Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
Department of Nuclear Medicine, China-Japan Union Hospital of Jilin University, 126 Xiantai Street, ErDao District, Changchun 13033, China.
Theranostics. 2018 Apr 3;8(9):2521-2548. doi: 10.7150/thno.23789. eCollection 2018.
Magnetic resonance imaging (MRI) is one of the most widely used diagnostic tools in the clinic. To improve imaging quality, MRI contrast agents, which can modulate local T and T relaxation times, are often injected prior to or during MRI scans. However, clinically used contrast agents, including Gd-based chelates and iron oxide nanoparticles (IONPs), afford mediocre contrast abilities. To address this issue, there has been extensive research on developing alternative MRI contrast agents with superior r and r relaxivities. These efforts are facilitated by the fast progress in nanotechnology, which allows for preparation of magnetic nanoparticles (NPs) with varied size, shape, crystallinity, and composition. Studies suggest that surface coatings can also largely affect T and T relaxations and can be tailored in favor of a high r or r. However, the surface impact of NPs has been less emphasized. Herein, we review recent progress on developing NP-based T and T contrast agents, with a focus on the surface impact.
磁共振成像（MRI）是临床中应用最广泛的诊断工具之一。为了提高成像质量，通常在 MRI 扫描前或扫描过程中注射磁共振对比剂，其可以调节局部 T1 和 T2 弛豫时间。然而，临床中使用的对比剂，包括基于 Gd 的螯合物和氧化铁纳米粒子（IONPs），其对比增强能力一般。为了解决这个问题，人们广泛研究开发具有更高 r1 和 r2 弛豫率的替代 MRI 对比剂。纳米技术的快速发展为制备具有不同尺寸、形状、结晶度和组成的磁性纳米粒子（NPs）提供了便利。研究表明，表面涂层也可以在很大程度上影响 T1 和 T2 弛豫，并可以根据高 r1 或 r2 进行定制。然而，NPs 的表面影响却较少受到关注。本文综述了基于 NP 的 T1 和 T2 对比剂的最新研究进展，重点关注表面影响。
