PREOPERATIVE LOCALIZATION OF PARATHYROID ADENOMAS BY TECHNETIUM-THALLIUM AND ULTRASOUND IMAGING

38 patients with biochemical evidence of primary hyperparathyroidism were studied. A 50K count image of the neck was computer acquired with a gamma camera and pinhole collimator 30 minutes after IV injection of 1 mCi of Tc-99m pertechnetate. Without patient movement, 1–2 mCi of T1–201 chloride was injected IV, and sequential 30 second images were acquired for 25 minutes. The thallium images were summed and computer subtraction of the normalized pertechnetate image was performed to identify areas of discordant radionuclide uptake. Ultrasound examination was performed using a B-mode static scanner with a 5 MHz transducer.12 patients have had surgery to date, each of whom had a single parathyroid adenoma. Nuclear imaging successfully localized 5/12 adenomas, including 4/5 inferior or upper mediastinal adenomas and 1/7 superior adenomas. There was 1 false positive. Ultrasound identified 4/12 adenomas, each of which was located posterior to the thyroid gland, including 2/5 inferior or mediastinal adenomas and 2/7 superior adenomas. There were 3 false positives by ultrasound. The combination of techniques successfully localized 7/12 adenomas, including 5/5 inferior or upper mediastinal adenomas and 2/7 superior adenomas.Nuclear imaging appears most sensitive for parathyroid adenomas located inferiorly or in the upper mediastinum, while ultrasound is useful for identifying adenomas located posterior to the thyroid gland.