Cardiac Shunt Assessment in Children with Macroaggregated Albumin Technetium-99m

Abstract

Right-to-left cardiac shunting is calculated following intravenous administration of macroaggregated albumin (MAA) tagged with 99mTa MAA entering the pulmonic circuit lodges in its capillary bed while that bypassing the lungs is impacted in the systemic circuit. A total body count is obtained with a gamma camera. Lung activity is measured separately. From these activity counts, the magnitude of right-to-left cardiac shunting is determined.