title: Renal Parenchymal Area Growth Curves for Children 0 to 10 Months Old.
abstract: OBJECTIVE
  Low renal parenchymal area, which is the gross area of the kidney in maximal longitudinal length minus the area of the collecting system, has been associated with increased risk of end stage renal disease during childhood in boys with posterior urethral valves. To our knowledge normal values do not exist. We aimed to increase the clinical usefulness of this measure by defining normal renal parenchymal area during infancy.
  
  
  METHODS
  In a cross-sectional study of children with prenatally detected mild unilateral hydronephrosis who were evaluated between 2000 and 2012 we measured the renal parenchymal area of normal kidney(s) opposite the kidney with mild hydronephrosis. Measurement was done with ultrasound from birth to post-gestational age 10 months. We used the LMS method to construct unilateral, bilateral, side and gender stratified normalized centile curves. We determined the z-score and the centile of a total renal parenchymal area of 12.4 cm(2) at post-gestational age 1 to 2 weeks, which has been associated with an increased risk of kidney failure before age 18 years in boys with posterior urethral valves.
  
  
  RESULTS
  A total of 975 normal kidneys of children 0 to 10 months old were used to create renal parenchymal area centile curves. At the 97th centile for unilateral and single stratified curves the estimated margin of error was 4.4% to 8.8%. For bilateral and double stratified curves the estimated margin of error at the 97th centile was 6.6% to 13.2%. Total renal parenchymal area less than 12.4 cm(2) at post-gestational age 1 to 2 weeks had a z-score of -1.96 and fell at the 3rd percentile.
  
  
  CONCLUSIONS
  These normal renal parenchymal area curves may be used to track kidney growth in infants and identify those at risk for chronic kidney disease progression.
authors.affiliation: Division of Urological Surgery, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Katherine
authors.initials: K
authors.lastname: Fischer
authors.affiliation: Center for Biomedical Image Analysis, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Chunming
authors.initials: C
authors.lastname: Li
authors.affiliation: Center for Biomedical Image Analysis, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Huixuan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Center for Biomedical Image Analysis, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Division of Nephrology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Susan
authors.initials: S
authors.lastname: Furth
authors.affiliation: Division of Urological Surgery, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Division of Pediatric Urology, Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; Center for Pediatric Clinical Effectiveness, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. Electronic address: tasiang@chop.edu.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Tasian
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D057238:Growth Charts; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000033:anatomy & histology* / Q000254:growth & development*; D008297:Male; D009929:Organ Size; D012016:Reference Values
keywords: abnormalities; chronic; kidney; organ size; renal insufficiency; ultrasonography