Analysis of gated blood-pool ventriculography by adaptive multiharmonic Fourier and gamma-variate fit

In past the number of harmonics in Fourier analysis of gated blood-pool ventriculography was fixed. Adam used first harmonic, Machac three harmonics while Bacharac determined the best number of harmonics with the smallest total error estimation for every functional parameter separately. In our method the number of harmonics for every regional time activity curve was determined from Fourier amplitude spectrum with rejection of approximately 95% of noise. In the second method we applied the gamma-variate fit to stroke activity curves. Both methods were compared to Fourier analysis with 1, 2, 3, 4 and 5 harmonics on a group of six patients. Total error estimation for amplitude, TES, PER, PFR, TPER and TPFR showed that adaptive multiharmonic Fourier analysis introduced nearly equal total error for all functional parameters than the best multiharmonic analysis with fixed number of harmonics. Gamma-variate fit was excellent for amplitude and TES computation but moderately worse for other functional parameters with the applied fitting procedure. A method for sequential presentation of emptying and filling amplitude was developed with gamma-variate fit and the examples of preconcentrations are shown. (Author)