Fetal MRI could outperform ultrasound in catching holoprosencephaly early
Fetal MRI can accurately diagnose holoprosencephaly as early as 18 weeks into a pregnancy, researchers from the Children’s National Health System in Washington, D.C., reported this week, providing parents with added time to prepare for the realities of caring for a child with complex care needs.
A team led by Children’s child neurology fellow Youssef A. Kousa, MS, DO, PhD, found the imaging modality could identify holoprosencephaly—a condition established around five weeks into pregnancy when a fetus’s brain fails to separate into its cerebral halves—up to six weeks before a traditional ultrasound would.
“Because of the strong link between the severity of brain abnormality and clinical outcomes, such early and accurate imaging is important for counseling families,” Kousa said in a release from Children’s.
Holoprosencephaly affects around one or two of every 10,000 live births, Kousa and co-authors wrote in the American Journal of Medical Genetics. But because it can be a severe brain defect, a few extra weeks of preparation can go a long way for an expectant family. And while prenatal ultrasound can diagnose the condition’s most severe forms based on abnormal facial features at 24 weeks, the method often struggles to distinguish between severe holoprosencephaly and other brain abnormalities.
During their study, Kousa et al. proved fetal MRI’s efficacy in identifying holoprosencephaly during a woman’s second trimester. Aside from that original finding, the team was also able to expand the current spectrum of holoprosencephaly phenotypes and some milder variants, including the more severe aprosencephaly, alobar, middle interhemispheric, semilobar and lobar forms of the defect.
“Using fetal MRI, holoprosencephaly and its severity can be accurately established by 18 weeks of gestation and, in some cases, in fetuses as young as 16 weeks,” Kousa said. “Our findings and our detailed descriptions of the differences between disease variants should help to inform these important conversations during complicated pregnancies.”