Abstract

^113mIn is an excellent radiopharmaceutical for pulmonary scanning. Seven physiopathological patterns are described after the study of the results of successive perfusion and inhalation pulmonary scans—pulmonary artery obstruction, complete bronchial obstruction, partial bronchial obstruction, bronchiolar obstruction, anatomical changes in the pulmonary parenchyma, pathological pulmonary dead space, and intrapulmonary arterio-venous shunting. Pulmonary artery obstruction can be diagnosed early, precisely, and safely by this method. Pathological pulmonary dead space and intrapulmonary shunting have well-defined characteristics; the ability to demonstrate their topography and size in patients with pulmonary emphysema may lead to surgical removal of the affected regions, thus improving overall pulmonary function. The scintigraphic procedures used revealed that bronchial obstruction is associated with absent pulmonary arterial perfusion in the corresponding bronchial territory; this finding is of the utmost importance, as it may permit the diagnosis of bronchial carcinoma before any radiological changes occur.