Angle between vein of Galen and straight sinus: a novel marker on microvascular flow imaging for prenatal assessment of tentorium cerebelli position

Posterior fossa anomalies (PFAs) are associated with a wide spectrum of neurodevelopmental disabilities, with presentation ranging from no obvious clinical symptoms to severe neurodevelopmental delay. The differential diagnosis of fetal PFAs using imaging is crucial for prenatal counseling and prognostic evaluation. Imaging of the tentorium cerebelli (TC) is critical for the differential diagnosis of fetal PFAs; however, achieving this using prenatal grayscale ultrasound is challenging. This study aimed to establish a reference range for a new measurement, the angle between the vein of Galen and the straight sinus (AVGS), measured using microvascular flow imaging, and to evaluate prospectively the effectiveness of AVGS for assessment of the position of the fetal TC.