Evaluation of the cross-sectional area of small pulmonary vessels in the diagnosis of chronic obstructive pulmonary disease by quantitative computed tomography

Patients with chronic obstructive pulmonary disease (COPD) have a reduced cross-sectional area (CSA) of small pulmonary vessels and decreased pulmonary function test (PFT) indexes. This study investigated the value of small pulmonary vessel CSA in diagnosing and evaluating the severity of COPD and its correlation with PFT.This retrospective case-control study included patients with COPD who underwent multi-slice spiral computed tomography (CT) between March 2015 and December 2018. COPD severity was graded. Patients with normal CT results were included as controls. The CSA of small pulmonary vessels at the sub-segmental (5-10 mm2) and sub-sub-segmental (<5 mm2) levels was measured. Receiver operating characteristic (ROC) curves were used to evaluate the effect of CSA for COPD risk prediction. The correlation between CSA% and PFT indexes was evaluated.There were 124 and 106 patients in the COPD and control groups, respectively. The %CSA <5 and %CSA5-10 were smaller in the COPD group than in controls (P < .05). The %CSA <5 in each subgroup stratified by COPD severity was smaller than in controls (P < .05). The % CSA5-10 was significantly smaller in the moderate and severe groups than in controls (P < .05). At 0.655%CSA <5 cut-off, the ROC area under the curve (AUC) was 0.765. For %CSA5-10, a 0.565 cut-off led to an AUC of 0.752. Both %CSA <5 and %CSA5-10 were positively correlated with all PFT indexes (r = 0.180-0.462, all P < .05).CSA was positively correlated with PFT. Analysis of small pulmonary vessel CSA based on CT images contributes to diagnosing and assessing the severity of COPD.