Magnetic resonance imaging (MRI) is recognized as the most powerful clinical imaging modality due to its ability to produce detailed three-dimensional anatomical images and high spatial resolution in a non-invasive manner without the use of harmful radioactive nuclides or ionizing radiation. Conventional small molecule contrast agents (CAs) for MRI, such as paramagnetic transition metal ion chelates or iron oxide nanoparticles, are limited by lower relaxivity, shorter blood circulation time and their potential toxic effects. Functional polymers capable of being detected by MRI have therefore become attractive, offering the unique advantage of pre-design due to their chemical flexibility, structural diversity, and tailoring of properties. Reversible addition-fragmentation chain-transfer (RAFT) polymerization is a powerful tool that not only enables the precise formation of macromolecular building blocks with complex structures and functions, but also provides a direct method for preparation of polymeric nanoparticles with multiple morphologies suitable for biomedical applications. In addition, when combining RAFT polymers with inorganic/metallic complex nanocomposites, the polymer provides the ability to encapsulate therapeutic molecules, thereby combining diagnostic and therapeutic functions in what is known as a theranostic nanomedicine. In this review, we highlight recent advances in the development of multifunctional polymers as MRI CAs designed and prepared by RAFT polymerization and their performance in diagnosis and treatment of disease. In addition, the review will address the challenges and future opportunities for RAFT-mediated MRI-based theranostics in guiding the treatment of diseases including malignant tumors.

磁共振成像 (MRI) 被认为是最强大的临床成像方式，因为它能够以非侵入性方式生成详细的三维解剖图像和高空间分辨率，且无需使用有害的放射性核素或电离辐射。用于 MRI 的传统小分子造影剂 (CA)，例如顺磁性过渡金属离子螯合物或氧化铁纳米粒子，受到弛豫度较低、血液循环时间较短及其潜在毒性作用的限制。因此，能够通过 MRI 检测的功能聚合物变得有吸引力，由于其化学灵活性、结构多样性和性能定制，提供了预先设计的独特优势。可逆加成断裂链转移（RAFT）聚合是一种强大的工具，不仅能够精确形成具有复杂结构和功能的大分子构件，而且为制备适合生物医学应用的多种形貌聚合物纳米粒子提供了直接方法。此外，当将 RAFT 聚合物与无机/金属复合纳米复合材料结合时，该聚合物提供了封装治疗分子的能力，从而将诊断和治疗功能结合在所谓的治疗诊断纳米药物中。在这篇综述中，我们重点介绍了通过 RAFT 聚合设计和制备的多功能聚合物作为 MRI CA 的开发最新进展及其在疾病诊断和治疗中的性能。此外，