Study on the differential diagnosis of thymoma and anterior mediastinal cyst based on Fisher's discriminant function model constructed using CT parameters
YANG Yuqi
WANG Sicong
LU Liqing
ZHANG Chunfang
CHENG Yuanda
Abstract：Objective To explore the value of Fisher's discriminant function model constructed using computed tomography(CT)parameters in differential diagnosis of thymoma and anterior mediastinal cyst.Methods The clinicopathological data of patients with anterior mediastinal cysts(including thymic cysts and bronchial cysts)or thymoma proven by pathology examination after surgical resection of the cysts in Department of Thoracic Surgery,Xiangya Hospital of Central South University from January 2015 to June 2025 were retrospectively collected.The ratios of plain scan and enhanced CT values of the tumors to the CT values of the aorta were calculated.One-way analysis of variance combined with Bonferroni's correction was used for inter-group comparisons.The Fisher's discriminant function was established based on the screened CT parameters and was verified.Results A total of 236 patients were included in this study,including 159 cases of thymoma(thymoma group),54 cases of thymic cysts(thymic cyst group),and 23 cases of bronchial cysts(bronchial cyst group).There was no statistically significant difference in age among the three groups(P＞0.05).Compared with those in the thymoma group and the thymic cyst group,the proportion of female patients was higher(P＜0.001),and the maximum diameter of tumors was smaller(P＜0.001)in the bronchial cyst group,and the proportion of lobulated tumors in the thymoma group was significantly higher than that in the thymic cyst group and the bronchial cyst group(P＜0.001).The clarity rate of fat space in the thymoma group was significantly lower than that in the thymic cyst group and the bronchial cyst group(P＜0.001).The plain and enhanced CT values and the ratios of plain and enhanced CT values to aortic CT values in the thymoma group and the bronchial cyst group were significantly higher than those in the thymic cyst group(P＜0.001),and the enhanced CT value and the ratio in the bronchial cyst group were lower than those in the thymoma group(P＜0.001).The enhanced CT values in the thymic cyst group and the bronchial cyst group were significantly lower than those in the thymoma group(P＜0.001).The established Fisher's discriminant functions:D1=0.245 × gender(0=female,1=male)+0.782 × tumor shape(1=unlobulated,2=lobulated)+0.644 × fat space(0=blur,1=clear)-0.344 × enhanced CT value+97.228 × aortic enhanced CT ratio+0.059 × CT enhancement value-9.357;D2=0.970 ×gender(0=female,1=male)+0.583 × tumor shape(1=unlobulated,2=lobulated)+0.903 × fat space(0=blur,1=clear)-0.094 × enhanced CT value+4.749 × aortic enhanced CT ratio+0.110 × CT enhancement value+0.546.The cross-validation results showed that the overall diagnostic accuracy rate of the model in differentiating thymoma from anterior mediastinal cyst was 95.76％.Conclusion The discriminant function diagnostic model established according to the CT parameters has a high diagnostic value in differentiating thymoma from anterior mediastinal cyst.
Keywords：ThymomaAnterior mediastinal cystThymic cyst(MTC)Bronchial cystComputed tomography(CT)valueDifferential diagnosisFisher's discriminant function model
Publication Date：2026-02-28
Online Publishing Date：2026-03-31(First online date of this platform, not the publication date of the document)
Pages：6( 214-219 )