Vein of Galen Aneurysm
Neonates with aneurysm of the vein of Galen may be macrocephalic at birth. Nevertheless, the most common neonatal presentations of vein of Galen aneurysm in the neonatal period are cardiac failure (Figure 289.1[A]), cerebral infarction, or cerebral bleed. The cause of cardiac failure is multifactorial. High cardiac output due to decreased cerebrovascular resistance, increased venous return, and cardiac ischemia due to decreased diastolic pressure contribute to the production of cardiac failure. Macrocephaly can be caused by the large size of the vein of Galen aneurysm, but most often it is caused by an obstruction of the aqueduct of Sylvius. A cranial bruit is often present in neonates with vein of Galen aneurysm.
Vein of Galen aneurysm is a malformation due to abnormal connections between intracranial vessels (usually thalamoperforators, choroidal, and anterior cerebral arteries), and a vein in the region of the vein of Galen (may not be the vein of Galen but a persistent fetal structure, the midline prosencephalic vein). Vein of Galen aneurysm is diagnosed by contrast-enhanced CT, MRI, or angiogram of the brain (Figure 289.1[B and C]).

A	B	C

Figure 289.1.— Vein of Galen aneurysm. [A] Congestive heart failure (large heart). [B] MRI demonstrating a vein of Galen aneurysm. [C] Arteriogram demonstrating collateral circulation to the aneurysm.

Cranial ultrasound will demonstrate a large echolucent area in the region of the vein of Galen. Embolization is the treatment of choice.

A	B	C

Figure 289.2.— Vein of Galen aneurysm (ultrasonographic appearance). [A] Midline sagittal view demonstrating a large echolucent area. [B] Coronal view demonstrating a vein of Galen aneurysm. [C] Ultrasonography demonstrating high flow in the area of the vein of Galen aneurysm.