NON-INVASIVEIMAGINGOFREGIONALLUNG FUNCTIONUSINGX-RAYCOMPUTEDTOMOGRAPHY

The use of imaging technologies has progressed beyond the depiction of anatomic abnormalities to providing non-invasive regional structure and functional information in intact subjects. These data are particularly valuable in studies of the lung, since lung disease is heterogeneous and signi¢cant loss of function may occur before it is detectable by traditional whole lung measurements such as oxygenation, compliance, or spirometry.While many imaging modalities are available, X-ray computed tomography (CT) is emerging as the pre- ferred method for imaging the lung because of its widespread availability, resolution, high signal/noise ratio for lung tissue, and speed. Utilizing the quantitative density and dimensional information available from conventional CT images, it is possible to measure whole and regional lung volumes, distribu- tion of lung aeration and recruitment behavior under various clinical conditions and interventions, and important regional mechanical properties. In addition, using the radiodense gas xenon (Xe) as a contrast agent, regional ventilation or gas transport may also be obtained. This communication will re- view recent advances in CT based techniques for the measure- ment of regional lung function.