Variation in supratentorial cerebrospinal fluid production rate in one day: measurement by nontriggered phase-contrast magnetic resonance imaging

Measuring the cerebrospinal fluid (CSF) production rate is important for understanding the physiology related to normal conditions and neurological disorders. Triggered phase-contrast magnetic resonance imaging (MRI) has been used to measure CSF production rate, but the use of nontriggered phase-contrast MRI has not been reported. The purposes of this study were to assess the feasibility of using nontriggered phase-contrast MRI to measure CSF flow and to determine whether CSF production exhibits circadian rhythm. The feasibility of phase-contrast MRI was assessed with a phantom simulated human cerebral aqueduct. CSF flow through the cerebral aqueduct was measured with nontriggered phasecontrast MRI four times during 1 day in 10 normal volunteers. In the phantom study, linear regression analysis gave the following measured values (ml/h): 0.80 x (value of steady flow) - 10.0 for triggered phase-contrast MRI and 1.27 x (value of steady flow) - 12.2 for nontriggered phase-contrast MRI. One-factor analysis of variance showed no significant effect of the time of the measurements (P = 0.47). The supratentorial CSF production rate was 510 +/- 549 ml/day (mean +/- SD). Nontriggered phase-contrast MRI provided good estimates of the flow rate in the phantom study. We observed no circadian rhythm in CSF production.