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The analysis of size, shape and contraction pattern of the right ventricle from angiocardiograms
Abstract:
This paper describes an approach to assess quantitatively videoangiocardiograms of the geometrically complex right ventricle with the aid of an automated roentgen-television-computer system. The influence of spatial positions and heart phase on the accuracy of right ventricular volume determination with biplane and single plane area-length and multiple slices methods was defined on the basis of a special cast study. Without considering position and phase a relative deviation - with a biplane procedure - of not equal to 11.9% has to be faced, which will be reduced to not equal to 8.8% when position, and to not equal to 6.2% when in addition the phase of the cardiac cycle is taken into consideration. Fourier analysis was applied to biplane silhouettes and 'true' cross-sections of mechanically sliced human right ventricular casts in order to arrive at 3-D 'norm ventricles' as reference for size and shape analysis of beating normal and diseased hearts. For contraction pattern analysis the dimensional information from each X-ray plane was processed independently. Selected points (anatomical landmarks), being marked with an x/y coder, served as internal reference system. Multiple parallel diameters, their directions given by a pair of indicated points or by a freely selected angle, were followed throughout the cardiac cycle. Applied was the method to angiocardiograms with normal hearts and those with ASD, pulmonic stenoses, and postoperative tetralogies of Fallot. It can be concluded that on the basis of videoangiocardiograms (1) right ventricular volume can be determinded with a defined and acceptable accuracy, with both biplane and single plane procedures, if one takes into consideration the spatial position and the cardiac phase, (2) right ventricular shape can be quantitated for an objective description, and (3) right ventricular contraction and relaxation processes can be assessed and quantitated for normal and diseased right ventricles.