Indium-111-pentetreotide scintigraphy in Graves' ophthalmopathy.
The radiolabeled somatostatin analog 111In-pentetreotide can sensitively demonstrate somatostatin receptor-positive localizations in diseases where activated lymphocytes play a role. Lymphocyte infiltration of retrobulbar tissue in Graves' ophthalmopathy is the rationale of receptor imaging with radionuclide-coupled 111In-pentetreotide.


METHODS
Forty patients with Graves' ophthalmopathy, 5 patients with orbital myositis and 10 control subjects were included in this prospective study. Indium-111-pentetreotide (110 MBq) was intravenously injected and SPECT images were obtained at 4 and 24 hr after injection. The scans were analyzed by a region of interest technique. An uptake ratio between the orbits and the brain was determined.


RESULTS
Compared to controls (4-hr 111In-pentetreotide uptake: median 6.0 counts/voxel/MBq, orbit-to-brain ratio 5.6), ophthalmopathy patients showed two- to threefold increased uptake (15.8 counts/voxel/MBq versus controls p = 0.0032; ratio 12.6 versus controls p = 0.003). When considering patients with active disease only, even higher uptake was registered (16.8 counts/voxel/MBq versus controls p = 0.0048, ratio 15.6 versus controls p = 0.0006). Untreated patients showed markedly higher uptake (23 counts/voxel/MBq) compared to patients under steroid therapy (12.6, p = 0.001). In myositis, high uptake (20 counts/voxel/MBq) was also registered.


CONCLUSIONS
In contrast to controls, ophthalmopathy patients showed markedly increased orbital accumulation of labeled 111In-pentetreotide. This sensitive nuclear medicine technique could possibly select those patients who might benefit from treatment with immunosuppressive agents and/or octreotide.
Kahaly
G
G
Department of Endocrinology/Metabolism, Johannes Gutenberg-University Hospital, Mainz, Germany.
Diaz
M
M
Hahn
K
K
Beyer
J
J
Bockisch
A
A
D005123:Eye / Q000000981:diagnostic imaging; D005260:Female; D006111:Graves Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D007205:Indium Radioisotopes; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000000981:diagnostic imaging; D016727:Orbital Pseudotumor / Q000000981:diagnostic imaging; D011446:Prospective Studies; D017481:Receptors, Somatostatin / Q000032:analysis; D013004:Somatostatin / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon
D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; D013004:Somatostatin; C081788:pentetreotide