Usefulness of Radio‐guided Surgery Using Technetium‐99m Methoxyisobutylisonitrile for Primary and Secondary Hyperparathyroidism

The efficacy of technetium-99m methoxyisobutylisonitrile (99mTc-MIBI)-guided surgery for detecting abnormal parathyroid glands in patients with secondary hyperparathyroidism (2-HPT) was evaluated and compared with the results from the same examination in patients with primary hyperparathyroidism (1-HPT). The results were also compared with those found by ultrasonography (US) and preoperative 99mTc-MIBI scintigraphy was also made. At operation 99mTc-MIBI accumulated in 64 nodules of 15 cases of 2-HPT, and all of 60 parathyroid swellings were detected (true-positives 60, sensitivity 100%, accuracy 94%). In the cases of 1-HPT, 99mTc-MIBI revealed 11 hot nodules in 10 cases, and the evaluation was true-positive 10, sensitivity 100%, and accuracy 91%. US and preoperative 99mTc-MIBI scintigraphy in patients with 2-HPT had a sensitivity of 75% and 67% and an accuracy of 70% and 66%, respectively. The usefulness of 99mTc-MIBI-guided surgery for detecting abnormal parathyroid tissue in 2-HPT patients was similar to that in 1-HPT patients but was superior to US and preoperative 99mTc-MIBI scintigraphy. Intraoperative 9mTc-MIBI for patients with 2-HPT is effective and makes the surgery easier, especially when the parathyroid glands are ectopic or when a few glands are markedly enlarged but the other glands are atrophied.