[Magnetic resonance imaging in myasthenia gravis. An alternative to mediastinal computerized tomography?]

Twenty patients with myasthenia gravis underwent magnetic resonance imaging (MRI) of the anterior mediastinum, 17 of them additionally computed tomography (CT). In 14 of the patients the imaging results were checked against the histological findings of a subsequent thymectomy, which revealed four thymomas and (with the exception of one normal thymus) hyperplastic changes in all the others. Overall, MRI was not better than CT for demonstrating blastomatous changes in the thymus. It was also no more sensitive in differentiating between thymoma and hyperplasia.