Imaging putative foetal cerebral blood oxygenation using susceptibility weighted imaging (SWI)
To evaluate the magnetic susceptibility, ∆χ v , as a surrogate marker of venous blood oxygen saturation, S v O 2, in second- and third-trimester normal human foetuses.
Thirty-six pregnant women, having a mean gestational age (GA) of 31 2/7 weeks, underwent magnetic resonance imaging (MRI). Susceptibility-weighted imaging (SWI) data from the foetal brain were acquired. ∆χ v of the superior sagittal sinus (SSS) was quantified using MR susceptometry from the intra-vascular phase measurements. Assuming the magnetic property of foetal blood, ∆χ do , is the same as that of adult blood, S v O 2 was derived from the measured Δχ v . The variation of ∆χ v and S v O 2, as a function of GA, was statistically evaluated.
The mean ∆χ v in the SSS in the second-trimester (n = 8) and third-trimester foetuses (n = 28) was found to be 0.34± 0.06 ppm and 0.49 ±0.05 ppm, respectively. Correspondingly, the derived S v O 2 values were 69.4% ±3.27% and 62.6% ±3.25%. Although not statistically significant, an increasing trend (p = 0.08) in Δχ v and a decreasing trend (p = 0.22) in S v O 2 with respect to advancing gestation was observed.
We report cerebral venous blood magnetic susceptibility and putative oxygen saturation in healthy human foetuses. Cerebral oxygen saturation in healthy human foetuses, despite a slight decreasing trend, does not change significantly with advancing gestation.
• Cerebral venous magnetic susceptibility and oxygenation in human foetuses can be quantified.
• Cerebral venous oxygenation was not different between second- and third-trimester foetuses.
• Foetal cerebral venous oxygenation does not change significantly with advancing gestation.
KeywordsSusceptibility-weighted imaging (SWI) Foetal Brain Oxygen saturation Susceptometry
Magnetic resonance imaging
Superior sagittal sinus
Venous oxygen saturation
Magnetic susceptibility difference between fully oxygenated and deoxygenated foetal blood
Foetal heart rate
The authors would like to thank Maria Cabrera and the research staff at the PRB for their help in volunteer recruitment.
Compliance with ethical standards
The scientific guarantor of this publication is Dr. Jaladhar Neelavalli, PhD.
Conflict of interest
The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
Statistics and biometry
One of the authors has significant statistical expertise.
Written informed consent was obtained from all subjects (patients) in this study.
Institutional Review Board approval was obtained.
• performed at one institution
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