The hyperperfused lung. Detection in congenital heart disease.

Thirty-nine children with various cardiac abnormalities were examined with perfusion lung scintigraphy with technetium Tc 99m macroaggregated albumin. Nuclide accumulation within each lung, which is proportional to the division of pulmonary arterial flow, was determined. Twenty-six patients had hyperperfusion of one lung, with a particularly high incidence occurring with the tetraoloy of Fallot, pulmonary artery stenosis or atresia, and following surgical systemic-pulmonic anastomoses. Consistent detection of imbalance in pulmonary flow by inspection of chest x-ray films was possible when one lung received at least 2 1/2 times the blood flow of the opposite side; with angiography, flow imbalance could be recognized when flow in one lung exceeded flow in the other by only 1 1/2 times. The radionuclide quantitative method was a more sensitive means of detecting early cases of mismatched pulmonary blood flow than roentgenography, which was nonquantitative and required the presence of relatively gross perfusion abnormalities before visual perception was possible.