Significance of follow-up thoracic imaging in myasthenia gravis

Objectives: Most patients with myasthenia gravis (MG) undergo thoracic imaging at initial diagnosis. However, the follow-up protocol is unclear. The objective of the present study was to clarify the follow-up status and main findings of thoracic imaging in patients with MG. Methods: A total of 649 patients with disease duration ≥1 year were included in the study. The follow-up rate and time from the initial scan to the latest thoracic imaging were evaluated. The rate of abnormality and details of abnormal findings in both non-thymomatous MG and thymoma-associated MG were investigated. Results: The follow-up thoracic imaging rate of 145 patients with thymoma-associated MG was 71.7%, whereas just 46.2% of 504 patients with non-thymomatous MG underwent follow-up imaging. Abnormal findings were detected in 8.6% of patients with non-thymomatous MG and 26.0% of those with thymoma-associated MG. Abnormal findings included cancer, lung infection and lymph node swelling in the former, and relapse or increased size of thymoma in the latter. Conclusions: Frequent follow up by thoracic imaging is necessary in patients with MG.