Investigation of Thymus In Myasthenia Gravis

Abstract

In this study. The sensitivity of CT and MR in distinguisbing thymic pathologies in 19patients with myasthenia gravis is compared. All patients had mediastinal CT and MR both without contrast. ln 14 patients both CT and MR revealed only mediastinal fat compatible with age, or normal or small thymus. Three patients had similar thymic pathologies in both imaging methods, two thymic enlargement and one thymoma. Thymoma was round, lobulated, calcified and probably invasive tumor in CT. MR could detect thymoma. nevertheless it couldn't show calcification as expected, and also couldn't distinguish invasiveness of the tumor which was proven during operation. ln two patients slightly enlarged thymus, normal for could be seen in CT, but not in MR. This discordance was explained by partial volume effect of MR. 4 patients were operated and their histopathologic diagnosis were compatible with radiodiagnostic findings.The results of our study reveled that in all patients, including thymoma, CT was either similar or superior to MR for evaluating thymus, CT was either similar or superior to MR for evaluatings thymus besides being more practical and cheaper.