[Recent advances in CT diagnosis of chronic obstructive pulmonary diseases].

With high-resolution CT (HRCT), morphological changes of the lung caused by chronic obstructive pulmonary disease can be evaluated in detail at the level of secondary pulmonary lobule. The location of emphysematous lesions within the lobule can be judged on HRCT images and bronchiolar abnormalities are also demonstrated as thickening of peripheral bronchovascular bundles. In addition to early detection of morphological changes, quantitative evaluation of the severity of the disease is also important. For this purpose, visual assessment with CT scores, quantitative evaluation using "density mask" technique, or histogram analysis are employed. Quantitative parameters provided by these methods correlate well with pathological scores and results of pulmonary function tests. Furthermore, respiratory dynamic CT or paired inspiratory and expiratory CT is also useful to detect air trapping caused by bronchiolar stenosis.