，并计算和比较弛豫率R1（1/T1）和R2（1/T2）。

结果

乙醇、1,4-二氧六环和DMSO与水或GBCA的混合物的弛豫率R1，以及DMSO与GBCA的混合物的R2，最初升高然后降低。相反，在与GBCA的混合物中，随着二甘醇、PEG 200和甘油比例的增加，R1和R2显著增加。弛豫率R1的增加与更大的粘度相关。当DMSO和二甘醇的比例超过20%时，随着含水量降低，R1的变化最小。