Radiologic diagnosis of renal colic: the role of plain films, excretory urography and sonography.

The accuracy of plain films, excretory urography and ultrasound for the clinical work-up of renal colic for detecting urinary calculi was evaluated prospectively in 49 patients. Excretory urography was the most sensitive and specific test. Plain films and sonography each had a sensitivity of approximately 60%, but combined yielded a sensitivity of 80%; specificity did not improve. A diagnostic algorithm where sonography was performed first followed by an excretory urography in case of a negative sonography was highly sensitive (93%) and rather specific (79%). This algorithm appears also to have a good cost-benefit rate.