Evaluation of Hot Nodules of Thyroid Gland Using Tc-99m Pertechnetate: a Novel Approach Using Quantitative Single-Photon Emission Computed Tomography/Computed Tomography / 대한핵의학회잡지

Planar scintigraphy using Tc-99mpertechnetate is useful for snapshot evaluation of hot thyroid nodules, which are pathologically follicular adenoma and seldom, if ever, malignant. The autonomy of the hot nodules has been demonstrated by the presence of thyroid-stimulating hormone-dependent extra-nodular thyroid tissue besides the hot nodules. Here, we present two cases of hot thyroid nodules in patients who underwent quantitative single-photon emission computed tomography/computed tomography (SPECT/CT). In addition to the nodules, contralateral normal thyroid parenchyma was evaluated based on standardized uptake values. One patient had a traditional follicular adenoma suppressing other thyroid tissue, whereas the other patient seemed to have a nodule erupting from underlying hyperfunctioning, not suppressed, thyroid tissue. This novel approach using quantitative SPECT/CT unveils a new pathology of hot thyroid nodule that does not suppress, but coincides with hyperfunctioning thyroid tissue.

Papillary Thyroid Carcinoma Hidden behind the Hot Nodule / 대한갑상선학회지

52-year-old woman was presented with palpitation and weight loss. Thyroid function test revealed low thyroid-stimulating hormone level with upper normal range of Free T4 and thyroid scan showed 2 cm hot nodule in left upper pole. Thyroid ultrasonography was also done and it showed two nodules in left upper pole. The one was considered as functioning benign nodule, but the other nodule was compatible with malignancy. She underwent total thyroidectomy and final pathology revealed papillary thyroid carcinoma.

A Comparison Technetium-99m and Iodine-123 Scan in Thyroid Hot Nodules / 대한내분비학회지

BACKGROUND: Pertechnetate ( Tc) has been widely employed for thyroid imaging. While pertechnetate and radioiodide have usually similar results in identifying thyroid nodules, occasionally differences have been noted. We intended to observe that the thyroid nodules which appeared to be hot on pertechnetate and to compare them with the images by radioiodide. METHODS: 'I scan was performed to thirty-eight cases (mean age: 48.9 +/- 13.2) presenting as hot nodule on Tc scan. Thyroid function test and pathologic diagnosis were obtained in all patients. RESULTS: Of the 38 patients, 24 had euthyroidism, 13 had hyperthyroidism, and 1 had hypothyroidism. Thirty patients had adenomatous goiter, 4 papillary carcinoma, 3 Hashimotos thyroiditis, and 1 had HQrthle cell tumor. 28 of 38 patients showed similar images, but the remaining 10 patients(26.3%) revealed discordant images on Tc and 131I scan. Among the concordant cases, 23 had adenomatous goiter, 3 had papillary carcinoma, and 2 had Hashimotos thyroiditis. Among the discordant cases, 7 had adenomatous goiter, 1 had papillary carcinoma, 1 had Hashimotos thyroiditis, and 1 had HQrthle cell tumor. The incidence of malignancy was 10.7% of concordant cases, and 20% of discordant cases and was revealed statistically insignificant (p>0.05). CONCLUSION: We observed higher incidence of malignancy in patients presenting hot nodules on 99mTc scan than ever reported. Fine needle aspiration should be performed to all patients with hot nodules and the 'I scan would not be recommended for further diagnostic study.