Tc-99m polyclonal human immunoglobulin G imaging in Graves' ophthalmopathy.
OBJECTIVE
The authors evaluated the utility of Tc-99m-labeled human immunglobulin G (HIG) in determining the severity of orbital inflammation and the relation of orbital Tc-99m HIG uptake and clinical parameters in patients with Graves' ophthalmopathy.


METHODS
Images were obtained in 23 patients (13 women, 10 men; mean age, 51+/-10 years) with Graves' ophthalmopathy. Planar orbital images were obtained and SPECT was performed using a triple-detector gamma camera 4 hours after 370 MBq (10 mCi) Tc-99m HIG injection. Tc-99m HIG uptake was classified using transaxial and coronal slices as 1, mild; 2, moderate; and 3, severe. The clinical severity of orbital disease was categorized, according to the criteria described by Feldon and Unsold, as class I, mild involvement; class II, moderate; and class III, severe. Disease was considered to be clinically inactive if symptoms and signs were stable or improved in the last two examinations performed at least 6 months apart.


RESULTS
Sixteen patients were clinically inactive, and seven patients were active. The mean Tc-99m HIG classes were 1.5+/-0.5 and 2.6+/-0.5, respectively (P = 0.02). There was not a good correlation between the clinical classification and Tc-99m HIG classification, whereas the presence of active disease showed a good correlation with Tc-99m HIG classification (r = 0.703; P = 0.0002).


CONCLUSIONS
Tc-99m HIG imaging showed possible ongoing subclinical inflammation in the orbits of the patients with Graves' ophthalmopathy regardless of the clinical classification. Tc-99m HIG SPECT seems a promising procedure for evaluating the presence of active orbital inflammation.
Durak
H
H
Dokuz Eylül University Medical School, Department of Nuclear Medicine, Inciralt, Izmir, Turkey. hdurak@kordon.deu.edu.tr
Söylev
M
M
Durak
I
I
Değirmenci
B
B
Capa Kaya
G
G
Uysal
B
B
D005260:Female; D006111:Graves Disease / Q000000981:diagnostic imaging*; D006801:Humans; D007074:Immunoglobulin G; D007765:Lacrimal Apparatus / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000000981:diagnostic imaging; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D007074:Immunoglobulin G; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C079358:technetium TC 99m polyclonal IgG