The present invention relates generally to diagnosing chronic obstructive pulmonary disease (COPD) and estimating of the severity thereof, in particularly the occurrence of emphysema. More particularly the present invention relates to a system and method for computerized quantification of airway collapse during forced expiration or total exhalation. Such airway collapse is correlated with the presence of emphysema that has been verified on computer tomography (CT) scan and that is due to the loss of alveolar attachments in emphysema. Moreover the present invention provides a computerized apparatus for detection of emphysema, a computerized system for detection of emphysema or a method of computer-aided detection of emphysema. This can also be used for quantifying the severity of emphysema in patients with COPD by an automated analysis of measurement of the amount (volume) and/or speed (flow) of a total or forced exhalation or the processing of the graphics of a pneumotachograph of a total or forced exhalation. Such measurements are obtainable by a spirometer. The apparatus, system or method of present invention correlates airway collapse during forced expiration in COPD with presence and severity of emphysema It was demonstrated that airway collapse during forced expiration could be quantified by measuring the angle between the two best fitting regression lines describing the cloud of point measurements obtained from peakflow to the end of forced expiration. Such angle in COPD correlates with presence and severity of emphysema, as assessed by computer tomography scan.La présente invention concerne d'une manière générale le diagnostic d'une maladie pulmonaire obstructive chronique (COPD) et l'estimation de la gravité de celle-ci, en particulier la survenue d'un emphysème. Plus particulièrement, la présente invention porte sur un système et un procédé pour une quantification informatisée d'un collapsus des voies aériennes durant une expiration forcée ou une exhalation
