Chest radiograph and functional radiology.

In the course of the years the concept of functional radiology has gradually been developed. It represents the integration of chest radiography with some basic concepts of respiratory pathophysiology. The correlation between the higher vascularization at the bases of lung as compared to the apex with the gravitation factor was the initial reference. From this data, combined with physiologic parameters, over the years, relatively simple but diagnostically significant semeiotic findings were achieved. The different combinations of acquired "morphofunctional" signs allow the differential diagnosis in a number of organic and hemodynamic alterations, adding to conventional "morphologic" radiology. New contributions to the functional radiology of the lung might come from procedures as high resolution computed tomography (HRCT) which with the dynamic study supplies morphologic and densitometric information to be correlated with changes in pulmonary flow and ventilation/perfusion ratio.