ORIGINAL PAPER Phase-contrast and three-dimensional driven equilibrium (3D-DRIVE) sequences in the assessment of paediatric obstructive hydrocephalus Shaimaa Abdelsattar Mohammad 1 & Noha Mohamed Osman 1 & Reham M. Khalil 1 Received: 9 February 2018 /Accepted: 21 May 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Background Recently, most cases of hydrocephalus are related to obstruction. Accurate localization of the site of obstruction is crucial in determination of the treatment strategy. Purpose To describe the phase-contrast and 3D-DRIVE findings in cases of obstructive hydrocephalus in paediatric patients and to determine their functional and anatomical correlates. Material and methods Brain MRIs of 25 patients (2 months to 11 years) with obstructive hydrocephalus were retrospectively reviewed. Phase-contrast and 3D-DRIVE were performed to assess cerebrospinal (CSF) pathways through the aqueduct of Sylvius and subarachnoid spaces. In addition to flow velocity measurement at the aqueduct of Sylvius, functional and anatomical correlation was analysed at the level of aqueduct of Sylvius, infracerebellar CSF space and at the third ventriculostomy using Spearman’ s rank test. Results Aqueduct of Sylvius was the most common site of obstruction (19 patients) either secondary to focal, multifocal or tubular stenosis, adhesions, or secondary to extrinsic compression. Functional and anatomical correlation was analysed in 58 regions revealing strong correlation (ro = 0.8, p < .001). Functional anatomical mismatch was found in nine regions. Flow velocity measurements revealed diminished flow in most of the cases with obstruction at the aqueduct and normal velocity in cases with obstruction proximal to aqueductal level, while accelerated flow was seen in cases with infra-aqeuductal obstruction. Conclusion Phase-contrast and 3D-DRIVE sequences are essential sequences in the diagnosis of hydrocephalus enabling perfect localization of the site of obstruction. Both sequences should be interpreted in conjunction to avoid false results. Velocity measurements through the aqueduct can help understand CSF hydrodynamics. Keywords CSF . Paediatric obstructive hydrocephalus . CSF velocity . Aqueduct stenosis Introduction Hydrocephalus is a complex neurological disease that can result in deleterious effects if untreated. It is characterised by dynamic imbalance between the production and absorption of the cerebrospinal fluid (CSF) leading to ventriculomegaly, that is mostly accompanied by increase in the intracranial tension [1, 2]. Recently, members of the international society for hydrocephalus and CSF research proposed that hydro- cephalus is mostly related to obstruction to the CSF pathway and the different types of hydrocephalus are differentiated according to the site of obstruction [3]. Among causes of hydrocephalus, aqueduct stenosis is the commonest that could be idiopathic or secondary to inflammatory or neoplastic pa- thologies [4, 5]. In addition to shunt surgeries, interventional procedures, such as endoscopic third ventriculostomy (ETV) and aqueductoplasty are among the treatment options [6, 7]. Accurate diagnosis of obstructive hydrocephalus with demon- stration of the site of obstruction and detection of combination of pathologies are crucial for proper selection of the treatment strategy and improving the postoperative outcome [8]. In addition to demonstration of the site of obstruction, con- ventional MRI sequences provide the specific morphologic features of hydrocephalus in the form of ventriculomegaly, decreased mamillopontine distance, and thinning and eleva- tion of the corpus callosum [9]. However, those signs are not specific for hydrocephalus with poor sensitivities [6, 10]. Therefore, new MRI techniques have been developed aiming for proper diagnosis of hydrocephalus and its differentiation * Shaimaa Abdelsattar Mohammad shaimaa96@hotmail.com 1 Department of Radiodiagnosis, Pediatric Radiology Section, Faculty of Medicine, Ain-Shams University, Abbasia, Cairo 11657, Egypt Child's Nervous System https://doi.org/10.1007/s00381-018-3850-6