Dilatation of the supra-pineal recess on prenatal imaging: early clue for obstructive ventriculomegaly downstream of the third ventricle.

OBJECTIVE

The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-pineal recess (SPR) in cases of ventriculomegaly.

METHOD: A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR.

RESULTS

Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic-haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy-Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging.

CONCLUSION

The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle.