=====Triventricular hydrocephalus===== On CT or MRI: enlargement of ventricles proximal to block (e.g. obstruction of the [[aqueduct of Sylvius]] → lateral and 3rd ventricular enlargement out of proportion to the [[fourth ventricle]], sometimes referred to as triventricular [[hydrocephalus]]) In patients under 1 month, the third [[ventriculostomy]] technique may be a better option than the shunt in selected cases ((Rivero-Garvía M, Márquez-Rivas J, Rueda Torres AB, Gutiérrez-González R, García-Iglesias A, Pascual-Argente D, Villena M, Regueiras M, Medina D. Cranial growth restriction, a fundamental measure for success of the endoscopy in children under 1 month of age. Is it possible to improve the outcome? J Pediatr Surg. 2013 Jul;48(7):1628-32. doi: 10.1016/j.jpedsurg.2013.02.060. PubMed PMID: 23895985. )).