Sensitivity and specificity of thallium-technetium subtraction scan in localization of the parathyroid adenoma [Persian]

Thirty one patients with biologic and clinical diagnosis of hyperparathyroidism were submitted to thalium-technetium scan prior to exploration of the neck. Scan findings were compared with the pathologic results. Surgical exploration of the neck showed a parathyroid adenoma in 24 patients, parathyroid carcinoma in one patient, normal parathyroid in another patient and parathyroid hyperplasia in 5 patients. TTc scan correctly detected and localized 19 out of 24(79%) of adenomas, and 7 out of 20(35%) of parathyroid hyperplasia. The scan was negative in a normal case and correctly localized a parathyroid carcinoma. Five false negatives and 3 false positives were found in the adenoma group with specificity of 95.8%. Scan sensitivity did not change with adenoma size and weight or serum calcium, phosporous or PTH levels. In conclusion, TTS is a sensitive and useful procedure for preoperative localization of parathyroid adenomas.