Pulmonary System

Abstract

AbstractLung scintigraphy entails a perfusion scan, a ventilation scan, or a combination of both. These studies provide qualitative and quantitative information on changes in lung perfusion and ventilation that may occur in various congenital and acquired conditions. They are used for initial assessment, for follow up and for evaluation of therapeutic interventions. Perfusion scans assess the blood flow distribution in the lungs. These studies are performed following the intravenous (IV) injection of radiolabelled microparticles that occlude pre-capillary arterioles. They provide useful visual and semi-quantitative information on lung perfusion physiology and pathophysiology. Ventilation scans assess the airspaces of the lungs. They are performed by inhalation of either radiolabelled aerosols or radioactive gases. Imaging with radiolabelled gases allows dynamic scintigraphy with a single breath, rebreathing (equilibrium) and washout phases that can occasionally provide useful information. The inclusion of SPECT and SPECT/CT in perfusion and ventilation scans significantly enhances the diagnostic utility of these studies. Pulmonary embolism, the most common indication for lung scintigraphy in adults, is far less common in children. Most lung scans in children are performed to evaluate the impact of congenital heart and lung conditions on pulmonary function and to assess the effects of corrective procedures.