Non-invasive imaging of regional lung function using X-ray computed tomography

The use of imaging technologies has progressed beyond the depiction of anat omic abnormalities to providing non-invasive regional structure and functio nal information in intact subjects. These data are particularly valuable in studies of the lung, since lung disease is heterogeneous and significant l oss of function may occur before it is detectable by traditional whole lung measurements such as oxygenation, compliance, or spirometry. While many im aging modalities are available, X-ray computed tomography (CT) is emerging as the preferred method for imaging the lung because of its widespread avai lability, resolution, high signal/noise ratio for lung tissue, and speed. U tilizing the quantitative density and dimensional information available fro m conventional CT images, it is possible to measure whole and regional lung volumes, distribution of lung aeration and recruitment behavior under vari ous clinical conditions and interventions, and important regional mechanica l properties. In addition, using the radiodense gas xenon (Xe) as a contras t agent, regional ventilation or gas transport may also be obtained. This c ommunication will review recent advances in CT based techniques for the mea surement of regional lung function.