Abstract: Benefiting from their unique magnetic properties and good biosafety, ferrite nanomaterials are widely used in magnetic resonance imaging (MRI) clinical diagnostics and imaging studies. Quasi-paramagnetic ultrasmall ferrite nanoparticles with the size of less than 5 nm possess high T₁ contrast power and rapid renal clearance, which can help to overcome the drawbacks of traditional gadolinium-based contrast agents with improved safety and efficacy, and are likely to become the next-generation MRI contrast agents. This review summarizes the research progress and challenges of clinical translation of quasi-paramagnetic ferrite nanoprobes as MRI T₁ contrast agents in terms of safety, T₁-T₂ signal enhancement properties, multimodal imaging and integration of diagnosis and treatment.