Abstract: Background Ventilator-assisted inspiratory:expiratory breath-hold computed tomography (I:E-BH CT) is superior to sedated CT but poses anesthetic risk. Reduction of motion artifact and ability to interpret inspiratory and expiratory phases can be overcome with sedated respiratory gated CT (RG-CT). Comparison of CT lung patterns (increased attenuation, decreased attenuation, nodular and linear patterns) and their sub-patterns have not been compared between I:E-BH CT and RG-CT in dogs. Hypothesis: We hypothesized that in dogs with respiratory signs, sedated RG-CT would be a minimally-invasive surrogate for anesthetized I:E-BH CT with no significant difference in presence of the four major CT lung patterns and their sub-patterns. Animals Forty-one client-owned dogs with respiratory clinical signs.
Methods: Sedated RG-CT and anesthetized I:E-BH CT images were prospectively acquired. A blinded board-certified radiologist assessed all scans for the presence CT lung patterns and sub-patterns. For each dog, a Fisher’s exact test was used to determine if there were nonrandom associations between the two scan types for each variable (significance, p<0.05).
Results: Motion artifact was minimal with both types of scans. For presence of the four major lung patterns and 14 sub-patterns, there was no significant difference between scan type (p <0.05 for all). Conclusions and clinical importance: Lung patterns and sub-patterns from I:E-BH and RG-CT scans are comparable in dogs with respiratory disease. Superior technique and detail of anesthetized I:E-BH CT allows for increased conspicuity of subtle sub-patterns than RG-CT in some dogs.
