Abstract

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.

Fig. 1 Overview of heterogeneous stress mapping using reverberant shear wave fields. a Schematic of wave-based mechanical imaging: tissue under compression becomes stiffer, and conventional shear wave elastography detects this via propagating waves along controlled excitation paths. b Under uniaxial stress in a Mooney–Rivlin hyperelastic material, shear waves exhibit direction- and polarization-dependent velocities. SV (shear vertical) and SH (shear horizontal) components show angular variation in speed depending on the propagation direction n relative to the stress axis a. c In the reverberant regime, the shear wave fields wavefield is modeled as a superposition of SV and SH components traveling in multiple directions, forming the basis of the traveling wave expansion (TWE) model. d Complex reverberant shear wavefields encode spatially varying stress-induced anisotropy. e A set of physics‑based operators is derived from shear wave behavior under stress and the traveling wave expansion model, and their application within a 4×4×4 kernel (as in d) yields a local stress estimate. f A spatial map of heterogeneous stress is reconstructed by sliding the kernel throughout the reverberant shear wave field.

Fig. 2  Intracranial pressure measurements across different populations. a Typical cortical surface pressure distribution patterns are shown in transverse (Tra), sagittal (Sag) and coronal (Cor) views for a patient with normal pressure hydrocephalus (NPH), a healthy young group, a healthy elderly group and an elderly mild cognitive impairment (MCI) group. b Box plots summarize the cortical surface pressure distributions for NPH patients, healthy young adults, healthy elderly adults, and elderly MCI patients. The box range covers from 25% to 75%, with statistical significance marked by asterisks (*: p <0.05, **: p<0.01).

https://doi.org/10.1038/s41467-026-76509-0