title: Reproducibility of fetal renal pelvis volume measurement using three-dimensional ultrasound.
abstract: OBJECTIVE
  To assess the reproducibility of fetal renal pelvis volume measurement in hydronephrotic kidneys using transabdominal three-dimensional (3D) ultrasound.
  
  
  METHODS
  The fetal renal pelvis volume was measured using 3D ultrasound in one kidney in each of 15 fetuses with hydronephrosis in the second or third trimester of pregnancy. Hydronephrosis was diagnosed when the fetus had an anteroposterior renal pelvis diameter > or = 5 mm. After volume acquisition by one of the observers, the repeatability of volume calculation with manual delineation of the fetal renal pelvis was assessed by six different observers using the Virtual Organ Computer-aided AnaLysis (VOCAL(trade mark)) imaging program. The intraclass correlation coefficients (ICC), coefficient of variation (CV) and within- and between-observer repeatability coefficient (r) were calculated and Bland-Altman plots were constructed.
  
  
  RESULTS
  Both intra- and interobserver reliability of the fetal renal pelvis volume measurements were considered to be very good. For intraobserver reliability, the ICC was 0.996 and the CV was 10.8%. For the overall interobserver reliability, the ICC was 0.998 and the CV was 15.7%; the interobserver reliability between pairs of observers had ICCs between 0.994 and 0.999, and CVs between 19.5% and 7.6% for inexperienced and experienced observers, respectively.
  
  
  CONCLUSIONS
  With 3D ultrasound using the VOCAL imaging program, it is technically feasible to reproduce fetal renal pelvis volume measurements. Further research to establish the clinical applications of this technology is warranted.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital, Maastricht, The Netherlands. lduin@sgyn.azm.nl
authors.forename: L K
authors.initials: LK
authors.lastname: Duin
authors.forename: C
authors.initials: C
authors.lastname: Willekes
authors.forename: M
authors.initials: M
authors.lastname: Vossen
authors.forename: M
authors.initials: M
authors.lastname: Beckers
authors.forename: J
authors.initials: J
authors.lastname: Offermans
authors.forename: J G
authors.initials: JG
authors.lastname: Nijhuis
mesh_terms: D000704:Analysis of Variance; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000196:embryology; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007682:Kidney Pelvis / Q000000981:diagnostic imaging* / Q000196:embryology; D015588:Observer Variation; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal / Q000379:methods*