Somatostatin receptor scintigraphy to predict the clinical evolution and therapeutic response of thyroid-associated ophthalmopathy

Management of thyroid-associated ophthalmopathy remains a topic of controve rsy. Immunosuppressive treatments have to be applied at peak disease activi ty and before criteria of severity develop. Expression of somatostatin rece ptors on activated lymphocytes allows scintigraphic imaging with indium-lll pentetreotide. We conducted a prospective study with 17 patients who prese nted seven ophthalmopathy (II Graves' disease, four Hashimoto's thyroiditis , two isolated in appearance: Means' syndrome). Each patient underwent horm onal (free T-3 and TSH) and immunological (TBII) assessment, an orbital com puted tomography scan or magnetic resonance imaging, a visual functional ex amination and In-111-pentetreotide orbital scintigraphy before undergoing t reatment by steroids and/or radiotherapy, independently of scintigraphic re sults. At 4 and 24 h after the intravenous injection of ill MBq of In-111-p entetreotide, planar imaging centred on the head and neck (anterior and bot h lateral views) was carried out. Retrobulbar uptake was assessed by visual semi-quantitative analysis (score given by two independent trained observe rs) and by quantitative analyses (regions of interest, orbit/brain uptake i ndices). Patients were ophthalmologically followed up for 6 months and then classified as improved or not. Visual semi-quantitative analysis of 4-h/24 -h planar images was correlated with the ophthalmological evolution (chi(2) test, P<0.01). All ten patients in whom scintigraphy was considered positi ve were clinically improved at 6 months, and of the seven patients in whom scintigraphy was negative, six were not improved. Nevertheless! objective q uantitative analysis did not succeed in confirming results. We conclude tha t In-111-pentetreotide scintigraphy requires further developments, includin g quantitative single-photon emission tomographic acquisition, if its role as a guide to therapeutic strategy in thyroid-associated ophthalmopathy is to be confirmed.