Quantitative lung perfusion scintigraphy in patients with congenital heart disease

The objectives of this article are to review different patterns and potential pitfalls of quantitative lung perfusion scintigraphy (LPS) in patients with congenital heart disease (CHD). The patterns of quantitative LPS in patients with CHD include normal symmetrical bilateral perfusion to both lungs, unilateral absent perfusion in one lung, unilateral decreased perfusion, and multiple segmental perfusion abnormalities that suggest pulmonary embolism. Knowledge of several potential pitfalls is very important to avoid false interpretations; common pitfalls are related to type of site of injection (upper versus lower extremities), right or left upper extremity in case of persistence of left superior vena cava and previous surgery. An important incidental finding that may prompt immediate attenuation is multiple segmental defect that suggests asymptomatic pulmonary embolism, which is relatively common in this population.