The many faces of prenatal imaging diagnosis of primitive aqueduct obstruction.

Objective: To describe the different prenatal imaging patterns related to primary aqueduct obstruction throughout pregnancy and their impact on prenatal counseling.

Method: Retrospective review of consecutive prenatal cases of isolated aqueduct obstruction diagnosed over a seven-year period (2010-2016). Prenatal imaging findings, postnatal imaging, pathological data and postnatal outcome, were analyzed.

Results: Twelve cases were included. In four cases, termination of pregnancy was performed, due to early severe ventriculomegaly in three cases suggestive of complete aqueduct obstruction. In eight cases in which pregnancy was continued, three different evolving imaging patterns were demonstrated. In three cases the ventriculomegaly evolved rapidly during third trimester and were subsequently associated with abnormal white matter changes on fetal MRI. Theses cases led to premature delivery in two cases and early surgical care in all, with focal cystic parenchymal damage shown on follow-up MRI in two cases. Slowly evolving ventriculomegaly in three cases diagnosed in the second and the third trimester which required delayed surgery during the first year of life. Stable ventriculomegaly in two cases which did not require any surgical procedure.

Conclusion: The diagnosis of primary aqueduct obstruction may be based on different prenatal imaging patterns that include either severe early ventriculomegaly, stable, slowly or rapidly evolving ventriculomegaly.