[Evaluation of 99mTc-albumin distribution ratio in the cardiac chambers and lungs].

In order to assess blood volume of the cardiac chambers and lungs, distribution ratio of 99mTc-albumin (HSA) was obtained from radionuclide angiocardiogram and non-gated or gated equilibrium cardiac pool scintigram, using a scintillation camera coupled to a minicomputer. The radio-activity of 99mTc of the entire cardiac blood pool including the large vessels (T), the right ventricle including the right atrium (RV) and the left ventricle (LV) was calculated from the 30 degrees anterior oblique cardiac pool scintigram. That of the both lungs (Lu) was calculated from the anterior cardiac pool scintigram. The radioactivity of total injected dose of HSA (H) was estimated from the initial transit of the tracer obtained by the radionuclide angiocardiogram. Then, distribution ratio of HSA of the each region of interest was expressed as RV/H, LV/H, T/H and Lu/H. RV/H, LV/H and T/H were 3.4 +/- 0.6%, 3.1 +/- 0.5% and 10.4 +/- 2.0% in controls, 6.0 +/- 0.8%, 2.6 +/- 0.8% and 14.2 +/- 2.4% in cor pulmonale, and 7.9 +/- 1.7%, 7.7 +/- 3.5% and 20.7 +/- 4.3% in heart diseases with left heart failure, respectively. Lu/H was 4.9 +/- 1.4% in controls, 4.4 +/- 1.1% in cor pulmonale and 6.6 +/- 1.9% in heart diseases without left heart failure. LV/H was correlated with left ventricular end-diastolic volume by contrast ventriculography. LV/H and RV/H were related with functional classification of NYHA. In conclusion, these parameters may be utilized as indices of the volume of blood pool of the heart chambers and lungs, and this method seems to be clinically applicable for the evaluation of pathophysiology in heart diseases.