Changes of thyroidal Tc-99m tetrofosmin uptake and wash-out in patients with hashimoto's thyroiditis

Abstract

Objective: Our aim was to investigate the changes in Tc-99m tetrofosmin uptake and wash-out in the thyroid gland of normal volunteers and Hashimoto's thyroiditis (HT) patients with either euthyroidism or hypothyroidism. Material and Methods: Thirty-four patients with HT (10 hypothyroid and 24 euthyroid) and 10 euthyroid healthy volunteers were enrolled in the study. In all cases, thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), anti-thyroid antibodies and thyroid volume were measured. Anterior thyroid images were acquired at 10, 30 and 120 min after intravenous injection of 740 MBq Tc-99m tetrofosmin. Thyroid/ background (T/B) ratios at 10, 30 and 120 min and wash-out indices (WI %) at 30 and 120 min were calculated. Results: In all groups, initial and late tetrofosmin T/B values did not differ from healthy control cases. At 120 min, the mean WI% of patients with hypothyroidism was significantly higher than that of volunteers; however this group is not statistically different from the euthyroid group. The value WI % at 120 min was significantly correlated with anti-Tg antibody levels (r= -0.673; p= 0.033). In the euthyroid group, both anti-TPO antibody levels and thyroid volume had significant correlations with the T/B ratios at 10, 30 and 120 min (r= 0.499, p= 0.013; r= 0.424, p= 0.039; r=0.528, p= 0.008 for Anti-TPO Antibody, and r= 0.577, p= 0.003; r= 0.606, p= 0.002; r= 0.645, p= 0.010, for thyroid volume, respectively). Conclusion: We can conclude that Tc-99m tetrofosmin uptake and wash-out kinetics in thyroid tissue may be changed with autoimmune thyrocyte destruction in HT. © 2010 by Türkiye Klinikleri.