Visualization of Rib and Diaphragm Motion in an Anaesthetized Mouse by Live Animal Synchrotron Imaging

Pulmonary research is challenging because of the lack of visualization of lung airspace by commonly used imaging modalities. Cyclic breathing and motion artifacts due to superimposed ribs and cardiac motion further confound the interpretation of lung imaging data. This is partly responsible for little progress in drug therapy or intervention for many lung diseases such as acute respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, cystic fibrosis, and lung cancer. Synchrotron sources can provide soft tissue contrast not available with conventional technologies by making use of phase contrast. Given the advantage of increased flux and narrow energy-range beams of collimated x-rays, there remains challenges in data analysis due to motion artifacts and lack of supporting image analysis algorithms for the correction of them. Therefore, we performed motion analysis of ribs and diaphragm for potential longitudinal functional lung imaging. The system utilized custom x-ray optics at the Canadian Light Source, for full field mouse imaging at 30 frames per second, on the biomedical beamline. This study presents a motion analysis of ribs and diaphragm of a spontaneously breathing anaesthetized mouse. To our knowledge this is the first temporal image analysis done in a spontaneously breathing individual without the aid of ventilation or extensive transducers. This is a feasibility study for future imaging of animal models of pulmonary diseases.