NEW ORLEANS, LA USA (UroToday.com) - When detecting kidney stones, KUB (Kidney-Ureter-Bladder) radiography is the gold standard. However, studies have shown that patients with urolithiasis encounter an annual radiation exposure that exceeds that of atomic energy workers. The aim is to minimize radiation exposure to these patients. Recent advancements in technology incorporating ultra low-noise solid-state CT detection and simultaneously working with software reconstruction algorithms, have allowed for ultra low-dose CT-KUB’s (ULDCT) to be possible. The authors sought to compare the efficacy and diagnostic performance of ULDCT against the gold standard, KUB radiography, and also their associated radiation dosage levels.
The authors performed both digital radiography KUB and unenhanced ULDCT on 51 consenting patients scheduled for shockwave lithotripsy (SWL), over a 3 month timeframe. Urologists and radiologists blindly reviewed the images and identified their respective size and locations.
After reviewing the images of 51 patients with the mean age of 56.2, 1.59 stones were visible via KUB, while 1.92 were visible on the ULDCT, with a p-value of 0.35. Interestingly, in 3 cases, ULDCT identified stones that were not detected via KUB. When looking at stone size, KUB and ULDCT revealed 6.47 mm and 6.98 mm, respectively. In terms of the effective dose, the mean radiation by usage of KUB was 0.50 mSv and for ULDCT was 0.28 mSv, with a p-value of 0.014.
The authors have concluded that the detection of urinary calculi prior to SWL was equivalent when using both modalities. However, ULDCT allows for a 44% reduction in radiation dosage. ULDCT offers a promising modality for the detection of stones prior to SWL, as compared to the standard KUB, however the cost of the two approaches will need to be taken into consideration for future studies.
Presented by Ben Chew at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
University of British Columbia, Vancouver, BC Canada
Reported by Victor Huynh (University of California-Irvine), medical writer for UroToday.com