Biliary tract opacification: effect of iodine concentration and luminal size

This study tested the hypothesis that the density of gallbladder and common duct visualization is dependent on the total amount of contrast material present (i.e., concentration and volume, rather than simply concentration). Finger cots (simulating gallbladders) and straws (simulating bile ducts) containing measured amounts of contrast material, were radiographed in a water phantom using standard radiographic factors. The films were classified by several radiologists as to their clinical usefulness. The concept that the gallbladder can be seen with lesser concentrations of iodine than the common duct, because the gallbladder is the thicker organ, was verified and is discussed.