Helical CT in the evaluation of renal colic.

This study assessed the clinical effectiveness of unenhanced helical (spiral) computed tomography (CT) for evaluation of patients presenting with symptoms of renal colic. Two hundred patients with symptoms and signs of renal colic (flank or groin pain, hematuria) were imaged. Unenhanced CT was performed using 5-mm collimation with a pitch of 1.5 to 1.8. Image reconstruction was performed at 3-mm intervals. Exam time was approximately 5 minutes. The financial charge at the study institution was the same as for an intravenous urogram. Clinical follow-up was performed by review of available medical records and patient interviews. The sensitivity for detecting clinically relevant ureteral and bladder calculi was 0.862 (0.95 confidence interval [CI] 0.771 to 0.927), the specificity was 0.914 (0.95 CI 0.837 to 0.962), and the accuracy was 0.89 (0.95 CI 0.833 to 0.931). Helical CT is an effective technique in the evaluation of suspected acute urinary tract obstruction.