The localization of parathyroid tissue by ultrasound scanning prior to surgery in patients with hyperparathyroidism

Abstract

Ultrasonic localization of parathyroid tissue has been attempted in 24 patients with hyperparathyroidism prior to surgical exploration of the neck. All 24 patients had biochemically proven hyperparathyroidism. Standard contact diagnostic ultrasound equipment fitted with a 5 MHz transducer was used, and transverse and longitudinal scans of the region of the thyroid gland were performed at 5 mm intervals. The normal anatomical structures identified were the lobes of the thyroid gland, trachea, common carotid arteries, and jugular veins. The longus colli muscle on each side was used as a major landmark. These structures define the site where most parathyroid glands are found in the neck. In 18 of the 24 patients the suspected parathyroid tumor was visualized preoperatively and confirmed at operation. The abnormal glands ranged in size from 5 to 12 mm in transverse diameter. In 3 patients false-positive diagnoses were made by ultrasound; at operation the abnormalities proved to be thyroid nodules protruding from the posterior surface of the thyroid gland. Ultrasonography is of little value in the presence of multinodular goiter. Three adenomas and 3 hyperplastic parathyroid glands greater than 5 mm in diameter were not identified. Localization of enlarged parathyroid glands by echography may be difficult when normal anatomical landmarks are altered by the presence of multinodular goiter or because of previous surgery. The sensitivity of this technique for identifying in the neck parathyroid glands larger than 5 mm in diameter was found to be 79.3% with 11.5% false-positive and 8.6% falsenegative results.