Ultrasonography plus direct radiography of the abdomen in the diagnosis of renal colic: still a valid approach?

PURPOSE: The authors analyze whether the imaging approach consisting of ultrasonography and plain film in patients with renal colic is still of value when urography is replaced by unenhanced helical CT (UHCT) in unsolved cases. MATERIAL AND METHODS: Eight hundred and three consecutive patients were investigated with US following hydration and KUB, 164 of whom (20.4%) subsequently underwent UHCT (42 with the aim of mapping the excretory pathway and 122 (15.2%) because US and KUB were not considered as fully diagnostic). RESULTS: The 42 patients with detectable ureteral stone (plus possible hydronephrosis) on KUB + US and subsequently examined by UHCT to plan interventional treatment all had a positive UHCT examination. In 62 patients the diagnosis following KUB + US was uncertain (possible stone or possible hydronephrosis) and UHCT depicted the stone and/or the hydronephrosis in 34. In 60 patients the combination of KUB + US was negative but colic recurred and UHCT was positive in 17 patients. DISCUSSION: The comparison of the present results with a previous study in which KUB and US were followed by IVU in unsolved cases underscores the value of the first approach with KUB and US. The need for further diagnostic investigations when KUB + US are either not conclusive or negative and colic recurs is also confirmed. On the basis of our present data and in agreement with the literature IVU can be safely replaced by UHCT. CONCLUSIONS: It is authors' opinion that in settings where KUB, US and UHCT are available throughout the 24 hr the approach consisting of KUB plus US and UHCT in unsolved cases can be preferred in view of its on lower cost and above all lower X-ray dose to patients as compared to UHCT as the sole investigation.