title: Sonographic evaluation of hydronephrosis in the pediatric population: is well-tempered sonography necessary?
abstract: OBJECTIVE
  Standardized protocols exist for diuretic renography. There are no specific guidelines regarding hydration before renal sonography. This study assessed the importance of the hydration status by sonographic measurements of the anteroposterior diameter and its effect on Society for Fetal Urology (SFU) hydronephrosis grading.
  
  
  METHODS
  Children aged 6 weeks to 16 years (mean age, 22 months) with unilateral SFU grade 3 or 4 hydronephrosis requiring diuretic renal scintigraphy were recruited to undergo prehydration and posthydration renal sonography. Hydrated diuretic renal scintigraphy, or "well-tempered" renography, was then performed. Renal sonograms were reviewed by a blinded pediatric radiologist and pediatric urologist. Two-sided statistical tests assessed whether SFU grades and the anteroposterior diameter changed significantly after hydration.
  
  
  RESULTS
  Among 67 kidneys, the pediatric urologist (L.P.M.) and pediatric radiologist (V.J.R.) reported no SFU grade change in 45 (67%) and 52 (78%) kidneys after hydration. In kidneys that changed, the posthydration grade was more likely to be higher. This difference was statistically significant (14 of 22 and 13 of 15 differences were higher grades after hydration for L.P.M. and V.J.R., respectively; P= .06; P= .007). Most kidneys that changed with hydration differed by only 1 SFU grade. Differences greater than 1 grade were seen in 5 control kidneys, which increased from SFU grade 0 to 2. The mean anteroposterior diameter increased significantly between prehydration and posthydration sonography for both hydronephrotic kidneys (1.46 versus 1.72 cm; P< .001) and control kidneys (0.22 versus 0.39 cm; P= .019), but did not correlate with increased SFU grades.
  
  
  CONCLUSIONS
  Hydration does have a substantial effect on the anteroposterior diameter, but it does not correlate with a substantial effect on the SFU grade; therefore, well-tempered sonography seems unnecessary.
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA. walkmr@gmail.com.
authors: Marc R
authors: MR
authors: Walker
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Sarkis
authors: S
authors: Babikian
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Alexander J
authors: AJ
authors: Ernest
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Troy S
authors: TS
authors: Koch
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Michael B
authors: MB
authors: Lustik
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Veronica J
authors: VJ
authors: Rooks
authors: Urology Service, Department of Surgery (M.R.W., A.J.E., L.P.M.), Pediatric Radiology Service, Department of Radiology (S.B., T.S.K., V.J.R.), and Department of Clinical Investigation (M.B.L.), Tripler Army Medical Center, Honolulu, Hawaii USA.
authors: Leah P
authors: LP
authors: McMann
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003950:Diagnostic Techniques, Urological; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging*; D007223:Infant; D008297:Male; D011446:Prospective Studies; D014463:Ultrasonography / Q000379:methods
keywords: Society for Fetal Urology grade; anteroposterior diameter; hydration; pediatric ultrasound; prenatal hydronephrosis; sonography