The Study For Diagnosis Of Tracheomalacia In Congenital Heart Disease By Dynamic Computed Tomography

Objective To study the clinical value of dynamic multi-detector computer tomography(MDCT)with volume helical shuttle(VHS)technique in the diagnosis of tracheomalacia in congenital heart disease.Methods Part 1.Five bama miniature pigs were divided into two groups: tracheomalacia group(n = 4)and control group(n = 1).Tracheal cartilages were removed by surgery in tracheomalacia group.MDCT with VHS technique was performed with 80 k Vp,tube current range from 20 ~ 80 m A,passes range from 4 and 8 times,and fiber bronchoscopy was performed.Mimics 17.0 software was used to automatically segment the CT images in different respiratory phases and the percentages of tracheal cross-sectional area were measured and calculated.To evaluate the feasibility of MDCT with VHS technique to evaluate tracheomalacia comparing with the results of fiber bronchoscopy.The optimal scanning parameters are selected by subjective and objective evaluation of CT images under different scanning parameters.Part 2.From October 2014 to January 2017,imaging and clinical data of 44 patients(27 male,17 female)underwent both MDCT with VHS technique and fiber bronchoscope were reviewed.According to the results of fiber bronchoscope,the patients were divided into two groups.The anatomy of the great arteries was demonstrated using maximum intensity projection and volume render reconstruction.The patterns of the tracheobronchial tree were demonstrated using minimum-intensity projection reconstruction.Using Mimics 17.0 software to automatically segment the CT images of different respiratory phases of each patient,and to measure the cross sectional area of the trachea.The results of MDCT were compared with the surgical and fiber bronchoscopic findings.Results Part 1.A high level of consistency was reported for the findings of fiber bronchoscopy and MDCT with VHS technique,and there was no statistically significant difference in changes of tracheal cross-sectional area between 4 and 8 pass times(P=0.801).Part 2.The patient with tracheomalacia group showed significantly greater changes of tracheal cross-sectional area(58.92±12.18% vs 31.50±14.53%,P=0.00)than the patients without tracheomalacia group.The sensitivity,specificity and accuracy of MDCT with VHS technique to diagnose tracheomalacia were 90.00%(9/10),87.50%(21/24)and 88.24%(30/34),respectively.MDCT with VHS technique was 100%(20/20)and 95.00%(19/20)accurate diagnosing extracardiac and intracardiac defects respectively.Conclusion Dynamic MDCT with VHS technique,with great temporal sampling and spatial resolution,has potential to provide the one-stop examination for diagnosis of tracheomalacia in children with congenital heart disease.