COPD affects more than 200 million people, causing three million deaths yearly. Almost 90% of COPD deaths occur in low- and middle-income countries. Currently, COPD is diagnosed with pulmonary function tests, which are insensitive to early emphysema. Early emphysema can be diagnosed with computed tomography or other more experimental methods, such as MRI with hyperpolarized gas. These methods, however, are not easily accessible in a clinical outpatient setting. As emphysema is irreversible, early diagnosis is needed to improve patient outcomes. Hence, there is a need for a simple, readily available method to diagnose emphysema at an early stage.
Nanoparticle deposition in diseased lung is not widely studied. Löndahl et al. 2012 found reduced deposition of particles <40 nm in ten COPD-patients relative to seven controls. There have been previous attempts to use the deposition patterns of larger particles to determine airspace dimensions. These methods, however, have not become clinically available, mainly due to cumbersome measurement protocols.
We believe the Airspace Dimension Assessment could differentiate between COPD and healthy subjects. The measurement protocol is simpler than the previously suggested aerosol-based methods. Hence, we believe this method may be developed to assess early emphysema.
The aim of this study is to test if this method can find early emphysema related changes. We also expect there to be a correlation between the AiDA outcomes and extent of emphysema as measured by spirometry, DLCO and computed tomography (CT) densitometry. The data collection will be conducted starting jan 2014, and is planned to last two years.