Dark-field Chest Radiography for Assessing Emphysema

A study published in Radiology reports that dark-field radiography may be useful as a diagnostic tool for pulmonary emphysema. The prospective study of 83 patients (mean age of 65 years, 52 men) found that dark-field chest radiographs had a lower and inhomogenous dark-field signal intensity in those with emphysema. The data correlated to emphysematous areas depicted with CT.

Introduced in 2008, X-ray dark-field imaging has demonstrated feasibility in animal and ex vivo human studies. Researchers from the Technical University of Munich used a clinical prototype consisting of a conventional imaging system with a diagnostic x-ray tube operated at 70 kVp and a flat-panel detector in combination with a three-grating interferometer (G0, G1, G2) for the detection of small-angle scattering.

Participants underwent both X-ray dark-field imaging and CT with both qualitative and quantitative analyses performed on both imaging data sets. Compared to healthy participants, those with emphysema had lower dark-field signal intensity and an inhomogeneous patchy appearance of the lungs on the dark-field chest radiographs. These areas of focal signal intensity loss on dark-field images corresponded well with emphysematous areas found on CT images.

The authors also note the lower cost and lower radiation exposure of chest radiography compared to chest CT, suggesting that CT may be less suitable for emphysema screening. They conclude that because pulmonary emphysema leads to a reduced signal intensity on dark-field chest radiographs, with relatively low radiation exposure, the method has potential for diagnosis of chronic obstructive pulmonary disease and other lung diseases that alter the alveolar interfaces in the lung.