Fourier analysis in ECG gated blood pool emission computed tomography

Using a rotating gamma camera system with a high-resolution parallel hole collimator, application of Fourier analysis to gated blood pool emission computed tomography (gated pool SPECT) with cardiac phantoms was carried out. The evaluation of wall motion abnormalities of 19 patients with old myocardial infarction (OMI) was examined. The obtained images were filtered for space high frequency noise by means of a weighted 9-point smoothing. In gated pool SPECT, a series of transverse view tomograms was reconstructed by means of Shepp and Logan's filtered back projection method in every 6 mm slice. From the processed data the functional images of the first and higher order compornents of the temporal Fourier transform were obtained. Through these functional images, the conditions of data acquisition and processing were examined. From the results of phantom study, the clinical application of gated pool SPECT was carried out in order to evaluate three dimensional wall motion abnormalities of the 19 patients of OMI (55 infarct sites). This gated pool SPECT method was similar to the left ventriculography method in superiority for detection of wall motion abnormality sites. The wall motion could be evaluated three dimensionally from functional images derived from Fourier analysis of gated pool SPECT reorganized images (sagittal, coronal and 4-chamber images). (author)