London, Nov 5 (IANS): Using high-energy X-rays, scientists have found how Covid-19 damages even the smallest blood vessels in human lungs.

Scientists from University College London and the European Synchrotron Research Facility (ESRF) used a new revolutionary imaging technology called Hierarchical Phase-Contrast Tomography (HiP-CT), to scan donated human organs, including lungs from a Covid-19 donor.

Using HiP-CT, the research team saw how severe Covid-19 infection 'shunts' blood between the two separate systems -- the capillaries which oxygenate the blood and those which feed the lung tissue itself.

Such cross-linking stops the patient's blood from being properly oxygenated, which was previously hypothesised but not proven, said the team in the paper published in the journal Nature Methods.

"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, Germany.

The HiP-CT technique provides the brightest source of X-rays in the world at 100 billion times brighter than a hospital X-ray.

Due to this intense brilliance, researchers can view blood vessels five microns in diametre (a tenth of the diametre of a hair) in an intact human lung, whereas a clinical CT scan only resolves blood vessels that are about 100 times larger, around 1mm in diametre.

The UCL-led team is now planning to use HiP-CT to produce a Human Organ Atlas. This will display six donated control organs: brain, lung, heart, two kidneys and a spleen, and the lung of a patient who died of Covid-19. There will also be a control lung biopsy and a Covid-19 lung biopsy. The Atlas will be available online for surgeons, clinicians and the interested public.

The researchers believe that the scale-bridging imaging from whole organ down to cellular level could provide additional insights into many diseases such as cancer or Alzheimer's Disease.