Need to know what emphysematous changes in lung means?

Altered structure: Emphysema is when the microscopic air sacs in the lungs are gradually destroyed, resulting in progressive shortness of breath. Emphysema is one form of chronic obstructive pulmonary disease (copd). Smoking is the leading cause of emphysema. In emphysema the lung alveoli (microscopic areas for oxygen exchange) are destroyed and the lung becomes less elastic making it difficult to breathe.