US Effective Initial Localization Study in Patients with Primary Hyperparathyroidism

Can ultrasound replace sestamibi scans in the pre-operative evaluation of patients with primary hyperparathyroidism?

Background: Pre-operative localization studies may allow directed and more limited surgery in patients with primary hyperparathyroidism. Ultrasound is inexpensive, avoids radiation exposure and allows detection of concurrent thyroid disease but is operator-dependent and does not detect ectopic glands. Sestamibi can detect ectopic disease and is less operator-dependent but costs more, involves radiation and may be inaccurate in patients with thyroid disease. The optimal pre-operative localization study is a matter of some debate.

Study design: Multi-institutional prospective study.

Setting: Universities of Iowa, Kansas, Minnesota, Nebraska and South Dakota-Sanford.

Synopsis: A total of 220 patients with primary hyperparathyroidism were studied. Ten percent had undergone a previous parathyroid operation. Pre-operative ultrasound was performed in 77 percent of patients, sestamibi in 93 percent and both studies in 69 percent. Pre-operative imaging allowed directed surgery (single gland or ipsilateral exploration) in 64 percent of all patients. Ultrasound localized parathyroid disease in 71 percent of patients and was accurate in 82 percent, while sestamibi localized parathyroid disease in 79 percent of patients and was accurate in 85 percent. In patients with nonlocalizing ultrasound exams, sestamibi accurately identified parathyroid disease in 47 percent, while in patients with nonlocalizing sestamibi scans, ultrasound accurately localized parathyroid disease in 41 percent. No difference in ultrasound localization was found based on differences in body mass index. Ultrasound detected thyroid pathology that led to concurrent thyroid surgery in 18 percent of patients.

Bottom line: Ultrasound is an effective initial localization study in patients with primary hyperparathyroidism, with accuracy comparable to the use of sestamibi. When ultrasound is non-localizing, sestamibi scanning will fail to accurately localize disease in more than 50 percent of patients.

Citation: Smith RB, Evasovich M, Girod DA, et al. Ultrasound for localization in primary hyperparathyroidism. Otolaryngol Head Neck Surg. 2013;149:366-371.

—Reviewed by Christine G. Gourin, MD