Chronic obstructive pulmonary disease (COPD), a respiratory disease commonly known as chronic bronchitis or emphysema, is the fourth leading cause of death worldwide.  600 million people live with COPD, and while researchers have yet to find any real treatment or cure, Grace Parraga of Robarts Research Institute at The University of Western Ontario is using various imaging techniques to gain new insight into the disease.    The World Health Organization officially recognized World COPD Day on Wednesday.