Analysis of CT Features and Quantitative Texture Analysis in Patients with Thymic Tumors: Correlation with Grading and Staging

Objectives: To evaluate potential relationship between qualitative CT features, quantitative texture analysis (QTA), histology, WHO staging, Masaoka classification and myasthenic syndrome in patients with thymic tumors.

Materials And Methods: Sixteen patients affected by histologically proven thymic tumors were retrospectively included in the study population. Clinical information, with special regard to myasthenic syndrome and serological positivity of anti-AchR antibodies, were recorded. Qualitative CT evaluation included the following parameters: (a) location; (b) tumor edges; (c) necrosis; (d) pleural effusion; (e) metastases; (f) chest wall infiltration; (g) tumor margins. QTA included evaluation of "Mean" (M), "Standard Deviation" (SD), "Kurtosis" (K), "Skewness" (S), "Entropy" (E), "Shape from Texture" (TX_sigma) and "average of positive pixels" (MPP). Pearson-Rho test was used to evaluate the relationship of continuous non-dichotomic parameters, whereas Mann-Whitney test was used for dichotomic parameters.

Results: Histological evaluation demonstrated thymoma in 12 cases and thymic carcinoma in 4 cases. Tumor necrosis was significantly correlated with QTA Mean (p = 0.0253), MPP (p = 0.0417), S (p = 0.0488) and K (p = 0.0178). WHO staging was correlated with Mean (p = 0.0193), SD (p = 0.0191) and MPP (p = 0.0195). Masaoka classification was correlated with Mean (p = 0.0322), MPP (p = 0.0315), skewness (p = 0.0433) and Kurtosis (p = 0.0083). Myasthenic syndrome was significantly associated with Mean (p = 0.0211) and MPP (p = 0.0261), whereas tumor size was correlated with Mean (p = 0.0241), entropy (p = 0.0177), MPP (p = 0.0468), skewness (p = 0.009) and Kurtosis (p = 0.006).

Conclusion: Our study demonstrates significant relationship between radiomics parameters, histology, grading and clinical manifestations of thymic tumors.