Insights into Non‐Metallic Magnetic Resonance Imaging Contrast Agents: Advances and Perspectives

Abstract Traditional metal‐based magnetic resonance imaging contrast agents (MRI CAs), such as gadolinium, iron, and manganese, have made significant advancements in diagnosing major diseases. However, their potential toxicity due to long‐term accumulation in the brain and bones raises safety concerns. In contrast, non‐metallic MRI CAs, which can produce a nuclear magnetic resonance effect, show great promise in MRI applications due to their adaptable structure and function, good biocompatibility, and excellent biodegradability. Nevertheless, the development of non‐metallic MRI CAs is slow due to the inherent low magnetic sensitivity of organic compounds, their rapid metabolism, and susceptibility to reduction. Designing effective multifunctional organic compounds for high‐sensitivity MRI remains a challenge. In this discussion, the mechanisms of various non‐metallic MRI CAs are explored and an overview of their current status, highlighting both their advantages and potential drawbacks, is provided. The key strategies for creating high‐performance MRI CAs are summarized and how different synthetic approaches affect the performance of non‐metallic MRI Cas is evaluated. Last, the challenges and future prospects for these promising non‐metallic MRI CAs are addressed.