Computed Tomography Colonography Technique: The Role of Intracolonic Gas Volume

Abstract

Introduction. Poor distention decreases the sensitivity and specificity of CTC. The total volume of gas administered will vary according to many factors. We aim to determine the relationship between the volume of retained gas at the time of image acquisition and colonic distention and specifically the presence of collapsed bowel segments at CTC. Materials and Methods. All patients who underwent CTC over a 12-month period at a single institution were included in the study. Colonic luminal distention was objectively scored by 2 radiologists using an established 4-point scale. Quantitative analysis of the volume of retained gas at the time of image acquisition was conducted using the threshold 3D region growing function of OsiriX. Results. 108 patients were included for volumetric analysis. Mean retained gas volume was 3.3 L. 35% (38/108) of patients had at least one collapsed colonic segment. Significantly lower gas volumes were observed in the patients with collapsed colonic segments when compared with those with fully distended colons 2.6 L versus 3.5 L (P = 0.031). Retained volumes were significantly higher for the 78% of patients with ileocecal reflux at 3.4 L versus 2.6 L without ileocecal reflux (P = 0.014). Conclusion. Estimation of intraluminal gas volume at CTC is feasible using image segmentation and thresholding tools. An average of 3.5 L of retained gas was found in diagnostically adequate CTC studies with significantly lower mean gas volume observed in patients with collapsed colonic segments.

Diagnostic Imaging of Gastrointestinal Tumours in Dogs and Cats: A Review

“…The procedure consist of the administration of 30 mL/kg of water as a neutral luminal contrast medium followed by the intravenous injection of iodinated contrast medium, obtaining a uniform distension of the gastric lumen and enhancing visualization of the gastric wall obtaining uniform distension of the gastric lumen and enhancing visualization of the gastric wall. Computed Tomography Colonography (CTC) technique is described in human medicine as a useful method for the assessment of colonic wall: The use of CO2 as a negative intraluminal contrast medium may enhance visualization of colonic wall's lesions by distension of the lumen and contrast enhancement between the mucosal surface and the filled gas (McLaughlin et al, 2013). After colonic preparation, gas insufflation is performed using an endorectal positioned foley catheter and image acquisition is immediately performed once an adequate and stable rectal pressure is reached.…”

High‐resolution impedance manometry characterizes the functional role of distal colonic motility in gas transit

“…Previous studies using gas insufflation have used much larger volumes (200 mL-720 mL 58,59 ), and insufflation volumes are also considerably larger in computed tomography colonography imaging (>2 L). 60,61 Nevertheless, the small volumes used in the present study consistently resulted in increases in cyclic Within these black and white regions, retrograde propagation is significantly greater than antegrade propagation at the same frequency. This is most marked between frequencies of 0.25-2 cpm.…”