High-resolution CT (HRCT) is invaluable in the diagnosis and management of patients with diffuse lung disease, providing anatomic detail comparable with gross pathology. Although HRCT has proved most useful in the diagnosis of diffuse infiltrative lung diseases, its application to the diagnosis of airway and obstructive lung diseases has recently been emphasized.<sup>68 Müller N.L., Miller R.R. Diseases of the bronchioles: CT and histopathologic findings Radiology 1995 ;  196 : 3

Cliccare qui per andare alla sezione Riferimenti, 102 Webb W.R. High-resolution computed tomography of obstructive lung disease Radiol Clin North Am 1994 ;  32 : 745

Cliccare qui per andare alla sezione Riferimenti</sup>

Expiratory HRCT techniques as an adjunct to inspiratory are particularly useful in assessing patients with obstructive lung diseases, providing physiologic information in regard to regional lung function. In patients with obstructive lung diseases, morphologic abnormalities visible on inspiratory scans can be subtle or nonspecific in some patients. CT or HRCT obtained during forced exhalation (dynamic expiratory CT),<sup>93 Stern E.J., Webb W.R., Gamsu G. Dynamic quantitative computed tomography: A predictor of pulmonary function in obstructive lung diseases Invest Radiol 1994 ;  29 : 564  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 103 Webb W.R., Stern E.J., Kanth N. , e al. Dynamic pulmonary CT: Findings in normal adult men Radiology 1993 ;  186 : 117

Cliccare qui per andare alla sezione Riferimenti</sup> during suspended respiration after forced exhalation (postexpiratory CT), or at a user-selected respiratory level controlled during exhalation using a spirometer (spirometrically triggered expiratory CT)<sup>41 Kalender W.A., Fichte H., Bautz W. , e al. Semiautomatic evaluation procedures for quantitative CT of the lung J Comput Assist Tomogr 1991 ;  15 : 248  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 42 Kalender W.A., Rienmuller R., Seissler W. , e al. Measurement of pulmonary parenchymal attenuation: Use of spirometric gating with quantitative CT Radiology 1990 ;  175 : 265

Cliccare qui per andare alla sezione Riferimenti, 49 Lamers R.J., Thelissen G.R., Kessels A.G. , e al. Chronic obstructive pulmonary diseases: Evaluation with spirometrically controlled CT lung densitometry Radiology 1994 ;  193 : 109

Cliccare qui per andare alla sezione Riferimenti</sup> have all been shown to be useful in the diagnosis of diseases characterized by airflow limitation or air-trapping. Focal, multifocal, or diffuse air-trapping visible using these expiratory or postexpiratory CT techniques as areas of abnormally low attenuation can confirm the presence of obstructive physiology in patients with airway abnormalities visible on inspiratory scans, allow the diagnosis of obstructive abnormalities in some patients with normal inspiratory scans, and help in distinguishing between obstructive disease and infiltrative disease as a cause of inhomogeneous lung opacity seen on inspiratory scans. Air-trapping on expiratory CT has been recognized in patients with various obstructive or airway diseases, such as emphysema,<sup>44 Kitahara Y., Takamoto M., Maruyama M. , e al. Differential diagnosis of pulmonary emphysema using the CT index: LL% [in Japanese] Nippon Kyobu Shikkan Gakkai Zasshi 1989 ;  27 : 689

Cliccare qui per andare alla sezione Riferimenti, 46 Knudson R.J., Standen J.R., Kaltenborn W.T. , e al. Expiratory computed tomography for assessment of suspected pulmonary emphysema Chest 1991 ;  99 : 1357  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 93 Stern E.J., Webb W.R., Gamsu G. Dynamic quantitative computed tomography: A predictor of pulmonary function in obstructive lung diseases Invest Radiol 1994 ;  29 : 564  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> asthma,<sup>74 Newman K.B., Lynch D.A., Newman L.S. , e al. Quantitative computed tomography detects air trapping due to asthma Chest 1994 ;  106 : 105  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> constrictive bronchiolitis (CB),<sup>6 Aquino S.L., Webb W.R., Golden J. Bronchiolitis obliterans associated with rheumatoid arthritis: Findings on HRCT and dynamic expiratory CT J Comput Assist Tomogr 1994 ;  18 : 555  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 26 Garg K., Newell J.D. , e al. Proliferative and constrictive bronchiolitis: Classification and radiologic features AJR Am J Roentgenol 1994 ;  162 : 803

Cliccare qui per andare alla sezione Riferimenti, 60 Marti-Bonmati L., Ruiz P.F., Catala F. , e al. CT findings in Swyer-James syndrome Radiology 1989 ;  172 : 477

Cliccare qui per andare alla sezione Riferimenti, 64 Moore A.D.A., Godwin J.D., Dietrich P.A. , e al. Swyer-James syndrome: CT findings in eight patients AJR Am J Roentgenol 1992 ;  158 : 1211

Cliccare qui per andare alla sezione Riferimenti, 76 Padley S.P.G., Adler B.D., Hansell D.M. , e al. Bronchiolitis obliterans: High-resolution CT findings and correlation with pulmonary function tests Clin Radiol 1993 ;  47 : 236  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 93 Stern E.J., Webb W.R., Gamsu G. Dynamic quantitative computed tomography: A predictor of pulmonary function in obstructive lung diseases Invest Radiol 1994 ;  29 : 564  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 97 Sweatman M.C., Millar A.B., Strickland B. , e al. Computed tomography in adult obliterative bronchiolitis Clin Radiol 1990 ;  41 : 116  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> and bronchiectasis.<sup>36 Hansell D.M., Wells A.U., Rubens M.B. , e al. Bronchiectasis: Functional significance of areas of decreased attenuation at expiratory CT Radiology 1994 ;  193 : 369

Cliccare qui per andare alla sezione Riferimenti, 93 Stern E.J., Webb W.R., Gamsu G. Dynamic quantitative computed tomography: A predictor of pulmonary function in obstructive lung diseases Invest Radiol 1994 ;  29 : 564  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup>