Steffey MA, Daniel S, Taylor SL, et al.
Introduction/Purpose: Computed tomography (CT) is not commonly utilized to image the colorectum in veterinary patients, as fecal material and the luminal collapse when empty can make interpretation difficult. CT pneumocolonography (CTP) is utilized in awake humans, however knowledge gaps exist in translating this technique to anesthetized animals. The objectives of this study were to investigate technical components that may contribute to an optimal protocol for CTP in the dog. We hypothesized that CTP would be a safe and effective method of distension , and that an optimal protocol of insufflation pressure, position, and time that would provide large bowel distension and enhancement of image interpretation could be identified.
Methods: Eight healthy purpose-bred male hound-mix dogs underwent CTP with mechanical insufflation of C02 via a transanal catheter. Measurements of colorectal wall thickness and cross-sectional lumen diameter and area were obtained at insufflation pressures of 0, 15, 20, and 25mmHg, insufflation times of 1, 5, 10, and 20 minutes , and in dorsal and sternal recumbency.
Results: Computed tomographic pneumocolonography was performed without complication in all dogs. Bowel distension was well maintained at all pressures, but 3/4 dogs experienced retrograde gas distension of the small intestine at 25 mm Hg. Body position did not significantly affect any variable measured. Ascending colon diameter and area significantly increased with insufflation time (p<0.05); no other variables showed a significant change with insufflation time.
Discussion/Conclusion: CT pneumocolonography is a feasible technique to provide consistent distension for imaging of the large bowel. The optimal pressure was determined to be 20 mm Hg. Further study on application of CTP in clinical patients is warranted.