Quantitative nuclear angiocardiography in valvular heart disease

A noninvasive method of quantitative nuclear angiocardiography was developed using a camera system and a computer. The investigation, which can be performed on an out-patient basis within 10-15 min, includes the following steps: injection of 10 mCi 99mTc-labelled human serum albumin into a femoral vein, and external recording of the passage of the bolus through the central circulation by a sequence of scintigraphic frames taken during diastole. From time--activity curves over the right ventricle, the pulmonary artery and the left ventricle, peak-to-peak times and mean circulation times were calculated. The method was applied to 424 patients with valvular heart disease proven by heart catherization. The following results were obtained: (1) The method proved to be highly sensitive in stating whether there was a hemodynamically significant valvular disease or not. But differential diagnosis concerning the different forms of valvular disease was not possible. (2) The prolongation of the circulation times correlated with the hemodynamic severity of the disease. (3) The circulation times were directly related to the cardiac index, the enddiastolic volume of the left ventricle and the pressures in the pulmonary vascular system. (4) The method could be used to evaluate the effect of surgery and for follow-up after operation. Quantitative nuclear cardiography may help to fill the gap between the nonquantitative, rather unspecific and the specific but invasive methods of cardiologic investigation.