#AUA14 - A randomized trial of ultrasound versus computed tomography for imaging patients with suspected nephrolithiasis - Session Highlights

ORLANDO, FL USA (UroToday.com) - When patients present to the emergency room with acute renal colic, imaging is obtained for further evaluation and diagnosis. Computed tomography (CT) imaging is considered the gold standard imaging modality for urolithiasis and has increasingly been used to exclude other diagnoses and confirm urinary stone disease.

However, CT is associated with significant ionizing radiation which increases the risks of variety of malignant diseases. To address this issue, Stoller and colleagues conducted a prospective randomized study to evaluate the utility of CT imaging compared to ultrasonography (US) imaging in the emergency room setting in patients suspected of acute renal colic.

auaIn this multicenter study, a total of 15 centers participated in a randomized comparative effectiveness trial. Total of 2 759 patients aged 18-75 years-old, presenting to emergency rooms with suspected nephrolithiasis, were randomly assigned to receive imaging with US performed by the emergency physician, US performed by a radiologist, or abdominal CT as their initial diagnostic test. Subsequent medical management including receipt of additional imaging, was performed at the discretion of the patients’ physicians. The incidence of serious adverse events (SAEs) diagnosed within 30 days, cumulative radiation exposure, and imaging costs during the subsequent 6 months were compared. Secondary outcomes, including pain on a 10-point visual analogue scale and return emergency room visits and hospitalizations were also measured.

SAEs occurred in 112 of 908 (12.3%) patients assigned to point-of-care US, 95 of 893 (10.6%) assigned to radiology US, and 106 of 958 (11.1%) assigned to CT. Severe SAEs occurred in 5 of 908 (0.55%) patients assigned to point-of-care US, 3 of 893 (0.34%) assigned to radiology US, and 4 of 958 (0.42%) assigned to CT (p=0.76). Average imaging costs were lower in patients assigned to point-of-care ultrasound demonstrating ($150) than radiology ultrasound which was $200 followed by CT ($300, p < .0001). Average cumulative radiation exposures were significantly lower for point-of-care (10.5 mSv) and radiology ultrasound (9.3 mSv) arms than CT arm (17.5 mSv, p < 0.0001). Average pain ratings showed no significant differences: by 7 days, average pain scores were 2.1, 1.9, and 2.0 for point-of-care ultrasound, radiology ultrasound, and CT arms, p=0.75. Return emergency room visits or hospitalizations were not different by arm at 1 week or 30 days.

For patients with suspicious renal colic in the emergency room, initial evaluation with ultrasonography was associated with lower cumulative radiation exposure and imaging costs with no significant difference in the risk of subsequent serious adverse events, pain resolution, return emergency room visits or hospitalizations.

Presented by Marshall Stoller, MD at the American Urological Association (AUA) Annual Meeting - May 16 - 21, 2014 - Orlando, Florida USA

Professor and Vice Chair of Urology, University of California (San Francisco) USA

Written by Zhamshid Okhunov, MD, University of California (Irvine), and medical writer for UroToday.com


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