Serial STIR magnetic resonance imaging correlates with clinical score of activity in thyroid eye disease

Purpose To assess the correlation between inflammatory activity in extraocu lar muscles measured with serial short tau inversion recovery (STIR) sequen ce magnetic resonance imaging (MRI) scans and clinical disease activity in thyroid eye disease. Methods In this retrospective study, 22 patients with thyroid eye disease w ho had undergone serial MRI scans using the STIR sequence were assessed. Th e signal intensity ratio (SIR) of the most inflamed extraocular muscle was compared with the Mourits score (a clinical measure of thyroid eye disease activity). Results The SIR value has previously been shown to correlate with clinical activity of thyroid eye disease. In a particular patient the SIR value incr eases in proportion with the clinical features of the disease as assessed b y the Mourits rating system. When the change in STIR sequence MRI is compar ed with the change in Mourits score rating for a given patient the correlat ion is highly significant (p < 0.001). Conclusions This study confirms that serial STIR sequence MRI scans correla te with clinical disease activity. Inflammatory activity in the most inflam ed muscle las measured by SIR) reflects overall disease activity. SIR value s obtained from MRI scans provide a useful measure of disease activity and may help in the monitoring and treatment of this condition.