A modified radiographic method for estimating segmental colonic transit time in subjects with rapid gut transit

In this study on Indian subjects, the single X-ray method was assessed for its reliability in measuring the transit of particulate matter through the colon, and if inaccurate a suitable and simple alternative was to be devised. Radio-opaque markers were serially followed in 20 normal male volunteers. This was done by three 12 hourly radiographs and by stool collection to determine the transit time through the colon and its segments. It was compared with similar parameters calculated from the same data using one radiograph and three combinations of two radiographs each. The mean +/- SD colonic transit time determined by using three X-rays was 18.0 +/- 6.6 h which agreed well with the mean mouth-to-anus transit time of 24.2 +/- 6.8 h (mean +/- SDdiff = -6.2 +/- 2.9). When two of the three X-rays were used in various combinations, the best results were obtained with the method including radiographs at 12 and 36 h. Parameters calculated from a single radiograph done 36 h after the ingestion of makers showed lesser agreement with the results of the three radiograph method. Therefore in subjects with rapid gut transit, the simplified method for estimating the colonic and segmental transit times using a single X-ray is inaccurate. Using two radiographs enhances the accuracy.