Abnormal fetal cerebral blood flow velocity waveforms as a sign of an aneurysm of the vein of Galen.

A cerebral midline cystic lesion was detected by real-time ultrasound in utero in the absence of other congenital abnormalities. Pulsed Doppler ultrasound assessment of fetal circulation demonstrated normal peripheral and intracardiac hemodynamics associated with decreased cerebral vascular resistance. Furthermore, a markedly turbulent flow pattern was evidenced within the cerebral lesion. The presence of a cerebral arteriovenous malformation with an aneurysm of the vein of Galen was suggested and the provisional diagnosis was later confirmed by computed tomography and carotid angiography performed after birth.