1819 TRIPLE D SCORE IS A REPORTABLE PREDICTOR OF STONE FREE RATES FOLLOWING SHOCKWAVE LITHOTRIPSY

Abstract

and past history of ureteral stone. The association with CT parameters of stone including diameter (D), length (H), volumetric stone burden (VSB; D H 5 / 6), estimated stone location (ESL; number of axial cut images between stone and UVJ), tissue rim sign (RS; 0-3), perinephric edema (0-3), hydronephrosis (0-3), and Hounsfield unit (HU) were also analyzed. Then a logistic regression model was developed using these variables to estimate the stone-free rate after URSL. RESULTS: The stone-free rate of URSL was 85.7% (203/237). Univariate analysis found that stone diameter, length, VSB, ESL, HU and RS significantly affect the stone-free rate (p 0.000, 0.000, 0.003, 0.000, 0.005, 0.000, respectively). Multivariate analysis indicated that stone diameter (HR 1.165, p 0.005), ESL (HR 1.074, p 0.001), and RS (HR 4.635, p 0.009) significantly affect the stone-free rate. Predictive model by logistic regression analysis for stone-free rate after URSL was defined as follows: stone free rate 1/[1 exp{6.146 0.153(D) 0.071(ESL) 1.534(RS)}] with AUC 0.825 from ROC curve. Internal validation showed that stone-free rate concordance was 0.774. CONCLUSIONS: Present study demonstrated that CT-measured parameters including stone diameter, ESL and RS are independent factors affecting URSL outcome. A CT-based predictive model using these factors helps to estimate stone-free rate after URSL in individual patients and facilitates treatment planning.