title: Age-related decrease in cardiopulmonary adrenergic neuronal function in children as assessed by I-123 metaiodobenzylguanidine imaging.
abstract: BACKGROUND
  Radioiodinated metaiodobenzylguanidine (MIBG) imaging has been used to evaluate adrenergic nerve activity in different organs. Cardiac and pulmonary MIBG uptake is important in predicting the prognosis of certain cardiopulmonary diseases. It has been reported that cardiac MIBG uptake decreases with age and is significantly lower in the elderly. However, there has been no systemic study on age-related changes in cardiac and pulmonary MIBG uptake in children. This study was undertaken to determine the changes in MIBG uptake in the developing heart and lung in children and adolescents.
  
  
  RESULTS
  MIBG scans of 44 children (16 female and 28 male; age range, 2 months to 19 years) without abnormal uptake were selected from a large pool of patients with whole-body MIBG imaging performed for evaluation of neuroblastoma. All of the selected subjects had a normal physiologic distribution of MIBG and no history of heart or lung diseases. The patients were divided into 4 groups by age: group 1, 0 to 24 months; group 2, 25 to 48 months; group 3, 49 to 72 months; and group 4, 73 months or greater. Cardiac and pulmonary MIBG uptake values (expressed as heart-to-mediastinum [H/M] ratio and lung-to-mediastinum [L/M] ratio, respectively) were determined and compared among the 4 groups. H/M and L/M ratios were noted to decrease with age. The mean H/M and L/M ratios were in group 1, 4.13 +/- 0.66 and 1.53 +/- 0.18, respectively; in group 2, 3.46 +/- 0.71 and 1.26 +/- 0.18, respectively; in group 3, 3.19 +/- 0.94 and 1.13 +/- 0.17, respectively; and in group 4, 2.84 +/- 0.48 and 1.14 +/- 0.14, respectively. There was a significant inverse correlation between H/M ratio and age (r = 0.711, P < .001) as well as between L/M ratio and age (r = 0.718, P < .001).
  
  
  CONCLUSIONS
  Cardiac and pulmonary MIBG uptake is inversely related to age in children.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania,, Philadelphia, PA, USA.
authors.forename: Wengen
authors.initials: W
authors.lastname: Chen
authors.forename: Elias H
authors.initials: EH
authors.lastname: Botvinick
authors.forename: Abass
authors.initials: A
authors.lastname: Alavi
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Steven
authors.initials: S
authors.lastname: Yang
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Perini
authors.forename: Hongming
authors.initials: H
authors.lastname: Zhuang
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation; D006801:Humans; D007223:Infant; D008168:Lung / Q000000981:diagnostic imaging / Q000294:innervation* / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009474:Neurons / Q000000981:diagnostic imaging / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D009638:Norepinephrine