High-speed single-breath-hold micro-computed tomography of thoracic and abdominal structures in mice using a simplified method for intubation.

Objectives: Respiratory gating with and without controlled ventilation has been applied for in vivo micro-computed tomography (micro-CT) of thoracic and abdominal structures in mice. We describe a simplified method for intubation and demonstrate its applicability for single-breath-hold micro-CT in mice. Methods: Mice (n = 10) were anesthetized, intubated, ventilated, and relaxed by intraperitoneal administration of rocuronium. Contrast-enhanced micro-CT of the complete thorax including the upper abdominal organs (80 kV; 37.5 μA; 190-degree rotation; 600 projections/20 seconds or 1200 projections/40 seconds; 39 × 39 x 50-μm voxel size) was performed with and without single—breath—hold technique. Results: The simplified method of intubation was fast (<1 minute) and required no special hardware in all mice. Relaxation of mice allowed prolonged single-breath-hold imaging of up to 40 seconds. Diameter of smallest identifiable lung vessels was 100 μm. Conclusions: The presented simplified method for intubation in mice is fast, safe, and effective. Additional relaxation allowed high-resolution single-breath-hold micro-CT in mice.