Diagnosing and mapping pulmonary emphysema on X-ray projection images

To assess whether grating-based X-ray dark-field imaging can
increase the sensitivity of X-ray projection images in the
diagnosis of pulmonary emphysema and allow for a more accurate
assessment of emphysema distribution. Lungs from three mice with
pulmonary emphysema and three healthy mice were imaged ex vivo
using a laser-driven compact synchrotron X-ray source. Median
signal intensities of transmission (T), dark-field (V) and a
combined parameter (normalized scatter) were compared between
emphysema and control group. To determine the diagnostic value of
each parameter in differentiating between healthy and emphysematous
lung tissue, a receiver-operating-characteristic (ROC) curve
analysis was performed both on a per-pixel and a per-individual
basis. Parametric maps of emphysema distribution were generated
using transmission, dark-field and normalized scatter signal and
correlated with histopathology. Transmission values relative to
water were higher for emphysematous lungs than for control lungs
(1.11 vs. 1.06, p