Could the falcine sinus hold the key to vein of Galen outcomes?

A Boston Children’s Hospital study uncovers how fetal magnetic resonance imaging (MRI) could be a game-changer in predicting outcomes for infants born with vein of Galen malformations (VOGMs). The study, just published in Stroke, focused on the width of the falcine sinus (FS) — the fetal structure that channels blood from the malformation back to the normal venous sinuses of the brain and, from there, to the rest of the circulation. All of which is clearly visible on fetal MRI, offering an important tool to guide clinical decisions, improve parental counseling, and optimize care for infants with these potentially life-threatening blood vessel abnormalities.

“We’re getting a clearer picture of how MRI can help us predict not just survival, but also long-term developmental and neurological outcomes for infants with VOGM,” Darren Orbach, MD, PhD, chief of Neurointerventional Radiology at Boston Children’s and lead author of the study.

What the falcine sinus can tell us

Researchers in the Cerebrovascular Surgery and Interventions Center found that determining FS, a simple but powerful measurement that can be achieved on almost any good quality fetal MRI scan, can help predict clinical outcomes such as developmental milestones, neurological and cardiac health, and overall survival.

In a retrospective study of 59 fetal subjects diagnosed with VOGM, the team found that larger FS diameters were associated with higher risks of developmental delays, neurological issues like brain abnormalities and persistent ventriculomegaly, cardiovascular conditions such as pulmonary hypertension and right ventricular dysfunction, and higher mortality. Infants with FS measurements over 9 mm had a greater than 90 percent mortality rate. In contrast, infants with an FS measurement of 5 mm or smaller had a mortality rate of under 20 percent. In terms of the risk of not meeting developmental milestones at age one year, fetuses of 4 mm or smaller had a greater than 70 percent chance of meeting milestones, while those with FS of seven or greater had less than a one in three chance of doing so.

How falcine sinus size guides VOGM treatment and follow-up care

It is well known that early intervention, such as endovascular embolization and expert NICU and cardiology care, are essential for good outcomes in newborns with aggressive VOGM. What this study demonstrates is that even accounting for treatment at an expert referral center, FS size remains an important factor in an infant’s prognosis, even after treatment.

“Several years ago, we had shown in that FS was strongly predictive of the baby becoming acutely ill in the NICU in the first few days after birth. This paper goes far beyond that, and shows that sinus size isn’t just a predictor of outcomes before any interventions; it also continues to provide valuable information about the child’s health and prognosis, regardless of the treatment given.”

Orbach says that measuring the FS prenatally can help providers predict the need for urgent care or more aggressive treatments after birth. Regular follow-up is critical for infants with larger sinuses, as they’re at higher risk of ongoing challenges such as ventriculomegaly and developmental delays.

What this means for patients and clinical practice

The group’s findings suggest that FS measurement can reliably predict short- and intermediate-term outcomes in infants with VOGM. It can help identify high-risk patients earlier, leading to more in-depth and informative discussions with prospective parents, faster intervention, more tailored treatment, and better outcomes. Orbach and his team have developed a new fetal surgical approach for treating high-risk fetuses with VOGM, and this study underscores that those high-risk fetuses face a daunting prognosis using current postnatal treatment approaches.

As for what comes next, Orbach says the study underscores the need for future research focused on identifying specific patient characteristics that will help determine the best treatments for them and then refining those treatments.

“This work paves the way for new and revised guidelines for vein of Galen intervention,” says Orbach. “It’s an exciting step toward more proactive care.”