Air insufflation: a useful adjunct to the single contrast barium enema for the evaluation of the rectum.

We examined whether insufflation of a small volume of air after a single-contrast barium enema would improve evaluation of the rectum. Eighty patients presenting for barium enema by single-contrast technique underwent examination of the colon including spot films with fluoroscopy and palpation during introduction of the barium and filled overhead views, using standard apparatus and technique. The examination was completed by draining barium from the rectum only, following which air in the barium enema bag was squeezed back into the rectum and three views of the rectum obtained (lateral, left posterior oblique, and frontal). Two reviewers then chose the best image of the rectum from each study with relevance to luminal distention and visibility of surface detail of the rectum. Following air insufflation, improved surface detail visualization was recognized by both reviewers in 69 (86%) patients and by one reviewer in 10 (12%) patients, a statistically significant observation (P < 0.0001). There was a trend towards improved rectal distention, recognized by both reviewers in 37 (46%) patients and by one reviewer in 18 cases (22%). In 25 (31%) patients neither reviewer recognized any improvement in rectal distention. Rectal abnormalities were identified in nine cases; there were two large carcinomas, two radiation strictures, two rectal fistulae, two small rectal polyps (5 and 7 mm), and one case of prolapsing rectal mucosa. All rectal abnormalities were visible on the air insufflation views. In the two cases of suspected rectal polyp and one of the cases of rectal fistula, the findings were not visible on the initial barium filled views. A normal rectum was observed in 71 cases. Follow-up of these 71 patients found no later evidence of any rectal abnormalities. Improved filling of the proximal colon following air insufflation was observed in 12 (15%) patients, an additional and unexpected benefit of this maneuver. Air insufflation is a simple addition to the SCBE study that improves visualization of the rectum.