Evaluation of the severity of chronic obstructive pulmonary disease with the percentage of the total cross-sectional area of small pulmonary vessels for the lung area in multi-slice CT

Abstract

Objective To investigate the role of the percentage of the total cross-sectional area of small pulmonary vessels for the lung area (%CSA) from multi-slice CT (MSCT) in evaluating the severity of chronic obstructive pulmonary disease (COPD). Methods One hundred and sixty-six COPD patients and 166 normal subjects underwent chest MSCT scans and all data were analyzed retrospectively. COPD patients underwent pulmonary function tests (PFT), including forced expiratory volume in one second (FEV1%) and FEV1/forced vital capacity (FEV1/FVC), and were classified into mild (n=32), moderate (n=65), severe (n= 69) groups according to pulmonary function results, respectively. The %CSA less than 5 mm2 and 5–10 mm2 for the lung area (% CSA<5 and % CSA5-10) of small pulmonary vessels were measured with Image J image-processing program. Comparison of %CSA<5 and %CSA5-10 between the COPD and control groups was perfomred using t test, and the comparison between the 3 COPD subgroups and control group were carried out using ANOVA test. The correlation between % CSA and PFT was evaluated by the Spearman rank correlation test. The sensitivity and specificity of % CSA to diagnose COPD and the best cutoff were calculated from areas under the ROC curves. Results % CSA 0.05). FEV1% and FEV1/FVC in COPD patients were (60.38±15.52)% and 57.95±22.27. %CSA<5 in COPD patients correlated positively with both FEV1% and FEV1/FVC (r=0.609 and 0.721, P<0.01, respectively). %CSA5-10 in COPD patients correlated positively with both FEV1% and FEV1/FVC (r=0.271 and 0.288, P<0.01, respectively). Conclusion The measurement of %CSA<5 and %CSA5-10 in MSCT images correlated with PFTs and %CSA<5, which may play an important role in evaluating the severity of COPD. Key words: Pulmonary disease, chronic obstructive; Respiratory function tests; Tomography, X-ray computed