Surgical Tribune International

New method to improve quality control of donor organs

By University of Graz
September 02, 2020

GRAZ, Austria: Of 790 patients currently waiting for a donor organ in Austria, approximately three quarters need a new kidney, followed by patients in need of a liver. Particularly in the latter case, the organ quality of the available liver decreases with increasing donor age. To enable a faster and more comprehensive assessment of the organ quality needed for transplantation, researchers at the University of Graz and the Medical University of Graz are working together to develop a new imaging process, using the liver as test model.

“Our method aims not only to increase the total number of successful transplantations, but also to simplify the identification of initially damaged organs. An optimised selection process prior to transplantation significantly reduces subsequent interventions,” explained the project leaders Philipp Stiegler associate professor at the division of transplantation surgery at the Medical University of Graz and Dr Robert Nuster from the institute of physics at the University of Graz.

The best of two worlds

Conventional methods of quality assessment, such as laboratory parameters or biopsies, are time-consuming and provide only limited and localised snapshots. Owing to the high perfusion, it is difficult to assess the condition of the liver without using invasive methods. The team combines the advantages of two state of the art imaging techniques: optical imaging and ultrasound imaging.

“Combining both increases contrast and resolution,” said Nuster. This method mainly uses short light pulses with diffuse propagation in biological tissue, which are absorbed by the blood vessels. This leads to a rapid, localized heat generation, which generates a broad spectrum of ultrasonic waves that are subsequently detected outside the organs. “Absorbing vessels function as sources of sonic emissions, whose magnitude and position we are able to reconstruct. This enables us to create high-resolution, high-contrast images, obtaining information about deep regions of the organ,” explained Nuster.

“If we are able to discover certain pathogenic processes in time and get them under control, we may be able to make these previously excluded organs fit for use after all”
— Philipp Stiegler, Medical University of Graz

The research team is confident that this new combination will provide far more informative images than was previously possible – for example about the condition of the smallest blood vessels or the spatial distribution of oxygen saturation. “These data ideally complement existing methods of assessment thereby shortening the evaluation process,” confirmed Stiegler. In the future, the research team will aim to increase the precision of their method to the extent that donor organs that were previously classified as unsuitable for transplantation, owing to minimal defects, could even be saved. “If we are able to discover certain pathogenic processes in time and get them under control, we may be able to make these previously excluded organs fit for use after all,” added Stiegler.

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