A Computer Model of CSF Dynamics

Abstract

CSF production per time unit (F) is linearly proportional to the pressure gradient between choroidal vessels and CSF space (1, 2). Thus, the following formula holds true:

$$ F = {{K}_{1}} \cdot \left( {{{P}_{A}} - {{P}_{{CSF}}} - {{\pi }_{{PL}}}} \right) $$

(a)

, where P_A = pressure in the choroidal vessels, π _PL = oncotic pressure of the blood, P_CSF = CSF pressure, and K₁ = a factor representing metabolic influences. The CSF pressure/absorption relationship was examined experimentally. The resulting curve for CSF pressure/ absorption relationship was transformed into a polynomial by regression analysis:

$$ A = {{a}_{o}} + {{a}_{l}}\left( {{{P}_{{CSF}}} - {{P}_{S}}} \right) + \ldots + {{a}_{n}}{{\left( {{{P}_{{CSF}}} - {{P}_{S}}} \right)}^{n}} $$

((b))

, where A = absorption of CSF per time unit, P_S = sinus pressure. The CSF volume (∆V) is given by

$$ V = \int\limits_{o}^{t} {\left( {F - A} \right)} \cdot dt $$

((c))

.