The changes of aerodynamic parameters in the tracheal stenosis before and after stent implantation and their clinical significance / 介入放射学杂志

ABSTRACT

Objective To explore the changes of the aerodynamic parameters in tracheal stenosis before and after stent implantation,and to discuss the significance of these changes.Methods The clinical data of 20 patients with tracheal stenosis,who were treated with stent implantation,were collected,and the clinical features as well as imaging findings were summarized.Using the computer fluid dynamics analysis software,the airflow dynamics simulation study on tracheal stenosis before and after stent implantation was conducted.The aerodynamic parameters of the region of interest were recorded and statistically analyzed.The mean values of quantitative data were compared by using t-test,and P＜0.05 was considered to be statistically significant.Results The nature of tracheal stenosis was malignant in all 20 patients,which was caused by tumor compression and invasion.Stenosis degree ＞50％ was seen in 18 patients,the stenosis was located in the middle of trachea in 10 patients,segmental stenosis was observed in 15 patients,and eccentric stenosis was found in 17 patients.After stent implantation,the lumen area at previous tracheal stenosis site became (2.03±0.32) cm2,which was larger than (0.96±0.18) cm2 measured before stent implantation.The pre-stenting velocity at the stenotic site of trachea was (1764±1484) cm/s,which was higher than (688±434) cm/s of the post-stenting velocity.The pre-stenting velocity and volume flow measured at the left main bronchus entrance were (308±209) cm/s and (359±255) ml/s respectively,both of them were smaller than those measured at the right main bronchus entrance,which were (464±246) cm/s and (526±283) ml/s respectively,the differences were statistically significant (both P＜0.05).After tracheal stent implantation,the differences in the velocity and volume flow between the left main bronchus entrance and the right main bronchus entrance were not statistically significant.Conclusion The aerodynamic parameters in tracheal stenosis are characterized by the presence of a high velocity of air flow at the stenosis site,and the stenosis of trachea has an effect on the velocity and volume flow at both left and fight main bronchus entrances.Tracheal stenting can remarkably increase the lumen area at tracheal stenosis site,reduce the high velocity at the stenotic site and make the airflow smoother,and the bronchial airflow of the right and left side can be balanced.The airflow dynamics simulation of tracheal stenosis before and after stent implantation has a certain value for the pathophysiological study of tracheal stenosis and for the evaluation of therapeutic effect.