Percentage of lung affected by emphysema and bronchial wall thickness on quantitative computed tomography (CT) are associated with chronic obstructive pulmonary disease (COPD) exacerbations, independent of the severity of airflow obstruction. That is according to a recent study published in Radiology.
The study examined a total of 1,002 individuals, who fulfilled the Global Initiative for Chronic Obstructive Lung Disease criteria for COPD and had quantitative CT analyses. The mean wall thickness and mean wall area percentage in six segmental bronchi were measured by an automated program, while a questionnaire was used to determine the frequency of COPD exacerbations in the previous year.
Researchers found that after adjusting for lung function, total emphysema percentage and bronchial wall thickness correlated with COPD exacerbation frequency. The annual exacerbation rate increased significantly with each 1 mm increase in bronchial wall thickness. Further, each 5 percent increase in emphysema in patients with 35 percent or greater emphysema correlated with a 1.18-fold increase in the annual exacerbation rate.
"Our study results, obtained by using quantitative CT metrics, demonstrated that the frequency of COPD exacerbations is related to both emphysema severity and airway disease," the authors write.