Prenatal imaging of posterior fossa disorders. A review

With advances in fetal imaging, prenatal diagnosis of posterior fossa anomalies has been greatly improved. Based on the anatomical approach proposed by Guibaud and Desportes in 2006, the main anomalies depicted according to the algorithm includes: (1) increased “fluid-filled” space of the posterior fossa, (2) abnormal biometry of the cerebellum, and (3) abnormal cerebellar anatomy. In this review, the spectrum of PF anomalies is covered in an attempt to update this approach in the light of both our experience, more than a decade since this algorithm was published, and the latest data in the literature. •A very comprehensive approach to diagnose posterior fossa (PF) anomalies is based on a precise imaging analysis of the posterior fossa anatomy.•Such imaging approach is based on axial sonographic plane on routine, but sagittal and coronal approach using ultrasound and MR are most often mandatory for precise anatomical analysis.•When facing increased “fluid-filled” space of the PF, analysis of both position of the tentorium and vermis anatomy is crucial, especially on sagittal plane.•Decreased cerebellar biometry encompasses many etiologies and is divided into global or focal reduction, the latest being suggestive of a clastic event.•Thanks careful analysis of cerebellum, brainstem and fourth ventricle, prenatal diagnosis of syndromic entities such as Joubert, Walker-Waburg, PHACE, CHARGE syndromes is possible.