Compare of Tc-99m MIBI uptake in euthyroid individuals and in patients with autoimmune thyroid disease

The aim of this study was to investigate the uptake of Tc 99m-MIBI in thethyroid of euthyroid volunteers and in patents with autoimmune thyroiddiseases.Twenty patients with Graves disease (14 females, 6 males), 47 patientswith Hashimoto?s thyroiditis (45 females, 2 males) and 10 euthyroid volunteers(4 females, 6 males) were included in the study.We performed Tc 99m-MIBI thyroid scintigraphy to all groups. Dynamicimages were acquared for 20 min, and static images were obtained 20, 60,120 min post injection. An image with 100,000 counts 5 min after injection wasextracted from the dynamic images. Five-, 20-, 60-, and 120-min uptake, timeto maximal uptake (Tmax) and T1/2 of tracer clearence were calculated.Additionaly we performed Tc-99m pertechnetate thyroid scintigraphy to allgroups at least 2 days after.Five-, 20-, 60-, 120-min uptake values of Graves diseases were allsignificantly different from those in all groups. But uptake values ofHashimoto?s thyroiditis were not statistically significant different from euthyroidvolunteers.Tc 99m-MIBI thyroid clearance of Graves disease is faster than euthyroidvolunteers. But Tc 99m-MIBI thyroid clearance of Hashimoto thyroiditis isslower than other two groups.No statistically significant difference was dedected in Tmax betweeneuthyroid volunteers, Graves disease and Hashimoto?s thyroiditis.In the all groups, there was no significant correlation between Tc-99m MIBIuptake and TSH or anti-thyroid antibody levels was dedected.In the euthyroid volunteers, Graves disease and Hashimoto?s thyroiditisgroups, Tc-99m MIBI uptake was not affected from thyroid hormone therapy.Our findings suggest that there is no necessity of stopping thyroid hormonetherapy before Tc-99m MIBI thyroid scintigraphy. Thus, it was thought thathypothyroidism could be prevented.Increased Tc-99m MIBI uptake are based on the histopathological findingsof Graves disease: incresed number of mitochondria and the inflammatoryinfiltrate. Our findings suggest that Tc-99m MIBI could be used as analternative radiopharmaceutical for thyroid gland scintigraphy in patients withGraves diseases.