Factor analysis in gated cardiac studies.

Factor analysis of dynamic structures (FADS) can automatically provide "physiological" factors related to anatomical structures that have different temporal behavior, even if these structures overlap; it also yields images corresponding to the factors' spatial distributions. In normal patients, two significant cardiac factors, corresponding to the atria and the ventricles, may be extracted. A third significant factor can be obtained when additional dynamic structures exist. However, the method does not provide an estimate of the background. It becomes part of the factors, but it does not modify their shapes. FADS has been applied to 45 gated cardiac studies. Results obtained by FADS were compared with those obtained from the amplitude and the phase of first-harmonic Fourier analysis (FA). The joint results were compared with the final diagnosis, established by real-time echocardiography and/or ventriculography. In normal patients, good agreement was obtained between the two approaches. On the whole set of patients, FADS was significantly better than FA (by sign test: p less than 5%).