In vivo micro-CT lung imaging via a computer-controlled intermittent iso-pressure breath hold (IIBH) technique.

Respiratory research with mice using micro-computed tomography (micro-CT) has been predominantly hindered by the limited resolution and signal-to-noise ratio (SNR) as a result of respiratory motion artefacts. In this study, we develop a novel technique for capturing the lung microstructure in vivo using micro-CT, through a computer-controlled intermittent iso-pressure breath hold (IIBH), to reduce respiratory motion, increasing resolution and SNR of reconstructed images. We compare four gating techniques, i.e. no gating, late expiratory (LE) gating, late inspiratory (LI) gating and finally intermittent iso-pressure breath hold (IIBH) gating. Quantitatively, we compare several common image analysis methods used to extract valuable physiologic and anatomic information from the respiratory system, and show that the IIBH technique produces the most representative and repeatable results.