The use of preoperative localization of adenomas of the parathyroid glands by thallium-technetium subtraction scintigraphy, high-resolution ultrasonography and computed tomography.

Thirty-six patients with primary hyperparathyroidism were studied preoperatively by thallium-201 and technetium-99m pertechnetate subtraction (Tl-201/Tc-99m) scintigraphy, high-resolution real time ultrasonography and computed tomographic (CT) scanning. None of the patients had had previous surgical treatment of the parathyroid or thyroid glands. All of the patients underwent systematic bilateral exploration of the neck. All of the patients were successfully explored and 41 abnormal parathyroid glands were identified. Five patients had two adenomas. In six instances, adenomas were identified in ectopic anatomic sites. The sensitivity of correctly localizing the abnormal glands with these techniques was 49 per cent for the Tl-201/Tc-99m scintigraphy, 34 per cent for ultrasonography and 41 per cent for CT scanning. The Tl-201/Tc-99m scintigrams detected two of the six ectopically located adenomas, CT detected one, while ultrasound detected none. The five patients with multiple adenomas were not accurately identified as having multiple gland enlargement by any of these studies. Therefore, preoperative localization studies with these three techniques did not provide reliable information for initial bilateral exploration of the neck.