The value of plain radiographs prior to oral cholecystography

The diagnostic significance of a routine preliminary plain radiograph of the right upper abdominal quadrant prior to oral cholecystography was evaluated retrospectively. The plain radiograph was decisive in the diagnosis in only one case out of 1,022 consecutive cholecystographic examinations (0.1%) (95% confidence limits: 0.00-0.55%). The sensitivity of oral cholecystography, now approximately 90%, would drop by only 0.43% (95% confidence limits: 0.01-2.14%) if the routine plain radiograph were omitted.