Multimodal MRI to elucidate cross-organ coupling mechanisms of the heart-brain axis

Cardiovascular and cerebrovascular diseases (CCVDs) are leading causes of mortality and disability worldwide, and their development is closely linked to bidirectional interactions between the heart and the brain. The heart-brain axis, a systemic framework that integrates neural, humoral, and inflammatory pathways, provides an important theoretical basis for understanding heart-brain comorbidities. With continuous advances in magnetic resonance imaging(MRI), research in this field has progressively shifted from the traditional single-organ diagnostic model to cross-organ and system-oriented strategies for prevention and management. Centered on cardiac magnetic resonance (CMR) and brain MRI, and complemented by quantitative, diffusion, functional, ultra-high-field, and metabolic imaging techniques, multimodal MRI has become a powerful tool for comprehensively characterizing myocardial remodeling, alterations in brain networks, and their coupling relationships. These techniques have been widely applied in studies of representative heart-brain comorbidities, including cardiac dysfunction associated with acute brain injury, cognitive impairment related to heart failure, and cardiovascular abnormalities associated with neurodegenerative diseases, such as Alzheimer's disease (AD). Such studies have not only revealed structural and functional alterations in the heart and brain but have also provided important insights into potential mechanisms, including autonomic imbalance, neuroendocrine activation, and inflammatory responses. However, current heart-brain axis research remains largely based on correlational analyses, whereas causal inference and characterization of dynamic mechanisms remain insufficient. In addition, significant challenges persist in multimodal data integration and clinical translation. Overall, MRI is driving heart-brain axis research from structural characterization toward mechanistic investigation. In the future, integrating imaging, physiological, and genetic information may enable early identification, risk stratification, and precision intervention for heart-brain comorbidities, thereby promoting a transition in medical practice from single-organ management to systemic prevention and treatment.