PET/CT May Be Useful for Challenging Cases of Hyperparathyroidism

By Marilynn Larkin

June 11, 2019

NEW YORK (Reuters Health) - For patients with hyperparathyroidism, 18F-fluorocholine positron emission tomography - computed tomography (PET/CT) may be indicated in difficult cases and when first-line tests are negative or discordant, researchers suggest.

"Identifying parathyroid glands correctly before a surgical procedure is essential to perform minimally invasive surgery," note Dr. Luis Alejandro Boccalatte of Hospital Italiano de Buenos Aires and colleagues. "First-line tests with discordant or negative results underscore the need for more accurate imaging tests, thus decreasing the requirement for bilateral neck exploration or reintervention."

To review the usefulness of 18F-fluorocholine PET/CT in this regard, the team searched the literature from 2014-2018 and identified 16 studies including a total of 619 patients. Ten were prospective cohort studies, five were retrospective cohort studies, and one was a case series.

They found that 18F-fluorocholine PET/CT "provides high rates of sensitivity, specificity, PPV, and diagnostic accuracy," according to their JAMA Otolaryngology-Head and Neck Surgery report, online May 30.

Hyperparathyroid subtypes diagnosed with the technique included 579 primary lesions; 22, secondary; one, tertiary; and seven associated with multiple endocrine neoplasia type I. From a pathological perspective, the neoplasms comprised 459 adenomas, 59 hyperplasia, and 19 double adenomas.

Most series do suggest the imaging technique is indicated when first-line tests are negative or discordant, the authors note. "However, it may also be useful in cases of hyperplasia or multiple lesions, persistent or recurrent hyperparathyroidism, small or ectopic adenomas, and normocalcemic hyperparathyroidism."

Dr. Charles Conte, chief of surgery at LIJ Forest Hills in New York City, told Reuters Health, "The cornerstone of localization in hyperparathyroidism has been ultrasound and sestamibi scanning. These studies have the limitation of poor quality imaging and discordant or negative results."

"Especially in this era of minimally invasive surgery when we are trying to limit the amount of dissection which we do, accurate localization is paramount," he said by email. "This review of 18F-fluorocholine PET/CET shows it to be a more accurate diagnostic entity. It appears to be useful especially in small or ectopic glands or when ultrasound and sestamibi scans are non-specific."

"Cost was not addressed, but it would surely be more expensive than ultrasound or sestamibi," he noted. "However, this cost would be offset by the decreased amount of surgery necessary with good localization."

Dr. Herbert Chen, chair of the department of surgery at the University of Alabama at Birmingham, commented by phone, "We are overusing imaging. Most patients with hyperparathyroidism do not need imaging studies. We can locate the parathyroid in the vast majority of cases without it."

"Imaging really is needed in patients who have failed surgeries before," he told Reuters Health. "We image to see why they failed, and maybe it's because it's in a place you didn't expect, but again, the vast majority of patients don't need imaging."

"This PET/CT technique seems to have impressive results," he noted. "My concern is that it could be overused and escalate the cost of healthcare for these patients. For patients in special situations, it's great to have options. There are lots of options available now, all with variable success. We need to see how this technique compares against others in the same patients."

The authors did not respond to requests for a comment.


JAMA Otolaryngol Head Neck Surg 2019.