2183 ULTRA-LOW DOSE CT COMPARABLE TO STANDARD CT IN PATIENTS WITH SUSPECTED RENAL COLIC

Abstract

You have accessJournal of UrologyImaging/Radiology: Uroradiology II1 Apr 20122183 ULTRA-LOW DOSE CT COMPARABLE TO STANDARD CT IN PATIENTS WITH SUSPECTED RENAL COLIC Jason Archambault, Carmen Hrymak, Sri Sivalingam, and Iain Kirkpatrick Jason ArchambaultJason Archambault Winnipeg, Canada More articles by this author , Carmen HrymakCarmen Hrymak Winnipeg, Canada More articles by this author , Sri SivalingamSri Sivalingam Madison WI More articles by this author , and Iain KirkpatrickIain Kirkpatrick Winnipeg, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2357AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Non-contrast computed tomography (CT) is currently the standard radiologic investigation for patients with suspected renal colic. Concerns over the number of CT scans being performed along with the long-term effects of CT radiation exposure have led to the evaluation of low dose radiation CT scans in diagnosing renal calculi. Our objective was to compare an ultra-low dose (study) CT scan protocol to standard CT in the evaluation of patients with suspected renal colic. METHODS Fifty-six emergency room patients with suspected renal colic underwent both a standard and study CT to assess for renal colic. The study CT protocol lowered the radiation exposure approximately 95% by fixing the tube current at 20 milliampere-seconds (mAs). Both CT scans were read twice by a group of 4 blinded radiologists. The primary outcome was stone detection rate. Secondary outcomes included signs of obstruction, inter-observer agreement, and stone characteristics. Patient body mass index (BMI) and alternative diagnosis were also evaluated. Patients were excluded if they were clinically unstable, or unable to provide informed consent. Study approval was received from the institutional health research ethics board. RESULTS Fifty-six patients had data available for comparison. Thirty-three of the 36 patients with a positive standard CT were identified on the study CT. This equates to a 92% sensitivity and 100% specificity for stone detection. Study CT sensitivity increased to >97% for stones > 2mm in size. There was no statistically significant difference between the two CT scans when directly compared for stone detection (McNemar's test p=0.63, alpha < 0.05). Inter-observer agreement for stone detection was excellent between all observers (all kappa values were greater than 0.8 with a combined mean of 0.9). The only false negative (no stone detected) with no indirect signs of obstruction was a 2mm distal stone in a patient with a BMI of 48. Although the false negative rate was low, stone size appeared significant based on 95% confidence intervals between group means. A similar comparison did not show significance for BMI. CONCLUSIONS Our ultra-low dose CT protocol approaches the sensitivity and specificity of standard non-contrast CTs in patients with suspected renal colic. This data strengthens the argument for developing reduced radiation CT protocols for screening patients with suspected renal colic. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e880 Peer Review Report Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jason Archambault Winnipeg, Canada More articles by this author Carmen Hrymak Winnipeg, Canada More articles by this author Sri Sivalingam Madison WI More articles by this author Iain Kirkpatrick Winnipeg, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...