Monitoring infection and inflammation in murine models of cystic fibrosis with magnetic resonance imaging

Purpose: To evaluate magnetic resonance imaging (MRI) in assessing lung inflammation longitudinally in genetic mouse models of cystic fibrosis (CF). MRI is used to view soft tissues noninvastvely, but the lung is challenging to image. Materials and Methods: Cftr^+/+ (wildtype) and Cftr ^-/- (CF) mice were inoculated with agarose beads laden with Pseudomonas aeruginosa. Longitudinal MR lung images were acquired with cardiac gating. The effects of echo time and respiration gating were evaluated to improve the detection of lung inflammation. Results: Cardiac gating and signal averaging sufficiently suppressed motion artifacts without requiring respiration gating. MRI detected moderate to severe inflammation in infected mice, which was confirmed by histology results. Conclusion: In vivo longitudinal MRI methods can assess lung inflammation in P. aeruginosa-infected mice, which obviates serial sacrifice. MRI was able to detect inflammation in the absence of other physiological symptoms.