High Resolution Computed Tomography and Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable respiratory disease with some significant extrapulmonary effects that may contribute to the severity in individual patients. Its pulmonary components are characterized by airflow limitation that is not fully reversible. COPD is a leading cause of morbidity and mortality worldwide. The economic and social burdens due to it are substantial and anticipated to increase in the coming decades due to continued exposure to COPD risk factors and the changing age profile of the world’s population. COPD mortality trends generally track several decades behind smoking trends. In US in 2000, more women than men died of COPD or its related complications. COPD comprise of a heterogeneous group of disorders conventionally including emphysema, chronic bronchitis, peripheral airways disease and pulmonary vascular disease. It is a disease state that has seen significant changes in defining and excluding criteria over past 50 years. Spirometry, the most frequently used tool to diagnose COPD and to assess response to treatment in these patients, can provide only functional assessment. In contrast to spirometry, radiological imaging allows for regional assessment of the various compartments involved i.e. airways, parenchyma and vasculature. High-resolution computed tomography (HRCT) is recommended for the non-invasive and sensitive assessment of morphological changes in emphysema and has been shown to correlate well with pathology. With the advent of new imaging techniques like multi-detector row CT (MDCT), contrast-enhanced CT methods, spirometric controlled MDCT, use of Xenon gas to assess regional ventilation of the lungs, magnetic resonance imaging (MRI) of the lung developing its own arsenal like hyperpolarized He-3 MRI – new avenues are being opened up which are now increasingly supplemented with advanced and dedicated softwares.