99mTc-DTPA SPECT/CT provided guide on triamcinolone therapy in Graves' ophthalmopathy patients

Introduction Distinguishing between the active and inactive stages of Graves' ophthalmopathy (GO) is essential for making treatment decisions. 99mTc-DTPA SPECT/CT is sensitive in identifying inflammation in extraocular muscles of GO patients, which we designate 99mTc-DTPA-active. This study aimed to evaluate the response of 99mTc-DTPA-active GO patients to local immunosuppressive therapy. Materials and methods Sixty-four 99mTc-DTPA-active GO patients (89 eyes) were retrospectively analyzed. Forty-five patients (64 eyes) received repeated peribulbar triamcinolone injection, and 19 patients (25 eyes) received no immunosuppressive treatment. Ophthalmological assessment, including clinical activity score, eyelid retraction, eyelid aperture, proptosis, diplopia, and ocular mobility, was recorded before and after treatment. Results Compared with untreated patients, the clinical activity score decreased significantly (P < 0.001) while eye symptoms (soft-tissue swelling and eyelid retraction and aperture) improved significantly (P = 0.02, P < 0.001, P < 0.001, respectively) in treated patients after six months. The inferior and medial recti were significantly smaller (P < 0.001, P < 0.001, respectively), and 99mTc-DTPA uptake in the two recti was significantly less (P = 0.001, P = 0.01, respectively) in treated patients than in untreated patients after 3 months. Conclusion Clinical activity score of < 3 does not indicate inactive GO, as revealed with 99mTc-DTPA SPECT/CT. Patients with 99mTc-DTPA-active GO can improve the symptoms with peribulbar triamcinolone injection.