1. Laboratorio de Pesquisa em Imagens Medicas, Pavilhao Pereira Filho, Santa Casa de Misericordia de Porto Alegre, Porto Alegre (RS) Brasil. 2. Pontificia Universidade Catolica de Porto Alegre, Porto Alegre (RS) Brasil. COPD involves destruction of alveolar septa in the lungs, associated with small airway dilation that is partially irreversible.(1) The first process leads to loss of surface area for gas exchange (restrictive component), whereas the second process is detrimental to an adequate respiratory cycle (obstructive component). COPD is an entity that has remarkable relevance in public health practice, because of its high prevalence and because it is associated with the occurrence of lung cancer and reduced life expectancy and quality of life.(2)