Neck radionuclide scanning: a pitfall in parathyroid localization

Radionuclide parathyroid scans are widely used to localize abnormal parathyroid glands. They are especially valuable for identifying ectopic glands, including those in the mediastinum. Two patients with hyperparathyroidism who had mediastinal glands that were not identified because only the neck was scanned prompted our review of the technique of parathyroid scanning at hospitals in our region and of the frequency of mediastinal parathyroid glands identified by scanning at our own institution. The nuclear medicine departments at 72 area hospitals were surveyed. Parathyroid scans were performed at 51 of these hospitals but only 13 (25%) routinely scanned the mediastinum and chest. At our institution 480 parathyroid scans were performed during a 9-year period. Twenty-six mediastinal parathyroid glands were identified by routine scanning of both the neck and mediastinum. Most of these glands could be removed through a cervical incision. However, four required formal thoracotomy and two thoracoscopy.

A radionuclide parathyroid scan limited to the neck is an incomplete study. Scans that do not include the thorax will miss mediastinal glands that occurred in 5 per cent of the patients in our series. Despite this, radionuclide parathyroid scanning was limited to the neck in 75 per cent of surveyed hospitals. This practice increases the chance for failed surgical exploration and increases potential patient morbidity.