Obstetric

		Introduction
		Clinical Guides 294
		Case Studies 26
		Feedback

		Create Document

Search Obstetric:

Vein of Galen - Aneurysm

Summary   Ultrasound Features   Differential Diagnoses   Images 4   Show All

The two internal cerebral veins unite superior and posterior to the thalami, just posterior to the pineal gland, forming the great vein of Galen, which then courses posteriorly to empty into the straight sinus. Aneurysms of this vein represent end-to-end anastomoses of a major artery to a vein without the usual intervening capillaries. This abnormality, sometimes erroneously called an aneurysm, is a gross dilatation of the vein of Galen, being fed directly by a large anomalous vessel or vessels arising from the carotid or basilar circulation. It appears that fetal arteriovenous malformations may develop in or enlarge to a detectable size over a short period of time, usually in the third trimester. To date, no vein of Galen aneurysm has been reported prior to 30 weeks gestation. The sonographic findings in this disorder are typical. In the transthalamic plane, a round or ovoid hypoechoic mass is seen posterior to the third ventricle. A tubular extension of the mass, representing a dilated straight sinus, can be traced posteriorly to the enlarged torcular of Herophilus (confluence of dural sinuses) which has a triangular shape. The combination of a dilated vein of Galen, straight sinus and torcular results in a key-hole shaped sonolucency. Doppler examination of the abnormality may show arterial and/or venous flow, depending on the area sampled. The posterior cerebral artery and its branches are the most commonly involved feeders to this malformation, resulting in turbulence at the confluence of arterial and venous streams. Occasionally this may be seen without resorting to Doppler scanning. Ventriculomegaly may be observed secondary to aqueductal compression. The disorder is associated with a poor outcome, but the infant's chance of survival can be maximized by planning delivery at a tertiary care centre appropriately equipped to manage the affected newborn. Heart failure, rather than hydrocephalus, is the major finding in symptomatic newborns. The antenatal appearance of the heart is variable, but generalized cardiomegaly or right ventricular enlargement is the rule. Coarctation of the aorta and transposition of the great vessels occur with increased frequency in infants with this abnormality. Title: Echocardiographic and sonographic clues for the prenatal diagnosis of cerebral arteriovenous malformations Author: Oberhoffer R, Grab D, Terinde R, Lang D Journal: J Matern Fetal Invest 4; 51-54 Year: 1994 Title: Early prenatal diagnosis of an ominous aneurysm of the vein of Galen by color Doppler ultrasound Author: Ballester M-J, Raga F, Serra-Serra V, Bonilla-Musoles F Journal: Acta Obstet Gynecol Scand 73: 592-595 Year: 1994 Title: Prognosis of antenatally diagnosed vein of Galen aneurysmal malformations Author: Rodesch G, Hui F, Alvarez H, Tanaka A, Lasjaunias P Journal: Childís Nerv Syst 10: 79-83 Year: 1994 Title: Prenatal diagnosis of fetal brain arteriovenous malformation: the use of color Doppler imaging Author: Dan U, Shalev E, Greif M, Weiner E Journal: J Clin Ultrasound 20:149-151 Year: 1992 Title: Fetal intracranial AVM presenting as enlarged cardiac chamber Author: Koven MB, Cohen HL, Goldman MA Journal: J Ultrasound Med 12: 177 Year: 1992 Title: Arteriovenous malformations: locations and evolution in the fetal brain Author: Comstock CH, Kirk JS Journal: J Ultrasound Med 10: 361-365 Year: 1991 Title: Prenatal diagnosis of vein of Galen arteriovenous malformation by duplex sonography Author: Strauss S, Weinraub Z, Goldberg M Journal: J Perinat Med 19: 227-230 Year: 1991 Title: Vein of Galen aneurysm Author: Suma V, Marini A, Saia OS, Rigobello L Journal: Fetus 1: 7478.1 Year: 1991 Title: Sonography of congenital midline brain malformations Author: Funk KC, Siegel MJ Journal: Radiographics 8: 11-25 Year: 1988 Title: Prenatal diagnosis of cerebral arteriovenous malformation using color Doppler ultrasonography: case report and review of the literature Author: Sepulveda W, Platt CC, Fisk NM Journal: Ultrasound Obstet Gynecol 6: 282-286 Year: 1995 Title: Prenatal sonographic diagnosis of a vein of Galen aneurysm; relevance of associated malformations for timing and mode of delivery Author: Doren M, Tercanli S, Holzgreve W Journal: Ultrasound Obstet Gynecol 6: 287-289 Year: 1995 Title: Differential diagnosis and outcome of fetal intracranial hypoechoic lesions: report of 21 cases. Author: Pilu G; Falco P; Perolo A; Sandri F; Cocchi G; Ancora G; Bovicelli L Journal: Ultrasound Obstet Gynecol Apr;9(4):229-36 Year: 1997

© 2004 Australasian Society for Ultrasound in Medicine