Theodora Tsirouki,1 Alexandra Bargiota,2 Stelios Tigas,3 Agathi Vasileiou,2 Eftichia Kapsalaki,4 Zoe Giotaki,3 Ioannis Asproudis,5 Agathokles Tsatsoulis,3 Georgios Koukoulis,2 Evangelia E Tsironi1 1Department of Ophthalmology, University Hospital of Larissa, Larissa, 2Department of Endocrinology, University Hospital of Larissa, Larissa, 3Department of Endocrinology, University Hospital of Ioannina, Ioannina, 4Department of Diagnostic Radiology, University Hospital of Larissa, Larissa, 5Department of Ophthalmology, University Hospital of Ioannina, Ioannina, Greece Objective: The aim of this study was to evaluate the safety and efficacy of an individualized steroid regimen in patients with moderate-to-severe Graves’ orbitopathy (GO) by monitoring clinical and imaging parameters. Methods: In total, 47 patients with active, moderate-to-severe GO were enrolled in this study. All the patients received the proposed treatment regimen by European Group on GO of 4.5 g of intravenous (IV) methylprednisolone for 12 weeks. At the end of the IV treatment, patients with persistent active GO (Group 1) who were assessed by clinical examination and orbital imaging with short tau inversion recovery-sequence magnetic resonance imaging (STIR MRI) received additional treatment with oral prednisolone, and those with inactive GO (Group 2) received no further treatment. Results: Of the 42 patients who completed the study, 22 (52.4%) patients formed Group 1 and 20 (47.6%) patients Group 2. At the 12th week, the overall response to IV treatment was 76.2%, and clinical activity score (CAS) improvement was 69%. At the 24th week, the overall response was 92.8%, and CAS improvement was 97.6%, without statistically significant difference in CAS and total eye score between these two groups (P=0.157 and P=0.856, respectively). Ophthalmic manifestations were improved, being absent or minimal in 78.6% of patients at the 24th week follow-up. Recurrence of disease activity occurred in 9.5% of patients up to 24 weeks after the completion of treatment, and major adverse events occurred in 6.4% of patients. Conclusion: In patients with moderate-to-severe GO, IV steroid treatment, followed by oral treatment, when needed, is an effective regimen with low rates of adverse events and recurrences. STIR MRI is a significant tool for recognizing patients who need additional steroid treatment. Keywords: Graves’ orbitopathy, magnetic resonance imaging, MRI, glucocorticoids