Prenatal 2D/3D Ultrasound in Fetal Dural Sinus Malformations: Case Series and Prognostic Insights

OBJECTIVE: To evaluate the benefit of three-dimensional (3D) ultrasound over two-dimensional (2D) imaging in diagnosing fetal dural sinus malformations (DSM) and to explore the correlation between sonographic features, such as thrombosis and sinus involvement, with perinatal and postnatal outcomes. METHODS: This retrospective case series included 8 fetuses diagnosed with DSM at our center from 2020 to 2025. All cases underwent 2D and 3D ultrasound, with findings correlated to perinatal and postnatal outcomes. A literature review was conducted using PubMed, Embase, and Web of Science, with keywords: "fetal dural sinus malformation," "prenatal ultrasound," and "3D ultrasound." RESULTS: The median gestational age at diagnosis was 27 weeks (range 20-35). Lesions involved the torcular Herophili (4/8), torcular and superior sagittal sinus (2/8), superior sagittal sinus (1/8), and posterior fossa venous region (1/8). Associated anomalies included hydrocephalus, mild ventriculomegaly, fetal growth restriction (FGR), and pleural and peritoneal effusions. 2D ultrasound identified cystic or anechoic lesions (18 × 19 mm to 90 × 110 mm), with 62.5% showing thrombosis. 3D ultrasound enhanced lesion delineation, venous continuity, thrombus morphology, and confirmed the absence of arterialization. Genetic testing (cfDNA and/or CMA) was normal in all cases. Among the 8 pregnancies, two were terminated, one resulted in fetal demise, and five were liveborn. Four (50%) had favorable neurodevelopmental outcomes at 29-60 months. CONCLUSIONS: Combined 2D/3D ultrasound improves prenatal DSM assessment, with key features, particularly thrombosis, correlating with adverse outcomes. 3D ultrasound should be integrated into routine diagnostic protocols.