Validity of the geometric mean correction in the quantification of whole bowel transit

The accurate interpretation of gastrointestinal transit studies often requires quantification of the data. Particles radiolabelled with indium-111 have been monitored using a gamma camera, during transit through the stomach and the small and large intestines of normal subjects. The count rates measured from either anterior or posterior images alone showed considerable variations, and depended on the site of the tracer within the gut. The geometric mean values of corresponding anterior and posterior count rates remained almost constant throughout each study.