title: Stone heterogeneity index as the standard deviation of Hounsfield units: A novel predictor for shock-wave lithotripsy outcomes in ureter calculi.
abstract: We investigated whether stone heterogeneity index (SHI), which a proxy of such variations, was defined as the standard deviation of a Hounsfield unit (HU) on non-contrast computed tomography (NCCT), can be a novel predictor for shock-wave lithotripsy (SWL) outcomes in patients with ureteral stones. Medical records were obtained from the consecutive database of 1,519 patients who underwent the first session of SWL for urinary stones between 2005 and 2013. Ultimately, 604 patients with radiopaque ureteral stones were eligible for this study. Stone related variables including stone size, mean stone density (MSD), skin-to-stone distance, and SHI were obtained on NCCT. Patients were classified into the low and high SHI groups using mean SHI and compared. One-session success rate in the high SHI group was better than in the low SHI group (74.3% vs. 63.9%, P = 0.008). Multivariate logistic regression analyses revealed that smaller stone size (OR 0.889, 95% CI: 0.841-0.937, P < 0.001), lower MSD (OR 0.995, 95% CI: 0.994-0.996, P < 0.001), and higher SHI (OR 1.011, 95% CI: 1.008-1.014, P < 0.001) were independent predictors of one-session success. The radiologic heterogeneity of urinary stones or SHI was an independent predictor for SWL success in patients with ureteral calculi and a useful clinical parameter for stone fragility.
authors.affiliation: Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Joo Yong
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Urology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
authors.forename: Jae Heon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dong Hyuk
authors.initials: DH
authors.lastname: Kang
authors.affiliation: Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Doo Yong
authors.initials: DY
authors.lastname: Chung
authors.affiliation: Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dae Hun
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Urology, Incheon Red Cross Hospital, Incheon, Korea.
authors.forename: Hae
authors.initials: H
authors.lastname: Do Jung
authors.affiliation: Department of Urology, Severance Check-Up, Yonsei University Health System, Seoul, Korea.
authors.forename: Jong Kyou
authors.initials: JK
authors.lastname: Kwon
authors.affiliation: Department of Urology, Gangnam Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kang Su
authors.initials: KS
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011857:Radiographic Image Interpretation, Computer-Assisted; D012044:Regression Analysis; D015203:Reproducibility of Results; D056910:Republic of Korea; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014513:Ureter / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014514:Ureteral Calculi / Q000000981:diagnostic imaging* / Q000628:therapy