Evaluation of suspected renal colic with noncontrast CT in the emergency department: a single institution study.

BACKGROUND AND
PURPOSE: Noncontrast CT (NCCT) has become the standard Imaging study in the emergency department (ED) diagnosis of nephro- and ureterolithiasis. We undertook to audit the results from the first 500 NCCTs performed for patients presenting to the ED with suspected renal colic. PATIENTS AND METHODS: In a retrospective study at one institution from October 2003 to February 2006, 500 patients with suspected stone disease were investigated. In the study, NCCT findings, patient clinical records, and urinary microscopy results were evaluated for 166 women and 334 men.
RESULTS: Renal or ureteral calculi were identified in 279 (56%) of NCCTs performed. Of the 500, 112 (19%) NCCTs performed identified unexpected intra-abdominal pathology. When the findings deemed to be of low clinical significance were excluded, the number of scans with additional pathology amounted to 67 (13%). These included vascular emergencies, new cancer diagnoses, and gastrointestinal conditions.
CONCLUSIONS: The variety of diagnoses found unexpectedly on the NCCT that alter a patient's treatment demonstrates the pivotal role of NCCT in the triage of these patients rapidly toward optimal therapy. The rapid acquisition time of NCCT has enabled definitive ED patient diagnosis and less bed occupancy for clinically insignificant calculi.