Noninvasive 3D mapping of tissue stress using reverberant shear wave.

Mechanical stress is a fundamental aspect of soft tissues that influences cellular behavior and tissue integrity, yet noninvasive imaging of stress in vivo remains a major challenge. Conventional magnetic resonance elastography (MRE) measures tissue stiffness but not stress. Employing a physics-informed model, we analyze reverberant shear wave fields recorded by MRE to capture the 3D mapping of tissue stress. By decomposing reverberant waves into anisotropic traveling wave components, we establish a direct relationship between wave speed, polarization, and local stress, without requiring wave direction knowledge. This method was validated with numerical simulations and phantom experiments. Applied to patients with meningiomas and pituitary adenomas, it generated high-resolution stress maps consistent with anatomy and physiology. Cortical stress measurements enabled intracranial pressure estimation, uncovering trends related to patient age and pathology. Our results demonstrate that noninvasive stress imaging provides a novel quantitative biomarker for mechanobiological research and suggests new possibilities for clinical applications.