Measurement of the dynamics of arteriolar diameter.

The diameter of the arteriolar vessels of the microcirculation undergoes a continuous variation as a consequence of vasomotion. The quantification of this process requires the implementation of spectral analysis techniques that model short data records of a finite number of superposed sinusoidal waveforms. The following techniques were tested with artificially synthetized records and actual data: the fast Fourier transform, the high-resolution autoregressive method, the maximum entropy method, and the Prony Spectral Line Estimator (PSLE). It was found that the PSLE provides the most accurate estimation of the spectral components of the dynamics of diameter changes because it does not require any assumption on the nature of the data outside the interval under analysis.