Evaluation of thymoma by thin-section CT images

With regard to thymoma, the location of the tumors, their internal structure, and their relationship with surrounding structures are the most important factors in clinical diagnosis. A positive finding influences not only the surgical procedure selected but also the prognosis of the patient as well. To investigate the usefulness of thin-section computed tomography (CT) in detecting invasion to structures surrounding tumors, we performed a prospective study of 20 patients with tumors, including 10 cases of non-invasive thymoma, 6 of invasive thymoma, and 4 of thymic cancer. A comparison of diagnoses based on the findings of a thin-section CT and pathologic examination showed that thin-section CT was 90% accurate in detecting invasion to structures surrounding tumors and 90% accurate for septum on internal analysis. Conventional CT, on the other hand, showed 45% accuracy for pleural invasion of interlobar fissures and 45% accuracy for septum. This leads to the conclusion that thin-section CT is helpful in attaining accurate evaluation of internal structures and invasion of structures by thymoma, especially in patients in whom findings by conventional CT suggests possible tumor invasion of surrounding structures. (author)