Volumetric expiratory HRCT of the lung: clinical applications.

Expiratory high-resolution CT (HRCT) of the chest offers a powerful adjunct to inspiratory HRCT in the detection of lung diseases involving the small airways. In 2003 a clinical HRCT scan protocol was developed. It has since been used for evaluation of diffuse lung disease with suspected airway abnormalities. It provides volumetric assessment of the entire thorax at end-inspiration and at end-expiration, and allows for detailed analysis of the airway and parenchyma. It offers a powerful adjunct to inspiratory HRCT in the detection of lung diseases involving the small airways. This article explores its clinical applications for chronic obstructive pulmonary disease, bronchiectasis, and sarcoidosis. It concludes that standardization of image acquisition and post-processing in CT examinations will be necessary for the real application of quantitative data derived from volumetric expiratory HRCT to daily clinical medical practice.