Brain–body interactions in systemic diseases: a survey from an imaging perspective

Many diseases are now recognized as systemic, involving extensive crosstalk between brain and body. Although existing reviews have elucidated the biochemical basis of these brain-body connections, their dynamic interactions remain largely unexplored by imaging approaches. To fill this gap, this review investigates brainbody axes from an imaging perspective across three research paradigms: (1) the impact of brain diseases on the body, including Alzheimer's disease, Parkinson's disease, psychiatric disorders, and cerebral small vessel disease; (2) the influence of body diseases on the brain, particularly those originating in the eye, heart, liver, and gut; and (3) the new frontier encompassing multi-organ data acquisition and integrative modeling methods for brain-body interactions. Spanning from biological hypotheses and inter-organ crosstalk to recent technical advances, this review not only summarizes the systemic manifestations of diseases across organs but also offers perspectives toward improved diagnostics and therapies. The integration of whole-body networks from an imaging perspective holds promise for advancing precision medicine and provides a new paradigm for investigating and diagnosing complex systemic diseases.