title: Abdominal fat distribution on computed tomography predicts ureteric calculus fragmentation by shock wave lithotripsy.
abstract: OBJECTIVE
  To assess the effects of abdominal fat on shock wave lithotripsy (SWL). We used pre-SWL unenhanced computed tomography (CT) to evaluate the impact of abdominal fat distribution and calculus characteristics on the outcome of SWL.
  
  
  METHODS
  One hundred and eighty-five patients with a solitary ureteric calculus treated with SWL were retrospectively reviewed. Each patient underwent unenhanced CT within 1 month before SWL treatment. Treatment outcomes were evaluated 1 month later. Unenhanced CT parameters, including calculus surface area, Hounsfield unit (HU) density, abdominal fat area and skin to calculus distance (SSD) were analysed.
  
  
  RESULTS
  One hundred and twenty-eight of the 185 patients were found to be calculus-free following treatment. HU density, total fat area, visceral fat area and SSD were identified as significant variables on multivariate logistic regression analysis. The receiver-operating characteristic analyses showed that total fat area, para/perirenal fat area and visceral fat area were sensitive predictors of SWL outcomes.
  
  
  CONCLUSIONS
  This study revealed that higher quantities of abdominal fat, especially visceral fat, are associated with a lower calculus-free rate following SWL treatment. Unenhanced CT is a convenient technique for diagnosing the presence of a calculus, assessing the intra-abdominal fat distribution and thereby helping to predict the outcome of SWL.
  
  
  CONCLUSIONS
  • Unenhanced CT is now widely used to assess ureteric calculi.                                                  • The same CT protocol can provide measurements of abdominal fat distribution.                                                  • Ureteric calculi are usually treated by shock wave lithotripsy (SWL).                                                  • Greater intra-abdominal fat stores are generally associated with poorer SWL results.
authors.affiliation: Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Hsu-Cheng
authors.initials: HC
authors.lastname: Juan
authors.forename: Hung-Yu
authors.initials: HY
authors.lastname: Lin
authors.forename: Yii-Her
authors.initials: YH
authors.lastname: Chou
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Yang
authors.forename: Paul Ming-Chen
authors.initials: PM
authors.lastname: Shih
authors.forename: Shu-Mien
authors.initials: SM
authors.lastname: Chuang
authors.forename: Jung-Tsung
authors.initials: JT
authors.lastname: Shen
authors.forename: Yung-Shun
authors.initials: YS
authors.lastname: Juan
mesh_terms: D050153:Abdominal Fat / Q000473:pathology*; D000328:Adult; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging*; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000000981:diagnostic imaging* / Q000628:therapy*; D053039:Ureterolithiasis