title: In vivo MRI measurement of blood oxygen saturation in children with congenital heart disease.
abstract: OBJECTIVE
  The purpose of this prospective study was to measure in vivo blood oxygen saturation (%O2) by MRI in children with congenital heart disease (CHD) using population-based values for T2O (T2 signal decay of fully oxygenated blood) and K (a parameter representing the deoxyhemoglobin effect) and compare the %O2 with direct cardiac catheterization measurements.
  
  
  BACKGROUND
  MRI can determine %O2 using in vivo measurement of signal decay (T2) and an in vitro calibration curve relating T2 and %O2, based on the equation: 1/T2 = 1/T2O + K(1-%O2/100)2. Recent studies have correlated the T2/%O2 in children with CHD with the adult calibration statistics.
  
  
  METHODS
  A total of ten children (five male, five female) with single ventricle CHD (median age 4.8 months, range 2 months to 4.4 years) undergoing cardiac catheterization were included in the study. The blood T2 measurements for each patient were performed in a 1.5 T GE CV scanner. The %O2 was then calculated based on the equation using values of T2O determined from individual hematocrits, and a population average value of K derived for children. The %O2 values were compared with direct %O2 measurements from cardiac catheterization.
  
  
  RESULTS
  The %O2 values by MRI were strongly correlated with direct cardiac catheterization measurements (R = 0.825; P < 0.001).
  
  
  CONCLUSIONS
  The study indicates that the noninvasive measurement of %O2 by MRI can accurately measure oxygen saturation in children with complex CHD.
authors.affiliation: The Hospital for Sick Children, Department of Paediatrics, Division of Cardiology, University of Toronto, 555 University Ave., Toronto, Ontario, Canada, M5G 1X8. steveandlynne@rogers.com
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Nield
authors.forename: Xiu-Ling L
authors.initials: XL
authors.lastname: Qi
authors.forename: Emanuela R
authors.initials: ER
authors.lastname: Valsangiacomo
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Macgowan
authors.forename: Graham A
authors.initials: GA
authors.lastname: Wright
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Hornberger
authors.forename: Shi-Joon
authors.initials: SJ
authors.lastname: Yoo
mesh_terms: D001011:Aorta / Q000473:pathology; D006328:Cardiac Catheterization; D002675:Child, Preschool; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006330:Heart Defects, Congenital / Q000097:blood* / Q000473:pathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000473:pathology; D014683:Vena Cava, Superior / Q000473:pathology
chemical_list: D010100:Oxygen