Characterization of the neoplastic potential of solitary solid thyroid lesions with Tc-99m-pertechnetate and Tc-99m-sestamibi scanning.

BACKGROUND: Radionuclide scans that use Tc-99m-pertechnetate or I-123 currently lack the specificity to assess the malignant potential of solitary solid lesions of the thyroid gland. Tc-99m-sestamibi scanning was used to determine the neoplastic potential of thyroid lesions.
METHODS: Patients with lesions of the thyroid underwent Tc-99m-sestamibi imaging to assess the neoplastic potential of their thyroid lesions, identified as solitary and cold by radionuclide imaging with Tc-99m-pertechnetate. Tc-99m-sestamibi uptake was correlated with fine-needle aspiration cytology or surgical pathology.
RESULTS: Twenty-seven patients were evaluated using Tc-99m-pertechnetate and Tc-99m-sestamibi scans: 14 had right thyroid lesions, and 13 had left thyroid lesions. Of 27 patients, 10 had a positive Tc-99m-sestamibi scan: one Hürthle cell adenoma, one papillary carcinoma, six follicular adenomas, and two nodular goiters. Of 27 patients, 17 had a negative Tc-99m-sestamibi scan: one follicular carcinoma, one papillary carcinoma, two follicular adenomas, one Hürthle cell adenoma, one metastatic adenocarcinoma, one medullary carcinoma, four nodular goiters, and six colloid nodules. Positive Tc-99m-sestamibi scan identified neoplasms with a sensitivity of 53%, a specificity of 83%, and a positive predictive value of 80%.
CONCLUSIONS: Tc-99m-sestamibi scanning lacks sufficient sensitivity for diagnosis of solitary thyroid nodules. Future work may define a role for its use in recurrent or metastatic thyroid neoplasms.