Synonyms:
a.k.a. vein of Galen aneurysm a.k.a. Galenic varix
General points:
This is a type of direct arteriovenous fistula AVF. It’s a misnomer because it involves the Median prosencephalic vein of Markowski. It is not an AVM because there is no nidus. It is not a dural arteriovenous fistula because it does not involve the dural primarily.
Diagnosis:
Catheter Angiogram/angiography:
- Shows arterial feeders & dilated draining median prosencephalic vein
- Arterial feeders:
- Choroidal (associated with neonatal presentation): pericallosal, anterior choroidal, thalamoperforating
- Mural (associated with infant presentation): collicular or posterior choroidal arteries
- Shows associated venous sinus abnormalities
CT:
- Hyperdense venous pouch
- +/-calcification of thrombus in venous wall
- +/-parenchymal calcification
- Hydrocephalus & parenchymal atrophy may occur
- Enhancement: of arteries & vein
CTA:
- Shows the features well
MRI:
- Arterial feeders: seen on T1 or flow voids on T2
- Thrombus in the venous wall: hyperintense on T1
- Mixed intensity in the draining vein: T2 & T1
- Features of ischemia/infarction in surrounding brain
Other tests:
- In neonates: CXR: cardiomegaly, oedema
- Ultrasound head:
- Mildly echogenic midline mass (draining vein)
- Doppler: arterial feeders, fast flow in draining vein
- Echocardiogram: features of CHF