X-ray darkfield chest imaging for the detection and quantification of emphysema in patients with chronic obstructive pulmonary disease

Technical University of Munich (TUM)

Image: Dark-field X-ray method visualizes early changes in alveolar structure due to lung disease COPD. Franz Pfeiffer, professor of biomedical physics, hopes this will significantly improve the early detection of lung diseases. see more 

For the first time, researchers at the Technical University of Munich (TUM) have successfully used a new X-ray method to diagnose patients' breathing. Dark-field X-rays visualize early changes in alveolar structure caused by COPD, a lung disease, and require only one fifty-fifth of the radiation dose commonly used in X-ray computed tomography. This allows a wide range of medical applications in the early detection of respiratory diseases and follow-up treatment.

There are millions of severe respiratory diseases that limit the quality of life. Every year, more than 4 million people worldwide die from severe respiratory diseases. Partial destruction of the alveoli and excessive lung inflation (emphysema) are typical features of life-threatening chronic obstructive pulmonary disease (COPD).

However, the subtle differences between healthy and diseased tissues are almost invisible on traditional chest X-rays. Only the 3D computer tomography method can be used to obtain detailed diagnostic information. In this method, the computer combines many individual images. So far, there has not been a fast and cost-effective option for early detection and follow-up inspections using low radiation exposure like ordinary chest X-rays.

A procedure developed by the Technical University of Munich can now fill this gap: dark-field chest X-ray. In the latest issue of The Lancet Digital Health, a research team led by Franz Pfeiffer, professor of biomedical physics and director of the Munich Institute of Biomedical Engineering, now presents the results of a preliminary clinical patient study that uses Developed a new X-ray technique for the diagnosis of COPD, a lung disease.

Key: the wave characteristics of X-rays

Traditional X-ray imaging is based on the attenuation of X-rays as they pass through the tissue. On the other hand, dark field technology uses the volatility of X-ray light, which is not available in traditional X-ray imaging.

Therefore, the new method uses the physical phenomenon of scattering in a manner similar to the long-known principle of visible light dark field microscopy. This allows visualization of the structure of most transparent objects. These structures appear in the microscope as bright images on a dark background, hence the name of the method.

"For the interface between air and tissue, the X-ray dark field signal is particularly strong," Pfeiffer points out. "This allows the dark-field X-ray image of the lungs to clearly distinguish between intact alveoli, that is, those filled with air, and areas where there are less complete alveoli."

In addition, the radiation dose involved in examinations using dark-field chest X-ray technology is much lower compared to the currently used computed tomography scans. This is because in contrast to the large number of personal images taken from different directions required for computed tomography, dark-field chest X-rays only require one exposure for each patient.

"We expect that radiation exposure will be reduced by a factor of 50," Franz Pfeiffer said. In addition, the first clinical results have confirmed that dark-field X-rays provide additional image information about the underlying microstructure of the lung.

“In view of the close connection between alveolar structure and lung function status, this ability is of great significance to pulmonary medicine,” explained Dr. Alexander Fingerle, a senior physician at the Klinikum rechts der Isar Department of Diagnostic and Interventional Radiology at TUM University Hospital. “In the future, Dark-field X-rays can help improve early detection of COPD and other respiratory diseases."

Better X-ray equipment for early detection in the future

Franz Pfeiffer hopes that these preliminary clinical results for patients will accelerate the execution of further clinical studies and the development of marketable devices using darkfield methods.

"Darkfield chest X-rays currently give us the opportunity to significantly improve the early detection of lung diseases, while implementing it on a broader basis than before," Pfeiffer points out.

Since dark-field imaging is not limited to COPD, it is very interesting for further translational studies of other lung pathologies (such as pulmonary fibrosis, pneumothorax, lung cancer, and pneumonia (including COVID-19)).

The research was supported by the European Research Council and Philips Medical Systems DMC Ltd. as part of the advanced funding. Co-author Thomas Köhler (Philips) is a Rudolph Diesel Industry Researcher at the TUM Institute for Advanced Study (TUM IAS), which itself is partly funded by the German Federal and State Government’s Excellence Program and the EU’s Marie Curie COFUND Program. Some of these studies It was carried out in cooperation with the Karlsruhe Nano-Microfacility (KNMF), the Helmholtz research infrastructure of the Karlsruhe Institute of Technology (KIT).

X-ray darkfield chest imaging to detect and quantify emphysema in patients with chronic obstructive pulmonary disease: a diagnostic accuracy study

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Andreas Battenberg Technical University of Munich (TUM) battenberg@zv.tum.de Office: 49-892-891-0510

Technical University of Munich (TUM)

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Copyright © 2021 American Association for the Advancement of Science (AAAS)