Perfusion and apparent oxygenation in the human placenta (PERFOX)

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging
• Physiology

Background:

• Placental function is crucial for fetal development, involving both perfusion and oxygenation.
• Current methods often assess perfusion and oxygenation separately, limiting comprehensive in vivo analysis.
• Quantitative, simultaneous assessment of these parameters is needed to understand placental health and disease.

Purpose of the Study:

• To simultaneously and quantitatively assess placental perfusion and oxygenation (using T2* as a surrogate) in vivo.
• To develop and validate a novel integrated MRI acquisition protocol (PERFOX) for this purpose.
• To evaluate changes in placental perfusion and T2* with advancing gestational age.

Main Methods:

• Fifteen pregnant women underwent MRI scans using a 3T scanner.
• A velocity-selective arterial spin labeling module was combined with a multi-echo gradient echo EPI readout.
• This integrated approach, termed PERFOX, allowed simultaneous measurement of T2* and perfusion, followed by motion correction and quantification.

Main Results:

• The PERFOX protocol successfully visualized and quantified placental perfusion and T2* in all participants.
• High perfusion areas correlated with the maternal basal plate, while high T2* areas correlated with the fetal chorionic plate.
• Gestational age showed a strong negative correlation with T2* and a weak negative correlation with perfusion.

Conclusions:

• The PERFOX sequence provides simultaneous, co-registered estimates of placental T2* and perfusion.
• While scan time per slice is increased, this method is valuable for quantifying transient physiological events.
• PERFOX offers a new approach to investigate the relationship between maternal supply and oxygen uptake in placental function and dysfunction.