Prenatal MR imaging of dural sinus malformation: a case report

Objective: To describe prenatal magnetic resonance imaging (MRI) findings of dural sinus malformation (DSM), a very rare, congenital form of dural arteriovenous shunt (DAVS), typically affecting newborns. Methods: Ultrasound (US) and MRI were performed at 34 weeks' gestation, and the findings of these examinations were compared with postnatal MRI studies performed at 2 days and 1 month. Results: US showed an anechoic, midline posterior fossa collection with irregular internal echodensities. Color Doppler showed prominent arterial vascularity at the lesion margins. The prenatal MRI showed a large, profoundly hypointense, midline retrocerebellar mass. Postnatal MRI, complemented with magnetic resonance (MR) angiography, showed the lesion to be a giant dural venous pouch fed by multiple mural arteriovenous shunts. Follow-up MRI at 1 month suggested latent venous hypertension and prompted endovascular treatment. Conclusion: Prenatal MR imaging is useful to establish the diagnosis, to assess complications such as hydrocephalus and tonsillar prolapse, and to help plan perinatal management, postnatal follow-up, and treatment decision-making.