Comparison of 4D computed tomography and F-18 fluorocholine PET for localisation of parathyroid lesions in primary hyperparathyroidism: A systematic review and meta-analysis

Initial Experience with Dual-Time-Point [18F]Flurpiridaz PET/CT for Localization of Parathyroid Adenomas in Primary Hyperparathyroidism

We aimed to evaluate the feasibility of [18F]flurpiridaz PET/CT for localization of parathyroid adenomas in patients with primary hyperparathyroidism (pHPT). Methods: Data for 11 patients with pHPT undergoing dual-time-point [18F]flurpiridaz PET/CT for localization of hyperfunctioning parathyroid glands were retrospectively analyzed. PET/CT findings were compared with results of other imaging tests, laboratory parameters, intraoperative findings, and final histology, serving as the reference standard. Results: [18F]flurpiridaz PET/CT identified parathyroid adenomas in 10 (91%) of the 11 patients studied. Parathyroid adenomas were exclusively visualized in early PET images. Uptake in adenomas declined over time (SUVmax, -65% ± 17%; P = 0.002), as did uptake in background thyroid tissue (-56% ± 16%; P = 0.002). Conclusion: [18F]flurpiridaz PET images after administration had high detection efficacy in pHPT. This work provides a rationale for larger prospective studies to evaluate the use of [18F]flurpiridaz PET/CT for localization of hyperfunctioning parathyroid glands in comparison with other imaging tests.

Contribution of 18 F-fluorocholine PET-CT to the preoperative localisation of parathyroid adenoma for the treatment of primary hyperparathyroidism

18 F-fluorocholine PET-CT is considered a second-line method for the preoperative localisation of parathyroid adenomas in primary hyperparathyroidism. The aim was to compare the diagnostic performance of 18 F-fluorocholine PET-CT and standard imaging modalities in the preoperative localisation of parathyroid adenomas in primary hyperparathyroidism. The primary objective was to assess the performance of 18 F-fluorocholine PET-CT in cases of negative or discordant standard imaging. The secondary objective was to evaluate the diagnostic performance of both 18 F-fluorocholine PET-CT and standard imaging in relation to patient characteristics. We conducted a retrospective, monocentric study, including 156 patients who underwent parathyroidectomy between 2017 and 2023. All patients underwent preoperative 18 F-fluorocholine PET-CT and had an indication for surgery due to primary hyperparathyroidism. A total of 156 patients were included in the study, the majority of whom were women (78%). Seven patients had multigland disease (4.49%). Sensitivity was 60.14% for cervical ultrasound, 46.21% for [99mTc]-MIBI scintigraphy, and 95.97% for 18 F-Fluorocholine PET-CT. 18 F-Fluorocholine PET-CT showed a higher sensitivity than cervical ultrasound and [99mTc]-MIBI scintigraphy, especially for multiple parathyroid adenomas (100, 57.14, and 42.86%, respectively). Univariate analysis showed better results for cervical ultrasound in men (p = 0.005). Larger adenomas showed better performance on [99mTc]-MIBI scintigraphy (p = 0.026), and elevated PTH levels were associated with significantly worse performance on 18 F-fluorocholine PET-CT (p = 0.023). Multivariate analysis showed that scintigraphy performance was worse in the presence of thyroid nodules (p = 0.049, RR = 2.046, 95% CI 1.005-4.166). 18 F-fluorocholine PET-CT is a valuable imaging modality for the preoperative localisation of parathyroid adenomas in primary hyperparathyroidism, with superior performance compared to conventional imaging modalities. [99mTc]-MIBI scintigraphy showed reduced diagnostic performance in the presence of thyroid nodules.

Association of primary hyperparathyroidism with pituitary adenoma and management issues

The co-occurrence of primary hyperparathyroidism (PHPT) and pituitary adenomas (PAs) is often indicative of underlying genetic syndromes such as Multiple Endocrine Neoplasia type 1 (MEN1) and, less commonly, MEN4. Although both conditions can occur sporadically, their simultaneous presence warrants evaluation for genetic mutations, with MEN1 mutations being the most frequent cause. The management of concurrent PHPT and PAs, especially in MEN1 patients, presents unique challenges. Management complexities arise from the syndromic nature, involving both surgical and medical interventions tailored to each condition. PHPT often manifests earlier and more aggressively in MEN1, requiring surgical intervention. However, recurrence rates remain high due to multiglandular involvement. Pituitary adenomas in MEN1 are primarily prolactinomas, and treatment with dopamine agonists results in significant tumour control in most cases. Overall, PAs associated with MEN1 are generally responsive to medical therapy, but careful long-term monitoring is essential. The utility of genetic screening cannot be overstated, as it aids in early detection, risk stratification, and management of both the index case and affected family members by cascade screening. A multidisciplinary approach is crucial for optimizing outcomes, with ongoing surveillance to manage recurrence and associated complications. In summary, the co-occurrence of PHPT and PAs, particularly in the context of MEN1, necessitates an integrated management strategy. Genetic testing is key in confirming diagnosis and guiding treatment, while surgical and medical interventions should be tailored to the extent and nature of glandular involvement. Close monitoring for recurrence and proactive family screening are essential components of long-term care.

Localization in primary hyperparathyroidism

Primary hyperparathyroidism is the main cause of hypercalcemia, resulting predominantly from parathyroid adenomas followed by hyperplasia. Diagnosis relies on clinical and biochemical parameters. Accurate pre-operative localization is mandatory for better surgical outcome. Various non-invasive imaging modalities includes cervical ultrasound, radionuclide scintigraphy with 99mTc-Methoxyisobutyl isonitrile combined with SPECT/CT, 4DCT, MRI and 18F-Choline PET/CT. Functional imaging has shown higher accuracy in localization especially in ectopic parathyroid adenomas and persistent or recurrent hyperparathyroidism. Combined ultrasound and 99mTc-MIBI has shown high sensitivity and specificity than individual imaging modality. 18F-Choline PET/CT has better diagnostic performance in identifying parathyroid hyperplasia and multiple adenomas. In patients with equivocal findings and concurrent thyroid nodular diseases, 18F-Choline PET/MRI and 4DCT helps in better characterization of lesion. Intraoperative probe guided surgery facilitates targeted and minimally invasive surgery resulting in better surgical outcome. More specific radiopharmaceuticals for parathyroid imaging need to be developed to reduce false positive results.

Endocrinology application of molecular imaging: current role of PET/CT

BACKGROUND

In recent years, nuclear medicine imaging methods have proven to be of paramount importance in a wide variety of diseases, particularly in oncology, where they are crucial for assessing the extent of disease when conventional methods fall short. Moreover, nuclear imaging modalities are able to better characterize lesions using target agents related to specific pathways (e.g. glucose metabolism, cellular proliferation, amino acid transport, lipid metabolism, specific receptor ligands). The clinical presentation of endocrine diseases encompasses a broad spectrum of sign and symptoms. Moreover, endocrine tumors show varying degrees of aggressiveness from well differentiated and indolent to highly aggressive cancers, respectively.

RATIONALE

With the application of new medicinal radio-compounds and increasingly advanced tomographic imaging technology, the utility of Positron Emission Tomography/Computed Tomography (PET/CT) in the field of endocrine diseases is expanding.

AIM

This review aims to analyze and summarize the primary indications of PET/CT, providing a practical approach for clinicians. A comprehensive literature search on PubMed was conducted to provide an updated overview of the available evidence regarding the use of PET/CT in endocrinology. Within this review, we will discuss the applications of PET/CT, compare different radiopharmaceuticals and highlight the uptake mechanism, excluding neuroendocrine carcinomas from discussion.

CONCLUSIONS

PET/CT is a valuable tool in diagnosing and managing endocrine disorders due to its capacity to furnish both functional and anatomical information, facilitate early lesion detection, guide treatment decisions, and monitor treatment response. Its non-invasive nature and precision make it an integral component of modern endocrine healthcare. This review aims to provide physicians with a clear perspective on the role of PET/CT imaging, discussing its emerging opportunities and appropriateness of use in endocrinological diseases.

Impact of perioperative diagnostic tools on clinical outcomes and cost-effectiveness in parathyroid surgery: a decision model-based analysis

OBJECTIVES

Preoperative and intraoperative diagnostic tools influence the surgical management of primary hyperparathyroidism (PHPT), whereby their performance of classification varies considerably for the two common causes of PHPT: solitary adenomas and multiglandular disease. A consensus on the use of such diagnostic tools for optimal perioperative management of all PHPT patients has not been reached.

DESIGN

A decision tree model was constructed to estimate and compare the clinical outcomes and the cost-effectiveness of preoperative imaging modalities and intraoperative parathyroid hormone (ioPTH) monitoring criteria in a 21-year time horizon with a 3% discount rate. The robustness of the model was assessed by conducting a one-way sensitivity analysis and probabilistic uncertainty analysis.

SETTING

The US healthcare system.

POPULATION

A hypothetical population consisting of 5000 patients with sporadic, symptomatic or asymptomatic PHPT.

INTERVENTIONS

Preoperative and intraoperative diagnostic modalities for parathyroidectomy.

MAIN OUTCOME MEASURES

Costs, quality-adjusted life-years (QALYs), net monetary benefits (NMBs) and clinical outcomes.

RESULTS

In the base-case analysis, four-dimensional (4D) CT was the least expensive strategy with US$10 276 and 15.333 QALYs. Ultrasound and 99mTc-Sestamibi single-photon-emission CT/CT were both dominated strategies while 18F-fluorocholine positron emission tomography was cost-effective with an NMB of US$416 considering a willingness to pay a threshold of US$95 958. The application of ioPTH monitoring with the Vienna criterion decreased the rate of reoperations from 10.50 to 0.58 per 1000 patients compared to not using ioPTH monitoring. Due to an increased rate of bilateral neck explorations from 257.45 to 347.45 per 1000 patients, it was not cost-effective.

CONCLUSIONS

4D-CT is the most cost-effective modality for the preoperative localisation of solitary parathyroid adenomas and multiglandular disease. The use of ioPTH monitoring is not cost-effective, but to minimise clinical complications, the Miami criterion should be applied for suspected solitary adenomas and the Vienna criterion for multiglandular disease.

Persistent primary hyperparathyroidism caused by an ectopic adenoma in the piriform sinus: case report and review of the literature

Introduction

Primary hyperparathyroidism (PHPT) is a common endocrine disorder in which surgery is the only curative therapy. Ectopic parathyroid adenoma in the pyriform sinus resulting from a pathological migration of parathyroid glands along the embryological development is a rare cause of PHPT. We describe a case of a persistent primary hyperparathyroidism after previous unsuccessful surgery due to an ectopic parathyroid adenoma within the pyriform sinus and we review the previous reports on this issue.

Case presentation

A 62-year-old woman was referred for persistent hypercalcemia following unsuccessful cervical exploratory surgery. Cervical ultrasound did not detect any parathyroid abnormalities. At variance, 99mTc-sestamibi SPECT/CT and CT scan of the neck identified a parathyroid adenoma in the left pyriform sinus, which was confirmed by endoscopy. The patient was successfully treated by transoral robotic resection and the pathology confirmed a parathyroid adenoma.

Conclusions

The ectopic parathyroid adenoma in the pyriform sinus is so uncommon that only fourteen cases have been reported. However, the pyriform sinus should be considered a possible location of ectopic parathyroid glands, especially in the setting of persistent or recurrent PHPT after parathyroid surgery.

Imaging Recommendations for Diagnosis and Management of Primary Parathyroid Pathologies: A Comprehensive Review

Parathyroid pathologies are suspected based on the biochemical alterations and clinical manifestations, and the predominant roles of imaging in primary hyperparathyroidism are localisation of tumour within parathyroid glands, surgical planning, and to look for any ectopic parathyroid tissue in the setting of recurrent disease. This article provides a comprehensive review of embryology and anatomical variations of parathyroid glands and their clinical relevance, surgical anatomy of parathyroid glands, differentiation between multiglandular parathyroid disease, solitary adenoma, atypical parathyroid tumour, and parathyroid carcinoma. The roles, advantages and limitations of ultrasound, four-dimensional computed tomography (4DCT), radiolabelled technetium-99 (99mTc) sestamibi or dual tracer 99mTc pertechnetate and 99mTc-sestamibi with or without single photon emission computed tomography (SPECT) or SPECT/CT, dynamic enhanced magnetic resonance imaging (4DMRI), and fluoro-choline positron emission tomography (18F-FCH PET) or [11C] Methionine (11C -MET) PET in the management of parathyroid lesions have been extensively discussed in this article. The role of fluorodeoxyglucose PET (FDG-PET) has also been elucidated in this article. Management guidelines for parathyroid carcinoma proposed by the American Society of Clinical Oncology (ASCO) have also been described. An algorithm for management of parathyroid lesions has been provided at the end to serve as a quick reference guide for radiologists, clinicians and surgeons.