Abstract
ABSTRACTObjectives Measurements of stone features may vary according to the non-contrast computed tomography (NCCT) technique. Using magnified bone window is the most accurate method to measure urinary stones. Possible differences between stone measurements in different NCCT windows have not been evaluated in stones located in the kidney. The aim of this study is to compare measurements of kidney stone features between NCCT bone and soft tissue windows in patients submitted to retrograde intrarenal surgery (RIRS).Materials and Methods Preoperative and 90th postoperative day NCCT were performed in 92 consecutive symptomatic adult patients (115 renal units) with kidney stones between 5 mm to 20 mm (< 15 mm in the lower calyx) treated by RIRS. NCCT were evaluated in the magnified bone window and soft tissue window in three axes in a different time by a single radiologist blinded for the measurements of the NCCT other method.Results Stone largest size (7.92±3.81 vs. 9.13±4.08; mm), volume (435.5±472.7 vs. 683.1±665.0; mm3) and density (989.4±330.2 vs. 893.0±324.6; HU) differed between bone and soft-tissue windows, respectively (p<0.0001) 5.2% of the renal units (6/115) were reclassified from residual fragments > 2 mm on soft tissue window to 0-2 mm on bone window.Conclusion Kidney stone measurements vary according to NCCT window. Measurements in soft tissue window NCCT of stone diameter and volume are larger and stone density is lesser than in bone window. These differences may have impact on clinical decisions.
Highlights
Non-contrast computed tomography (NCCT) has become the gold standard for diagnosing urinary stones [1]
Stone volume is the best predictor of operative time and is an independent predictor of stone-free status in retrograde intrarenal surgery (RIRS) for kidney stones [3, 4]
From August 2016 to August 2017, preoperative and 90th postoperative day (POD) NCCT were performed in consecutive symptomatic adult patients with kidney stones that chose to be treated by RIRS
Summary
Non-contrast computed tomography (NCCT) has become the gold standard for diagnosing urinary stones [1]. NCCT is able to provide stone features as size, volume and density that are relevant for making clinical decisions. Stone volume is the best predictor of operative time and is an independent predictor of stone-free status in retrograde intrarenal surgery (RIRS) for kidney stones [3, 4]. Hounsfield units (HU) density is able to differentiate uric acid stones, to predict success of shockwave lithotripsy and to impact on operative time of RIRS using holmium laser lithotripsy [5,6,7,8,9]. The measurements of these stone features may vary according to the NCCT technique [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
