NeoQuest July 2025: A Newborn Infant With a Posterior Fossa Abnormality Free

A male infant, born at 37 weeks’ gestation, is cyanotic and tachypneic after delivery, with an Apgar score of 6 and 9 at 1 and 5 minutes of age, respectively. The infant is placed on high-flow nasal cannula and admitted to the neonatal intensive care unit. A third-trimester prenatal ultrasonography was concerning for a posterior fossa abnormality. The infant undergoes brain magnetic resonance imaging (MRI) after stabilization (Figure 1).

Figure 1: Axial brain MRI for the infant in the vignette. Image from: Romald JH, Tiwari P, George L. Outcome of late preterm infant. Neoreviews. 2025;26(7):e516–e523.¹

Based on the results of the brain MRI, which would be the most appropriate next diagnostic investigation for this infant?

1. Echocardiogram
2. Lumbar puncture
3. Renal ultrasonography
4. Whole genome sequencing

Answer: Option A.  Echocardiogram

Explanation:

The brain MRI for this infant shows a large void in the region of the porencephalic vein (Figure 1). This finding is consistent with a vein of Galen malformation (VGM). VGMs are congenital malformations of the cerebral vasculature.² Despite the condition’s name, the vein of Galen is not usually the dilated vessel. There is an embryonic venous structure called the median porencephalic vein of Markowski that normally involutes at 11 weeks’ gestation. However, in VGM, this structure persists, and fistula formations connect it to the choroidal circulation, which causes it to enlarge.³ The condition may be diagnosed prenatally based on fetal ultrasonography, or it may not be diagnosed until postnatal life.

Cranial ultrasonography is initially performed as part of the postnatal diagnostic evaluation of VGM. Images in affected infants show a dilated vessel in the posterior fossa (Figure 2). Following, brain MRI and magnetic resonance angiography (MRA) are obtained to better delineate the intracranial anatomy. As in Figure 1, the MRI will show a dilated VGM. The images may also reveal hydrocephalus and dilation of the falcine and straight sinuses (Figure 3).⁴

Figure 2: Coronal view of a cranial ultrasound of an infant with a vein of Galen malformation. The ultrasound demonstrates dilation of a venous structure in the posterior fossa (black arrow). Image from: Aemissegger B, Presti A, Rios J. Case 2: Premature infant with a fontanelle bruit. Neoreviews. 2015 July;16(7):e434-436.³

Figure 3: Prenatal brain MRI of a fetus with VGM. The MRI shows dilation of the persistent embryonic median prosencephalic vein (blue arrow), straight sinus (green arrow), and transverse/sagittal sinus confluence (pink arrow). Adapted from: Cordova EG, Levy P, Kheir et al. Vein of Galen malformation. Neoreviews. 2020 Oct;21(10):e678-686.⁴

Infants with VGM are at risk of developing high-output cardiac failure. Therefore, the most appropriate next investigation for this infant is an echocardiogram to assess cardiac dysfunction as a cause of his cyanosis and tachypnea (Option A). The spectrum of presentation varies from mild cardiac symptoms that can be medically managed until endovascular embolization, which usually occurs after 6 months of age, to refractory cardiogenic shock that requires immediate embolization.⁵

In utero, fetuses with VGMs do not develop signs of heart failure because the low-resistance placental circulation competes with the intracerebral shunt, resulting in low flow through the VGM. Affected fetuses may develop pulmonary hypertension due to increased pulmonary blood flow.⁶ The mechanisms for developing pulmonary hypertension are complex and incompletely understood but are hypothesized to be due to blood bypassing the cerebral capillaries—leading to higher oxygen saturations in the superior vena cava, right ventricle (RV), and pulmonary arteries. This causes in utero pulmonary vasodilation, resulting in a three to fourfold increase in blood flow through the pulmonary vascular bed compared to that of healthy fetuses.

After delivery, with clamping of the umbilical cord and removal of the low placental circulation, there is a significant increase in blood flow through the VGM, and heart failure results with systemic hypoperfusion.⁷ The RV in these infants is already experiencing pressure overload, and the addition of volume overload after delivery causes right ventricular dilation and dysfunction. The left ventricle (LV) is also at risk of dysfunction because it must supply both the systemic circulation and the shunt. There may also be diastolic steal by the VGM, which can cause coronary artery ischemia, thereby worsening both LV and RV failure.⁸

Echocardiographic features are variable in infants with VGM. Classically, there is excess volume load in the right heart from increased return through the VGM, so that the right atrium may be dilated (Video 1).

Video 1: Apical four-chamber echocardiogram of an infant with VGM showing dilation of the right atrium. Video from: Cordova EG, Levy P, Kheir et al. Vein of Galen malformation. Neoreviews. 2020;21(10):e678-686.⁴

An echocardiogram will also likely show high RV and LV output, due to the need to supply blood to the shunt. Diastolic “steal” through the arteriovenous malformation may be identified in the aorta and is seen on echocardiogram as reversed diastolic flow.⁸ Signs of persistent pulmonary hypertension may be seen, including persistent right-to-left shunting through a patent ductus arteriosus (if a patent ductus arteriosus is present) and flattening and bowing of the interventricular septum into the LV (which may further impair LV function). An echocardiogram is also important to look for other associated congenital heart defects, including anomalies of pulmonary venous return, aortic arch abnormalities, and both ventricular and atrial septal defects.^5,9

Lumbar puncture (Option B) is not a part of the diagnostic evaluation of vein of Galen malformations, though some infants who present in extremis may undergo a lumbar puncture as part of a sepsis evaluation prior to the VGM diagnosis. Over time, hydrocephalus may develop in VGM due to poor cerebrospinal fluid absorption, intraventricular hemorrhage, or physical obstruction of the cerebral aqueducts by the enlarged venous malformation.¹⁰

Renal ultrasonography (Option C) is not routinely recommended for infants with VGM. Infants are at risk of acute kidney injury due to reduced renal blood flow from shunting through the VGM, so renal function should be closely monitored.

Whole genome sequencing (Option D) may reveal an underlying genetic association with VGM. However, even rapid testing takes up to 5 days to result and thus is not an immediate diagnostic priority. VGM can be seen in capillary malformation-arteriovenous malformation syndrome (due to mutations in RASA1) as well as hereditary hemorrhagic telangiectasia (due to mutations in ENG and ACVRL1), although these account for only a small proportion of VGMs.¹¹ VGM is not a common presenting feature of hereditary hemorrhagic telangiectasia but should be considered as a possibility in infants with a family history of hemorrhagic or mucocutaneous telangiectasias who present with high-output cardiac failure.¹²

The overall mortality of VGM is as high as 50%, and the presence of pulmonary hypertension and heart failure are poor prognostic indicators.⁵ Infants who survive are at high risk of neurodevelopmental impairment. In one review, only 30% of infants were discharged without any neurological impairment.¹³

Did you know?

The Lasjuanias classification divides VGM into two subtypes: choroidal (type I) and mural (type II)¹⁴. The choroidal type has multiple feeding vessels that converge on a fistula on the anterior median prosencephalic vein. The mural type has fewer fistulas, which are present in the subarachnoid space and shunt into the inferolateral wall of the median prosencephalic vein. Type II VGMs typically present later than type I VGMs. Determining the subtype can help guide the timing of intervention.

What other scoring system is available to help guide the timing of embolization? To find the answer, please read the following article: Cordova EG, Levy P, Kheir et al. Vein of Galen malformation. Neoreviews. 2020;21(10):e678-686.⁴

NeoQuest July 2025 Authors:
Andrew Beverstock, MBChB, FAAP, Baylor College of Medicine, Houston, TX
Allison N. J. Lyle, MD, MA, FAAP, University of Louisville, Louisville, KY

References

1. Romald JH, Tiwari P, George L. Outcome of a late preterm infant with prenatally diagnosed Vein of Galen malformation. Neoreviews. 2025;26(7):e516–e523
2. Devarajan A, Goldman D, Shigematsu T, Berenstein A, Fifi JT. Vein of Galen malformations. Neurosurg Clin N Am. 2024;35(3):363-374
3. Aemisegger B, Presti A, Rios J. Case 2: Premature infant with a fontanelle bruit. Neoreviews. 2015;16(7):e434-e436
4. Cordova EG, Levy P, Kheir JN, Orbach DB, Barnewolt C, Estroff JA. Vein of Galen malformation. Neoreviews. 2020;21(10):e678-e686
5. Cory MJ, Durand P, Sillero R, et al. Vein of Galen aneurysmal malformation: rationalizing medical management of neonatal heart failure. Pediatr Res. 2023;93(1):39-48
6. Mendez A, Codsi E, Gonzalez Barlatay F, Lapointe A, Raboisson MJ. Pulmonary hypertension associated with vein of Galen malformation. Fetal cardiac hemodynamic findings and physiological considerations. J Perinatol. 2022;42(1):143-148
7. Gupta AK, Varma DR. Vein of Galen malformations: Review. Neurol India. 2004;52(1)
8. Patel N, Mills JF, Cheung MMH, Loughnan PM. Systemic haemodynamics in infants with vein of Galen malformation: assessment and basis for therapy. J Perinatol. 2007;27(7):460-463
9. McElhinney DB, Halbach VV, Silverman NH, Dowd CF, Hanley FL. Congenital cardiac anomalies with vein of Galen malformations in infants. Arch Dis Child. 1998;78(6):548
10. Paramasivam S. Hydrocephalus in Vein of Galen malformations. Neurol India. 2021;69(Suppl 2):S376-S379
11. Duran D, Karschnia P, Gaillard JR, et al. Human genetics and molecular mechanisms of vein of Galen malformation. J Neurosurg Pediatr. 2018;21(4):367-374
12. De Luca C, Bevilacqua E, Badr DA, et al. An ACVRL1 gene mutation presenting as vein of Galen malformation at prenatal diagnosis. Am J Med Genet A. 2020;182(5):1255-1258
13. D’Amico A, Tinari, Sara, D’Antonio, Francesco, et al. Outcome of fetal Vein Galen aneurysmal malformations: a systematic review and meta-analysis. J Matern Fetal Neonatal Med. 2022;35(25):5312-5317
14. Lasjaunias PL, Alvarez H, Rodesch G, et al. Aneurysmal malformations of the Vein of Galen. follow-up of 120 children treated between 1984 and 1994. Interv Neuroradiol J Peritherapeutic Neuroradiol Surg Proced Relat Neurosci. 1996;2(1):15-26