title: Exorenal circulation of pediatric kidney: evaluation with Power Doppler imaging.
abstract: OBJECTIVE
  The aims of the study were to evaluate the ability of Power Doppler (PD) sonography to demonstrate the collateral circulation of the kidney in pediatric patients and to assess the change in this circulation in patients with decreased cortical blood flow.
  
  
  METHODS
  Seventy-seven children were studied by PD sonography to identify capsular and perforating collateral vessels. The study included healthy subjects and patients with acute pyelonephritis (APN) or prenatal pyelectasia. Three age groups were established: neonates, children from 1 month to 2 years old, and a group from 2 to 15 years old.
  
  
  RESULTS
  In all neonates, PD sonography was able to identify perforating vessels and the exorenal arcade. In the group of children age 1 month to 2 years, perforating vessels and the exorenal arcade were also visualized. Patients of this group affected by APN presented an increased caliber of capsular vessels surrounding avascular pyelonephritic areas. In the group ranging from 2 to 15 years old, capsular and perforating vessels were seen in the younger children. There was a decrease in caliber and number of vessels in older children.
  
  
  CONCLUSIONS
  Exorenal circulation can be visualized in the normal pediatric kidney by the use of PD sonography. Caliber and number of vessels are greater during the neonatal period and decrease in older children. Our results also suggest that hypoperfused conditions, such as extensive APN, may cause variations of this vascularity.
authors.affiliation: Department of Radiology, Hospital General de Granollers, University of Barcelona, Av. Francesc Ribas s/n, Granollers 08400 (Barcelona), Spain.
authors.forename: Victoria Garriga
authors.initials: VG
authors.lastname: Farriol
authors.forename: Nuria Rosón
authors.initials: NR
authors.lastname: Gradaille
authors.forename: Xavier Pruna
authors.initials: XP
authors.lastname: Comella
authors.forename: Miguel Cuadrado
authors.initials: MC
authors.lastname: Blázquez
authors.forename: Mateo Martinez
authors.initials: MM
authors.lastname: Hervas
authors.forename: Manoli Zarcero
authors.initials: MZ
authors.lastname: Estévez
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011446:Prospective Studies; D011704:Pyelonephritis / Q000000981:diagnostic imaging*; D012016:Reference Values; D012039:Regional Blood Flow / Q000502:physiology; D012079:Renal Circulation / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color / Q000379:methods*