We describe a fully automated method for quantification of left ventricular performance by equilibrium radionuclide ventriculographic studies, based on subdivision of the left ventricular region into 9 equiangular sectors. The precise identification of the left ventricular contours is achieved by the use of morphological and functional criteria in a sequential edge detection algorithm with a success rate of 96%. In addition to left ventricular global and sectorial ejection fraction the first harmonic of the corresponding Fourier spectrum is approximated to each sectorial time-activity curve and to the global one. Sectorial phase is calculated as the difference between the phase of the sectorial and global first Fourier component. Computerized comparison between the sectorial parameters at rest and during peak exercise localizes and classifies the degree of global and regional impairment in response to exercise. The processing time of 60 sec makes this method suitable for routine use. The validity of our procedure has been tested in 34 patients before and after successful transluminal coronary angioplasty. In these patients, 73% of the stenosed vessels before dilatation were localized by sectorial ejection fraction, 77% by sectorial phases, and 88% by the combination of both.
A fully automated computer program is described for processing equilibrium radionuclide ventriculography data with regard to global and sectorial left ventricular ejection fraction. The precise identification of the left ventricular outline, a prerequisite for reproducible determination of sectorial ejection fraction, was achieved by using morphological and functional criteria in a sequential edge detection technique. The high reproducibility of this method (correlation coefficient r: global ejection fraction r = 0.96, sectorial ejection fraction r = 0.82-0.97) allows the evaluation of a mean normal sectorial ejection fraction profile and its adaptation to the individual left ventricle. Computerized comparison between individual and adjusted normal sectorial ejection fraction permits quantitation of the degree and localization of functional impairment at rest, sectorial comparison between ejection fraction at rest and during peak exercise is used for the detection of ischemic functional impairment. The success rate of end diastolic left ventricular edge detection of 96% and the processing time of 150 s makes this method suitable for routine use.
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