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A technique for simultaneously measuring pulsation, translation and diffusion of a radioactive tracer in the spinal cerebrospinal fluid (CSF) has been described. To evaluate the accuracy and precision of this method for measuring CSF oscillation in the spine, an apparatus was designed that moved a radioactive source sinusoidally with known amplitude along a line. With list mode acquisition of radioactive emissions, the amplitude of oscillation was measured for a series of peak-to-peak amplitudes ranging from 0.01 mm to 3.8 mm. For oscillations larger than 0.35 mm peak-to-peak, measured values were within 6.1 percent of the expected values. For the spinal CSF, oscillation larger than 0.4 mm should be measured accurately with this technique.

The authors devised a new technique for measuring cerebrospinal fluid movement in the spine. With gated list mode acquisition of radioactive emissions, bulk flow, oscillations, and dispersion of a bolus of isotope can be measured. The accuracy of the technique was measured in a simulation in which fluid oscillated at 71 cycles/minute and displaced at 6.5 cm/minute. With this method, the measured oscillation frequency and amplitude and the rate of translation were within 10% of actual values.