Prenatal depiction of angioarchitecture of an aneurysm of the vein of Galen with three-dimensional color power angiography

dA fetus with a large supratentorial cyst and cardiomegaly tl,as encountere d at 33 weeks of gestation. The cyst appeared as an aneurysmal, fluid-fille d structure extending posteriorly with a finger-like appendage. Using color flow mapping, we disclosed rapid in-and-out blood flow with marked turbule nce within the cyst. For evaluation of its blood supply and venous drainage of the vascular malformation, a three-dimensional reconstruction of the po wer Doppler image was conducted. The results revealed that the vascular mal formation was supplied by a small contralateral aneurysm from the branches of Willis' circle, draining posteriorly into an abnormal falcine sinus and then into the superior sagittal sinus. No other fetal abnormality such as h ydrocephalus or hydrops was discovered. The prenatal diagnosis of an aneury sm of the vein of Galen was made on the basis of the gray-scale, color Dopp ler findings, and also the angioarchitecture obtained by three-dimensional power Doppler imaging. The woman was admitted at 37 weeks of gestation due to labor onset and delivered the baby via the vaginal route without complic ation. Postnatal angiography and magnetic resonance imaging confirmed the d iagnosis of an aneurysm of the vein of Galen, and the angioarchitecture dep icted it before birth. We suggest that three-dimensional power Doppler ultr asonography may assist in the diagnosis of an aneurysm of the vein of Galen , and precisely delineate the complicated col responding vasculature. This may guide postnatal management and predict the prognosis more accurately .