TC-99-SESTAMIBI SCAN IN THE PREOPERATIVE LOCALIZATION OF ABNORMAL HYPERFUNCTIONING PARATHYROID-GLANDS

Hyperparathyroidism is a relatively frequent condition mostly due to a solitary parathyroid adenoma. Although it has been claimed that surgi cal exploration is the best way to visualize the abnormal parathyroid grand, several imaging techniques have been proposed to localize it in order to simplify and shorten the surgical procedure. Echography, tha lium-technetium scintigraphy, computerized tomography and nuclear magn etic resonance have shown a mean sensitivity of 75% which can be incre ased to about 90% by combining 2 or more of these procedures. In this study, we evaluated the utility of Tc-99m-sestamibi scintigraphy in 13 patients with hyperparathyroidism (II primary, 2 secondary). High res olution neck echography was carried out in all of the cases. Cervical scans were obtained 10-15 min and 3 hours after giving an i.v. injecti on of 25 mCi Tc-99m-sestamibi in all the patients; suppression studies with combined 131-I were also done. Positive scans were obtained in 1 1 out of the 13 patients. Abnormal parathyroid glands were found and s urgically excised in all the cases (10 adenomas, 1 carcinoma, 2 hyperp lasias). Echographic localization had a sensitivity of only 33.3%. On the contrary, Tc-99m-sestamibi showed a sensitivity of 56% for the who le group, increasing to 82% in the 11 patients with primary hyperparat hyroidism whereas the positive predictive value was of 91% and 90%, re spectively. We conclude that Tc-99m-sestamibi is a Very useful tool in localizing abnormal parathyroid glands and should be the first choice before reoperation after surgical failure or before the first parathy roid surgery whenever it is desired to shorten the surgical and anesth etic duration.