Placental MRI: Effect of Maternal Position and Uterine Contractions on Placental BOLD MRI Measurements


Esra Abaci Turk, Mazdak S Abulnaga, Jie Luo, Jeffrey N Stout, Henry A Feldman, Ata Turk, Borjan Gagoski, Lawrence L Wald, Elfar Adalsteinsson, Drucilla J Roberts, Carolina Bibbo, Julian N Robinson, Polina Golland, Ellen P Grant, and William H Barth. 2020. “Placental MRI: Effect of Maternal Position and Uterine Contractions on Placental BOLD MRI Measurements.” Placenta, 95, Pp. 69-77.


INTRODUCTION: Before using blood-oxygen-level-dependent magnetic resonance imaging (BOLD MRI) during maternal hyperoxia as a method to detect individual placental dysfunction, it is necessary to understand spatiotemporal variations that represent normal placental function. We investigated the effect of maternal position and Braxton-Hicks contractions on estimates obtained from BOLD MRI of the placenta during maternal hyperoxia. METHODS: For 24 uncomplicated singleton pregnancies (gestational age 27-36 weeks), two separate BOLD MRI datasets were acquired, one in the supine and one in the left lateral maternal position. The maternal oxygenation was adjusted as 5 min of room air (21% O), followed by 5 min of 100% FiO. After datasets were corrected for signal non-uniformities and motion, global and regional BOLD signal changes in R* and voxel-wise Time-To-Plateau (TTP) in the placenta were measured. The overall placental and uterine volume changes were determined across time to detect contractions. RESULTS: In mothers without contractions, increases in global placental R* in the supine position were larger compared to the left lateral position with maternal hyperoxia. Maternal position did not alter global TTP but did result in regional changes in TTP. 57% of the subjects had Braxton-Hicks contractions and 58% of these had global placental R* decreases during the contraction. CONCLUSION: Both maternal position and Braxton-Hicks contractions significantly affect global and regional changes in placental R* and regional TTP. This suggests that both factors must be taken into account in analyses when comparing placental BOLD signals over time within and between individuals.
Last updated on 06/08/2020