Computed tomography imaging of lungs in mouse models of human disease : advancing the computing interfaces with physiology

New research applications for imaging can come from combining advances in anesthetic management and respiratory synchronization with computed tomography (CT) algorithms. CT imaging has the potential to provide lung pathologic details non-invasively, and to facilitate the structural and functional studies in mouse models of human diseases. Examples include atelectasis in lungs of transgenic mice expressing sickle hemoglobin, and bacterial pneumonia. However, human high-resolution CT is typically obtained during a breath-hold, asking the patient to voluntarily hold her breath for several seconds and hold still for a crisp image. Mice cannot cooperate in this manner, so inhalational general anesthesia keeps the animal in position but breathing spontaneously during the 20 to 40 minutes of scans. Mice with pleural effusion and with severe pulmonary fibrosis survived micro CT under anesthesia. Imaging can be gated to obtain one set of images in the expiratory phase of the respiratory cycle, and another in the inspiratory phase. Respiratory gating provides superior image quality, and comparing inspiratory vs. expiratory lung volume provides an estimate of tidal volume. Correlating human conditions with pathophysiology in mouse models will permit more translational research.