Longitudinal Placental Blood Volume Measurements in Zika-Infected Rhesus Macaques Using Ferumoxytol Enhanced MRI.

Area of Science:

• Biomedical Imaging
• Maternal-Fetal Medicine
• Primate Models

Background:

• Placental vasculature deficiencies can impact pregnancy outcomes.
• Accurate measurement of maternal fractional blood volume (mFBV) is crucial for diagnosis.
• Current methods for quantitative blood volume mapping are challenging for clinical use.

Purpose of the Study:

• To assess the feasibility of ferumoxytol-enhanced variable flip angle (VFA) T1-mapping for measuring mFBV.
• To evaluate this technique in a non-human primate model, specifically Zika-infected rhesus macaques.
• To establish a preliminary method for potential human clinical applications.

Main Methods:

• Seven pregnant rhesus macaques were longitudinally imaged across gestation.
• Four macaques received Zika virus (ZIKV) injection; three served as controls.
• Quantitative mFBV was assessed using ferumoxytol-enhanced VFA T1-mapping with T1-weighted spoiled gradient echo sequences.

Main Results:

• Successful acquisition and analysis of all scans with no significant motion artifacts.
• 3D mFBV maps revealed regional heterogeneities within placental slices.
• Both FBV and total placental blood volume showed an increasing trend with advancing gestation.

Conclusions:

• Ferumoxytol-enhanced VFA T1-mapping is a feasible method for measuring mFBV in non-human primates.
• This technique holds promise for future clinical evaluation of placental health.
• The study provides a foundation for developing non-invasive diagnostic tools for placental disorders.