MRI tracer study of the cerebrospinal fluid drainage pathway in normal and hydrocephalic guinea pig brain.

OBJECTIVE: Using magnetic resonance imaging (MRI), sequential information regarding the dynamic movement of the cerebrospinal fluid (CSF) from the subarachnoid space and the ventricles to the drainage pathway in response to the CSF pressure was obtained in guinea pigs. In this study, a new mechanical hydrocephalus model in a guinea pig was developed to investigate the CSF kinetics in an acute hydrocephalic brain. MATERIALS AND METHODS: A total of 18 adult male guinea pigs were studied. In the ventricular injection group, The CSF in the lateral and third ventricles was isolated by inserting a polyethylene tube with a cotton ball into the aqueduct of Sylvius. By infusing artificial CSF through this tubing acute ventriculomegaly was created. In the subarachnoid injection group, a polyethylene tube was placed at the cisterna magna. Using MRI with gadoteridol as a tracer, the movement of CSF from the subarachnoid space and dilated ventricles was monitored at various pressures. The CSF drainage pathway from the subarachnoid space in the hydrocephalic condition was examined and compared with the CSF drainage pathway in normal condition. RESULTS: Gadoteridol cleared from the lateral and third ventricles and reached the nasal mucosa via brain parenchyma; the movement was proportional to the CSF pressure. Gadoteridol from the subarachnoid space also reached the nasal mucosa and periorbital region in a similar manner. However, it was not observed to reach either over the convexity of the brain or adjacent to the superior sagittal sinus.