Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Italy.
Curr Med Chem. 2010;17(31):3684-700. doi: 10.2174/092986710793213823.
The role of MRI in the armory of diagnostic modalities for the medicine of the forthcoming years largely depends on how chemistry will provide advanced tools to meet the medical needs. This review aims at outlining the most innovative approaches that have been undertaken in the recent history of MRI contrast agents for tackling the challenges of sensitivity and specificity required by the new generation of contrast agents that should allow the visualization of pathological processes occurring on cellular and molecular scale (the so-called Molecular Imaging). Most of the classes of MRI agents clinically approved or currently under investigation in a preclinical phase exploit peculiar magnetic properties of metals. The conventional agents acting as T(1) or T(2)/T(2)* relaxation enhancers are primarily based on the paramagnetic or the superparamagnetic properties of Gd(III)-, Mn(II)- and iron oxides systems. Recently, there has been a renewed interest towards paramagnetic lanthanide complexes with an anisotropic electronic configuration thanks to their ability to induce strong effect on the resonance frequency of the spins dipolarly coupled with them. Such systems, formerly mainly used as shift reagents, have now attracted much attention in the emerging field of Chemical Exchange Saturation Transfer (CEST) MRI agents.
在未来几年的医学诊断手段中，MRI 的作用在很大程度上取决于化学将提供何种先进工具来满足新代造影剂的灵敏度和特异性要求。本综述旨在概述最近在 MRI 造影剂领域所采用的最具创新性的方法，以应对新一代造影剂所要求的挑战，这些造影剂应能实现对细胞和分子水平上发生的病理过程的可视化（所谓的分子成像）。大多数在临床上批准或目前处于临床前阶段研究的 MRI 造影剂类别都利用了金属的特殊磁性质。作为 T(1)或 T(2)/T(2)*弛豫增强剂的常规造影剂主要基于 Gd(III)-、Mn(II)-和氧化铁系统的顺磁或超顺磁性。最近，由于具有诱导与其偶极子耦合的自旋共振频率的强烈影响的能力，各向异性电子构型的顺磁镧系配合物重新引起了人们的兴趣。这些系统以前主要用作位移试剂，现在在新兴的化学交换饱和转移（CEST）MRI 造影剂领域引起了广泛关注。
