Clinical and Imaging Preliminary Observation of Right Paratracheal Air Cysts in the Thoracic Inlet

Objective To explore the clinical and imaging features of right paratracheal air cysts(RPAC) in the thoracic inlet and its significance.Materials and Methods In the PACS,the thoracic clinical and MSCT information of patients treated in the past six months was browsed,in which the RPAC imaging data found by MSCT was collected and analyzed;and 60 cases without RPAC in chest were randomly selected as the control group,The trachea index between the study group and the control group was compared.Results The RPAC in the thoracic inlet were found in 64 of 6213 patients,the ratio was 1.03%,The position of RPAC was located at the right posterolateral aspect of trachea in 63 of 64 patients,only one was located at the left posterolateral aspect of trachea.The mean diameter of RPAC was 1.26±0.64 cm in the axial plane and 2.02±1.21 cm in the vertical plane,The mean volume of RPAC was 1.92±1.05 cm3in all 64 patients and 2.13±0.94cm3 in bronchitis emphysema groups and 0.95±0.47 cm3 in no bronchitis emphysema groups,There were significant differences(P0.05) between two groups;The volume change of RPAC in 38 cases by review was 0.12±0.08 cm3,This change was no statistically significant(P0.05).With age-related increase,the incidence and proportion of RPAC were increased.The mean value of trachea index was 0.64±0.27 in the RPAC group and 1.16±0.35 in the control group,There were significant differences(P0.05) between two groups.The fine tubular airway shadows between RPAC and trachea was displayed 7 cases in conventional thick layer(7 mm) and 27cases in sub-millimeter thin layer(.75 mm)(P0.01);The limited sag or holes in endotracheal surface was displayed in 35 cases by CTVE;The space connective relations between RPAC and trachea was clear display in 27 cases by VR.Conclusion The most probable nature of RPAC in the thoracic inlet is tracheal diverticulum,MSCT can show the image characteristics and its relationship with the trachea,and to provide theoretical evidence for diagnosis and suggest the possibilities of presence of obstructive lung disease or emphysema.