Measuring the structure of the lung is difficult; even lung scans cannot reliably detect changes in the alveoli, the smallest parts of the lung. And it is precisely there, in the deep tissue structure, that some lung diseases can be identified. Pulmonary emphysema is one of them.
The Airspace Dimension Assessment (AiDA) measurement method can provide more answers about the smallest tissue structures in the lung. The method has now been applied to over 800 study participants and compared with established techniques such as lung X-ray, lung function measurements and magnetic resonance imaging (MRI) with hyperpolarised gas.
Madeleine Petersson Sjögren, one of the researchers who studied and evaluated the method, has recently presented her results in a thesis in aerosol technology. She says:
“Our results show that the method can be used to identify pathological changes in the lung. The examination is fast and provides information that, according to our research, is consistent with more advanced methods for measuring the structure of the lung.”
The amount of trapped particles tells us about the tissue structure of the lung
The method is based on the knowledge that nanoparticles move in a certain way in air, and that the tissue structure of a healthy and diseased lung is different.
“By breathing in a low concentration of nanoparticles and measuring how many particles get stuck, we can calculate distances in the lungs, which is a measure of the size of the alveoli. The distances can tell us whether there are pathological changes or not,” says Madeleine Petersson Sjögren.
In a healthy lung, the alveoli are small, well-defined and with short distances between the tissue parts. Thus, there are many surfaces for the particles to adhere to, which means that few particles travel with the exhaled air. In a diseased lung, it’s the other way around:
“If you have emphysema, the alveoli break down and you have larger cavities in the lung. There are fewer surfaces for inhaled particles to adhere to, and more particles travel with the exhaled air.”
