磁共振钆造影剂纳米制剂的研究进展

Progress in research of nanomedicine-based gadolinium contrast agents for magnetic resonance imaging

磁共振成像作为一种有效的非侵入性的成像技术,具有较高的分辨率,在一定程度上可以显示生理学和解剖学细节,且没有电离辐射。但是磁共振成像的分辨率在某些情况下还不能满足临床需要,所以在某些磁共振检查中需要使用磁共振造影剂以达到增强造影的目的。据文献报道大约30%的磁共振检查需要使用造影剂。钆螯合物是临床上常用的一种磁共振造影剂。传统的钆造影剂缺乏靶向性、半衰期较短、弛豫效能较低且大量使用可导致毒副作用等。目前,已有较多文献报道将钆造影剂制备成纳米制剂后可以使其具有靶向性,延长血中滞留时间,提高弛豫效能,减少总剂量从而降低毒副作用等。钆造影剂纳米制剂主要包括:脂质体、树形分子、胶束、纳米粒、碳纳米管和富勒烯等。

Magnetic resonance imaging （MRI） is a powerful and non-invasive imaging technique that pro- vides very high resolution. It shows both physiological and anatomical details to a certain extent and has no ionizing radiation. However, its resolution cannot meet the clinical needs in some eases, so contrast agents should be used to achieve higher resolution MR images. Data show that about 30% of MRI exams need the use of contrast agents. Gadolinium chelates is one of the most common clinical MRI contrast agents. Traditional gadolinium contrast agents lack specific targeting property, have short half-life and low relaxivity, and cause side effects when large doses of them are used. Recently, the field of nanomedicine-based contrast agents holds great promise for overcoming many traditional hurdles of contrast agents including specific targeting property, half-life, relaxivity, and toxicities. These nanomedicine-based contrast agents mainly include liposomes, dendrimers, micelles, nanoparticles, nanotubes and fullerenes.