Direct Comparison of Preoperative Imaging Modalities for Localization of Primary Hyperparathyroidism: A Systematic Review and Network Meta-analysis

Adolescent primary hyperparathyroidism

Adolescent primary hyperparathyroidism (PHPT) is a rare endocrine disorder bearing distinctions from the adult form. This review examines its unique aspects, focusing on clinical presentation, genetic etiologies, genotype-phenotype correlations, and therapeutic management. Adolescent PHPT often has a genetic basis, whether familial, syndromic, or apparently sporadic, and identifying the underlying genetic cause is important for patient care. The clinical presentation is predominantly symptomatic worldwide. Unique manifestations in this age group include rickets, short stature, and slipped capital femoral epiphysis. Genotype-specific differences are evident in the adolescent PHPT characteristics. Diagnostic evaluation requires careful interpretation of biochemical and dual-energy X-ray absorptiometry findings using age and gender-specific reference ranges, with targeted screening for syndrome-associated neoplasms. Surgery remains the cornerstone of management. Current knowledge gaps in their management include treatment protocols for multiple endocrine neoplasia type 1-associated PHPT, the efficacy and safety of nonsurgical options, and long-term post-surgical outcomes.

Results of 18F-choline and 11C-methionine positron emission tomography/computed tomography for the preoperative localization of hyperfunctional parathyroid glands in primary hyperparathyroidism

BACKGROUND

Preoperative localization of hyperfunctioning parathyroid glands in primary hyperparathyroidism is essential for successful parathyroid surgery, particularly in patients with previous negative imaging or reoperations.

METHODS

A multicenter registry study was performed in 776 patients with primary hyperparathyroidism from 53 hospitals in Germany and Austria who underwent parathyroid surgery after preoperative 18F-choline or 11C-methionine positron emission tomography/computed tomography (PET/CT).

RESULTS

In 683 of 776 patients (88%) (78% female, aged 15-86 years), primary hyperparathyroidism was caused by a single-gland parathyroid adenoma. A total of 9.2% patients had multiglandular disease, 0.4% had parathyroid carcinoma, and, in 2.4%, no hyperfunctional parathyroid glands were found intraoperatively. The sensitivity of 18F-choline PET/CT was 87.9% compared with 83.2% for 11C-methionine PET/CT with a positive predictive value for 18F-choline PET/CT and 11C-methionine PET/CT of 88.5% and 85.6%, respectively. A subgroup analysis revealed more positive results for 18F-choline PET/CT in patients with previous neck surgery (89.0%) than for 11C-methionine PET/CT (74.2%, P = .0411). Positive PET/CT results significantly reduced surgery times decreasing from 93 minutes (±56.54) to 71 minutes (±43.48, P < .0001). Postoperative normalization of calcium levels was achieved in 729 patients (93.9%). In the case of positive PET/CT findings, 97.2% of the patients were cured (P < .0001).

CONCLUSION

Both PET/CT tracers showed excellent detection rates of hyperfunctioning parathyroid glands in primary hyperparathyroidism, especially in a setting with a high percentage of reoperations and negative sestamibi scans.

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.

[18F]fluorocholine PET vs. [99mTc]sestamibi scintigraphy for detection and localization of hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism: outcomes and resource efficiency

BACKGROUND

Minimally invasive parathyroidectomy is the treatment of choice in patients with primary hyperparathyroidism (PHP), but it needs a reliable preoperative localization method to detect hyperfunctioning parathyroid tissue. Higher sensitivity and lower radiation exposure was demonstrated for [18F]fluorocholine PET/CT (FCh-PET/CT) in comparison to [99mTc]sestamibi (MIBI) scintigraphy. However, data of its efficiency in resource use and patient outcomes is lacking. The aim of our study was to determine the resource efficiency and patient outcomes of FCh-PET/CT in comparison to conventional MIBI scintigraphy.

PATIENTS AND METHODS

A group of 234 patients who underwent surgery after MIBI scintigraphy was compared to a group of 163 patients who underwent surgery after FCh-PET/CT. The whole working process from the implementation of imaging to the completion of surgical treatment was analyzed. The economic burden was expressed in the time needed for the required procedures.

RESULTS

The time needed to perform imaging was reduced by 83% after FCh-PET/CT in comparison to MIBI scintigraphy. The time needed to perform surgery was reduced by 41% when intraoperative parathyroid hormone monitoring was not used. There was no significant difference in the time of surgery between FCh-PET/CT and MIBI scintigraphy.

CONCLUSIONS

FCh-PET/CT reduces the time of imaging, the time of surgery and potentially reduces the number of reoperations for persistent disease.

The detection of pathological parathyroid glands is facilitated by identifying vascular features on ultrasound: the potential benefit of a low-frequency vascular probe

PURPOSE

To evaluate the potential benefit of adding a low frequency vascular probe to the conventional pre-operative ultrasound examination of patients with primary hyperparathyroidism.

METHODS

A prospective cohort of 136 patients with primary hyperparathyroidism underwent a conventional ultrasound examination of the neck with a high frequency ( > 10 MHz) linear ultrasound probe, followed by an add-on examination with a low frequency vascular probe. For each ultrasound probe, and for every potential parathyroid lesion, the presence of a feeding vessel, a polar placement of the feeding vessel, and the presence of a vascular arch was recorded.

RESULTS

A total of 146 ultrasound lesions were evaluated for vascularity by each probe. For both ultrasound probes, the odds of a hyperfunctioning parathyroid gland being correctly identified increased with the number of visible vascular features. The vascular probe identified a significantly higher number of vascular features among ultrasound true positive glands compared with the conventional probe (p < 0.0001). Among histopathologically verified pathological parathyroid glands, the vascular probe identified 20% more feeding vessels, 27% more polar placements of the feeding vessel, and 65% more vascular arches than the high frequency probe. However, the diagnostic confidence score for true positive glands did not differ significantly between the probes (p = 0.11).

CONCLUSION

The addition of a low frequency vascular probe increases the number of visible vascular features in hyperfunctioning parathyroid glands, which facilitates their preoperative detection. Whether or not this can increase the diagnostic confidence of ultrasound examiners has yet to be substantiated.

18F-Fluorocholine-Positron Emission Tomography/Computerized Tomography (FCH PET/CT) Imaging for Detecting Abnormal Parathyroid Glands: Indication, Practice, Interpretation and Diagnostic Performance

In patients with confirmed hyperparathyroidism (HPT) scheduled for surgical treatment, the preoperatory imaging permits to optimize the operatory protocol of parathyroidectomy (PTX), in particular by selecting those patients who can benefit from minimally invasive PTX (MIPTX). The MIPTX has the merit to shorten the operative time, incision length, and to reduce the operatory risks. With preoperative localization studies, the rate of PTX failure, in particular due to nonsuspected multiglandular or ectopic disease, has been profoundly decreased. The first cases of incidental localization of abnormal parathyroid glands (PTs) on FCH PET/CTs performed for another indication were reported more than one decade ago. Since then, significant amount of data from heterogeneous series of patients consistently confirmed better diagnostic performances of FCH PET/CT (sensitivity for detection of abnormal PT 97%, range 96%-98%) in comparison with other radiopharmaceuticals, ultrasonography or 4D-CeCT in localizing hyperfunctioning parathyroid glands (HFPTGs) in case of primary HPT. Utility of FCH PET/CT in case of renal HPT has been reported in fewer series. The article discusses and summarizes the bibliographic evidence on documented indications of FCH PET/CT in patients with HPT, its safety profile, the practice of FCH PET/CT and interpretation of FCH PET/CT findings, including potential interpretation pitfalls and tips to avoid them. Our real-world experience over 12 years reinforces published evidence supporting the use of FCH PET/CT as the first-line radionuclide imaging technique in patients with all types of HPT in whom surgery is an option.

The polar vessel sign: insights from CT imaging analysis in Asian Indian primary hyperparathyroidism

PURPOSE

Data on the polar vessel sign (enlarged feeding vessel terminating in parathyroid lesions) on four-dimensional computed tomography (4D-CT) is limited. We performed a retrospective analysis to determine the prevalence, predictors, and adjunctive utility of polar vessel sign in pre-operative 4D-CT of patients with primary hyperparathyroidism (PHPT).

METHODS

One radiologist blinded to the patients' details reported the 4D-CT of eighty-four operated patients with histopathology-proven single-gland PHPT. Two protocols were used to obtain arterial-phase images: timed via bolus tracking (n = 41) or fixed at 20 s after contrast injection (n = 43).

RESULTS

Seventy-one patients were symptomatic for PHPT, with median serum calcium 12.1 mg/dL. On the arterial phase of 4D-CT, 88.1% of lesions had the polar vessel sign, including 7/9 asymptomatic patients, 6/6 parathyroid carcinomas, and 3/4 ectopic(1:mediastinum, 2:thyro-thymic ligament). Predictors of polar vessel sign were maximum lesion dimension (2.2 vs. 1.4 cm; P = 0.03), solid-cystic CT morphology (47.3% vs. none; P = 0.004), and bolus tracking-timed arterial phase (55.4% vs. none; P = 0.001). Of these, bolus tracking improved the polar vessel's visualization (100% vs. 76.7%; P = 0.001) independent of lesion dimension and solid-cystic morphology. The latter two predicted polar vessel sign in images obtained at a fixed interval (20 s). A significantly lower proportion of bolus tracking-timed scans had lesion percentage arterial enhancement (PAE) < 128.9% (2/41 vs. 9/43; P = 0.04). Even with suboptimal PAE, the polar vessel helped identify 9/11 lesions.

CONCLUSION

The polar vessel sign demonstrated an additive role to PAE during CT reporting. Bolus tracking is valuable in optimizing vessel and tumor arterial enhancement and is easily incorporated into parathyroid 4D-CT protocol.

Cost-effectiveness of one-stop-shop [18F]Fluorocholine PET/CT to localise parathyroid adenomas in patients suffering from primary hyperparathyroidism

PURPOSE

We conducted a cost-effectiveness analysis in which we compared a preoperative [18F]Fluorocholine PET/CT-based one-stop-shop imaging strategy with current best practice in which [18F]Fluorocholine PET/CT is only recommended after negative or inconclusive [99mTc]Tc-methoxy isobutyl isonitrile SPECT/CT for patients suffering from primary hyperparathyroidism. We investigated whether the one-stop-shop strategy performs as well as current best practice but at lower costs.

METHODS

We developed a cohort-level state transition model to evaluate both imaging strategies respecting an intraoperative parathyroid hormone monitored treatment setting as well as a traditional treatment setting. The model reflects patients' hospital journeys after biochemically diagnosed primary hyperparathyroidism. A cycle length of twelve months and a lifetime horizon were used. We conducted probabilistic analyses simulating 50,000 cohorts to assess joint parameter uncertainty. The incremental net monetary benefit and cost for each quality-adjusted life year were estimated. Furthermore, threshold analyses regarding the tariff of [18F]Fluorocholine PET/CT and the sensitivity of [99mTc]Tc-methoxy isobutyl isonitrile SPECT/CT were performed.

RESULTS

The simulated long-term health effects and costs were similar for both imaging strategies. Accordingly, there was no incremental net monetary benefit and the one-stop-shop strategy did not result in lower costs. These results applied to both treatment settings. The threshold analysis indicated that a tariff of €885 for [18F]Fluorocholine PET/CT was required to be cost-effective compared to current best practice.

CONCLUSION

Both preoperative imaging strategies can be used interchangeably. Daily clinical practice grounds such as available local resources and patient preferences should inform policy-making on whether a hospital should implement the one-stop-shop imaging strategy.

F18-Choline PET/CT or MIBI SPECT/CT in the Surgical Management of Primary Hyperparathyroidism: A Diagnostic Randomized Clinical Trial

Importance

Whether F18-choline (FCH) positron emission tomographic (PET)/computed tomographic (CT) scan can replace Tc99m-sestaMIBI (MIBI) single-photon emission (SPE)CT/CT as a first-line imaging technique for preoperative localization of parathyroid adenomas (PTA) in patients with primary hyperparathyroidism (PHPT) is unclear.

Objective

To compare first-line FCH PET/CT vs MIBI SPECT/CT for optimal care in patients with PHPT needing parathyroidectomy and to compare the proportions of patients in whom the first-line imaging method resulted in successful minimally invasive parathyroidectomy (MIP) and normalization of calcemia 1 month after surgery.

Design, Setting, and Participants

A French multicenter randomized open diagnostic intervention phase 3 trial was conducted. Patients were enrolled from November 2019 to May 2022 and participated up to 6 months after surgery. The study included adults with PHPT and an indication for surgical treatment. Patients with previous parathyroid surgery or multiple endocrine neoplasia type 1 (MEN1) were ineligible.

Interventions

Patients were assigned in a 1:1 ratio to receive first-line FCH PET/CT (FCH1) or MIBI SPECT/CT (MIBI1). In the event of negative or inconclusive first-line imaging, they received second-line FCH PET/CT (FCH2) after MIBI1 or MIBI SPECT/CT (MIBI2) after FCH1. All patients underwent surgery under general anesthesia within 12 weeks following the last imaging. Clinical and biologic (serum calcemia and parathyroid hormone levels) assessments were performed 1 and 6 months after surgery.

Main Outcomes and Measures

The primary outcome was a true-positive first-line imaging-guided MIP combined with uncorrected serum calcium levels of 2.55 mmol/l or less 1 month after surgery, corresponding to the local upper limit of normality.

Results

Overall, 57 patients received FCH1 (n = 29) or MIBI1 (n = 28). The mean (SD) age of patients was 62.8 (12.5) years with 15 male (26%) and 42 female (74%) patients. Baseline patient characteristics were similar between groups. Normocalcemia at 1 month after positive first-line imaging-guided MIP was observed in 23 of 27 patients (85%) in the FCH1 group and 14 of 25 patients (56%) in the MIBI1 group. Sensitivity was 82% (95% CI, 62%-93%) and 63% (95% CI, 42%-80%) for FCH1 and MIBI1, respectively. Follow-up at 6 months with biochemical measures was available in 43 patients, confirming that all patients with normocalcemia at 1 month after surgery still had it at 6 months. No adverse events related to imaging and 4 adverse events related to surgery were reported.

Conclusions

This randomized clinical trial found that first-line FCH PET/CT is a suitable and safe replacement for MIBI SPECT/CT. FCH PET/CT leads more patients with PHPT to correct imaging-guided MIP and normocalcemia than MIBI SPECT/CT thanks to its superior sensitivity.

Trial Registration

ClinicalTrials.gov Identifier: NCT04040946.

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.

Comparative Study of Different Imaging Modalities for Diagnosis of Bone Metastases of Prostate Cancer: A Bayesian Network Meta-analysis

PURPOSE

This study aimed to compare the diagnostic performances of 8 different imaging modalities for preoperative detection of bone metastases in prostate cancer patients by performing a network meta-analysis using direct comparison studies with 2 or more imaging techniques.

PATIENTS AND METHODS

We searched PubMed, Embase, and Cochrane Library for studies evaluating the performances of 8 different imaging modalities for the preoperative detection of bone metastases in prostate cancer patients. The network meta-analysis was performed in patient-based analysis. The consistency was evaluated by examining the agreement between direct and indirect treatment effects, and the surface under the cumulative ranking curve (SUCRA) values were obtained to calculate the probability of each imaging modality being the most effective diagnostic method.

RESULTS

A total of 999 patients from 13 direct comparison studies using 8 different imaging modalities for preoperative detection or follow-up of bone metastases in prostate cancer patients were included. For the detection of bone metastases of prostate cancer, 68 Ga-PSMA-11 PET/CT showed the highest SUCRA values of sensitivity, positive predictive value, accuracy, and diagnostic odds ratio. In addition, 18 F-NaF PET/CT and SPECT/CT showed high SUCRA values.

CONCLUSIONS

68 Ga-PSMA-11 PET/CT showed the highest SUCRA values. Other imaging modalities showed complementary diagnostic roles for preoperative detection of bone metastases in patients with prostate cancer, except bone scintigraphy and MRI.

Mitigation of cold stress in Nile tilapia (Oreochromis niloticus) through dietary lipids supplementation: a preliminary network meta-analysis

There is a growing body of evidence suggesting that water temperature can significantly impact the dietary fatty acid requirements of Nile tilapia (Oreochromis niloticus). Therefore, this study assessed the effectiveness of different dietary lipid sources on the growth performance of Nile tilapia reared at suboptimal temperatures. A network meta-analysis was performed, including searches of PubMed and Scopus from inception to January 2022, for trials that evaluated the effects of lipid sources on cold-stressed Nile tilapia. The Bayesian hierarchical framework was used to pool and compare the effect sizes of growth parameters such as weight gain, feed intake, and feed conversion ratio (FCR). Furthermore, the surface under the cumulative ranking curve (SUCRA) was obtained to calculate the probability that each lipid source was the most effective against cold stress. All subsequent numbers refer to comparisons with diets containing only fish oil. Dietary Aurantiochytrium significantly increased weight gain (SMD = 2.00, CrI: 0.70 to 3.40). In contrast, diets containing coconut oil led to significantly lower weight gain (SMD = - 3.30, CrI: - 6.00 to - 0.63) and higher FCR (SMD = 17.0, CrI: 6.70 to 27.0). Additionally, dietary corn oil was associated with a decrease in feed intake (SMD = - 2.32, CrI: - 3.91 to - 0.80), while a combination of fish and corn oil reduced FCR (SMD = - 5.70, CrI: - 11.0 to - 0.81). In general, the analysis of SUCRA values revealed that in cold-stressed Nile tilapia, Aurantiochytrium, sunflower oil, and the combination of fish and corn oil were the most effective lipid sources for improving growth at suboptimal temperatures. The results of the current study can serve as a basis for future studies that focus on the use of dietary lipid sources to mitigate cold stress in Nile tilapia.

Diagnostic Performance of Magnetic Resonance Imaging for Parathyroid Localization of Primary Hyperparathyroidism: A Systematic Review

Accurate preoperative localization is crucial for successful minimally invasive parathyroidectomy in primary hyperparathyroidism (PHPT). Preoperative localization can be challenging in patients with recurrent and/or multigland disease (MGD). This has led clinicians to investigate multiple imaging techniques, most of which are associated with radiation exposure. Magnetic resonance imaging (MRI) offers ionizing radiation-free and accurate imaging, making it an attractive alternative imaging modality. The objective of this systematic review is to provide an overview of the diagnostic performance of MRI in the localization of PHPT. PubMed and Embase libraries were searched from 1 January 2000 to 31 March 2023. Studies were included that investigated MRI techniques for the localization of PHPT. The exclusion criteria were (1) secondary/tertiary hyperparathyroidism, (2) studies that provided no diagnostic performance values, (3) studies published before 2000, and (4) studies using 0.5 Tesla MRI scanners. Twenty-four articles were included in the systematic review, with a total of 1127 patients with PHPT. In 14 studies investigating conventional MRI for PHPT localization, sensitivities varied between 39.1% and 94.3%. When employing more advanced MRI protocols like 4D MRI for PHPT localization in 11 studies, sensitivities ranged from 55.6% to 100%. The combination of MR imaging with functional techniques such as 18F-FCH-PET/MRI yielded the highest diagnostic accuracy, with sensitivities ranging from 84.2% to 100% in five studies. Despite the limitations of the available evidence, the results of this review indicate that the combination of MR imaging with functional imaging techniques such as 18F-FCH-PET/MRI yielded the highest diagnostic accuracy. Further research on emerging MR imaging modalities, such as 4D MRI and PET/MRI, is warranted, as MRI exposes patients to minimal or no ionizing radiation compared to other imaging modalities.

The role of 18F-fluoromethylcholine-positron emission tomography-computed tomography for preoperative localization of hyperfunctioning parathyroid glands with special emphasis on multiglandular disease: a retrospective cohort study

Background

Primary hyperparathyroidism (PHPT) is a common endocrine disorder. Definitive treatment is surgical. Preoperative localization of diseased glands increases the chance of successful treatment. The aim of this study is to investigate the diagnostic performance of 18F-fluoromethylcholine-positron emission tomography-computed tomography (18F-FCh-PET-CT) in preoperative localization of diseased parathyroid glands, when first-line examinations were inconclusive.

Methods

This is a retrospective study. All patients with PHPT who underwent 18F-FCh-PET-CT, after inconclusive ultrasound examination and 99mTc-methoxyisobutylisonitrile/single-photon emission CT-CT, were included in cohort I. Patients who were subsequently operated for their parathyroid disease, were included in cohort II. The performance of 18F-FCh-PET-CT was analyzed in two sets: per-lesion, and per-gland analysis.

Results

Out of 52 patients in cohort I, 18F-FCh-PET-CT identified single or multiple parathyroid lesions in 43 patients (83%). Nine patients had multiglandular disease. Thirty-four (65%) patients were subsequently operated and included in cohort II. Forty-four lesions were removed from these patients and 33 patients (97%) were cured. 18F-FCh-PET-CT localized 40 out of 44 lesions, with per-lesion and per-gland sensitivities of 97% and 95%, and positive predictive values (PPVs) of 93% and 87%, respectively, in addition to a specificity of 97% and a negative predictive value (NPV) of 94% in the per-gland analysis. Comparable excellent results were detected in multiglandular disease with sensitivity of 94.1%, specificity of 89%, PPV of 84%, and NPV of 94%.

Conclusions

Our study demonstrates the high diagnostic performance of 18F-FCh-PET-CT in the preoperative localization of diseased parathyroid gland in patients with PHPT, especially in multiglandular PHPT.

Diagnostic Value of Four-Dimensional Dynamic Computed Tomography for Primary Hyperparathyroidism in Patients with Low Baseline Parathyroid Hormone Levels

Low baseline levels of parathyroid hormone (PTH) are associated with a higher rate of multiglandular disease, lower localization rates of preoperative imaging modalities, and a higher rate of unsuccessful minimally invasive parathyroidectomies. The objective of this study is to assess the diagnostic value of four-dimensional dynamic computed tomography (4D-CT) in localizing primary hyperparathyroidism (pHPT) in patients with low baseline PTH levels, compared to patients with high baseline PTH levels. Patients with pHPT who received a 4D-CT scan as part of their standard diagnostic evaluation were divided into two groups based on the following criteria: (1) preoperative PTH levels less than 100 pg/mL and (2) patients with preoperative PTH levels greater than 100 pg/mL. All patients underwent parathyroidectomy based on 4D-CT findings, with intraoperative parathyroid hormone monitoring. The lesion-based sensitivity of 4D-CT was 88% in patients with low baseline PTH levels and 94.7% in patients with high baseline PTH levels (p = 0.33). However, the success rate of image-guided resection based on 4D-CT findings was 71.4% in the low baseline PTH group compared to 90.6% in the high baseline PTH group (p = 0.06). Our study demonstrated that 4D-CT has a high lesion-based sensitivity in patients with pHPT and low baseline PTH levels but led to a relatively low rate of successful image-guided resection in patients with low baseline PTH levels. Therefore, it is important to exercise increased caution during 4D-CT-guided surgical exploration of patients with low baseline PTH levels to ensure successful surgical resection of all parathyroid lesions.

Parathyroid Imaging

Primary hyperparathyroidism (1° HPT) is a relatively common endocrine disorder usually caused by autonomous secretion of parathormone by one or several parathyroid adenomas. 1° HPT causing hypercalcemia, kidney stones and/or osteoporosis should be treated whenever possible by parathyroidectomy. Accurate preoperative location of parathyroid adenomas is crucial for surgery planning, mostly when performing minimally invasive surgery. Cervical ultrasonography (US) is usually performed to localize parathyroid adenomas as a first intention, followed by 99mTc- sestamibi scintigraphy with SPECT/CT whenever possible. 4D-CT is a possible alternative to 99mTc- sestamibi scintigraphy. Recently, 18F-fluorocholine positron emission tomography/computed tomography (18F-FCH PET/CT) has made its way in the clinics as it is the most sensitive method for parathyroid adenoma detection. It can eventually be combined to 4D-CT to increase its diagnostic performance, although this results in higher dose exposure to the patient. Other forms of hyperparathyroidism consist in secondary (2° HPT) and tertiary hyperparathyroidism (3° HPT). As parathyroidectomy is not usually part of the management of patients with 2° HPT, parathyroid imaging is not routinely performed in these patients. In patients with 3° HPT, total or subtotal parathyroidectomy is often performed. Localization of hyperfunctional glands is an important aid to surgery planning. As 18F-FCH PET/CT is the most sensitive modality in multigland disease, it is the preferred imaging technic in 3° HPT patients, although its cost and availability may limit its widespread use in this setting.

Evaluation of Surgeon-Performed Ultrasonography With or Without Contrast Enhancement vs Scintigraphy in Patients With Primary Hyperparathyroidism

Importance

Scintigraphy and ultrasonography are common imaging modalities for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism. When comparing the 2 modalities, the benefits of ultrasonography in terms of convenience, patient comfort, duration, cost, and lack of radiation should be taken into account.

Objective

To investigate whether surgeon-performed ultrasonography, with or without contrast-enhanced ultrasonography (CEUS), is noninferior to scintigraphy for localizing pathological parathyroid glands in patients with primary hyperparathyroidism.

Design, Setting, and Participants

Prospective, paired, noninferiority cohort study performed at a high-volume tertiary referral center for parathyroidectomy with blinded examiners and a 6-month follow-up. Participants were adults (age ≥18 years) referred for parathyroidectomy due to primary hyperparathyroidism. Of 207 eligible patients, 35 were excluded, leaving 172 enrolled in the study. Inclusion lasted from September 2019 until February 2021. Follow-up ended in December 2021.

Exposures

99mTechnetium-pertechnetate/99mtechnetium-sestamibi subtraction scintigraphy with 99mtechnetium-sestamibi single-photon emission computed tomography/computed tomography, followed by surgeon-performed ultrasonography and CEUS.

Main Outcomes and Measures

The sensitivity of each imaging modality in localizing pathological parathyroid glands, calculated on a per-quadrant and a per-patient basis, respectively. The a priori noninferiority margin was a lower 95% confidence limit for the difference in sensitivity not falling below -10%.

Results

Out of 172 participants, 139 (80.8%) were women, the median (range) age was 65 (24-87) years, and the median (IQR) follow-up was 200.5 (181-280.25) days. Quadrant sensitivity (95% CI) was 70.9% (63.2%-78.5%) for ultrasonography, 68.4% (60.4%-76.5%) for ultrasonography plus CEUS, and 67.0% (60.0%-74.0%) for scintigraphy. The sensitivity difference (95% CI) compared with scintigraphy was 3.9% (-4.1% to 11.8%) for ultrasonography and 1.5% (-6.4% to 9.3%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. Per-patient sensitivity was 81.4% (74.8%-86.9%) for ultrasonography and 79.1% (72.2%-84.9%) for both scintigraphy and ultrasonography plus CEUS. The sensitivity difference compared with scintigraphy was 2.3% (-6.8% to 11.4%) for ultrasonography and 0.0% (-9.1% to 9.1%) for ultrasonography plus CEUS, establishing noninferiority for both modalities.

Conclusions and Relevance

In this cohort study, conventional ultrasonography by an experienced parathyroid surgeon-sonographer was noninferior to scintigraphy and may constitute a valid first-line imaging modality in patients with primary hyperparathyroidism, even without the addition of CEUS. Further imaging should be reserved for cases that are equivocal or nonlocalizing on ultrasonography.

Dual-phase computed tomography for localization of parathyroid lesions in children and adolescents with primary hyperparathyroidism

BACKGROUND

Childhood and adolescent primary hyperparathyroidism (PHPT) is a rare disease caused by single adenomas in 65-94% of patients. In this patient group, there is no data on computed tomography (CT) for pre-operative parathyroid localization that may facilitate focused parathyroidectomy.

METHODS

Two radiologists reviewed dual-phase (nonenhanced and arterial) CT images of twenty-three operated children and adolescents [20:single-gland disease(SGD), 3:multi-glandular disease(MGD)] with proven histopathological PHPT. Percentage arterial enhancement (PAE) was calculated as [100*{arterial-phase Hounsfield unit (HU)-nonenhanced phase HU}/nonenhanced HU] of the parathyroid lesion(s), thyroid, and lymph node.

RESULTS

Dual-phase CT lateralized 100%, localized to the correct quadrant/site 85% SGD (including 3/3 ectopic), and identified 1/3 MGD. PAE (cutoff ≥ 112.3%) was sensitive (91.3%) and specific (99.5%) in distinguishing parathyroid lesions from local mimics (P<0.001). The average effective dose was 3.16±1.01mSv, comparable to the planar/single photon emission CT (SPECT) Technetium 99m(Tc)-sestamibi and choline positron emission tomography (PET)/CT scans. Solid-cystic morphology identified in 4 patients harboring pathogenic germline variants (3:CDC73, 1:CASR) may serve as a radiological clue to molecular diagnosis. Nineteen out of 20 (95%) patients with SGD who had undergone single gland resection based on pre-operative CT findings were in remission over a median follow-up of 18 months.

CONCLUSION

As most children/adolescents with PHPT have SGD, dual-phase CT protocols which reduce the effective radiation dose with high localization sensitivity for single parathyroid lesions may be a sustainable pre-operative imaging modality in this patient group.

Head-to-Head Comparison of Tc-99m-sestamibi SPECT/CT and C-11-L-Methionin PET/CT in Parathyroid Scanning Before Operation for Primary Hyperparathyroidism

PURPOSE

The preferred nuclear medicine method for identification of hyperfunctioning parathyroid glands in hyperparathyroidism (HPT) develops continuously in relation to the technological progress. Diagnostic methods based on PET/CT have during recent years evolved with new tracer possibilities competing with traditional scintigraphic methods. This investigation is a head-to-head comparison of Tc-99m-sestamibi SPECT/CT gamma camera scintigraphy (sestamibi SPECT/CT) and C-11-L-methionin PET/CT imaging (methionine PET/CT) for preoperative identification of hyperfunctioning parathyroid glands.

PROCEDURES

The study is a prospective cohort study including 27 patients diagnosed with primary hyperparathyroidism (PHPT). Two nuclear medicine physicians assessed all examinations independently and blinded. All scanning assessments were matched to the final surgical diagnosis as confirmed by histopathology. Biochemical monitoring of the therapeutical effects was performed preoperatively by PTH-measurements and followed postoperatively for up to 12 months. Comparisons were made for differences in sensitivity and positive predictive value (PPV).

RESULTS

Twenty-seven patients (18 females, 9 males; mean age (range): 58.9 years (34.1-79)) were enrolled into the study. The 27 patients had a total of 33 identified sites of lesions of which 28 (85%) turned out to be histopathological verified hyperfunctioning parathyroid glands. The sensitivity and PPV for sestamibi SPECT/CT were 0.71 and 0.95; that of methionine PET/CT was 0.82 and 1, respectively. Both sensitivity and PPV were slightly lower for sestamibi SPECT/CT than for methionine PET PET/CT (-0.11, 95% confidence interval (95% CI): -0.29 to 0.08; -0.05, 95% CI: -0.14 to 0.04, respectively), but not to a statistically significant extent (p=0.38 and p=0.31). The sensitivity and PPV for diagnostic CT were 0.64 (95% CI: 0.44 to 0.81) and 1 (95% CI: 0.81 to 1).

CONCLUSIONS

Methionine PET/CT performed comparable to sestamibi SPECT/CT with respect to identification and localization of hyperfunctioning parathyroid glands prior to surgery.

C11 choline PET/CT succeeds when conventional imaging for primary hyperparathyroidism fails

BACKGROUND

Focused parathyroidectomy in primary hyperparathyroidism is possible with accurate preoperative localization. A growing body of data exists regarding the role of radio-labeled C¹¹ choline positron emission tomography/computed tomography. In cases of nonlocalized disease, it may be a useful adjunct to ultrasound, (123)I/(99)Tc-sestamibi (I-123 sestamibi), or 4-dimensional computed tomography imaging.

METHODS

Patients who received a neck and chest limited coverage C¹¹ choline positron emission tomography/computed tomography for evaluation of primary hyperparathyroidism from 2017 to 2021 at a single institution were retrospectively reviewed. We assessed the sensitivity, positive predictive value, and false negative rate. We also compared these rates to the standard modalities of ultrasound, I-123 sestamibi, 4-dimensional computed tomography, and examined concordance rates.

RESULTS

We identified 43 patients, of whom 33 had a positive C¹¹ choline positron emission tomography/computed tomography finding. This cohort of patients had failed to localize on multiple standard imaging modalities. Twenty-five patients proceeded to surgery, 72% of whom were reoperative cases. Twenty (80%) achieved an intraoperative cure. Analysis showed that C¹¹ choline positron emission tomography/computed tomography achieved a sensitivity of 64% (95% confidence interval 47%-82%) and positive predictive value of 72% (95% confidence interval 54%-90%). There were 5/25 (20%) false positive positron emission tomography C¹¹ choline results found to be lymph nodes, normal parathyroid, and 1 recurrent laryngeal nerve neuroma.

CONCLUSION

C¹¹ choline positron emission tomography/computed tomography is a useful adjunct for parathyroid localization in a complex population of patients who have failed standard localization techniques including ultrasound, I-123 sestamibi, or 4-dimensional computed tomography and/or prior operations. Although routine inclusion of C¹¹ choline positron emission tomography/computed tomography imaging may not be necessary, it may aid in preoperative localization in the reoperative setting.

Usefulness of PET/CT with Carbon-11-Labeled Methionine in the Diagnosis of Tertiary Hyperparathyroidism

Introduction: Tertiary hyperparathyroidism (tHP) may develop in patients treated with hemodialysis or peritoneal dialysis. Parathyroidectomy may result in a significant reduction in the severity of symptoms. For the effective surgical treatment of hyperparathyroidism, proper localization of the parathyroid glands prior to surgery is essential. The sensitivity of scintigraphy in the diagnosis of tHP is lower than in the diagnosis of primary hyperparathyroidism. In recent years, positron emission tomography (PET/CT) has been gaining importance, usually as a complementary technique. Aim: The aim of this study was to determine the usefulness of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tertiary hyperparathyroidism caused by chronic kidney disease, in whom first-line diagnostic methods did not allow the localization of pathologically parathyroid glands. Material and methods: The study was conducted in a group of 19 adult patients with severe tHP who were resistant or intolerant to non-invasive treatment, with negative results of scintigraphy and ultrasonography of the neck. The study protocol included measurement of the concentration of calcium, phosphorus, and PTH in the blood serum and performing PET/CT with [11C]MET. Results: A positive result of PET/CT was obtained in 89.5% of the patients (17/19). Parathyroidectomy was performed in 52.9% of the patients (9/17) with positive results of PET/CT with [11C]MET, which were fully consistent with the results of the histopathological examinations of the removed parathyroid glands. On this basis, the sensitivity of PET/CT with [11C]MET in the preoperative localization diagnosis of patients with tHP was found to be 100%. Multiple lesions were visualized in 57.9% of the patients (11/19). Ectopic lesions were visualized in 21.1% of the patients (4/19). Conclusions: PET/CT with [11C]MET is a sensitive technique for the second-line preoperative imaging of parathyroid glands in patients with tertiary hyperparathyroidism in whom first-line examinations, such as ultrasound and scintigraphy, has failed.

Comparison of Preoperative Imaging Modalities for the Assessment of Malignant Potential of Pancreatic Cystic Lesions: A Network Meta-analysis

PURPOSE

The aims of this study are to compare the performance of various preoperative imaging modalities for assessing the malignant potential of pancreatic cystic lesions (PCLs) through a network meta-analysis (NMA) and to clarify the role of 18 F-FDG PET in the management of patients with PCL.

METHODS

PubMed, EMBASE, and Cochrane Library were searched for the studies evaluating the performance of preoperative imaging modalities for identifying malignant PCLs. The NMA was performed for 4 representative categories of various imaging modalities in terms of diagnostic performance for differentiating malignant from benign PCL and intraductal papillary mucinous neoplasms only as a subgroup analysis. To calculate the probability of each imaging modality being the most effective diagnostic method, the surface under the cumulative ranking curve values were obtained.

RESULTS

A total of 1018 patients from 17 direct comparison studies using 2 or more preoperative imaging modalities were included for differentiating malignant from benign PCL. The positive predictive value (PPV) and accuracy of 18 F-FDG PET were significantly higher than that of CT (PPV: odds ratio [OR], 2.66; 95% credible interval [CrI], 1.21-6.17; accuracy: OR, 2.63; 95% CrI, 1.41-5.38) or MRI (PPV: OR, 2.50; 95% CrI, 1.09-6.26; accuracy: OR, 2.50; 95% CrI, 1.28-5.47) in all PCLs, as well as in the subgroup analysis for intraductal papillary mucinous neoplasm only. 18 F-FDG PET showed the highest surface under the cumulative ranking curve values in all diagnostic performance areas of sensitivity, specificity, PPV, negative predictive value, and accuracy, followed by MRI or CT.

CONCLUSIONS

The results from this NMA suggest that 18 F-FDG PET is the best preoperative imaging modality for differentiating malignant from benign PCLs and that it can be used for the preoperative evaluation of PCLs.

Association Between Size of Dominant Candidate Lesion on Four-Dimensional CT and Four-Gland Hyperplasia among Patients with Primary Hyperparathyroidism

BACKGROUND

Four-dimensional (4D) CT localization allows minimally invasive parathyroidectomy as treatment for primary hyperparathyroidism (PHPT), but false positive localization is frequent. We sought to characterize the ability of 4D CT to predict four-gland hyperplasia (HP) based on the size of candidate lesions.

STUDY DESIGN

We retrospectively analyzed patients with PHPT who underwent 4D CT imaging and parathyroidectomy between 2014 and 2020 from a prospectively collected institutional database. The cohort was stratified into two groups, HP vs single adenoma (SA) and double adenoma (DA), based on operative findings and pathology. Logistic regression models assessed the association between the greatest diameter of the dominant candidate lesion on 4D CT and the outcomes of four-gland hyperplasia vs SA and DA.

RESULTS

Among a cohort of 240 patients, 41 were found to have HP, and 199 had adenomas (SA = 155, DA = 44). Patients with HP were less likely to have a preoperative calcium level greater than 1 mg/dL above the upper limit of normal compared with patients with adenomas (63% vs 81%, p = 0.02) and more likely to report symptoms (61% vs 43%, p = 0.04). After adjusting for BMI, we found an estimated 13% reduction in odds of HP for every 1-mm increase in the greatest diameter of dominant candidate lesions identified on 4D CT scan (odds ratio 0.87, 95% CI 0.78 to 0.96, p = 0.009).

CONCLUSIONS

A smaller size of the dominant lesion on 4D CT scan is associated with an increased risk of HP in PHPT. Use of 4D CT imaging localization may provide evidence for differentiating HP from adenomas.

Contemporary Multimodality Imaging of Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a disorder characterized by hypercalcemia and an elevated or inappropriately normal parathyroid hormone level. Classic features include bone pain, fractures, renal impairment, nephrolithiasis, and mental disturbance. However, most cases of PHPT are now asymptomatic at diagnosis or associated with nonspecific neurocognitive changes. The most frequent cause of PHPT is a solitary adenoma that secretes parathyroid hormone without the normal suppressive effect of serum calcium. A smaller number of cases can be attributed to multigland disease. Parathyroidectomy is curative and is considered for nearly all affected patients. Although PHPT is primarily a clinical and biochemical diagnosis, imaging is key to the localization of adenomas, which can lie in conventional locations adjacent to the thyroid gland or less commonly at ectopic sites in the neck and mediastinum. In addition, accurate localization facilitates the use of a minimally invasive or targeted surgical approach. Frequently used localization techniques include US, parathyroid scintigraphy, and four-dimensional CT. Second- and third-line modalities such as MRI, PET/CT, and selective venous sampling with or without parathyroid arteriography can increase confidence before surgery. These localization techniques, along with the associated technical aspects, relative advantages, and drawbacks, are described. Local expertise, patient factors, and surgeon preference are important considerations when determining the type and sequence of investigation. A multimodality approach is ultimately desirable, particularly in challenging scenarios such as multigland disease, localization of ectopic adenomas, and persistent or recurrent PHPT. Online supplemental material is available for this article. ^©RSNA, 2022.

Management and Long-Term Follow-Up of Hyperparathyroidism in Multiple Endocrine Neoplasia Type 1: Single Center Experience

Background: Primary hyperparathyroidism (PHPT) in the most common and earliest manifestation of multiple endocrine neoplasia type-1 (MEN1). Epidemiological data have been reported in MEN1 patients but data on long-term follow-up focusing on PHPT are scarce. Methods: In this retrospective cohort study, we included patients diagnosed with MEN1-related PHPT that were under regular follow-up in our institution. Results: Data on 68 patients (39 males), with a mean age at MEN1-diagnosis of 39 ± 13.06 years, were analyzed. Pancreatic neuroendocrine tumors were encountered in 82% (71% nonsecreting) followed by pituitary adenomas in 66% (49% nonsecreting). Mean age at PHPT diagnosis was 35.2 ± 4.0 years. Parathyroidectomy was performed in 57 patients (82.3%), of whom 56% achieved long-term remission, while 12.2% and 31.5% had persistent and recurrent disease, respectively (median follow-up of 4 years; range 1–21 years). Cinacalcet restored serum calcium levels in 33.8%, both as first and as a second line treatment. Permanent hypoparathyroidism occurred in 19.2%. MEN1 pathogenic variants were identified in 77.2% of the tested individuals, but no genotype-phenotype associations were reported. Conclusions: MEN1-related PHPT involves a multiglandular disease and its management remains a therapeutic challenge, as recurrent disease can develop even after 20 years of follow-up. Prolonged follow-up of these patients at referral centers is critical for their optimal management.

Ultrasound Identification of Normal Parathyroid Glands

Ultrasound has become indispensable for identification of thyroid and parathyroid pathology, but normal parathyroid glands have historically been considered too subtle to accurately detect. Inability to identify and protect parathyroid glands can result in hypoparathyroidism and hypocalcemia during thyroidectomy surgery as well as misinterpretation of central neck structures in the postoperative neck. Advances in ultrasound resolution have opened the door to novel applications for this technology. In this study, we report the first surgeon-performed ultrasound identification of normal parathyroid glands in a series of 6 patients, confirmed by parathyroid tissue aspirate or parathyroid autofluorescence. Recognition of normal parathyroid glands using ultrasound can be valuable for preventing postoperative hypoparathyroidism and in increasing the accuracy of postsurgical ultrasound surveillance.