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A computer-aided operator-interactive method has been developed to measure changes in the diameter of the coronary arteries as a result of the contractile motion of the heart and of vasodilators and constrictors. The method has been tested in animal models: mongrel dogs of 15-20 kg weight were subjected to cinefluorograohic procedures taken at a rate of 30 frames/sec. The selected width of segments of coronary arteries were measured with an EyeCom image analyzer interfaced to a VAX 11/780 comnuter at a resolution of -20 microns on 100 frames per injection. Ten scan lines were averaged for each segment: furthermore, in order to reduce scanning noise, each scan line was taken four times and averaged. The blood vessel diameter was determined as the horizontal distance of the base points in the blood vessel image profile. Autocorrelograms, power spectra and an ad-hoc method termed F-technique were used to analyze periodicities in the data. It was found that the amplitudes of periodic oscillations in the blood vessel diameters may be almost as large as the changes caused by some vasodilators and constrictors.
Sándor et al. (Wed,) studied this question.