Graves’ ophthalmopathy (GO) is a chronic inflammatory autoimmune disease of periorbital tissue, conjunctiva and retrobulbar structures, especially involving extraocular muscles (EOM). The clinical course is characterized by two phases: the “active phase”, which hystologically shows mononuclear cell infiltration, fibroblasts proliferation and oedema within the extra-ocular muscles, lachrymal glands and orbital adipose tissue, and the “inactive phase”, in which fibrosis predominates1-4. In patients with a clinical suspect of GO, it is mandatory to identify the disease phase and severity in order to establish the correct treatment1,5....

MR examinations of 58 patients with affected by GO were retrospectively included. In each patient "signal intensity ratio" values (SIR) in the most affected extrinsic orbital muscle, chosen on the basis of a greater signal intensity in both T2 and post-contrast T1-weighted sequences, ocular proptosis and optical nerve impingement (estimated with Barrett’s Index) were evaluated. The reference line adopted to measure proptosis was the interzygomatic line and the normal distance from this line to the posterior sclera was considered about 9.9 +/- 1.7 mm10. Barrett's...

The statistical analysis showed a significant correlation between T2-SIR value and CAS (p=0.023) at diagnosis and during follow-up. CE-SIR correlated only with TRAb title (p=0.008). Finally the global MR index (T2 SIR + proptosis + optical nerve impingement) correlated with both CAS (p=0,036) and antibodies (p=0,014).

In our study, MR orbits evaluation demonstrates a good correlation with clinical informations in patients affected by GO at diagnosis and during follow-up. Our results confirm the utility of a global MR index to support clinicians in the management of GO, improving a multidisciplinary approach to the disease. Starting from these results we propose the use of an MR index which associates T2 Signal Intensity Ratio, proptosis and optical nerve impingement (estimated with Barrett’s Index), to evaluate GO clinical activity. Moreover, consistent with previous studies5,...

1. Dickinson AJ, Perros P. Thyroid-associated orbitopathy: who and how to treat. Endocrinol Metab Clin N Am. 2009; 38 (2): 373-388. 2. Prummel MF, Gerding MN, Zonneveld FW, et al. The usefulness of quantitative orbital magnetic resonance imaging in Graves’ Ophthalmopathy. Clin Endocrinol. 2001; 54 (2): 205-209. 3. Kirsch EC, Kaim AH, De Oliveira MG, et al. Correlation of signal intensity ratio on orbital MRI-TIRM and clinical activity score as a possible predictor of therapy response in Graves’ orbitopathy – A pilot study at 1.5...