The efficacy of fluorine-18-choline PET/CT in comparison with 99mTc-MIBI SPECT/CT in the localization of a hyperfunctioning parathyroid gland in primary hyperparathyroidism

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.

Is intraoperative parathyroid monitoring during minimally invasive parathyroidectomy still justified?

Introduction

Primary hyperparathyroidism (PHPT) is the third most common endocrine disease. With parathyroidectomy, a cure rate of over 95% at initial surgery is reported. Localization of the abnormal parathyroid gland is critical for the operation to be successful. The aim of this study is to analyze data of patients with single gland disease (SGD) and positive concordant localization imaging undergoing minimally invasive parathyroidectomy (MIP) and intraoperative parathyroid hormone monitoring (IOPTH) to evaluate if IOPTH is still justified in patients with localized SGD.

Methods

A retrospective database analysis of all minimally invasive operations with IOPTH for PHPT and positive concordant localization in ultrasound (US) and 99mTc-sestamibi scintigraphy (MIBI) between 2016-2021. When both US and MIBI were negative, patients underwent either choline or methionine PET-CT. The patients were also analyzed a second time without applying IOPTH.

Results

In total, 198 patients were included in the study. The sensitivity of US, MIBI and PET-CT was 96%, 94% and 100%, respectively. Positive predictive value was 88%, 89% and 94% with US, MIBI and PET-CT, respectively. IOPTH was true positive in 185 (93.4%) patients. In 13 (6.6%) patients, no adequate IOPTH decline was observed after localizing and extirpating the assumed enlarged parathyroid gland. Without IOPTH, the cure rate decreased from 195 (98.5%) to 182 (92%) patients and the rate of persisting disease increased from 2 (1.0%) to 15 (7.5%) patients.

Conclusion

Discontinuing IOPTH significantly increases the persistence rate by a factor of 7.5 in patients with concordantly localized adenoma. Therefore, IOPTH appears to remain necessary even for this group of patients.

Comparison of Neck Ultrasonography, Dual Phase 99mTc-Sestamibi with early SPECT-CT & 18F-Fluorocholine PET-CT as First Line Imaging in Patients with Primary Hyperparathyroidism

Introduction

Successful surgical treatment for primary hyperparathyroidism requires accurate localization of abnormal parathyroid tissue in terms of location and number. Imaging is important for localizing the parathyroid adenoma, and there has been significant interest in 18F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) for this purpose.

Aim

This study attempted to ascertain the utility of 18F-FCH PET/CT as a first-line investigation in preoperative localization of abnormal parathyroid tissue in primary hyperparathyroidism, in comparison with 99mTc-sestamibi dual-phase scintigraphy with early single-photon emission computed tomography (SPECT)/CT and neck ultrasonography.

Materials and Methods

Fifty-five patients with biochemical features of primary hyperparathyroidism were enrolled in this study. They underwent neck ultrasonography, 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT, and 18F-FCH PET/CT for localization of parathyroid lesions. Thirty-three patients underwent surgical resection of the detected lesions. For two patients, clinical and biochemical follow-up was used as a gold standard.

Results

A total of 40 lesions were resected in the 33 patients who underwent surgery. A further two lesions were localized in two patients with clinical and biochemical follow-up as the gold standard. Of these 42 lesions, 41 were detected in preoperative imaging and 1 lesion was noted intraoperatively and resected. 41/42 lesions were detected by 18F-FCH PET/CT (detection rate: 97.6%), 33/42 by 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT (detection rate: 78.5%), and 30/42 by neck ultrasonography (detection rate: 71.4%).

Conclusion

Detection rates on 18F-FCH PET/CT were superior to both 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT and neck ultrasonography in preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism.

18F-fluorocholine PET/MRI versus ultrasound and sestamibi for the localization of parathyroid adenomas

PURPOSE

Accurate preoperative localization is imperative to facilitate a minimally invasive parathyroidectomy (MIP) in primary hyperparathyroidism (pHPT). This study aims to compare the diagnostic value of standard-of-care localization techniques (ultrasound [US] and 99mTechnetium (99mTc) -sestamibi scintigraphy) to [F-18]-fluorocholine positron emission tomography/magnetic resonance imaging (FCH-PET/MRI) to determine the additional clinical usefulness of PET/MRI in a Canadian cohort.

METHODS

We conducted a prospective, appropriately powered, study to compare the diagnostic value of -FCH PET/MRI to that of the US and 99mTc-sestamibi scintigraphy for localization of parathyroid adenomas in a patient with pHPT. The primary outcome was the per-lesion sensitivity and positive predictive value (PPV) of FCH-PET/MRI, US, and 99mTc-sestamibi scintigraphy. Intraoperative surgeon localization, parathormone levels, and histopathological findings were used as reference standards.

RESULTS

Forty-one patients underwent FCH-PET/MRI of which 36 patients had parathyroidectomy. In these 36 patients, 41 parathyroid lesions were histologically confirmed as adenomas or hyperplastic glands. Per-lesion sensitivity of FCH-PET/MRI was 82.9% and of US and 99mTc-sestamibi scintigraphy combined at 50.0%, respectively. The sensitivity of FCH-PET/MRI was superior to that of US and 99mTc-sestamibi scintigraphy (p = 0.002). In the 19 patients in whom both US and 99mTc-sestamibi scintigraphy were negative, PET/MRI correctly identified the parathyroid adenoma in 13 patients (68%).

CONCLUSIONS

FCH-PET/MRI is a highly accurate imaging modality for localization of parathyroid adenomas in a tertiary center in North America. It is a superior functional imaging modality to 99mTc-sestamibi scintigraphy alone and more sensitive for localization of parathyroid lesions than US and 99mTc-sestamibi scintigraphy combined. This imaging modality could become the most valuable preoperative localization study given its superior performance in localizing parathyroid adenomas.

Surgery for primary hyperparathyroidism in Germany, Switzerland, and Austria: an analysis of data from the EUROCRINE registry

PURPOSE

EUROCRINE is an endocrine surgical register documenting diagnostic processes, indication for surgical treatment, surgical procedures, and outcomes. The purpose was to analyse data for PHPT in German speaking countries regarding differences in clinical presentation, diagnostic workup, and treatment.

METHODS

All operations for PHPT performed from 07/2015 to 12/2019 were analysed.

RESULTS

Three thousand two hundred ninety-one patients in Germany (9 centres; 1762 patients), Switzerland (16 centres; 971 patients) and Austria (5 centres; 558 patients) were analysed. Hereditary disease was seen in 36 patients in Germany, 16 patients in Switzerland and 8 patients in Austria. In sporadic disease before primary operation, PET-CT showed the highest sensitivity in all countries. In re-operations, CT and PET-CT achieved the highest sensitivities. The highest sensitivity of IOPTH was seen in Austria (98.1%), followed by Germany (96.4%) and Switzerland (91.3%). Operation methods and mean operative time reached statistical significance (p<0.05). Complication rates are low. Overall, 656 (19.9%) patients were asymptomatic; the remainder showed bone manifestations, kidney stones, fatigue and/or neuropsychiatric symptoms.

CONCLUSION

Early postoperative normocalcaemia ranged between 96.8 and 97.1%. Complication rates are low. PET-CT had the highest sensitivity in all three countries in patients undergoing primary operation as well as in Switzerland and Austria in patients undergoing re-operation. PET-CT could be considered a first-line preoperative imaging modality in patients with inconclusive ultrasound examination. The EUROCRINE registry is a beneficial and comprehensive data source for outcome analysis of endocrine procedures on a supranational level.

Evolving Role of [18F]Flurocholine PET/CT in Assessing Primary Hyperparathyroidism: Can It Be Considered the First-Line Functional Imaging Approach?

The accurate detection of hyperfunctioning parathyroid tissue (HFPT) is pivotal in the preoperative assessment of primary hyperparathyroidism (PHPT). PET/CT using [¹⁸F]fluorocholine ([¹⁸F]FCH) showed superior diagnostic performance compared to conventional functional imaging modalities. We aimed to evaluate the diagnostic performance of [¹⁸F]FCH PET/CT as a first-line functional imaging approach in patients with clinically diagnosed PHPT. The imaging and clinical data of 321 PHPT patients, including 271 overt PHPT and 50 mild PHPT, who underwent [¹⁸F]FCH PET/CT as first-line imaging were analysed in this retrospective study. Histopathology was the reference standard. In case of no available histopathology evaluation (conservative management), imaging and clinical follow-ups were considered reference standards. In the overt group (n = 271), [¹⁸F]FCH PET/CT showed sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 0.99, 0.91, 1.00, 0.80, and 0.99, respectively. Regarding the correlation of the index lesions and initial laboratory data, all [¹⁸F]FCH PET/CT parameters (SUVs, SULs, and mSAD) were significantly correlated with the serum iPTH level. Additionally, SUVmax, SULpeak, and mSAD were significantly associated with the serum calcium level. In the mild group (n = 50), [¹⁸F]FCH PET/CT showed a sensitivity, specificity, PPV, NPV, and accuracy of 0.93, 0.75, 0.95, 0.67, and 0.90. In conclusion, [¹⁸F]FCH PET/CT revealed high diagnostic performance in the detection of HFPTs and the potential to be considered as a first-line imaging modality in the assessment of PHPT, including both overt and mild types. However, its cost-benefit concerning the clinical impact of early PHPT detection should be investigated in future studies.

An Unusual Case of Primary Hyperparathyroidism: Case Report of a Bifocal Intrathyroidal Parathyroid Carcinoma

Intrathyroidal parathyroid carcinoma is an extremely rare cause of primary hyperparathyroidism. We reported a 51-year old woman who presented symptoms of hypercalcemia. 99mTc sestamibi single-photon emission computed tomography/computed tomography (CT) revealed a large hypermetabolic nodule in the left thyroid lobe suggestive of hyperfunctioning parathyroid tissue. 11C-methionine positron emission tomography/computed tomography (PET/CT) and 18F-fluorocholine PET/CT confirmed the nodule in the left thyroid lobe and also revealed a hypermetabolic activity on the posterior surface of the lower left pole. The patient underwent a total thyroidectomy and parathyroidectomy, and a diagnosis of bifocal intrathyroidal parathyroid carcinoma was confirmed. We present the first reported case of bifocal intrathyroidal carcinoma and discuss the discordant imaging results.

Comparison of [18F]fluorocholine PET/CT with [99mTc]sestamibi and ultrasonography to detect parathyroid lesions in primary hyperparathyroidism: a prospective study

BACKGROUND

Primary hyperparathyroidism is a common endocrine disorder produced by the increase of parathyroid hormone (PTH) due to a benign adenoma of a single parathyroid gland, or as multiple gland hyperplasia, or as a rare malignant tumor. Preoperative imaging scans are frequently necessary for the minimally invasive parathyroidectomies to identify the location of enlarged parathyroid glands and to design the procedure.

METHODS

The diagnostic reliability of [18F]fluorocholine positron emission tomography/computed tomography (FCH PET/CT), [99mTc]sestamibi [multiplexed ion beam imaging (MIBI)] and cervical ultrasonography was analyzed in 37 patients diagnosed with primary hyperparathyroidism undergoing minimally invasive parathyroidectomy. The three preoperative imaging techniques were correlated with intraoperative and histopathological findings as well as changes in biochemical parameters (serum PTH and calcium levels). Statistical analysis was carried out with SPSS version 24.0.

RESULTS

In 30 of 37 patients (81.1%), FCH PET/CT correctly localized the pathological gland. In 3 cases of ectopic adenomas, the accuracy of the techniques was 100% (3/3) for FCH PET/CT, 66.7% (2/3) for MIBI, and 33.3% (1/3) for neck ultrasonography. Neither neck ultrasonography nor MIBI were able to locate pathological parathyroid glands in those patients with multiglandular disease, while FCH PET/CT correctly located one patient (1/3, 33.3%) with two adenomas and 3 patients (3/6, 50.0%) with hyperplasia. The three imaging techniques, FCH PET/CT, MIBI and neck ultrasound yielded a sensitivity of 92.1%, 57.9% and 32.4%, a positive predictive value of 94.6%, 84.6% and 78.6%, and a diagnostic accuracy of 96.4%, 85.7% and 79.0%, respectively.

CONCLUSIONS

In this group of patients diagnosed with primary hyperparathyroidism, FCH PET/CT was superior to MIBI and neck ultrasound in detecting adenomas, particularly in the presence of ectopic glands or multiglandular disease.

Update on Preoperative Parathyroid Localization in Primary Hyperparathyroidism

Parathyroidectomy is the treatment of choice for primary hyperparathyroidism when the clinical criteria are met. Although bilateral neck exploration is traditionally the standard method for surgery, minimally invasive parathyroidectomy (MIP), or focused parathyroidectomy, has been widely accepted with comparable curative outcomes. For successful MIP, accurate preoperative localization of parathyroid lesions is essential. However, no consensus exists on the optimal approach for localization. Currently, ultrasonography and technetium-99m-sestamibi-single photon emission computed tomography/computed tomography are widely accepted in most cases. However, exact localization cannot always be achieved, especially in cases with multiglandular disease, ectopic glands, recurrent disease, and normocalcemic primary hyperparathyroidism. Therefore, new modalities for preoperative localization have been developed and evaluated. Positron emission tomography/computed tomography and parathyroid venous sampling have demonstrated improvements in sensitivity and accuracy. Both anatomical and functional information can be obtained by combining these methods. As each approach has its advantages and disadvantages, the localization study should be deliberately chosen based on each patient's clinical profile, costs, radiation exposure, and the availability of experienced experts. In this review, we summarize various methods for the localization of hyperfunctioning parathyroid tissues in primary hyperparathyroidism.

Preoperative imaging in primary hyperparathyroidism: Are 11 C-Choline PET/CT and 99m Tc-MIBI/123 Iodide subtraction SPECT/CT interchangeable or do they supplement each other?

OBJECTIVE

Preoperative location of hyperfunctioning parathyroid glands (HPGs) is vital when planning minimally invasive surgery in patients with primary hyperparathyroidism (PHPT). Dual-isotope subtraction scintigraphy with ^99m Tc-MIBI/¹²³ Iodide using SPECT/CT and planar pinhole imaging (Di-SPECT) has shown high sensitivity, but is challenged by high radiation dose, time consumption and cost. ¹¹ C-Choline PET/CT (faster with a lower radiation dose) is non-inferior to Di-SPECT. We aim to clarify to what extent the two are interchangeable and how often there are discrepancies.

DESIGN

This is a prospective, GCP-controlled cohort study.

PATIENTS AND MEASUREMENTS

One hundred patients diagnosed with PHPT were included and underwent both imaging modalities before parathyroidectomy. Clinical implications of differences between imaging findings and negative imaging results were assessed. Surgical findings confirmed by biochemistry and pathology served as reference standard.

RESULTS

Among the 90 patients cured by parathyroidectomy, sensitivity was 82% (95% confidence interval [CI]: 74%-88%) and 87% (95% CI: 79%-92%) for Choline PET and Di-SPECT, respectively, p = .88. In seven cases at least one imaging modality found no HPG. Of these, neither modality found any true HPGs and only two were cured by surgery. When a positive finding in one modality was incorrect, the alternative modality was correct in approximately half of the cases.

CONCLUSION

Choline PET and Di-SPECT performed equally well and are both appropriate as first-line imaging modalities for preoperative imaging of PHPT. When the first-line modality fails to locate an HPG, additional preoperative imaging with the alternate modality offers no benefit. However, if parathyroidectomy is unsuccessful, additional imaging with the alternate modality has merit before repeat surgery.

Performance of quantitative measurements in [18F]fluorocholine positron emission tomography/computed tomography for parathyroid imaging (P2TH study)

Objective

[¹⁸F]Fluorocholine positron emission tomography/computed tomography (PET/CT) is used frequently in addition to [^99mTc]Tc-Sestamibi scintigraphy and ultrasonography for the location of hyperfunctioning parathyroid glands. The aim of this study is to evaluate the performance of quantitative criteria in [¹⁸F]fluorocholine PET/CT for localization of hyperfunctioning parathyroid glands. The secondary objective is to highlight a correlation between the detection rate of [¹⁸F]fluorocholine PET/CT and serum parathyroid hormone (PTH) level.

Materials and methods

In two academic centers, we retrospectively included patients with biological hyperparathyroidism (HPT) and who had [¹⁸F]fluorocholine PET/CT. After a visual analysis, to measure the overall performance of [¹⁸F]fluorocholine PET/CT, a blind reading was carried out with standardized measurements of maximum standardized uptake value (SUV_max), liver ratio, thyroid ratio, and size ratio. We analyzed the quantitative criteria of [¹⁸F]fluorocholine PET/CT compared to the histological results, in particular to identify differences between adenomas and hyperplasias. We compared the performance of each quantitative criterion to the overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of [¹⁸F]fluorocholine PET/CT. The detection rate of hyperfunctioning parathyroid glands was calculated in subgroups of serum PTH level.

Results

The quantitative criteria in [¹⁸F]fluorocholine PET/CT were measured for 120 patients (135 lesions). The areas under the receiver operating characteristic (ROC) curve representing SUV_max and liver ratio were significantly increased. The optimal cut-off values represented by the maximum Youden index was >4.12 for SUV_max and >27.4 for liver ratio. Beyond certain threshold values of SUV_max (>4.12) or liver ratio (>38.1), all the lesions were histologically proven adenomas. SUV_max and liver ratio were significantly higher for adenomas than for hyperplasias and differential diagnosis (p = 0.0085 and p = 0.0002). The positivity of [¹⁸F]fluorocholine PET/CT was correlated with PTH level. Detection rates were 55.56, 75.56, and 87.5%, respectively, for serum PTH < 70, 70 to 120, and >120 ng/ml.

Conclusion

Semi-quantitative measurements (SUV_max and liver ratio) should be considered as additional tools in interpretation of [¹⁸F]fluorocholine PET/CT. These quantitative parameters have lower overall performance but higher specificity than overall visual analysis in identifying an adenoma. Above certain threshold values, all lesions are adenomas. [¹⁸F]fluorocholine PET/CT confirms excellent performance for the detection of hyperfunctional parathyroids. For serum PTH levels < 70 ng/ml, the detection rate of [¹⁸F]fluorocholine PET/CT is strongly decreased.

Functional imaging for hyperparathyroidism

Once hyperparathyroidism has been proven, the goal of parathyroid functional imaging is to identify one or more pathological glands in view of guiding a possibly targeted surgical procedure, while maximizing the chances for recovery. Currently, parathyroid radionuclide imaging is based on two techniques, parathyroid scintigraphy and ¹⁸F-fluorocholine - positron emission tomography (PET). The main radiopharmaceutical in scintigraphy is ^99mTc-sestamibi, which can be used alone, in the dual-phase parathyroid scan, or in comparison with a thyroid radiotracer, pertechnetate (NaTcO₄) or iodine 123 (dual-tracer method). The acquisitions can be planar and/or tomographic (SPECT). It is now recognized that the ^99mTc-sestamibi - iodine 123 dual-tracer method is more efficient than the dual-phase scan, while SPECT-CT improves the sensitivity and specificity of the scintigraphy. This imaging and cervical ultrasonography are considered to be the two first-line reference techniques in preoperative assessment of hyperparathyroidism. More recently developed, ¹⁸F-fluorocholine detected by PET-CT has shown excellent performance, at least equal to that of scintigraphy. Initially considered as a second-line technique, its advantages over scintigraphy have prompted some authors to suggest it as the only examination to be performed in preoperative assessment of hyperparathyroidism. That said, due to a lack of specificity in ¹⁸F-fluorocholine uptake, which has been observed on inflammatory lesions and, particularly, in the mediastinal lymph nodes, and given the absence of simultaneous comparison of thyroid function, this strategy remains contested, and possibly reserved for patients without any associated thyroid pathology; large-scale evaluation would be justified.

Diagnostic performances of cervical ultrasound, sestamibi scintigraphy and contrast-enhanced 18F-fluorocholine positron emission tomography in primary hyperparathyroidism

Purpose: Preoperative localization of pathological parathyroids is crucial for a minimally invasive treatment of primary hyperparathyroidism (PHPT). This study compares contrast-enhanced ¹⁸F-fluorocholine positron emission tomography (FCH-PET/CT), cervical ultrasound (CU) and conventional scintigraphic imaging modalities (MIBI scintigraphy), combined and individually for preoperative localization of hyper-functional parathyroids in PHPT. The gold standard is histological examination. Methods: Data from consecutive patients with a clinical suspicion of PHPT were retrospectively collected. All three imaging modalities were systematically performed. MIBI scintigraphy, consisted of ^99mTc-sestamibi/¹²³I-sodium iodide SPECT/CT, ^99mTc-sestamibi/¹²³I-sodium iodide planar subtraction imaging and ^99mTc-sestamibi planar dual-phase imaging. The ability of FCH-PET/CT, CU and MIBI scintigraphy to identify a hyper-functional parathyroid and specify the side or identify an ectopic location was noted. Patients underwent surgical exploration if at least one exam was positive. CU + MIBI scintigraphy combined was considered as a positive test if CU and MIBI scintigraphy separately showed a hyper-functional parathyroid gland on the same side, or the same ectopic location, and negative in other cases. The composite judgment criterion for pathological parathyroid combined histological analysis and normalization of PTH and calcium levels. Results: 149 pathological parathyroids were found in 143 of the 144 included patients. FCH-PET/CT diagnosed 148/149 pathological parathyroids. Only four false positives and one false negative were found. The FCH-PET/CT sensitivity of 99.3% was superior to that of CU at 75.2% (P < 0.0001), MIBI scintigraphy at 65.1% (P < 0.0001) and CU + MIBI scintigraphy combined at 89.9%, (P = 0.0009). 5/5 ectopic locations were diagnosed by FCH-PET/CT, 2/5 by MIBI and 0/5 by CU. Accuracy was better for FCH-PET/CT at 98% than CU at 84% (P < 0.0001), MIBI scintigraphy at 81% (P < 0.0001) or CU + MIBI scintigraphy at 91% (P < 0.0001). Among the 72 (50%) patients who had a negative CU + MIBI scintigraphy combined test, FCH-PET/CT correctly identified hyper-functional thyroids in 70 (97.2%) patients. Average FCH-PET/CT hyperfunctional parathyroid uptake was higher than the adjacent thyroid (SULmax 6.45 vs 2.15) (P < 0.0001). Conclusion: Accuracy of FCH-PET/CT is higher than CU and MIBI scintigraphy for localization of hyper-functional parathyroids, justifying the systematic use of FCH-PET/CT as the first-line method for PHPT diagnosis.

18F-Choline PET/CT, MRI, and Software-Based Image Fusion Analysis in Patients With Primary Hyperparathyroidism

PURPOSE

The aim of this study was to evaluate the diagnostic performance of 18F-choline PET and MRI in patients with primary hyperparathyroidism. Furthermore, the additional value of software-based PET/MRI scan fusion was analyzed.

PATIENTS AND METHODS

This retrospective study includes 42 patients (38 women) with an age between 32.5 and 79.1 years. PET/CT scans were performed on a dedicated system after injection of 250 to 350 MBq 18F-choline. For the MRI examination, T1-weighted images of the cervical region were used. The image fusion was made by anatomical coregistration using an automated algorithm based on mutual information.

RESULTS

A total of 46 lesions were discovered and histologically confirmed in 42 patients. Histopathological examination revealed 38 adenomas and 8 hyperplasias. This means that, in 4 of these 42 patients, 2 lesions per patient were discovered. PET/CT also detected 46 abnormal findings, but only 43 were correctly recognized, whereas the other 3 were false-positive (FP). Six lesions could not be detected correctly: 3 were FP and 3 false-negative, which resulted in a sensitivity of 93.5% and a specificity of 97.5%. The site-specific evaluation showed 18 true-positive enlarged parathyroid glands with MRI, but also produced 13 FP findings and failed to detect 28 lesions; the sensitivity and specificity are thus 39.1% and 89.3%, respectively. The difference in detection rate between 18F-choline PET/CT and MRI was statistically significant (P < 0.001).

CONCLUSIONS

18F-choline PET/CT is clearly superior to MRI for localization diagnostics in primary hyperparathyroidism. Image fusion of both modalities can be helpful for more precise anatomical assignment.

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

Importance

Accurate preoperative localization of primary hyperparathyroidism (pHPT) is an important and challenging issue for a successful parathyroidectomy. Although new imaging modalities have been introduced during the past decade, direct comparative studies on advanced imaging techniques are limited.

Objective

To compare the performance of different preoperative imaging modalities for the localization of pHPT by performing a network meta-analysis (NMA).

Data Sources

PubMed, Embase, and the Cochrane Library were searched from the earliest available indexing date through September 28, 2020.

Study Selection

The inclusion criteria were diagnostic tests with sensitivities of 2 or more different preoperative imaging modalities for the same indivduals.

Data Extraction and Synthesis

Two researchers independently reviewed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension statement of health care intervention guidelines for network meta-analyses.

Main Outcomes and Measures

After classifying various imaging modalities into 8 representative imaging categories, the pooled estimation between the odds ratio and 95% credible intervals (CrIs) was calculated in the sensitivity for localization of pHPT. 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 8495 patients from 119 direct comparative studies using 2 or more imaging modalities for localization of pHPT were included. The sensitivity of choline positron emission tomography and computed tomography (PET-CT) was significantly higher than that of technetium 99m sestamibi single-photon emission computed tomography (MIBI SPECT) in both patient-based and lesion-based analyses (patient-based analysis: odds ratio, 5.22; 95% CrI, 2.36-11.80; lesion-based analysis: odds ratio, 17.70; 95% CrI, 5.79-60.10). Among 8 representative imaging modality categories, choline PET-CT showed the highest SUCRA value in both patient-based and lesion-based analyses. In patient-based analysis after 2010, choline PET-CT showed the highest SUCRA value, followed by the CT category, although MIBI SPECT had the highest SUCRA value in analysis before 2009.

Conclusions and Relevance

The results from this network meta-analysis suggest that choline PET-CT showed the best performance in both patient-based and lesion-based analyses and that choline PET-CT would be the best preoperative imaging modality for localization of pHPT.

Preoperative imaging predicts change in bone mineral density after parathyroidectomy for primary hyperparathyroidism

BACKGROUND

Bone Mineral Density (BMD) improves after parathyroidectomy (PTX), but data on factors that predict bone recovery are limited. No studies have evaluated if preoperative imaging findings are associated with postoperative change in BMD. We hypothesized that larger, metabolically active glands would be associated with greater increase in BMD after PTX.

METHODS

Patients with primary hyperparathyroidism (PHPT) who underwent combined Tc-99m sestamibi and 4D-CT imaging prior to PTX and had pre- and post-operative dual-energy X-ray absorptiometry (DXA) at our institution were considered for inclusion. Retrospectively, data were collected from imaging studies on each parathyroid gland, including estimated weight (using the ellipsoid formula) and contrast enhancement on 4D-CT as well as sestamibi avidity. Total estimated parathyroid weight was calculated. The main outcome measure was the percent change in BMD at the lumbar spine (LS) from pre- to post-operative DXA. Predictors of change in BMD at the LS were assessed.

RESULTS

Complete DXA data was available in 25 patients. Median total parathyroid weight on 4D-CT was 270 mg, and mean change in BMD at the LS was 2.4 ± 4.3%. The increase in BMD was best predicted by higher preoperative serum calcium (p = 0.01), greater estimated parathyroid weight (p = 0.001), sestamibi avidity (p = 0.03), and increased time between DXA scans (p = 0.03) in the multivariable model (R² = 0.79, p < 0.0001).

CONCLUSION

In PHPT, higher preoperative serum calcium, parathyroid gland weight on imaging, and sestamibi avidity are associated with greater increases in BMD after curative PTX. These findings suggest that larger, metabolically active adenomas may mobilize more calcium from bone.

A retrospective analysis of the diagnostic performance of 11C-choline PET/CT for detection of hyperfunctioning parathyroid glands after prior negative or discordant imaging in primary hyperparathyroidism

Background

Identifying the correct location of a parathyroid adenoma in patients with primary hyperparathyroidism (pHPT) is crucial as it can guide surgical treatment. This study aimed to determine the diagnostic performance of ¹¹C-choline PET/CT in patients with pHPT as a next in-line scan after primary negative or discordant first-line imaging.

Methods

This was a retrospective single-center cohort study. All patients with pHPT that were scanned utilizing ¹¹C-choline PET/CT, after prior negative or discordant imaging, between 2015 and 2019 and who subsequently underwent parathyroid surgery were included. The results of the ¹¹C-choline PET/CT were evaluated lesion-based, with surgical exploration and histopathological examination as the gold standard.

Results

In total, 36 patients were included of which three patients were known to have Multiple Endocrine Neoplasia (MEN) syndrome. In these 36 patients, 40 lesions were identified on ¹¹C-choline PET/CT and 37 parathyroid lesions were surgically removed. In 34/36 (94%) patients a focused parathyroidectomy was performed, in one patient a cervical exploration due to an ectopically identified adenoma, and in one patient a bilateral exploration was performed because of a double adenoma. Overall, per-lesion sensitivity of ¹¹C-choline PET/CT was 97%, the positive predictive value was 95% and the accuracy was 94% for all parathyroid lesions.

Conclusions

In patients with pHPT and prior negative or discordant first-line imaging results, pathological parathyroid glands can be localized by ¹¹C-choline PET/CT with high sensitivity and accuracy.

Diagnostic Value of Choline PET in the Preoperative Localization of Hyperfunctioning Parathyroid Gland(s): A Comprehensive Overview

Hyperparathyroidism is a metabolic disorder characterized by the excessive production of the parathyroid hormone. The diagnosis is based on clinical and laboratory data. In most cases the only treatment is surgery and a correct preoperatory localization of the hyperfunctioning parathyroid gland(s) is essential. Currently, ultrasonography combined with [^99mTc]Tc-MIBI parathyroid scintigraphy, optionally associated with single photon emission computed tomography/computed tomography (SPECT/CT), represent the standard preoperative imaging. In recent years, a number of studies have evaluated the potential role of choline positron emission tomography (PET) in hyperparathyroidism with promising results. Most of the recent evidence underlined its higher sensitivity and diagnostic accuracy in the localization of hyperfunctioning parathyroid glands. Choline PET has a higher spatial resolution that is useful for the detection of smaller parathyroid glands and it also has shorter examination times and favorable radiation exposure. These are just a few of the aspects that support it to overcome traditional imaging. Moreover, from the preliminary data, the choline uptake mechanism seems to also have an impact on its better performance. For these reasons, if first used as second level imaging in patients with negative or inconclusive traditional imaging results, several authors have supported its use as a first line investigation. This comprehensive overview aims to provide an accurate description of the preliminary results available in the literature about the use of choline PET/CT in hyperparathyroidism and to compare these results with the performance of traditional imaging methods.

11C-Choline PET/CT vs. 99mTc-MIBI/123Iodide Subtraction SPECT/CT for Preoperative Detection of Abnormal Parathyroid Glands in Primary Hyperparathyroidism: A Prospective, Single-Centre Clinical Trial in 60 Patients

BACKGROUND

In patients with primary hyperparathyroidism (PHPT) locating hyperfunctioning glands (HPGs) is crucial when planning minimally invasive surgery. Dual-isotope subtraction scintigraphy with ^99mTc-MIBI/¹²³Iodide using SPECT/CT and planar pinhole imaging (Method A) has previously shown a sensitivity >93%. However, the method is costly and time consuming and entails a high radiation dose. ¹¹C-Choline PET/CT (Method B) is an appealing candidate method unencumbered by these disadvantages.

METHODS

Sixty patients with newly diagnosed PHPT participated and were scanned using both methods prior to parathyroidectomy. We investigated whether sensitivities of Method A and Method B are similar in a method-to-method comparison when using surgical findings as the true location.

RESULTS

At the patient level, sensitivities were (A) 0.98 (95% CI: 0.90-1.00) and (B) 1.00 (95% CI: 0.93-1.00). At the gland level, sensitivities were (A) 0.88 (95% CI: 0.78-0.94) and (B) 0.87 (95% CI: 0.76-0.92). With a non-inferiority margin of ∆ = -0.1, we found a 1-sided p-value < 0.001.

CONCLUSION

Our methods comparison study found that sensitivity of Method B was not inferior to Method A. We suggest that ¹¹C-Choline PET/CT is a clinically relevant first-choice candidate for preoperative imaging of PHPT and that Method B can likely replace Method A in the near future.

18F-choline PET/CT and PET/MRI in primary and recurrent hyperparathyroidism: a systematic review of the literature

The aims of the present systematic review were to: (1) assess the role of ¹⁸F-fluorocholine (FCH) positron emission tomography (PET) with computed tomography (CT) and PET with magnetic resonance imaging (MRI) in patients with biochemically known hyperparathyroidism; (2) compare the diagnostic performance of FCH PET/CT or PET/MRI with conventional morphological and functional imaging. A literature search until December 2019 was performed in the PubMed, Scopus and Web of Science databases, using the terms “choline” AND “PET” AND “hyperparathyroidism”. The search was conducted with and without the addition of filters (e.g., language: English only; type of article: original article; subjects: humans only) and selecting only articles published in the last 5 years. Twenty-three articles and 1112 patients were considered. Different FCH PET/CT acquisition protocols were adopted across the studies, using dynamic, early or delayed scans. FCH PET/CT proved more accurate than ultrasonography (US) or 99mTc-sestamibi single-photon emission tomography (SPET). PET/MRI also seemed to be more accurate than MRI alone in detecting benign parathyroid lesions. FCH PET/CT is more accurate than conventional morphological and functional imaging modalities (US or SPET) for the detection of benign parathyroid lesions. It could, therefore, be a reliable tool in both primary and recurrent hyperparathyroidism.

18F-Fluorocholine PET and Multiphase CT Integrated in Dual Modality PET/4D-CT for Preoperative Evaluation of Primary Hyperparathyroidism

The present retrospective study evaluates the diagnostic value of integrated ¹⁸F-Fluorocholine positron emission tomography/four-dimensional contrast-enhanced computed tomography (¹⁸F-FCH PET/4D-CT) as second-line imaging in preoperative work-up of primary hyperparathyroidism (pHPT), and compares ¹⁸F-FCH PET with 4D-CT. Patients with pHPT and negative/discordant first-line imaging addressed for integrated ¹⁸F-FCH PET/4D-CT were retrospectively selected. Sensitivity and detection rate (DR%) of ¹⁸F-FCH PET/CT, 4D-CT, and PET/4D-CT were calculated according to the per patient and per lesion analyses, and afterwards compared. Histology associated with a decrease more than 50% of perioperative parathyroid hormone (PTH) blood level was used as a gold standard. Persistent high serum PTH and calcium levels during a 6-month follow-up was considered as presence of pHPT in both operated and non-operated patients. 50 patients (55 glands) were included. 44/50 patients (88%) were surgically treated. On a per patient analysis, sensitivity was 93%, 80%, and 95%, and DR% was 82%, 68%, and 84%, respectively for PET/CT, 4D-CT, and PET/4D-CT. PET/CT was more sensitive than 4D-CT (p = 0.046). PET/4D-CT performed better than 4D-CT (p = 0.013) but was equivalent to PET/CT alone. On a per gland analysis, sensitivity PET/CT, 4D-CT, and PET/4D-CT was 88%, 66%, and 92%, and DR% was 79%, 57%, and 83%, respectively. PET/CT and PET/4D-CT were more sensitive than 4D-CT alone (p = 0.01, p < 0.001, respectively). However, PET/CT and PET/4D-CT performed similarly. In conclusion, ¹⁸F-FCH PET provides better identification of hyperfunctioning parathyroids than 4D-CT and the combination of both did not significantly improve diagnostic sensitivity. Further investigations involving larger populations are necessary to define the role of ¹⁸F-FCH PET/4D-CT as a “one-stop shop” second-line imaging in preoperative work-up of pHPT, especially considering the additional patient radiation exposure due to multi-phase CT.

18F-choline PET/4D CT in hyperparathyroidism: correlation between biochemical data and study parameters

BACKGROUND

Hyperparathyroidism (HPT) is characterised by increased levels of parathyroid hormone (HPT), surgical excision being the only definitive curative option. After establishing the need for surgery, it is essential to identify the parathyroid glands in the preoperative period to use a minimally invasive approach. Negativity and / or discrepancy in first-line studies (ultrasound and Tc-99m MIBI parathyroid scintigraphy) require more accurate images to reduce the likelihood of bilateral cervical exploration or reintervention.

OBJECTIVES

a) To demonstrate the sensitivity of ¹⁸F-fluorocholine (¹⁸F-choline) positron emission tomography (PET)/4D computed tomography (4D CT) in HPT. b) To check whether there is a correlation between calcaemia and preoperative PTH versus size and early and late SUVmax (Standardized Uptake Value) of the gland, determined by ¹⁸F-choline PET/4D CT and c) to study the behaviour of parathyroid lesions with intravenous contrast (IV).

MATERIAL AND METHODS

A total of 28 patients were included between 2016 and 2019 in a single institution. Prospective observational cohort study. Correlations were analysed using Pearson's coefficient for variables with normal distribution and Spearman (rho) for those with non-normal distribution. Anatomopathological analysis was the benchmark standard to determine sensitivity was. A p<.05 was interpreted as significant. STATA 13 software was used.

RESULTS

Of the 28 patients who underwent ¹⁸F-choline PET/4D CT, 18 were operated. Of the 26 lesions diagnosed by ¹⁸F-choline PET/4D CT as suggestive of parathyroid lesions, 23 corresponded to glandular disease (adenoma or hyperplasia) establishing a sensitivity of 88.5%. There was a correlation between the patient's preoperative PTH and the maximum size of the gland on ¹⁸F-choline PET/4D CT. (Spearman=.66; p=.0014). The parathyroid lesions showed, in addition to IV contrast enhancement, distinctive behavioural characteristics identified as highly suggestive.

CONCLUSIONS

18F-choline PET/CT 4D is an anatomical and functional study with high sensitivity in patients with HPT with negative or discrepant first-line studies. Preoperative PTH showed a correlation with maximum gland size on ¹⁸F-choline PET/CT 4D. Parathyroid lesions behave in a highly suggestive way and are enhanced by IV contrast.

Preoperative F-18 fluorocholine PET/CT for the detection of hyperfunctioning parathyroid glands in patients with secondary or tertiary hyperparathyroidism: comparison with Tc-99m sestamibi scan and neck ultrasound

OBJECTIVES

Currently, neck ultrasound is the preferred preoperative imaging in patients with secondary/tertiary hyperparathyroidism, and the use of Tc-99m sestamibi scan is limited in these patients. We conducted this study to compare the diagnostic utilities of F-18 fluorocholine PET/CT, Tc-99m sestamibi scintigraphy, and neck ultrasound for localizing hyperfunctioning parathyroid glands in secondary/tertiary hyperparathyroidism.

METHODS

We prospectively enrolled 30 dialysis patients with a diagnosis of secondary/tertiary hyperparathyroidism; of these, 27 participants underwent all three imaging modalities, including dual-phase F-18 fluorocholine PET/CT (PET acquired 5 and 60 min after tracer injection), dual-phase Tc-99 m sestamibi SPECT/CT, and neck ultrasound. All patients underwent parathyroidectomy after imaging. We compared the lesion-based sensitivity, specificity, and accuracy of the three image tools using histopathology as the reference.

RESULTS

A total of 27 patients (107 lesions) underwent all three imaging modalities and entered the final analysis. The lesion-based sensitivities of F-18 fluorocholine PET/CT, Tc-99m sestamibi, and ultrasound were 86%, 55%, and 62%, respectively (both p < 0.001, when comparing F-18 fluorocholine PET/CT to Tc-99 m sestamibi scan and to ultrasound). F-18 fluorocholine PET/CT, Tc-99m sestamibi, and ultrasound had similar specificities of 93%, 80%, and 87%, respectively. The accuracy of F-18 fluorocholine PET/CT (87%) was significantly higher than that of Tc-99m sestamibi (59%) and ultrasound (65%) (both p < 0.001). F-18 fluorocholine PET/CT identified more hyperplastic glands than ultrasound in 52% (14/27) patients. The sensitivity of F-18 fluorocholine PET/CT reached 95% for hyperplastic parathyroid masses as low as 200 mg.

CONCLUSIONS

F-18 fluorocholine PET/CT shows superior accuracy over the conventional imaging modalities in patients with secondary or tertiary hyperparathyroidism. The combination of F-18 fluorocholine PET/CT and neck ultrasound may enable better surgical planning in these patients.

REGISTRATION IDENTIFICATION NUMBER

NCT04316845.

The role of 18F-FCH PET/CT in patients with uremic hyperparathyroidism compared with 99mTc-sestaMIBI SPECT/CT and ultrasonography

BACKGROUND

The aim of this study was to evaluate the diagnostic efficacy of ¹⁸F-fluorocholine (¹⁸F-FCH) PET/CT for uremic hyperparathyroidism (uHPT) compared to ^99mTc-sestaMIBI SPECT/CT and ultrasonography (US).

METHODS

A total of 17 uHPT patients with stage 5 chronic kidney disease (CKD) were prospectively enrolled. All patients underwent US, ^99mTc-sestaMIBI SPECT/CT, and ¹⁸F-FCH within 2 months and received surgical treatment. Visual and quantitative methods were used for image analyses. Intraoperative localization and postoperative histological results of the reference standard as well as the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the three modalities were analyzed using Pearson's χ² tests. In addition, the diagnostic efficacy of ¹⁸F-FCH PET/CT for uHPT was evaluated. The relationships between PET parameters and laboratory parameters were assessed using the Spearman correlation coefficient.

RESULTS

A total of 63 parathyroid hyperplasia lesions were resected in 17 uHPT patients, and 53 lesions were detected using ¹⁸F-FCH PET/CT with no false-positive results. The sensitivity, specificity, accuracy, PPV, and NPV were 84.13%, 100%, 86.49%, 100%, and 52.38%, respectively. In comparison, the corresponding values for ^99mTc-sestaMIBI SPECT/CT and US were 63.49%, 90.91%, 67.57%, 97.56%, and 30.30% and 61.90%, 81.82%, 64.86%, 95.12%, and 27.27%, respectively. The volume of hyper-functioning parathyroid glands was significantly different between lesions positive in ¹⁸F-FCH PET/CT and negative in ¹⁸F-FCH PET/CT (mean volume 1.36 ± 0.55 cm³ vs. 0.83 ± 0.26 cm³; P = 0.019). US misidentified intrathyroidal parathyroid hyperplasia as thyroid nodules in three patients, while ¹⁸F-FCH PET correctly identified the anatomy. No significant associations were observed between PET parameters and laboratory parameters in uHPT.

CONCLUSION

¹⁸F-FCH PET/CT was more sensitive and accurate for uHPT than ^99mTc-sestaMIBI SPECT/CT and US, and had better preoperative diagnostic efficacy, particularly for lesions diagnosed as a thyroid nodule by US.

Semi-quantitative analysis of 99mTc-sestamibi retention level for preoperative differential diagnosis of parathyroid carcinoma

Background

To investigate the role of ^99mTc-labeled sestamibi (^99mTc-MIBI) retention level in the assessment of malignant potential of parathyroid lesions.

Methods

Twenty patients with parathyroid carcinomas and forty controls with benign parathyroid lesions who underwent preoperatively ^99mTc-MIBI dual-phase planar and SPECT/CT imaging were retrospectively enrolled in this study. The mean and peak of retention index (RI_mean and RI_peak) were measured for evaluating the retention level of ^99mTc-MIBI in the parathyroid lesions. Diagnostic accuracies of RI for differentiating malignant parathyroid lesions from benign ones were assessed by receiver operating characteristic analyses (area under the curve; AUC).

Results

RI_peak (AUC =0.87, P<0.001) and RI_mean (AUC =0.78, P<0.001) showed significant difference between the malignant and benign lesions. The diagnostic sensitivity, specificity, positive and negative predictive values, accuracy of RI_peak were respectively 80.0%, 85.0%, 72.7%, 89.5% and 83.3% when its cutoff value was -19.03%. In addition, the level of serum parathyroid hormone (PTH) slightly correlated with RI_peak (r=0.260, P=0.044) or RI_mean (r=0.281, P=0.029).

Conclusions

Parathyroid carcinomas have higher retention level of ^99mTc-MIBI than benign parathyroid lesions. RI_peak may contribute to preoperative differential diagnosis of parathyroid carcinoma.

Parathyroid imaging with 18F-fluorocholine PET/CT as a first-line imaging modality in primary hyperparathyroidism: a retrospective cohort study

BACKGROUND

¹⁸F-fluorocholine (FCH) PET/CT is a promising technique for visualizing hyperfunctioning parathyroid glands in hyperparathyroidism. It is still under debate whether to use this technique as a first-line imaging modality or to use it when conventional techniques such as ^99mTc-sestamibi scintigraphy or ultrasonography are inconclusive. This study evaluates FCH PET/CT as a first-line modality.

METHODS

Patients with primary hyperparathyroidism, referred between June 2015 and December 2018 for FCH PET/CT as a first-line imaging method, were included in this study. Baseline characteristics, clinical data, scan results, and type of treatment were recorded. The rate of correct detection was calculated on a per patient-based and a per lesion-based analysis. The reference standard comprised histopathological results, intraoperative response to parathyroidectomy, and clinical follow-up.

RESULTS

Two hundred and seventy-one patients were included, of which 139 patients underwent parathyroidectomy, 48 were treated with calcimimetics, and 84 patients received further follow-up without active treatment. In the surgically treated group, a single adenoma was suspected in 127 scans, double adenoma in three scans, and one scan showed evidence of three hyperfunctioning glands. In eight scans, no lesions were visualized. A total of 154 parathyroid glands were surgically removed. The rate of correct detection was calculated at 96% and 90%, on a per patient-based and per lesion-based analysis, respectively.

CONCLUSION

This retrospective study in a large cohort shows high detection rates of FCH PET/CT in primary hyperparathyroidism, which is in accordance to literature. The use of FCH PET/CT as a first-line imaging modality in preoperative planning of parathyroid surgery may therefore be a suitable choice.

Preoperative Localization Studies in Primary Hyperparathyroidism

Primary hyperparathyroidism (pHPT) is the third most frequently seen endocrine disease and it is the most common cause of hypercalcemia seen in ambulatory patients. PHPT is most often (80%-85%) caused by a single parathyroid adenoma, followed by double adenoma (4%-5%), multiple gland hyperplasia (10%-15%), and parathyroid carcinoma (<1%). The diagnosis of pHPT is biochemically established and the only curative treatment is surgery. Since the cause of pHPT is typically single-gland disease, it is possible to determine the majority of pathological glands with preoperative localization methods and use the minimally invasive parathyroidectomy (MIP) approach. MIP has become the standard treatment for pHPT in selected patients. There are both noninvasive and invasive preoperative localization methods. Noninvasive methods currently used include ultrasonography (US), parathyroid scintigraphy, 4-dimensional computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT with 18F-fluoroquinolone and 11C-methionine. Preoperative invasive localization methods include parathyroid hormone (PTH) measurement with fine-needle aspiration biopsy, lateralization with PTH measurement via bilateral jugular vein sampling, selective venous sampling, and parathyroid arteriography. The aim of this study was to evaluate preoperative localization studies used in cases of pHPT.