Development of ventricular expansion and increased pulsatile CSF flow in a rat model

Adult rats were injected with kaolin in the basal cistern to impede cerebrospinal fluid flow and induce communicating hydrocephalus. Development and progress of CH was monitored using magnetic resonance imaging (MRI) for a period of over 30 days. TrueFISP images were used to measure volume of the cerebral aqueduct and the lateral, third and fourth ventricles as well as hydrodynamic resistance of the aqueduct. Retrospectively gated phase contrast gradient echo images were used to measure stroke volume of CSF in the aqueduct. Based on ventricular volumes, animals could be divided into 3 groups where Groups 2 & 3 developed mild and severe hydrocephalus respectively, while Group 1 did not. Ventricular volumes and stroke volumes of Group 3 increased over time, as expected, while in Group 2, ventricular volume increased but stroke volume increased and then decreased, a phenomenon that has not been reported before. Hydrodynamic resistance of aqueductal flow was found to correlate negatively with stroke volume for Groups 2 and 3, although at different levels.