A multiregional kinetics model for cerebrospinal fluid.

A mathematical model was developed to describe the multiregional flow of intrathecal indium-111 DTPA, and hence indirectly the flow of cerebrospinal fluid, in sequential spinal and cerebral CSF images. The model provides for an arbitrary input function, transport delay between appropriate compartments, transmeningeal and transependymal transport, and for bidirectional flow between most compartments. Two- and eight-compartment models were evaluated. The set of eight nonlinear differential equations was solved using numerical techniques. This model provides a quantitative basis for the interpretation of CSF kinetics.