hi elizabeth.. i wil be glad to answr ur query.. (HIDA scan) is a nuclear imaging procedure to evaluate the health and function of the gallbladder. A radioactive tracer, usually technetium-99m, is injected through any accessible vein, then allowed to circulate to the liver, where it is excreted into the biliary system and stored by the gallbladder and biliary system. In the absence of disease, the gallbladder is visualized within 1 hour of the injection of the radioactive tracer. If the gallbladder is not visualized within 4 hours after the injection, this indicates either cholecystitis or cystic duct obstruction. so it depends on the time at which image is taken.. diagnosis also varies according to the variation in image n the time of taking an image after injection of radiotracer.. so ur radiologist who did the proedure n saw the images of hida scan can answer ur question better.. i hope this will be helpful to you..