Optoacoustic brain imaging: A systematic review and field mapping

Optoacoustic (OA) imaging has emerged as a powerful hybrid modality for investigating brain structure and function by combining optical absorption contrast with ultrasonic detection. This approach enables high-resolution imaging beyond the optical diffusion limit while preserving the strong molecular sensitivity of optical methods, thereby providing a unique platform for mapping cerebral vasculature, hemodynamics, oxygen metabolism, and disease-specific labels across spatial scales ranging from microvascular networks to whole-brain volumes. Here we present a systematic review on OA brain imaging, including both technological advances and biomedical applications while also providing a quantitative overview of the evolving research landscape. Specifically, we map the development of the field by analyzing worldwide research activity, including the geographical distribution of contributing institutions, yearly publication trends. This analysis provides a comprehensive perspective on the state of the art and emerging research directions. We then summarize recent advances in OA microscopy and tomography dedicated to brain imaging and discuss emerging multimodal platforms integrating fluorescence imaging, electrophysiology, ultrasound, and magnetic resonance imaging to enable multiparametric interrogation of brain dynamics. Applications in animal models of major neurological disorders are reviewed, highlighting functional and molecular biomarkers of disease progression and therapy. Finally, we discuss key challenges facing the field, including spectral quantification, transcranial imaging, system standardization, and clinical translation. Overall, this review serves as a comprehensive reference for capturing the multi-scale trajectory of OA neuroimaging.