Prenatal diagnosis of vein of Galen aneurysmal malformation: report of two cases with proposal for prognostic indices.

Vein of Galen aneurysmal malformation (VGAM) is a rare, intracranial vascular anomaly that, until recently, has usually been diagnosed postnatally. Today, however, with the advances in high-resolution ultrasonography and colour Doppler, prenatal diagnosis is relatively easy. Due to novel intravascular embolization techniques, the prognosis of neonates with VGAM has markedly improved. A healthy infant with normal neurodevelopmental and cardiovascular status is now a reality. For the best outcome, however, careful planning of the appropriate time, mode, and place of delivery should be undertaken. To achieve this goal, in utero prognostic factors should be determined. This report illustrates, for the first time, prenatal ultrasonographic indices that may predict the outcome in two cases with a prenatal diagnosis of VGAM. The indices included mapping of intracranial feeding arteries, assessment of the width of the straight sinus, assessment and measurement of flow in the straight sinus, existence of 'steal' retrograde aortic flow, and the appearance of high-output cardiac state. By using these prenatal ultrasonographic parameters, fetal outcome may be predicted and appropriate management decided upon.