Stratification of bile in the normal gallbladder during intravenous cholangiography

Stratification in the gallbladder with a radiolucent zone of nonopacified bile may be a physiologic phenomenon during intravenous cholangiography, and should not be confused with floating cholesterol gravel or sludge. A post-fatty-meal and/or delayed films may aid in the differentiation of these two conditions. If a fatty stimulus is given at least 1 hr. prior to the X-ray study, the stratification phenomenon may be avoided.