Chinese scientists develop non-invasive method for long-term brain imaging in mice

BEIJING -- Chinese researchers have created a new imaging system that allows for long-term, high-resolution imaging of the mouse brain in a non-invasive manner, penetrating the intact scalp and skull without the use of contrast agents, China Science Daily reported on Tuesday.

Non-invasive long-term brain imaging is essential for understanding brain function and investigating the pathological mechanisms of brain disorders. However, imaging through the scalp and skull of mice presents significant challenges due to light refraction, strong optical scattering and acoustic attenuation caused by these complex structures.

A research team from the Southern University of Science and Technology, located in Shenzhen in South China's Guangdong province, has developed an integrated photoacoustic imaging system named PACMes. This system achieves synergistic optimization across three key dimensions: near-infrared optical excitation, low-frequency acoustic detection and computational reconstruction.

This approach enables efficient penetration through the intact scalp and skull, reduces interference from light scattering, and ensures high-sensitivity, full-angle detection of photoacoustic signals.

It also effectively mitigates acoustic attenuation from biological tissues and suppresses background artifacts, resulting in isotropic high-resolution imaging across the entire field of view. These findings have been published in Science Advances.

Notably, the system operates without exogenous contrast agents and can image a 13-millimeter-diameter area, covering the entire mouse cerebral cortex, with a spatial resolution of 33 micrometers. It supports continuous monitoring for over five months, offering a powerful tool for longitudinal studies.

In a mouse model of mild ischemic stroke, the PACMes system enabled dynamic observation over more than five months. It captured the full trajectory of vascular changes in the infarct region. Moreover, the system non-invasively revealed the key pathological feature of new collateral circulation formation in the infarct area 72 hours after modeling, a crucial pathological feature that provides direct insight into post-stroke vascular repair mechanisms.

The technology represents an ideal platform for monitoring the chronic progression of brain diseases. It also holds promise for advancing research into a range of cerebrovascular disorders, including Alzheimer's disease and epilepsy, and may offer new avenues for studying disease mechanisms and evaluating therapeutic interventions.