[Role of cerebral echography in the diagnosis of aneurysms of the vein of Galen].

Cerebral ultrasound imaging by a transfontanelle approach is now a common investigation during the first year of life. This exploratory procedure is non-invasive, non-irradiating, requires no sedation and can be carried out at the infant's bedside. In addition, the classical apparatus can be completed by deep Doppler allowing deep cerebral vessels to be studied. Three cases are reported of aneurysm of Galen's ampulla detected by ultrasound imaging during the neonatal period. Images demonstrated the presence of an abnormal fluid mass in the region of Galen's ampulla, confirmed as of vascular origin by Doppler, and allowed assessment of degree of subjacent ventricular dilatation and possible secondary ischemic lesions. In massive neonatal forms this exploration may be sufficient since prognosis is poor, but in lesions of moderate size CT scan and angiographic examinations and perhaps MR imaging are required. This technique allows detection of this malformation in the fetus and could therefore influence therapy.