Keh SY, Sohn JM, Choi MH, et al.
Introduction/Purpose: Computed tomography (CT) is a routine examination of gastrointestinal tract in human because of the features that all the gastrointestinal segments can be imaged without overlapping, providing more detailed information about extra-intestinal abnormal condition. CT enterography requires adequate luminal distension for evaluating mural alteration correctly. The purpose of this study was to describe and optimize CT enterography techniques in normal dogs, determining the appropriate scanning time of each segment of small intestine.
Methods: Fifteen healthy dogs were used. In control group (n=7), CT examination was performed without oral contrast administration. In group 1 (n=5), 60 ml/kg of 1.34 g/ml lactulose diluted with tepid water in the ratio of 1:4 was bolus administrated. In group 2 (n=8), same dose and dilution of lactulose solution was administrated for 45 minutes. CT was performed at 0, 10, 20, 30, 40, 50 and 60 minutes in both groups. CT images were evaluated by two radiologists. The luminal distension of each segment was qualitatively evaluated using a 3 point scale (0: poor, 1: good, 2: optimal), Quantitative analysis of luminal distension was performed by measuring diameter of five points randomly using electronic calipers on the monitor. Adverse effects including nausea, vomiting and diarrhea were checked throughout the CT enterography.
Results: In qualitative analysis, the control group showed poor distension at any segments. The ascending duodenum showed the highest luminal distension score (1.63 ± 0.61) at 10 and 30 minutes, jejunum showed the highest luminal distension score (1.44 ± 0.51) at 20 minute in group 2 (p < 0.05). There was no significant difference in descending duodenum and ileum between two groups (p > 0.05). In quantitative analysis, there was no significant difference between two groups in descending and ascending duodenum (p > 0.05). Data of jejunum and ileum showed low inter-observer reproducibility (ICC 0.443-0.775). There were mild gastrointestinal signs in group 2.
Discussion/Conclusion: CT entrography with administrating lactulose solution slowly provided more appropriate images for evaluating intestinal wall of ascending duodenum in 10 or 30 minutes and jejunum in 20 minute. Further studies about several factors which can affect the degree of luminal distension and image quality including the feeding method , the type , amount and dilution rate of contrast agents , the use of prokinetic agents, CT scanning time and time interval are also needed.