Pediatric aneurysms and vein of Galen malformations

Abstract

Pediatric aneurysms are different from adult aneurysms - they are more rare, are giant and in the posterior circulation more frequently than in adults and may be associated with congenital disorders. Infectious and traumatic aneursyms are also seen more frequently. Vein of Galen malformations are even rarer entities. They may be of choroidal or mural type. Based on the degree of AV shunting they may present with failure to thrive, with hydrocephalus or in severe cases with heart failure. The only possible treatment is by endovascular techniques - both transarterial and transvenous routes are employed. Rarely transtorcular approach is needed. These cases should be managed by an experienced neurointerventionist.

Keywords: Pediatric aneurysms; Vein of Galen malformations; choroidal malformations; endovascular embolization; mural malformations.

Figure 1

Schematic drawing of the afferent choroidal, collicular arteries, and the efferent venous channels during vascularization of the basal ganglia and thalamus

Figure 2

Vertebral angiography. (a) and (b) Markedly dilated anerysmal vein of Galen is penetrated by numerous choroidal and perforator branches in a choroidal type of malformation. Right carotid angiography. (c) and (d) Fetal origin of the posterior cerebral artery and its branches feed the dilated Galenic choroidal malformation

Figure 3

Transcranial duplex sonography demonstrating markedly dilated vein of Galen and high velocity flow

Figure 4

Plain and contrast enhanced CT scan. (a) Hyperdense midline vein of Galen and enlarged straight sinus noted. (b) Intense enhancement of the malformation is seen on contrast administration

Figure 5

Plain X rays of skull. (a) and (b) Curvilinear midline calcification in the wall of aneurysm of vein of Galen

Figure 6

MRI of brain. Sagittal T1 weighted image shows partial agenesis of straight sinus in its proximal segment. Alternate venous drainage is seen from the falcine sinus into the superior sagittal sinus from the vein of Galen

Figure 7

Lateral view of carotid angiogram. (a) Fenestrated falcine sinus is appreciated draining into the posterior end of superior sagittal sinus. (b) Duplicated falcine sinus is seen in another patient. Vertebral angiogram. (c) and (d) AP and lateral views demonstrate occipital sinuses connecting the torcular to the jugular bulbs on both sides symmetrically forming a falcine loop

Figure 8

(a) Contrast enhanced CT scan. A daughter sac is attached to the main vein of Galen revealing marked enhancement. (b) Vertebral angiography. Mural type. Early arterial phase shows rapid opacification of the vein of Galen and dural sinuses. (c) Stenosis of the origin of straight sinus. (d) and (e) Post-embolization angiogram. Using isobutyl 2¬ cyanoacrylate the malformation is completely obliterated restoring the normal circulation in the posterior fossa. (f) Plain X ray of skull. Cast of the cyanoacrylate is appreciated in the malformation, following embolization

Figure 9

Right carotid angiogram. (a) and (b) Globular enlargement of the vein of Galen is supplied by a single hole fistula from posterior cerebral artery (mural type). Right carotid angiogram. (c) and (d) AP and lateral views demonstrate complete obliteration of the malformation by a detachable balloon. Plain X rays of skull. (e) and (f) Partially inflated mini-balloon is detached in the feeding artery by coaxial technique. Shunt tube is noted in place

Figure 10

(a) Carotid angiogram. AP view shows a complex choroidal type malformation with early draining vein. (b) and (c) Vertebral angiogram AP and lateral views reveal multiple arterial feeders and sinus anomalies. Embolization (d) Guiding catheter is placed in the aneurysmal dilatation of vein of Galen via the sigmoid sinus, transverse sinus and straight sinus. (e) Basket of coil and a mesh is deposited in the dialted varix. (f) Subsequent arterial catheterisation is performed for glue injection. (g) Pre embolization vertebral angiogram. Large Shunt is shown across the straight sinus from the vein of Galen. (h) Tras venous and trans arterial embolization reduces the shunt remarkably showing residual malformation.