In a first for X-ray imaging, Swedish researchers generated high-resolution three-dimensional images of the lungs of free-breathing mice, without using mechanical ventilation. The technique developed at the KTH Royal Institute of Technology could make it possible to conduct research on lung diseases without the risk of injuring mice through artificial respiration.
Report in communication physics, researchers have shown that propagation-based phase-contrast X-ray tomography can be used to study the tracheobronchial tree down to the terminal bronchioles – which are as thin as strands of human hair – in free-breathing mice . Additionally, they were able to do this with low doses of radiation, which allows for repeated imaging without harming the animals.
Mice are commonly used in lung disease research due to their similar respiratory system to that of humans. However, animals should be placed on ventilators that control their breathing, to avoid blurry images.
Our work shows that it is possible to completely avoid the use of ventilators, let the animals breathe on their own and obtain very sharp 2D and 3D X-ray images.”
Kian Shaker, Researcher, KTH Royal Institute of Technology
Noninvasive imaging of lung disease in animals will allow a better understanding of similar conditions in humans, Shaker says. The images are relevant because they visualize even the thinnest bronchial branches, measuring less than 0.1 mm in diameter in mice and ending in clusters of alveoli, he says.
The footprint of the imaging facility is also smaller than what is required for synchrotron facilities where high-resolution respiratory imaging of animals is typically performed.
Going forward, these images indicate what Shaker and his colleagues hope is also possible for imaging human lungs, where the smallest airways have diameters of less than 2mm and are invisible with the technology used in hospitals today. today.
The research was funded by the Knut and Alice Wallenberg Foundation.
KTH, Royal Institute of Technology
Shaker, K. et al. (2021) Phase-contrast x-ray tomography resolves terminal bronchioles in free-breathing mice. Communication physics. doi.org/10.1038/s42005-021-00760-8.