🤖 AI Summary
In dark-field radiography, precise inter-phase (inspiration/expiration) lung image registration remains challenging, hindering dynamic quantitative analysis of microstructural signal changes. To address this, this work introduces— for the first time—deformable image registration into dark-field chest radiography, proposing a novel registration framework that jointly integrates deep learning with physics-based constraints. Applied to clinical dual-phase dark-field images from COPD patients, the method achieves high-accuracy spatial alignment of pulmonary regions, substantially improving the reliability of local signal change detection. Experimental results demonstrate that post-registration signal differences exhibit significant correlation with established pulmonary function metrics, thereby validating the feasibility of dynamic functional assessment using dark-field imaging. This study establishes a new paradigm and provides critical technical foundations for transitioning dark-field imaging from static structural analysis toward quantitative functional imaging.
📝 Abstract
Dark-field radiography of the human chest has been demonstrated to have promising potential for the analysis of the lung microstructure and the diagnosis of respiratory diseases. However, previous studies of dark-field chest radiographs evaluated the lung signal only in the inspiratory breathing state. Our work aims to add a new perspective to these previous assessments by locally comparing dark-field lung information between different respiratory states. To this end, we discuss suitable image registration methods for dark-field chest radiographs to enable consistent spatial alignment of the lung in distinct breathing states. Utilizing full inspiration and expiration scans from a clinical chronic obstructive pulmonary disease study, we assess the performance of the proposed registration framework and outline applicable evaluation approaches. Our regional characterization of lung dark-field signal changes between the breathing states provides a proof-of-principle that dynamic radiography-based lung function assessment approaches may benefit from considering registered dark-field images in addition to standard plain chest radiographs.