Dark-field imaging and computed tomography : Novel X-ray-based contrast imaging modality with great promise for pulmonary imaging

Abstract

The spatial and contrast resolution of conventional planar or computed tomographic X‑ray techniques is not sufficient to investigate microstructures of tissues. Dark-field imaging with X‑rays is an emerging technology that recently provided the first clinical results and makes diagnostic use of interactions of the beams with tissue due to their wave character. Dark-field imaging can provide information about the microscopic structure or porosity of the tissue under investigation that is otherwise inaccessible. This makes it avaluable complement to conventional X‑ray imaging, which can only account for attenuation. Our results demonstrate that X‑ray dark-field imaging provides pictorial information about the underlying microstructure of the lung in humans. Given the close relationship between alveolar structure and the functional state of the lung, this is of great importance for diagnosis and therapy monitoring and may contribute to abetter understanding of lung diseases in the future. In the early detection of chronic obstructive pulmonary disease, which is usually associated with structural impairment of the lung, this novel technique could help to facilitate its diagnosis. The application of dark-field imaging to computed tomography is still under development because it is technically difficult. Meanwhile, aprototype for experimental application has been developed and is currently being tested on avariety of materials. Use in humans is conceivable especially for tissues whose microstructure favors characteristic interactions due to the wave nature of the X‑rays.