title: Relaxation properties of human umbilical cord blood at 1.5 Tesla.
abstract: To characterize the MRI relaxation properties of human umbilical cord blood at 1.5 Tesla.
  
  
  
  Relaxometry measurements were performed on cord blood specimens (N = 88, derived from six caesarean deliveries) spanning a broad range of hematocrits (Hct = 0.19-0.76) and oxygen saturations (sO2= 4-100%), to characterize the dependence of T1and T2on these blood properties. Adult blood data (N = 31 specimens, derived from two volunteers) were similarly studied to validate our experimental methods by comparison with existing literature. Using biophysical models previously developed for adult blood, new model parameters were estimated, which relate Hct and sO2to the observed cord blood relaxation times.
  
  
  
  Fitted biophysical models explained more than 90% of the variation in T1and T2. In general, T2relaxation times of cord blood were longer (by up to 35%) than those of adult blood, whereas T1relaxation times were slightly shorter (by up to 10%).
  
  
  
  The models and fitted parameters presented here can be used for calibration of future MRI investigations of fetal and neonatal blood physiology. This study is an important step in facilitating accurate, noninvasive assessments of fetal blood oxygen content, a valuable diagnostic parameter in the identification and treatment of fetal hypoxia. Magn Reson Med 77:1678-1690, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.|Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Sharon
authors.initials: S
authors.lastname: Portnoy
authors.affiliation: Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Osmond
authors.affiliation: Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
authors.forename: Meng Yuan
authors.initials: MY
authors.lastname: Zhu
authors.affiliation: Division of Cardiology, Hospital for Sick Children, Toronto, ON, Canada.|Department of Pediatrics and Diagnostic Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Mike
authors.initials: M
authors.lastname: Seed
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.|Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada.|Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.
authors.forename: John G
authors.initials: JG
authors.lastname: Sled
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.|Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, ON, Canada.|Labatt Family Heart Centre, Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Macgowan
mesh_terms: D003198:Computer Simulation; D017097:Electric Impedance; D005312:Fetal Blood / Q000737:chemistry* / Q000000981:diagnostic imaging*; D006801:Humans; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008955:Models, Cardiovascular; D008956:Models, Chemical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: fetus; hematocrit; longitudinal relaxation time; oxygenation; transverse relaxation time; umbilical cord blood