Relaxation properties of human umbilical cord blood at 1.5 Tesla

Sharon Portnoy; Mark Osmond; Meng Yuan Zhu; Mike Seed; John G Sled; Christopher K Macgowan

doi:10.1002/mrm.26231

Relaxation properties of human umbilical cord blood at 1.5 Tesla

Magn Reson Med. 2017 Apr;77(4):1678-1690. doi: 10.1002/mrm.26231. Epub 2016 Apr 5.

Authors

Sharon Portnoy^{1

2}, Mark Osmond³, Meng Yuan Zhu⁴, Mike Seed^{5

6}, John G Sled^{1

2

3}, Christopher K Macgowan^{1

7

8}

Affiliations

¹ Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
² Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada.
³ Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.
⁴ Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
⁵ Division of Cardiology, Hospital for Sick Children, Toronto, ON, Canada.
⁶ Department of Pediatrics and Diagnostic Imaging, University of Toronto, Toronto, ON, Canada.
⁷ Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, ON, Canada.
⁸ Labatt Family Heart Centre, Hospital for Sick Children, Toronto, ON, Canada.

Abstract

Purpose: To characterize the MRI relaxation properties of human umbilical cord blood at 1.5 Tesla.

Methods: 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 T₁ and T₂ on 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 sO₂ to the observed cord blood relaxation times.

Results: Fitted biophysical models explained more than 90% of the variation in T₁ and T₂ . In general, T₂ relaxation times of cord blood were longer (by up to 35%) than those of adult blood, whereas T₁ relaxation times were slightly shorter (by up to 10%).

Conclusions: 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.

Keywords: fetus; hematocrit; longitudinal relaxation time; oxygenation; transverse relaxation time; umbilical cord blood.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Computer Simulation
Electric Impedance
Fetal Blood / chemistry*
Fetal Blood / diagnostic imaging*
Humans
Magnetic Fields*
Magnetic Resonance Imaging / methods*
Models, Cardiovascular*
Models, Chemical*
Reproducibility of Results
Sensitivity and Specificity

Grants and funding

130403-1/Canadian Institutes of Health Research/Canada