The accuracy of the plain abdominal radiograph in assessing colonic faecal contamination.

A prospective study of 333 out-patients assessed the accuracy of determining colonic cleansing from the plain abdominal radiograph. The results indicate that the amount of colon contaminated with faeces was significantly underestimated and the difference in efficacy between the best and worst preparation regimens could not be detected from the plain film. Nevertheless, plain films have been used in comparative studies of preparation regimens for barium enema. It is suggested that results so obtained are misleading and that comparisons are best made on barium films alone.