Advanced MRI detects placental abnormalities early in CHD-affected pregnancies

Specialized imaging technology known as velocity-selective arterial spin labeling (VSASL) could detect placental abnormalities in fetuses affected by congenital heart disease (CHD) before they become irreversible, a Children’s National Health System research team has announced.

Congenital heart disease is a common birth defect, affecting eight in 1,000 newborns worldwide, lead researcher and author Catherine Limperopoulos, PhD, and colleagues wrote in Scientific Reports, and can lead to fetal abnormalities like growth restriction and preeclampsia if untreated. To ensure a newborn’s healthy growth, placental arteries dynamically remodel themselves to accommodate the need for increased blood flow during developmental periods; if those arteries are motionless, the fetus risks oxygen and nutrient deprivation.

“The placenta is a vital organ for fetal growth and development during pregnancy,” Limperopoulos et al. wrote. “Despite the parallel development of the placenta and fetal heart early in pregnancy, very few studies suggested an association between placental dysfunction and fetal CHD.”

The researchers recruited 48 pregnant women for their trial—31 healthy volunteers and 17 diagnosed with fetal CHD—and used advanced MRI techniques, namely VSASL, to achieve placental perfusion imaging. VSASL, which directly measures the rate of delivery of arterial blood to organs like the brain, was paired with 3D image acquisition for whole-placenta coverage, according to the study.

The trial marks the first time non-invasive whole-placental perfusion was imaged in utero.

Limperopoulos and co-authors found that in pregnancies affected by CHD, glocal placental perfusion significantly decreased, while regional variation of placental perfusion significantly increased with advancing gestational age. The same wasn’t true, however, for healthy pregnancies.

“Just like the human brain, heart and kidneys—organs that can commandeer heightened blood flow when needed—the placenta may employ an autoregulatory mechanism to optimize perfusion,” Limperopoulos said in a release from the Children’s National Health System. “The early increased global placental perfusion in  pregnancies complicated by CHD may represent an attempt to correct for insufficient fetal blood flow.”

Global placental perfusion also appeared to be significantly higher in fetal CHD versus control cases, the authors reported, in the lateral side-lying patient position versus supine and in the posterior placental position versus anterior placental position.

These results suggest placental VSASL could be a biomarker of placental dysfunction in CHD-diagnosed fetuses, the study read.

“The predictive value of VSASL imaging, which we continue to study, holds the promise of detecting dysfunction before placental abnormalities become irreversible,” Limperopoulos said in the release.