Renal colic: comparison of use and outcomes of unenhanced helical CT for emergency investigation in 1998 and 2002

Abstract

Purpose: To determine retrospectively whether there had been any change between 1998 and 2002 in the use and outcome of computed tomography (CT) performed in the emergency department for patients presenting with symptoms of renal colic.

Materials and methods: Approval from the Research Ethics Board was obtained, and informed consent was waived. All CT examinations ordered from the emergency department of a tertiary care hospital and performed from July to December 1998 and July to December 2002 were identified. Reports were reviewed, and results were categorized as either (a) positive for urinary tract calculus disease (category I), (b) indicative of an alternate diagnosis (category II), or (c) negative for findings to account for the patient's symptoms (category III). The corresponding emergency department charts were reviewed for urine dipstick results for hematuria and for patient history of stone disease. For statistical analysis, chi2 testing and odds ratios were used.

Results: During the 6-month period in 1998, 179 CT examinations were performed in patients who were admitted to the emergency department. During the same period in 2002, 234 CT examinations were performed. After correction for the total number of emergency department visits, it was determined that there was a relative increase of 21.3% (95% confidence interval: -0.0009, 0.47) in number of CT examinations performed in the emergency department. A total of 117 (65.4%) of 179 CT studies in 1998 and 153 (65.4%) of 234 CT studies in 2002 demonstrated renal calculus disease (category I), nine (5.0%) of 179 CT studies in 1998 and 17 (7.3%) of 234 CT studies in 2002 were used to identify an alternate diagnosis for patient symptoms (category II), and 53 (29.6%) of 179 CT studies in 1998 and 64 (27.4%) of 234 CT studies in 2002 were negative (category III). There were no significant differences between the rates of category I, II, or III results and the positivity rates for hematuria and urinary tract stone history during 1998 and 2002.

Conclusion: Despite a definite trend of increased CT use during 1998 and 2002, there was no significant decrease in the rates of positive renal colic results or alternate diagnoses.