Diagnosis and Management of a Vein of Galen Malformation …

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86 JDMS  26:86-90  March/April 2010

Diagnosis and
Management
of a Vein of Galen
Malformation
in a Neonate

STACY L. FRENCH, RT(R), RDMS, RVT

Vein of Galen arterial malformation (VGAM)
is an arteriovenous malformation between cere-
bral vessels of the circle of Willis and the vein
of Galen. VGAM is a direct communication
between an artery and a vein resulting in increased
cardiac output due to arterial blood flowing
directly into a vein and returning directly to the
heart, without traversing the full vascular system.
If left untreated, it can result in heart failure,
developmental disabilities, or death. The treat-
ment of choice is endovascular embolization.
Postembolization, these patients often require
medical imaging follow-up. This is a case in
which neonatal neurosonography was used to
image the VGAM postembolization.

Key words: aneurysm, vein of Galen,
embolization

Vein of Galen malformation (VGAM) is a rare
intracranial arteriovenous malformation that usu-
ally causes cardiac failure due to the shunting of
blood. It is often detected in utero but may be
discovered with neonatal neuroimaging studies.
Sonography is one imaging method used to detect
a VGAM, which also may be used to follow treat-
ment of the VGAM. This case study discusses
follow-up for VGAM and the important protocol
additions that should be performed by the sonogra-
pher when evaluating postembolization treatment.

Case Report

From UWHC Ultrasound School, Madison, Wisconsin.
Correspondence: Stacy L. French, RT(R), RDMS, RVT, UWHC
Ultrasound School, 600 Highland Avenue, Madison, WI 53792.
E-mail: staceuw21@yahoo.com.

DOI: 10.1177/8756479310361522

A 5-day-old male infant presented to the emer-
gency room with increased respirations and refusal
to feed. The infant was born at 40 weeks’ gestation
without complications. The patient was transferred
to another facility where an echocardiogram and

VEIN OF GALEN MALFORMATION IN A NEONATE / French      87

FIGURE 1. A sagittal view obtained from the anterior fonta-
nelle demonstrating the low-resistant arterial signal in the vein
of Galen malformation after the first embolization procedure.

FIGURE 2. A sagittal view obtained from the anterior fonta-
nelle demonstrating the pulsatile venous signal in the draining
vein of the vein of Galen malformation after the first emboli-
zation procedure.

neonatal head sonogram were performed. The echo-
cardiogram demonstrated an enlarged right atrium,
enlarged right ventricle, mild narrowing of the aor-
tic arch, and a large patent ductus arteriosus with
bidirectional flow. The sonogram demonstrated a
vein of Galen malformation. The patient was then
transferred to a tertiary care center and magnetic
resonance imaging (MRI)/magnetic resonance angi-
ography (MRA) was performed. The MRI/MRA
demonstrated a choroidal fistula; markedly dilated,
tortuous intracranial vessels; and enlargement of the
cerebral veins, including the vein of Galen. These
findings confirmed a large choroidal-type vein of
Galen malformation.

Because of the intracranial shunt, cardiac failure
ensued, which led to multisystem organ failure,
including respiratory and liver failure. On the basis
of these findings, the patient underwent a coiling
embolization. Because of the size of this malfor-
mation, it was decided that this patient would need
multiple procedures. Postembolization, the patient
was followed with MRI and sonography. Both
imaging modalities demonstrated a persistent high-
velocity arteriovenous (AV) shunt and a complex
arteriovenous malformation (AVM) posterior to
the third ventricle (Figures 1 and 2) after the sec-
ond coiling embolization procedure. The internal
jugular vein remained enlarged and demonstrated
arterialized flow. After the third coiling emboliza-
tion procedure, the arterial signal became higher
resistant, and the venous signal was noted to be less
pulsatile (Figures 3 and 4).

FIGURE 3. A coronal view through the anterior fontanelle
demonstrating a higher resistant arterial signal in the vein of
Galen malformation after the second embolization procedure.

FIGURE 4. A sagittal view through the anterior fontanelle
demonstrating a decreased pulsatile venous signal in the drain-
ing vein of the vein of Galen malformation after the third
embolization procedure.

88 JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY    March/April 2010    VOL. 26, NO. 2

Discussion

The vein of Galen is located inferior to the cor-
pus callosum and courses inferiorly until it becomes
the straight sinus.1 In the past, this malformation
has been called a misleading and inaccurate name:
a vein of Galen aneurysm. A vein of Galen malfor-
mation is, however, not a true aneurysm but is an
AVM between vessels of the circle of Willis and
the vein of Galen.2 It is a rare form of an AV shunt,
making up only 1% of all intracranial vascular
malformations,3 and is considered a sporadic event
with a male dominance.4 It is located midline in the
choroidal fissure and consists primarily of the ante-
rior and posterior choroidal arteries and the ante-
rior cerebral artery.5,6 Drainage of blood is toward
one single deep vein, which becomes aneurysmally
dilated. Because VGAM is a direct connection
between arteries and veins, it lacks capillaries,
which results in elevated velocities flowing through
these vessels. Also, with this direct communication
between arteries and vein, there is a direct shunt of
blood flow directly back to the heart. This direct
shunt back to the heart significantly increases the
workload of the heart, which may result in cardiac
failure.7 The site of the anastomosis is termed the
nidus. The nidus is defined as a group of anoma-
lous blood vessels that can enlarge by incorporat-
ing adjacent blood vessels. As the malformation
enlarges, it can replace normal areas of the brain.6
Patients who have an intracranial AVM may pres-
ent with cerebral hemorrhage, seizures, or
decreased brain function.8 VGAM can be associated
with many different abnormalities, but the most
common are hydrocephalus and congestive heart
failure (CHF). CHF is the most common cause of
death in infants.2,6,9 Hydrocephalus causes an
enlarged head, seizures, and delayed development.
Older children are often identified because of an
enlarged head circumference and failure to meet
developmental milestones. Other clinical presenta-
tions of VGAM include symptoms of spontaneous
VGAM thrombosis and failure to thrive.6 Intracranial
imaging findings suggestive of VGAM include areas
of infarction or ischemia, which is due to the shunt-
ing. Extracranial findings include cardiomegaly,
hepatomegaly, hydrops, and polyhydramnios in
utero. Although most children present with

FIGURE 5. An image demonstrating the coarctation of the
aorta (arrow) associated with this case.

symptoms earlier in life, some can have problems
later on such as macrocrania or prominent veins
of the face caused by obstruction of the draining
veins of the malformation.2

Congenital heart defects also may be associated
with VGAM, the most common being septal defects
and coarctation of the aorta. This patient had a mild
coarctation (Figure 5). Transposition of the great
arteries and aortic stenosis also have been reported.6,10
Other anomalies one might also see with VGAM are
supernumerary digits and hypospadias.6

Different classifications of VGAMs have been
discussed. Mitchell et al.11 categorized VGAMs into
two separate types: choroidal and mural. The choroi-
dal type, as seen in this case, usually has bilateral
blood supply from the choroidal and pericallosal
arteries and usually presents in neonates who also
have cardiac failure. Mitchell et al. classified the
mural type as VGAMs that arise from collicular and
postchoroidal arteries.

Prenatal diagnosis of VGAM is essential so
treatment plans can be made upon delivery. Even
in utero, this abnormality early on may lead to heart
failure and hydrops. If the fetus presents with no
effects in utero, it may have many problems after
birth caused by alterations in blood flow that impede
the transition from fetal to neonatal circulation.10
Sonography has proven to be an excellent modal-
ity in diagnosing VGAM in utero and in infancy,
especially with the improvement of Doppler and
new 3D/4D technology.

On a prenatal sonogram, VGAM will appear as a
tubular, hypoechoic structure situated midline in the
fetal head superior to the thalamus and posterior to

VEIN OF GALEN MALFORMATION IN A NEONATE / French      89

the third ventricle.6,10 This area has been termed the
“comet tail” or “keyhole” sign.10 If high-output car-
diac failure is present as well, sonography may
show an enlarged heart, hydrops, tricuspid regurgi-
tation, and an arterialized umbilical vein.6 The mal-
formation often enlarges as the pregnancy progresses
and is sometimes not detected until the third trimes-
ter. Unless there is an indication to perform a third-
trimester obstetric sonogram, one will not be
ordered; therefore, most diagnoses must be made
after delivery.10

For neonatal neuroimaging, 2D sonography
offers a portable, lower cost examination without
exposure to ionizing radiation. With the many
advances that have been made, such as color
Doppler, extended field of views, harmonic imag-
ing, and high-resolution transducers, sonography
is a particularly valuable technique to evaluate and
follow up vascular anomalies such as VGAMs.12,13
The most recent change for neonatal head sono-
grams is the implementation of 3D/4D sono-
graphy. This has proven to be extremely beneficial
because it allows for volume sweeps of the entire
cerebral anatomy and any pathology present.12

A transfontanellar approach is the most common
method for imaging neonatal heads. Common find-
ings on the sonogram are multiple, hypoechoic
tubular structures situated midline near the circle
of Willis. Color Doppler will then show increased
amounts of blood flow within this area.8 Doppler
flow patterns that are associated with a VGAM are
(1) low-resistance arterial flow and (2) arterialized
venous flow.2 It is important for the sonographer to
identify the feeding artery and draining vein anasto-
mosis (nidus), as this will help direct the treatment
for the malformation. Bartels14 reviewed the follow-
up in a 26-year-old patient in whom a 1-year follow-
up postembolization of an AVM demonstrated a
higher resistant vascular signal, which was inter-
preted as a decrease in the number of feeding arter-
ies due to embolization. Griffith et al.8 also reported
a surgical approach that relied on Doppler findings:
if a low-resistant signal was demonstrated, the sur-
geon was directed to continue dissection, and if a
higher resistance Doppler flow signal was shown,
then it was assumed that the procedure was success-
ful. The higher resistant Doppler signal was believed

to represent restoration of normal arterial flow
passing through the surgical bed. Therefore, when
sonographers perform follow-up examinations,
they should look for a higher resistance signal in
the artery and decreased pulsatility in the vein. The
differential diagnoses for VGAM include holo-
prosencephaly, hematoma, choroid papilloma, and
agenesis of the corpus callosum.2,6 Other differen-
tials include arachnoid cysts, porencephalic cysts,
and choroid plexus cysts, but presence of color
flow would eliminate these.2,6,8,10

Vein of Galen malformation is always fatal if
treatment is not initiated. Intense medical manage-
ment for the cardiac failure is vital for patients’
survival.7 By using medical treatment, intervention
may then be put off until the infant is 5 to 6 months
of age, which is the recommended time for inva-
sive procedures to be done.5,7,11 At that point, inter-
vention is much safer and easier for these neonates.
However, if the patient begins to deteriorate
quickly, treatment may need to be performed
earlier than 5 to 6 months.5,11

Surgery has been proven to be very difficult in
neonates because of the hypervascularity and
frailty of the brain as well as limited access to the
feeding vessels.8,11 According to Griffith et al.,8 the
morbidity and mortality rate is directly related to
the size, which arteries and veins are involved, and
what part of the brain is affected. Gray-scale and
color Doppler can be very useful in localizing the
vessels and confirming that the malformation has
been completely removed.8 Regrettably, this surgi-
cal ablation has very poor outcomes for the patient
because of the invasiveness and brain injury.

Treatment has greatly improved with the
advances made in transcatheter percutaneous
embolization. Survival rates reported with this
form of endovascular management are 70% to
80%, and it has a cure rate of about 50%.9 If treat-
ment is required prior to 6 months of age, the tim-
ing of the first embolization depends on what
symptoms the neonate presents with and how the
patient responds to the medical therapy.11 Emboli-
zation is performed via a catheter. The catheter is
positioned into the femoral artery and, under sono-
graphic guidance, is advanced until it reaches the
vascular malformation. A metal coil is then placed

90 JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY    March/April 2010    VOL. 26, NO. 2

in the feeding artery, resulting in occlusion of the
feeding vessel.7 To achieve successful treatment,
multiple procedures must be done over an extensive
period of time.7 The complications of embolizing
a VGAM are perforating the feeding vessels or sur-
rounding vessels or infarction.9 Another complica-
tion that also has been reported by McElhinney
et al.9 is the migration of the coil into the malfor-
mation and possibly beyond. Although emboliza-
tion is the preferred method of treatment, complete
occlusion of the malformation is rarely obtained,
and supplementary surgical clipping may then be
necessary. In this case, the patient had received six
coiling procedures by 3 months of age, and each
one was successful in coiling off a segment of the
malformation, although complete occlusion was
not obtained.

Prognosis for patients depends crucially on when
the malformation is detected. The most severe types
are often detected in utero.2,6 Neonates have a
reported mortality rate of 91.4%,6 whereas infants
with CHF and VGAM combined have a survival
rate of only 8%.2 VGAMs that are discovered later
on in infancy have a variable prognosis, whereas
those that are symptomatic in childhood or adult-
hood usually do very well.2 Those who have treat-
ment still have mortality rates ranging between
50% and 100%.10

Conclusion

Vein of Galen malformation is a serious, life-
threatening problem that usually results in a poor
prognosis. The standard treatment is multiple coil-
ing embolization procedures requiring imaging
follow-up. This case report demonstrates the find-
ings associated with serial neonatal head sonograms
performed on a patient with a VGAM. The signifi-
cance of understanding where the malformation is
located and an attempt to identify the number of
feeding vessels are very important in determining
treatment plans. Sonographers also need to under-
stand the hemodynamics associated with VGAM
so that the examination can be tailored to demon-
strate the success of the treatment. Specifically with
effective embolization, the feeding artery develops

a progressively higher resistant signal than the prior
sonogram, and the draining vein develops decreased
pulsatility.

References

1. Ahuja AT, Antonio GE, Griffith GE, et al: Brain and
Spine, in Ahuja AT, Antonio GE, Griffith GE, et al (eds):
Diagnostic and Surgical Imaging Anatomy: Ultrasound.
Salt Lake City, UT, Amirsys, 2007, p I-34.

2. Vandy ZK, Drose JA: Color flow detection of vein of
Galen malformation in utero. J Diagn Med Sonography
1992;8:143–145.

3. Gupta AK, Varma DR: Vein of Galen malformations: a

review. Neurol India 2004;52:43–53.

4. Hagen-Ansert SL: Neonatal echoencephalography, in
Hagen-Ansert SL (ed): Textbook of Diagnostic Ultra-
sonography. 6th ed. St. Louis, MO, Elsevier, 2006,
pp 579–613.

5. Bhattacharya JJ, Thammaroj J: Vein of Galen malforma-
tions. J Neurol Neurosurg Psychiatry Pract Neurol 2003;74:
i42–i44.

6. Liriano B, Levy R: Prenatal sonographic diagnosis of a
vein of Galen aneurysmal malformation in a twin. J Diagn
Med Sonography 2003;19:242–247.

7. Center for Endovascular Surgery: Vein of Galen malfor-
mations. 2009. http://neuro.wehealny.org/endo/cond_
vein-of-galen.asp

8. Griffith S, Pozniak MA, Mitchell CC, et al: Intraoperative
sonography of intracranial arteriovenous malformations:
how we do it. J Diagn Med Sonography 2004;23:
1065–1072.

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:
548–551.

10. Moore LE, Gonzales I, Brogdon K: Diagnostic challenge.

J Diagn Med Sonography 2008;24:43–44.

11. Mitchell PJ, Rosenfeld JV, Dargaville P, et al: Endovascu-
lar management of vein of Galen aneurysmal malforma-
tions presenting in the neonatal period. Am J Neuroradiol
2001;22:1403–1409.

12. Riccabona M, Nelson TR, Weitzer C, Resch B, Pretorius DP:
Potential of three-dimensional ultrasound in neonatal and
pediatric neurosonography. Eur J Radiol 2003;13:
2082–2093.

13. Rumack CM, Drose JA: Neonatal and infant brain
imaging, in Rumack CM, Wilson SR, Charboneau JW,
Johnson JM (eds): Diagnostic Ultrasound. 3rd ed. St. Louis,
MO, Elsevier Mosby, 2005, pp 1623–1702.

14. Bartels E: Evaluation of arteriovenous malformations
(AVMs) with transcranial color-coded duplex sonography.
J Ultrasound Med 2005;24:1511–1517.