Pulmonary vascular alteration in chronic obstructive pulmonary disease patients based on quantitative CT analysis

Objective: To evaluate the ability of the quantitative CT analysis in pulmonary vascular alteration, and the association of small pulmonary vessels with the extent of emphysema in chronic obstructive pulmonary disease (COPD). Methods: A quantitative CT measurement was used to assess of both pulmonary vessels in 121 COPD patients, and its longitudinal changes over 2 years in 48 patients. The extent of emphysema was defined as percentage of low attenuation areas less than a threshold of -950 HU in whole lung (%LAA-950) on CT scan; the changes of small pulmonary vessels was evaluated with the number of small pulmonary vessels per unit area. The correlation between number of pulmonary vessels and %LAA-950 was analyzed. Results: The total number of small pulmonary vessels in the level of the fifth generation of bronchus of right upper lobe section had the significant negative correlations with %LAA-950 (r=-0.87, P<0.01). The number of small pulmonary vessels per unit area was less in current smokers (P=0.02) than in former smokers (P=0.07). Conclusion: CT can quantitatively analyze pulmonary vascular changes in COPD patients, which is intuitive and quantifiable. Changes of small pulmonary vessels in COPD patients can be affected by smoking status and emphysema quantification.