¹⁸F‐fluorocholine PET/CT in MEN1 Patients with Primary Hyperparathyroidism

Abstract

Background Primary hyperparathyroidism (HPT1) is the most frequent endocrinopathy in multiple endocrine neoplasia type 1 (MEN1). Its surgical management is challenging. We aimed to describe and compare the imaging findings of parathyroid ultrasound (US), sestaMIBI scintigraphy (sestaMIBI), and 18F‐fluorocholine (FCH) PET/CT in a series of MEN1 patients with HPT1. Methods Retrospective analysis of a cohort of MEN1 patients with HPT1 assessed by parathyroid US, sestaMIBI scintigraphy and SPECT/CT, and FCH‐PET/CT for potential surgery between 2015 and 2019. Results Twenty‐two patients with a confirmed diagnosis of MEN1 who presented with HPT1 and were assessed by the 3 imaging modalities were included. After imaging workups, 11 patients were operated on for the first time, 4 underwent a redo surgery, and 7 did not undergo an operation. The overall patient‐based positivity rate of imaging was 91% (20 of 22) for parathyroid US and 96% (21 of 22) for both sestaMIBI and FCH‐PET/CT. The 3 imaging modalities demonstrated negative findings in 1/22 patient who did not undergo surgery. Overall, 3 pathologic glands were not detected by any imaging technique. SestaMIBI and FCH‐PET/CT both resulted in the same 3 false‐positive results in ectopic areas with a significant uptake on two thymic carcinoid tumors and one inflammatory lymph node. FCH‐PET/CT provided more surgically relevant data than sestaMIBI in 4/11 patients with initial surgery and in 1/4 patient who underwent redo surgery. Conclusions Compared to sestaMIBI scintigraphy, FCH‐PET/CT provides additional information regarding the number of pathologic parathyroid glands and their localization in MEN1 patients with HPT1.

European expert consensus on practical management of specific aspects of parathyroid disorders in adults and in pregnancy: recommendations of the ESE Educational Program of Parathyroid Disorders (PARAT 2021)

“…When persistent or recurrent PHPT is confirmed and a surgical approach is favored, it should be considered that about two-thirds of recurrent disease is due to a single adenoma, up to a third due to multiglandular disease, and rarely due to parathyroid carcinoma, a distinctly different profile from de novo PHPT (77,81). Thus, preoperative localization procedures that are more sensitive to detect multiglandular disease and/or small lesions should be preferred (18F-fluorocholine PET/CT, with or without enhanced arterial imaging, and 4D-CT) (82,83,84). This is especially when conventional preoperative imaging before the first intervention was inconclusive.…”

The EANM practice guidelines for parathyroid imaging

“…Radionuclide parathyroid imaging is also useful in conjunction with cUS, foremost in patients with hereditary disorders, such as MEN-1, MEN-2, and MEN-4, although sensitivity for hyperplasia is lower compared with sporadic adenoma. In this context, PET/CT might be preferred, owing to its higher spatial resolution [40]. The identification of hyperfunctioning glands can be supported by a γ-probe during surgery, especially in patients who underwent previous surgical treatment [41].…”

“…According to the study by Rep et al, the recommended imaging time is one hour after the administration of the radiopharmaceutical, and, if possible, preceded by imaging acquired 5 min after the injection (starting as dynamic acquisition and followed by static), as some lesions may show uptake in the early phase only [79]. One acquisition 20 min after injection with delayed images in case of a negative result is also an option [40]. The field of view can be limited from the nose to the chest down to the base of the heart as for scintigraphy, to obtain a low radiation exposure from CT.…”

Does 18F-Fluorocholine PET/CT add value to positive parathyroid scintigraphy in the presurgical assessment of primary hyperparathyroidism?

“…In this setting only few data are available comparing the imaging findings of parathyroid US, 99m Tc-sestamibi scintigraphy, and 18 F-FCH PET/CT. In a recent retrospective study including 22 MEN1 patients with pHPT, 18 F-FCH PET/CT provided more surgically relevant data regarding the number of pathologic parathyroid glands and their localization than 99m Tc-sestamibi scintigraphy in 4/11 patients with initial surgery and in 1/4 patient who underwent second surgery ( 23 ). Additional large cohort studies are still necessary to confirm the usefulness of 18 F-FCH PET/CT in patients with hereditary disorders, such as MEN.…”