Quantitative computed tomographic measurement of a cross-sectional area of a small pulmonary vessel in nonsmokers without airflow limitation.

PURPOSE: Pulmonary vascular alterations are not exclusive to pulmonary vascular disorders; they are also present in patients with mild chronic obstructive pulmonary disease (COPD) with normal pulmonary function. Moreover, vascular alteration is closely related to lung ventilation. We hypothesized that pulmonary vascular alterations might occur even in nonsmokers with subtle airflow limitation, and there could be a significant correlation between pulmonary vascular alterations and airflow impairment. The purpose of this study was to evaluate the correlation between the vascular alterations measured by cross-sectional area (CSA) and airflow impairment in nonsmokers with normal pulmonary function.
MATERIALS AND METHODS: Thirty patients (1 man, 29 women; mean age 55 ± 14 years, range 33-81 years) underwent pulmonary function tests (PFTs) within 2 weeks of undergoing multidetector computed tomography (CT) scans. Total vessel CSA < 5 mm(2) was calculated by a threshold technique using imaging software. Forced expiratory volume in 1 s (FEV(1)), the ratio of FEV(1) to FVC (FEV(1)/FVC), and the mid-expiratory phase of the forced expiratory flow (FEF(25%-75%)) were obtained from PFTs. We calculated Spearman correlation coefficients between %CSA < 5 and the results of PFTs.
RESULTS: %CSA < 5 had a significant positive correlation with FEV(1)/FVC (r = 0.651, P < 0.0001) and FEF(25%-75%) (r = 0.627, P = 0.0002), whereas CSA < 5% had no significant correlation with FEV(1) (r = 0.172, P = 0.362).
CONCLUSION: There was a significant correlation between pulmonary small vascular alteration and airflow impairment even in nonsmokers without airway obstruction.