MRI In The Evaluation Of Cerebrospinal Fluid Flow Dynamics

Objective: Motion of the cerebrospinal fluid (CSF) in and around the brain and spinal cord was examined in normal volunteers and a number of patients with abnormalities of the CSF circulation with MRI in phase contrast cine mode (MRI cine PC).Materials and Methods: Periphery gated, multiframe (cine frames), reduced flap angle (20 degrees), phase-contrast sequences On a 1.5T GE TwinExit MRI unit were displayed flow were determined. The minimum TR and TE value were chosen. A field-of-view (FOV) of 22cm and a slice thickness of 5mm were used. The matrix was always 256 X 192. Velocity encoding was along cranial-caudal direction. 16 images were taken at different points in the cardiac cycle. Magnitude and /or phase reconstructed images were played in a cosed loop cine format for qualitative evaluation. The qualitative cine MRI allows a rapid and dramatic evaluation of both normal and abnormal patients in a visual form. Quantitative evaluation of CSF flow via phase reconstruction permits a more precise mapping of the intracranial and intraspinal flow patterns is more sensitive in detecting fluid motion and allows calculation of CSF velocity and flow volume. Results: The CSF circulation is propelled by a pulsating flow. This flow is produced by the alternating pressure gradient, which is a consequence of the systolic expansion of the intracranial arteries causing expulsion of CSF into the compliant and contractible spinal subarachnoid space. The intracranial dynamics may be regarded as the result of an interplay between the demands for space by the four components of the intracranial content, i.e. the arterial blood , brain volume, venous blood and the CSF. With systole there is downward(caudal) of CSF in the aqueduct of Sylvius, the foramen of Magendie, the basal cisterns and the dorsal and ventral subarachnoid...