[Pathophysiological approach to infiltrative lung diseases on CT].

The analysis of HRCT findings of interstitial lung diseases frequently allows to predict the reversible nature of abnormalities, to recognize the involved components of the lung and to suggest the underlying pathophysiological mechanisms. Pathologic alterations in the anatomy of secondary pulmonary lobules include interlobular septal thickening or/and diseases with peripheral lobular distribution, centrilobular abnormalities, and panlobular abnormalities. Consolidations and ground glass opacities are better analyzed by taking into account the way lung responds to injury rather than anatomic distribution of lesions. The recognition of the topographic distribution of lesions and associated abnormalities, including airway diseases, pulmonary hypertension and embolus, diaphragmatic and pharyngeal dysfunctions, provides a better understanding of underlying disease mechanisms and allows a limited differential diagnosis.