[Measurement of cardiac volume by computed tomography (author's transl)].

Noninvasive cardiac volume measurement by computed tomography (CT) was attempted in this study. It was found that non-gated CT images were very close to the end-diastolic images by ECG-gated CT. Ten to fifteen non-gated scannings were obtained serially from the upper atria to the left diaphragm in 9 normal subjects and 72 patients (6 hypertensives, 7 aortic valvular diseases, 22 mitral valvular diseases, 5 shunt lesions and 33 ischemic heart diseases). To demarcate each chamber, contrast enhancement CT was performed by drip infusion in most cases, but it was done by 4-6 times bolus injections at the level of the left ventricle (LV) to visualize LV lumen in ischemic cardiac patients who had ventriculography. The volume was calculated by summing each slice's volume which was obtained from the area times slice thickness (Fig. 2). The total cardiac volume and the volume of each chamber (LA, RA, RV and LV) were calculated. The interventricular septum and LV wall were included into LV volume. There was a good relationship (r = 0.90) between the total cardiac volume by CT and that by chest X-ray (PA and lateral views) (Fig. 4). Each volume by CT in 9 normal subjects was: 353 +/- 30 ml/m2 in total, RA: 53 +/- 17 ml/m2, LA: 54 +/- 21 ml/m2, RV: 90 +/- 15 ml/m2, and LV: 123 +/- 15 ml/m2 (mean +/- SD), respectively, and an increment of each volume was shown according to the hemodynamic features of various heart diseases: the total volume was increased significantly in valvular disease (Fig. 5), RA and RV volumes in mitral valvular disease with tricuspid regurgitation and ASD (Figs. 6, 7) LA volume in mitral valvular disease and shunt lesion (Fig. 8) and LV volume in aortic valvular disease and mitral regurgitation (Fig. 9). Between the left ventricular lumen volume by Ct and its end-diastolic volume by ventriculography (area-length method), there was a good relationship (r - 0.81) in 17 cases without cardiac aneurysms out of 22 ischemic cardiac patients examined by ventriculography (RAO and LAO views) (Fig. 11). The cardiac CT was found very useful for measurements of cardiac volume, since it is noninvasive and quite simple yet reasonably accurate.