181 - Altered Placental Perfusion in Pregnancies Complicated by Fetal Congenital Heart Disease

Publication Number: 181.3795

Rachel L.. Leon, University of Texas Southwestern Medical School, Dallas, TX, United States; Marjorie Navalta, The University of Texas Southwestern, Dallas, TX, United States; Joshua S.. Greer, Philips, Cincinnati, OH, United States; Ananth Madhuranthakam, Mayo Clinic, Rochester, MN, United States; Durga Udayakumar, Mayo Clinic, Rochester, MN, United States

Background: The etiology of congenital heart disease (CHD) is unknown in the majority of patients. The placenta has emerged as a potential contributor in some forms of CHD, which purportedly arises from hemodynamic disturbances between the fetal heart and placenta as they develop concurrently. In vivo evaluation of placental perfusion may provide insights into whether placental hemodynamics is altered in pregnancies complicated by fetal CHD.

Objective: To test the feasibility of non-contrast quantitative perfusion magnetic resonance imaging (MRI) at 1.5 Tesla using Flow Alternating Inversion Recovery Arterial Spin Labeling (FAIR-ASL) to non-invasively measure in vivo human placental perfusion in a pilot cohort of patients with pregnancies complicated by fetal CHD.

Design/Methods: In this prospective, pilot feasibility study, we recruited pregnant people in 2nd or 3rd trimester with fetuses diagnosed with moderate to severe CHD and healthy controls. MRI was performed on a 1.5 T MR scanner using our own implementation of the FAIR sequence. The FAIR sequence began by saturating the imaging region, followed by labeling with a pair of slice-selective and slab-selective inversions in successive repetitions, using a hyperbolic secant pulse centered on the imaging region. For each subject, one of the two slices closest towards the maternal side with measurable perfusion was used for analysis. Quantitative perfusion values were measured using a region of interest drawn over the entire placenta (Figure 1). We examined differences between groups at GA < 32 weeks and GA ≥32 weeks. The mean perfusion values were compared between cohorts using Mann-Whitney U test.

Results: Our pilot cohort of 30 pregnant subjects included 20 with healthy fetus at 24+1 to 36+1 weeks gestation and 10 with pregnancy complicated by fetal CHD imaged at 27+4 to 38+2 weeks gestation. Placental perfusion images were successfully acquired in all subjects (Figure 2A). The mean placental perfusion at GA < 32 weeks was 106±58 mL/100g/min for subjects with CHD fetus and 61±21 mL/100g/min for subjects with healthy fetus (P < 0.05) (Figure 2B). The corresponding placental perfusion for GA≥32 weeks was 86±28 mL/100g/min for subjects with CHD fetus and 84±32 mL/100g/min for subjects with normal fetus and was not significantly different (Figure 2C).

Conclusion(s): FAIR-ASL is a novel, noninvasive, and feasible method to measure placental perfusion in vivo. In our pilot cohort we found that early placental perfusion is significantly higher in pregnancies complicated by fetal CHD compared to healthy controls, but these differences do not persist beyond 32 weeks gestation.

Representative Flow Alternating Inversion Recovery Arterial Spin Labeling (FAIR-ASL) Images and Perfusion Analysis.
Representative quantitative perfusion map (A), overlaid on anatomical T2-weighted coronal image (B), and the prescribed slices (orange and green lines) shown on sagittal T2 image (C) in a 23 year old pregnant subject with CHD fetus at 32+5 weeks gestation. Colorbar represents 0-300 mL/100g/min.

Comparison of Placental Perfusion in Healthy and Fetal CHD Placentas at <32 and ≥32 Weeks Gestation Using FAIR-ASL
Panel A: Representative quantitative perfusion maps (left) and overlaid perfusion maps on anatomical T2-weighted images (right), shown for a 33 year old pregnant subject with healthy fetus at 28+5 weeks gestation (top) and 35 year old pregnant subject with CHD fetus (Tetrology of Fallot) at 29+2 weeks gestation (bottom). Colorbar represents 0-300 mL/100g/min. Panel B: Quantitative placental perfusion measured using FAIR-ASL showed significantly higher perfusion in CHD fetus compared to healthy fetus at gestation age <32 weeks (P <0.05). Panel C: Placental perfusion values were not significantly different between CHD and healthy fetuses at ≥32 weeks gestation.