Design of Gd(III)-Based Magnetic Resonance Imaging Contrast Agents: Static and Transient Zero-Field Splitting Contributions to the Electronic Relaxation and Their Impact on Relaxivity
作者:Meriem Benmelouka、Alain Borel、Loick Moriggi、Lothar Helm、André E Merbach
DOI:10.1021/jp0633289
日期:2007.2.1
electron paramagnetic resonance (EPR) study on low molecular weight gadolinium(III) complexes for potential use as magnetic resonance imaging (MRI) contrast agents has been performed. Peak-to-peak linewidths Delta Hpp and central magnetic fields have been analyzed within the Redfield approximation taking into account the static zero-field splitting (ZFS) up to the sixth order and the transient ZFS up to the
对低分子量g(III)配合物的多频(9.4-325 GHz)和变温(276-320 K)电子顺磁共振(EPR)进行了研究,潜在地将其用作磁共振成像(MRI)造影剂执行。已在Redfield近似中分析了峰到峰的线宽Delta Hpp和中心磁场,其中考虑了直到第六阶的静态零场分裂(ZFS)和高达第二阶的瞬态ZFS。纵向电子弛豫主要由低磁场(B <0.3 T)下的静态ZFS贡献和高磁场(B> 1.5 T)上的瞬态ZFS决定。静态ZFS显然取决于螯合配体的性质,而瞬态ZFS则不然。对于研究的相对快速旋转的分子,水质子弛豫性主要受快速旋转的限制,而电子弛豫仅在低于30 MHz的频率下具有显着影响。从我们的EPR结果中,我们可以得出结论,电子弛豫不会影响基于Gd(III)的MRI造影剂的效率,该造影剂被设计用于在非常高的磁场(B> 3T)下进行研究。