HiP-CT provided a close-up of the lung lobe of a 54-year-old male COVID-19 victim. The image shows the airspaces in cyan, open blood vessels in red and blocked blood vessels in yellow. [Image courtesy of Paul Tafforeau, lead scientist at ESRF]
Their technique — called Hierarchical Phase-Contrast Tomography (HiP-CT) — relies on X-rays from the European Synchrotron Research Facility particle accelerator in Grenoble, France. Following its Extremely Brilliant Source upgrade (ESRF-EBS), European Synchrotron can produce X-rays 100 billion times brighter than a hospital X-ray. They’re the brightest X-rays in the world, according to the researchers.
The result is that researchers can view blood vessels that are five microns in diameter — a tenth of the diameter of a hair — in an intact, donated human lung. The tiny size is 100 times smaller than the 1 mm-diameter blood vessels that a typical clinical CT scan can capture.
“The ability to see organs across scales like this will really be revolutionary for medical imaging,” Claire Walsh of University College London Mechanical Engineering said in a November 2021 news release. (National Geographic recently featured the work.)
“As we start to link our HiP-CT images to clinical images through AI techniques, we will – for the first time – be able to highly accurately validate ambiguous findings in clinical images. For understanding human anatomy, this is also a very exciting technique; being able to see tiny organ structures in 3D in their correct spatial context is key to understanding how our bodies are structured and how they therefore function.”
Paul Tafforeau, the lead scientist at ESRF, described the work as a real breakthrough. “ESRF-EBS has allowed us to go from deciphering the secrets of fossils to seeing the human body as never before.”
For example, HiP-CT enabled researchers to see how severe Covid-19 infection “shunts” blood between the capillaries which oxygenate the blood and those which feed the lung tissue itself. Scientists had already hypothesized that such cross-linking occurred and prevented blood oxygenation. But until the HiP-CT images, they hadn’t proved it.
“By combining our molecular methods with the HiP-CT multiscale imaging in lungs affected by COVID-19 pneumonia, we gained a new understanding how shunting between blood vessels in a lung’s two vascular systems occurs in Covid-19 injured lungs, and the impact it has on oxygen levels in our circulatory system,” said Danny Jonigk, professor of Thoracic Pathology at Hannover Medical School in Germany.
