PD37-11 EFFECTIVE ULTRA LOW DOSE CT PROTOCOL WITH LOWER RADIATION DOSE THAN ABDOMINAL X-RAY

Abstract

You have accessJournal of UrologyImaging/Radiology: Uroradiology III1 Apr 2018PD37-11 EFFECTIVE ULTRA LOW DOSE CT PROTOCOL WITH LOWER RADIATION DOSE THAN ABDOMINAL X-RAY Kymora Scotland, Jean Buckley, James Nugent, Savvas Nicolaou, Charles Zwirewich, Patrick McLaughlin, and Ben Chew Kymora ScotlandKymora Scotland More articles by this author , Jean BuckleyJean Buckley More articles by this author , James NugentJames Nugent More articles by this author , Savvas NicolaouSavvas Nicolaou More articles by this author , Charles ZwirewichCharles Zwirewich More articles by this author , Patrick McLaughlinPatrick McLaughlin More articles by this author , and Ben ChewBen Chew More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.1746AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Standard computed tomography of the kidneys, ureters and bladder (CT-KUB) is the most definitive modality used to identify renal calculi. However its use is concerning for radiation exposure particularly in recurrent stone formers. At this institution, KUB radiographs are routinely performed immediately prior to shockwave lithotripsy (SWL). Conventional low dose CT-KUBs (2.2-3.0 mSv) are only performed if stones are not visible on KUB (10-15% of cases). One disadvantage of routinely using low dose CT instead of KUB in this setting is the radiation exposure. Recent advances in integrated circuit CT detector design and image reconstruction algorithms have made sub-milliSievert ultra-low dose CT (ULDCT) acquisition feasible, but the diagnostic performance of these ULDCTs in comparison with KUB has not yet been reported. In this prospective study we compare the radiation dose and diagnostic performance of ULDCT to KUB in patients prior to SWL. We hypothesized that ULDCT will detect more symptomatic calculi than KUB at less radiation exposure prior to SWL. METHODS Patients were enrolled prospectively to receive a KUB and an ULDCT prior to SWL. If no stones were identified, they received a standard low dose abdominal CT. Radiation exposure parameters were recorded and both examinations were read in random order by 2 blinded radiologists to determine image quality and diagnostic accuracy. RESULTS 102 patients with a mean age of 55.7 ± 13.8y were enrolled. ULDCT detected stones with 95% sensitivity and 98% specificity with effective radiation dose 48% lower (0.28 ±0.08 mSv) compared to KUB (0.54 ±0.11 mSv, p<0.001). Negative and positive predictive values were 95% and 98% for ULDCT (83%, 92% for KUB).The number of stones seen on both modalities was similar: KUB was 1.59 ±1.27 vs 1.92±01.51 for ULDCT (p=0.35). However in 12 cases (12%), the ULDCT localized ureteral stones that were not detected on KUB. Measurement of stone size was equivalent using ULDCT (6.47 ±3.34mm) compared to KUB (6.98 ±3.41mm, p=0.455). ULDCT reduced the requirement for repeat conventional dose CTKUB. CONCLUSIONS ULDCT delivers 48% less radiation than a KUB radiograph and is superior at detecting the number and size of stones. In 12% of cases, ULDCT identified and localized ureteric stones prior to SWL that were not seen on KUB.ULDCT can be safely and effectively used in recurrent stone formers with smaller radiation dose than low dose CT. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e735 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Kymora Scotland More articles by this author Jean Buckley More articles by this author James Nugent More articles by this author Savvas Nicolaou More articles by this author Charles Zwirewich More articles by this author Patrick McLaughlin More articles by this author Ben Chew More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...