A Method for Determination of Blood Flow with Use of Roentgen Contrast Medium

Abstract

THE PUMPING capacity of the heart is in a high degree dependent upon the effectiveness of the valves. There is still, however, no practical method by which reliable quantitative data concerning this function can be obtained, although important contributions toward the solution of this problem have been made from several quarters (2, 32,46-48,50). The estimation of the insufficiency component in connection with aortic and mitral lesions has hitherto been made largely with physical diagnostic methods, but above all with the help of cardioangiography. Thus, with an injection of contrast medium in the ascending aorta it is possible to make a rough estimation of the insufficiency component in the aortic valves (4, 31, 43, 44, 50, 61). If at the same time the mitral valve is insufficient, it is sometimes possible to see a part of the contrast fluid regurgitate from the left ventricle to the left atrium. In cases of mitral insufficiency, however, it is as a rule easier to estimate this through injection of contrast medium into the left ventricle (1, 21, 36, 55, 57, 60). The use of roentgen cinematography instead of the previously more common serial roentgenography has considerably improved the possibilities of estimating the degree of regurgitation (11, 23, 24). Quantitative data concerning the magnitude of the regurgitation have not, however, been obtained in this way. Attempts have been made (5) to assess the degree of regurgitation in cases of mitral insufficiency by determining how far the contrast fluid has passed into the aorta after injection into the left ventricle when the left atrium has been filled. Even in this case, however, the assessment of the magnitude of the insufficiency is approximate. Of great interest in the attempts to solve the problems in question are the roentgen methods for the determination of the stroke volume of the left ventricle (3, 4:7, 48). After calculation of the stroke volurne with the help of simultaneously exposed frontal and lateral films during the passage of contrast fluid through the left ventricle, the pump volume per minute has been calculated by multiplying by the stroke frequency per minute (3, 11, 23). These values have then been compared with determination of the minute-volume according to Fick or with the help of the dilution curve for injected contrast material or isotopes according to Stewart-Hamilton's principle (3, 22, 54). In such investigations it is not possible to carry out determinations of flow according to Fick simultaneously with the roentgen determinations of stroke volume and frequency. There have often been rather big differences in the calculated flow obtained by the two procedures. For one and the same patient with sufficient valves the difference between the determinations of flow with the Fick method and the angiographic method amounted to no less than 50 per cent of the value arrived at with the Fick method.