A novel approach to assess pulmonary function in patients with chronic obstructive pulmonary disease using tissue velocity imaging.

Abstract

Aims: To explore the feasibility of quantitative evaluation of pulmonary function in patients with chronic obstructive pulmonary disease (COPD) using tissue velocity imaging (TVI) and strain rate imaging (SRI) via transthoracic lung ultrasonography. Material and methods: Eighty inpatients with clinically diagnosed COPD underwent pulmonary function test and transthoracic lung ultrasound on the same day. Lung ultrasound variables and pulmonary function parameters were analyzed. Results: All patients with COPD had faster breathing and significant reduced lung function compared with healthy participants 

(p<0.05). The lung ultrasound parameters, velocity (max-min, cm/s), displacement (max-min, mm), strain (max-min, %) and strain rate (max-min, 1/s) were significantly higher in patients with COPD (p<0.05). A good negative correlation was found between lung ultrasound variables and pulmonary function parameters in patients with COPD. Stepwise multiple regression analysis indicated that the velocity (max-min, cm/s) was the only independent determinant of FEV1/FVC (%). With the use of FEV1/FVC<70% as the criteria of irreversible pulmonary function impairment to distinguish an abnormal pulmonary function, the area under the ROC was 0.99 for the velocity (max-min, cm/s) of the lung tissue in the process of breathing. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the cut off value (1.19 cm/s) was 97.63%, 100%, 100%, 80%,  and 98%, respectively (p<0.001). Conclusions: Tissue velocity imaging via transthoracic lung ultrasound is a useful modality in the assessment of pulmonary function in patients with COPD.