Fetal MRI demonstrating vein of Galen malformations in two successive pregnancies--a previously unreported occurrence.

PURPOSE: Vein of Galen malformations are rare and are usually detected in utero using ultrasonography. No definite genetic predisposition has been described in the literature. We present a case with two successive pregnancies complicated by vein of Galen malformations, which were assessed using fetal MRI. The putative role of genetic mutations is also discussed.

METHODS: A 30-year-old primigravida presented in the third trimester with a fetus diagnosed with vein of Galen malformation on sonography. MRI and MR angiography were performed for further assessment. The subsequent pregnancy was again complicated by vein of Galen malformation. In addition to MRI, genetic analysis was carried out on both fetuses and on the parents.

RESULTS: MR angiography revealed that both fetuses suffered from the choroidal sub-type of vein of Galen malformation, with multiple arterial feeders fistulating onto a midline venous pouch. The visualised anatomy obtained was far superior than on sonography and allowed categorisation of vein of Galen malformation sub-type. Genetic analysis on the mother and both fetuses showed variant RASA1 gene mutation.

CONCLUSIONS: This case demonstrates that fetal MRI is a powerful tool in the investigation of in utero neurovascular malformations. A genetic mutation was identified, but this was of uncertain significance.