IN-111-OCTREOTIDE IMAGING IN PATIENTS WITH LONG-STANDING GRAVES OPHTHALMOPATHY

The aim of this study was to examine patients with long-standing Grave s' ophthalmopathy using (111)Inoctreotide scintigraphy. Sixteen patien ts with inactive ophthalmopathy of up to 114 months duration and 14 no rmals were investigated for 48 h following an injection of 200 MBq In- 111-octreotide. No significant tracer accumulation in the orbital regi on could be identified in any of the patients with long-standing Grave s' ophthalmopathy. The orbit to brain (O/B) ratios after 24 and 48 h w ere 2.39 +/- 0.36 and 2.15 +/- 0.44 Versus 2.17 +/- 0.33 and 2.20 +/- 0.37 for the patients and normals, respectively (N.S.). In-111-octreot ide accumulation in ophthalmopathy described in the literature may thu s be a passing event limited to its active stage, which is consistent with the concept of imaging a lymphocytic infiltration. In this study, the lack of accumulation of In-111-octreotide in the orbital region d uring the inactive stage demonstrates an absence of somatostatin recep tors in orbital tissue itself. Thus, in patients with inactive Graves' ophthalmopathy, there is no basis for a diagnostic approach with soma tostatin.