title: Can stone density on plain radiography predict the outcome of extracorporeal shockwave lithotripsy for ureteral stones?
abstract: OBJECTIVE
  The objective was to determine whether stone density on plain radiography (kidney-ureter-bladder, KUB) could predict the outcome of extracorporeal shockwave lithotripsy (ESWL) for ureteral stones.
  
  
  METHODS
  A total of 223 patients treated by ESWL for radio-opaque ureteral stones of 5 to 20 mm were included in this retrospective study. All patients underwent routine blood and urine analyses, plain radiography (KUB), and noncontrast computed tomography (NCCT) before ESWL. Demographic, stone, and radiological characteristics on KUB and NCCT were analyzed. The patients were categorized into two groups: lower-density (LD) group (radiodensity less than or equal to that of the 12th rib, n=163) and higher-density (HD) group (radiodensity greater than that of the 12th rib, n=60). Stone-free status was assessed by KUB every week after ESWL. A successful outcome was defined as stone free within 1 month after ESWL.
  
  
  RESULTS
  Mean stone size in the LD group was significantly smaller than that in the HD group (7.5±1.4 mm compared with 9.9±2.9 mm, p=0.002). The overall success rates in the LD and HD groups were 82.1% and 60.0%, respectively (p=0.007). The mean duration of stone-free status and average number of SWL sessions required for success in the two groups were 21.7 compared with 39.2 days and 1.8 compared with 2.3, respectively (p<0.05). On multivariate logistic analysis, stone size and time to ESWL since colic and radiodensity of the stone on KUB were independent predictors of successful ESWL.
  
  
  CONCLUSIONS
  Our data suggest that larger stone size, longer time to ESWL, and ureteral stones with a radiodensity greater than that of the 12th rib may be at a relatively higher risk of ESWL failure 1 month after the procedure.
authors.affiliation: Department of Urology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Ki Hong
authors.initials: KH
authors.lastname: Lim
authors.affiliation: Department of Radiology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Radiology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Jae Hyun
authors.initials: JH
authors.lastname: Kwon
authors.affiliation: Department of Radiology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Yong Seok
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Urology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Jungbum
authors.initials: J
authors.lastname: Bae
authors.affiliation: Department of Urology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Cho
authors.affiliation: Department of Urology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Department of Urology, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Hae Won
authors.initials: HW
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D003085:Colic; D005260:Female; D006801:Humans; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000000981:diagnostic imaging* / Q000628:therapy*
keywords: Bone density; Lithotripsy; Ureteral calculi