Basic physiopathological patterns of perfusion and inhalation pulmonary scintigraphy.

l"imIn 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. Pulmonary scintigraphy, which demonstrates the topographic distribution of perfusion and ventilation , is a useful method for evaluating regional lung function, and Ernst, Iglauer, Kronschwitz, and Spode (1958) were the first to use radio-isotopes for this purpose.taneously developed the technique of pulmonary scintigraphy by perfusion of albumin macro-aggregates labelled with 13II, or mlI, or 5Cr, or 91mTc. In 1966, Stern, Goodwin, Wagner, and Kramer introduced a technique of perfusion of particles of indium hydroxide (llmln) plus iron hydroxide, these being easy to produce. Recently, Zolle, Rhodes, Buchanan, and Wagner (1967) published a new method of perfusion pulmonary scintigraphy, using albumin microspheres of uniform size and shape that could be labelled by adsorption with any radioisotope. When administered intravenously, these particles were retained, according to their diameter, in the pulmonary arterioles. The degree of accumulation in the different areas of the lung was in direct proportion to the regional blood flow, i.e., regions of high radioactivity were the better perfused. the technique of inhalation scintigraphy consisting of inhaling albumin radioaerosol labelled with 99mTc: this enabled them to study bronchial patency and the distribution of ventilation in the different regions of the lungs. The particles accumulated in the bronchioles and alveoli in direct proportion to the pulmonary ventilation, i.e., the regions of higher radioactivity were the better ventilated. Therefore, with perfusion and inhalation pulmonary scintigraphy, the magnitude and extent of perfusion and ventilation of the pulmonary parenchyma could be evaluated. The use of the two procedures in succession in normal individuals and in several pathological conditions has allowed us to …