To describe the ultrasound findings and perinatal outcomes of cases with a prenatal diagnosis of cerebral vascular malformations (CVM). CVMs are rare, among them the arteriovenous malformation of the vein of galen (AVM-VG) and AVM of dural sinuses (AVM-DS) are the most frequently diagnosed in fetal life. The AVM-VG presents increased blood flow through the venous system, preload increase, and high-flow heart failure. The AVM-DS presents a dilation formed by low-flow AV fistulae, and predisposition to thrombus formation. In torcular thrombosis, a decrease in size correlates with better prognosis. Retrospective study of 4 cases with antenatal diagnosis of CVM from 2016-2019 at a teaching tertiary care centre in the city of Medellin, Colombia. Cases were diagnosed between 29-32 weeks of pregnancy. Ethics committee approval. 3/4 cases showed an elongated echolucent lesion in the midline, which displaced structures; with colour Doppler, turbulent flow was seen throughout the lesion, with a high-flow peripheral component at the level of the VG (image a); all cases presented tricuspid regurgitation and heart failure. Pregnancy was completed between 32-36 weeks, with early neonatal death. One case presented an echogenic image at the occipital level, corresponding to severe dilation of the torcula, with thrombosis, secondary dilation of the venous system and posterior fossa compression (image b). Birth at 36 weeks, currently in neurological follow-up. No postnatal studies were performed. AVMs have a high perinatal mortality associated with heart failure; torcula thrombosis could reduce the risk of heart failure mortality. Supporting information can be found in the online version of this abstract Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.