Parathyroid Adenomas In Primary Hyperparathyroidism Research Articles

Head-to-head comparison of [11C]methionine PET, [11C]choline PET, and 4-dimensional CT as second-line scans for detection of parathyroid adenomas in primary hyperparathyroidism.

Accurate preoperative localization is imperative to guide surgery in primary hyperparathyroidism (pHPT). It remains unclear which second-line imaging technique is most effective after negative first-line imaging. In this study, we compare the diagnostic effectiveness of [11C]methionine PET/CT, [11C]choline PET/CT, and four dimensional (4D)-CT head-to-head in patients with pHPT, to explore which of these imaging techniques to use as a second-line scan. We conducted a powered, prospective, blinded cohort study in patients with biochemically proven pHPT and prior negative or discordant first-line imaging consisting of ultrasonography and 99mTc-sestamibi. All patients underwent [11C]methionine PET/CT, [11C]choline PET/CT, and 4D-CT. At first, all scans were interpreted by a nuclear medicine physician, and a radiologist who were blinded from patient data and all imaging results. Next, a non-blinded scan reading was performed. The scan results were correlated with surgical and histopathological findings. Serum calcium values at least 6months after surgery were used as gold standard for curation of HPT. A total of 32 patients were included in the study. With blinded evaluation, [11C]choline PET/CT was positive in 28 patients (88%), [11C]methionine PET/CT in 23 (72%), and 4D-CT in 15 patients (47%), respectively. In total, 30 patients have undergone surgery and 32 parathyroid lesions were histologically confirmed as parathyroid adenomas. Based on the blinded evaluation, lesion-based sensitivity of [11C]choline PET/CT, [11C]methionine PET/CT, and 4D-CT was respectively 85%, 67%, and 39%. The sensitivity of [11C]choline PET/CT differed significantly from that of [11C]methionine PET/CT and 4D-CT (p = 0.031 and p < 0.0005, respectively). In the setting of pHPT with negative first-line imaging, [11C]choline PET/CT is superior to [11C]methionine PET/CT and 4D-CT in localizing parathyroid adenomas, allowing correct localization in 85% of adenomas. Further studies are needed to determine cost-benefit and efficacy of these scans, including the timing of these scans as first- or second-line imaging techniques.

FRI689 First-line F18-choline PET/CT Versus Tc99m-sestaMIBI SPECT/CT In The Surgical Management Of Primary Hyperparathyroidism: The Multicentre APACH2 Phase III Trial

Abstract Disclosure: E. Quak: None. A. Lasne-cardon: None. M. Cavarec: None. B. Lireux: None. V. Bastit: None. N. Roudaut: None. P. Salaun: None. N. Keromnes: None. G. Potard: None. P. Vaduva: None. A. Esvant: None. F. Jegoux: None. O. Crouy-chanel: None. A. Devillers: None. C. Guery: None. C. Lasnon: None. R. Ciappuccini: None. M. Sali dauda: None. B. Legrand: None. A. Estienne: None. J. Grellard: None. S. Bardet: None. B. Clarisse: None. Introduction: Whether F18-choline PET/CT (FCH PET/CT) should replace Tc99m-sestaMIBI SPECT/CT (MIBI SPECT/CT) as a first-line imaging technique for preoperative localisation of parathyroid adenomas in primary hyperparathyroidism (pHPT) is unclear. Methods: We conducted a multicentre randomized open diagnostic intervention phase III trial in adults with primary hyperparathyroidism and indication for surgical treatment. Patients were assigned in a 1:1 ratio to receive first-line FCH PET/CT (FCH1) or MIBI SPECT/CT (MIBI1). In case of negative or inconclusive first-line imaging, patients received second-line FCH PET/CT (FCH2) after MIBI1 or MIBI SPECT/CT (MIBI2) after FCH1. The main aim of the trial was to compare the proportions of patients in whom the first-line imaging method resulted in successful mini-invasive parathyroidectomy (MIP) and cure, defined as the normalisation of serum calcium and parathyroid hormone levels at 1 month. We hypothesized a 30% superiority of FCH1 over MIBI1 for sample size determination (Quak et al, BMC Endocr Disord. 2021, PMID: 33413316). Results: From 11/2019 to 05/2022, 58 patients were assigned to receive FCH1 (n=30) or MIBI1 (n=28). Baseline patient characteristics were similar between groups. FCH1 was positive in 23/29 patients and led to successful MIP and cure in 22/23 patients. MIBI1 was positive in 18/28 and led to MIP in 16/17 operated patients, and video-assisted thoracoscopy (VATS) in 1/17 patient. Cure was obtained in 15/17 patients. The proportion of patients in whom the first-line imaging exam led to successful MIP and cure was 22 (76%) for FCH1 and 13 (50%) for MIBI1 (p=0.047). Diagnostic performances were superior for FCH1 than for MIBI1: sensitivity (92% vs 68%), specificity (100% vs 75%), positive predictive value (100% vs 94%), negative predictive value (67% vs 30%), and area under the ROC curve (96% vs 71%, p=0.022), respectively. Ten patients received FCH2 and 6 patients received MIBI2. FCH2 was positive in 8/10 patients, leading to 7/9 MIP and 2/9 bilateral cervical explorations (surgery recused in 1 patient), and cure in 9/9 patients. MIBI2 was positive in 2/6 patients, leading to 1 MIP and 1 VATS; all 6 patients were cured. No adverse events related to imaging and 4 adverse events related to surgery were reported. Conclusions: The proportion of patients who underwent correct imaging-guided MIP leading to cure was higher for FCH1 than for MIBI1, 76% vs 50% respectively. Diagnostic performances were better for FCH1 than for MIBI1. Cost-benefit analyses should elucidate whether first-line FCH PET/CT in pHPT management is justified. Presentation: Friday, June 16, 2023

Usefulness of 18F-Fluorocholine Positron Emission Tomography-Computed Tomography in locating parathyroid adenomas in primary hyperparathyroidism

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Effectiveness and safety of the radiofrequency ablation of single hyperfunctioning parathyroid lesions suggestive of adenomas in primary hyperparathyroidism.

Radiofrequency ablation (RFA) has emerged as a minimally invasive approach to single parathyroid adenoma in primary hyperparathyroidism; however, there is limited evidence on its effectiveness. To evaluate the effectiveness and safety of RFA to treat hyper-functioning parathyroid lesions suggestive of adenomas. A prospective study was conducted in consecutive patients with primary hyperparathyroidism treated with RFA for single parathyroid lesions in our reference center between November 2017 and June 2021. Pre-treatment (baseline) and follow-up analytical data were gathered on total protein-adjusted calcium, parathyroid hormone [PTH], phosphorus, and 24-h urine calcium. Effectiveness was defined as complete response (normal calcium and PTH), partial response (reduced but not normalized PTH with normal serum calcium), or disease persistence (elevated calcium and PTH). SPSS 15.0 was used for statistical analysis. Four of thirty-three enrolled patients were lost to the follow-up. The final sample comprised 29 patients (22 females) with mean age of 60.93 ± 13.28years followed up for a mean of 16.29 ± 7.23months. Complete response was observed in 48.27%, partial response in 37.93%, and hyperparathyroidism persistence in 13.79%. Serum calcium and PTH levels were significantly lower at 1 and 2years of post-treatment than at baseline. Adverse effects were mild, with two cases of dysphonia (self-limited in one patient) and no cases of hypocalcaemia or hypoparathyroidism. RFA may be a safe and effective technique to treat hyper-functioning parathyroid lesions in selected patients.

Preoperative Location Of Parathyroid Adenomas In Primary Hyperparathyroidism: The Role of Cervical Doppler Ultrasound.

Parathyroid adenoma is the most frequent cause of primary hyperparathyroidism. In recent years, the preoperative location of parathyroid adenomas allowed minimally invasive surgical techniques that have become preferred over the traditional bilateral neck exploration. The more recent guidelines on this subject highlight the role of nuclear medicine imaging tests. The aim of this study was to review the current role of Doppler ultrasound (US) in assessing the preoperative location of parathyroid adenomas in patients with primary hyperparathyroidism. Retrospective study based on data from patients with primary hyperparathyroidism that underwent parathyroidectomy between January 2013 and January 2022 at the Centro Hospitalar Universitário Lisboa Central. Statistical analysis was performed with IBM SPSS Statistics, version 26.0.0.0®. Parathyroidectomy was performed in 171 patients (77.8% females) with primary hyperparathyroidism. Cervical Doppler ultrasound was the most performed test (64.3%, n = 110) for preoperative location and detected a suspicious lesion in 98 patients (89.1%). The preoperative location of the parathyroid adenomas was assessed through the Doppler ultrasound and was compared with the surgical reports and histological findings; a correct identification was made in 76 patients (77.6%). Doppler ultrasound slightly underestimated the mean adenoma size (18.1 ± 7.7 mm preoperative versus 22 ± 8.4 mm postoperative). Calcium, parathyroid hormone levels, adenoma size and concomitant presence of thyroid nodules did not affect the accuracy of Doppler ultrasound. Doppler ultrasound showed high diagnostic accuracy even in patients with nodular thyroid disease regardless of calcium and parathyroid hormone levels and adenoma size. Furthermore, its safety, affordability and availability should favor its use as first line test in primary hyperparathyroidism to assess the preoperative location of parathyroid adenomas.

The Role of Surgeon-Performed Office and Preincision Ultrasounds in Localization of Parathyroid Adenomas in Primary Hyperparathyroidism

ObjectiveWe studied the use of surgeon-performed office ultrasound (OU) and preincision ultrasound (PIU) in preoperatively localizing parathyroid adenomas in primary hyperparathyroidism (PHPT). MethodsA retrospective chart review was performed for patients with PHPT who underwent parathyroidectomy between 2013 and 2015. The results of OU and PIU were recorded and compared with the final surgical pathology. ResultsOf 348 patients with PHPT, 285 (81.9%) had single-lesion disease, 49 (14.1%) had double-lesion disease, and 14 (4.0%) had multigland disease with 3 or more lesions. For single-lesion disease, the overall sensitivity and specificity of OU to correctly lateralize the lesion were 64.2% and 91.2%, while those of PIU were 89.4% and 93.6%, respectively. The sensitivity and specificity of PIU were comparable to those of 4-dimensional computed tomography (87.1% and 90.7%, respectively) and 99mTc-sestamibi scintigraphy (70.4% and 95.9%, respectively). While the majority of PIU cases were preceded by other imaging studies, the accuracy in localizing lesions was not largely affected by the presence of prior computed tomography and/or 99mTc-sestamibi scintigraphy, as opposed to ultrasounds only. For detecting the presence of multigland disease, the sensitivity and specificity of OU were 26% and 92.2%, while those of PIU were 64.3% and 94.7%, respectively. ConclusionSurgeon-performed OU and PIU are valuable tools in preoperatively localizing the parathyroid adenoma in single-lesion disease, while their utility may be limited for double-lesion or multigland disease. PIU in particular yields high accuracy in detecting parathyroid lesions in combination with other imaging modalities.

Intrathyroidal Parathyroid Adenomas in Primary Hyperparathyroidism: Clinical and Imaging Findings.

ObjectivesPrimary hyperparathyroidism (PHPT) is a common endocrine disease. Ectopic adenomas may cause a failed surgery which results in persistence or recurrence. Intrathyroidal parathyroid adenoma (ITPA) is a rare reason for PHPT and site of ectopia. Herein, we aimed to investigate the clinical and imaging features of patients with ITPAs and the effectiveness of radiological tools for localization at a tertiary reference center.MethodsThe files of 708 consecutive patients who underwent parathyroidectomy for PHPT in our department between January 2007 and December 2021 were investigated retrospectively. PHPT patients with ITPA were included in the study. Patients with missing data were excluded from the study. Clinicopathological features of the patients and radiological evaluation findings were investigated.ResultsTwenty-eight (28/708: 3.9%) patients were included in the study. The complete intrathyroidal gland and subcapsular parathyroid gland were observed in 8 (1.1%) and 20 (2.8%) patients, respectively. The ultrasound and parathyroid scintigraphy revealed the accurate localization of ITPA in 25 (89.3%) and 18 (64.3%) patients, respectively. Additional imaging modalities were applied for 10 patients in which conventional localization studies were discordant or inconclusive. ITPAs were most commonly found in the lower gland (n=20) localization. All patients had a successful parathyroidectomy and neither persistence nor recurrence was occurred in the study group.ConclusionThe ITPAs are rare in PHPT. The ultrasound has a high diagnostic rate in experienced hands. The second-line imaging methods may be favorable in the presence of negative or discordant scans. The pre-operative localization studies can detect the ITPAs in most patients, so blind thyroidectomy should be avoided.

Preoperative 4D CT Scan Facilitates Localization of Small and Ectopic Parathyroid Adenomas in Primary Hyperparathyroidism

Preoperative 4D CT Scan Facilitates Localization of Small and Ectopic Parathyroid Adenomas in Primary Hyperparathyroidism

Colour doppler ultrasound: Preoperative location of parathyroid adenomas in primary hyperparathyroidism

Colour doppler ultrasound: Preoperative location of parathyroid adenomas in primary hyperparathyroidism

Trial Comparing 2 Diagnostic Strategies for Preoperative Localization of Parathyroid Adenoma in Primary Hyperparathyroidism:TEMP / CT With Tc99m-sestaMIBI or PET / CT With F18-choline in First Intention

Trial Comparing 2 Diagnostic Strategies for Preoperative Localization of Parathyroid Adenoma in Primary Hyperparathyroidism:TEMP / CT With Tc99m-sestaMIBI or PET / CT With F18-choline in First Intention

Diagnostic Performance of 4D CT and Sestamibi SPECT/CT in Localizing Parathyroid Adenomas in Primary Hyperparathyroidism.

Background There currently is no consensus on the optimal localization procedure and imaging protocol for parathyroid adenoma. Parathyroid four-dimensional (4D) CT has emerged as a promising method for preoperative localization. Purpose To evaluate the diagnostic performance of parathyroid 4D CT and technetium 99m-sestamibi (hereafter, referred to as sestamibi) SPECT/CT in preoperative localization in patients with primary hyperparathyroidism. Materials and Methods This was a single-institution retrospective study of patients with primary hyperparathyroidism who underwent a combined imaging protocol of sestamibi SPECT/CT and 4D CT (noncontrast, contrast agent-enhanced, arterial, and delayed venous phases) acquired in a single setting from February 2013 to May 2016, with subsequent parathyroidectomy within 6 months. Reference standard for correct localization was on the basis of location denoted on operative reports, with pathologic confirmation of parathyroid adenoma or hyperplasia. By using a four-quadrant analysis, sensitivity, specificity, and area under the curve (AUC) for localization of the hyperfunctioning parathyroid gland or glands at sestamibi SPECT/CT and 4D CT were compared, per modality and in combination. Results Four hundred patients (319 women, 81 men; mean age, 61 years ± 14 [standard deviation]) were evaluated. Similar diagnostic performance was found in both combined 4D CT with sestamibi SPECT/CT and 4D CT alone (area under the curve [AUC], 0.88 [95% CI: 0.86, 0.90] and 0.87 [95% CI: 0.85, 0.90], respectively; P = .82). Both modalities outperformed sestamibi SPECT/CT (AUC, 0.78; 95% CI: 0.76, 0.81; P < .001). Four-dimensional CT showed higher sensitivity than did sestamibi SPECT/CT (sensitivity, 79.3% [414 of 522] vs 58.0% [303 of 522], respectively; P < .001). In a subset analysis, 4D CT had higher sensitivity than sestamibi SPECT/CT in patients with single-gland disease (sensitivity, 92.5% [297 of 321] vs 75.1% [241 of 321], respectively; P < .001) and with multigland disease (sensitivity, 58.2% [117 of 201] vs 30.8% [62 of 201], respectively; P < .001). Conclusion Four-dimensional CT provided superior preoperative localization compared with sestamibi SPECT/CT in patients with single and multigland disease. The combination of the two modalities did not improve diagnostic performance compared with four-dimensional CT alone. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Sinha and Oates in this issue.

Thyroid oncocytes may complicate 18F-fluorocholine PET-CT localization of parathyroid adenomas in primary hyperparathyroidism

Thyroid oncocytes may complicate 18F-fluorocholine PET-CT localization of parathyroid adenomas in primary hyperparathyroidism

Intrathyroidal parathyroid adenoma in primary hyperparathyroidism: Are we overdiagnosing? case series and learning outcomes

Intrathyroidal parathyroid (IP) adenoma as a cause of primary hyperparathyroidism (PHPT) presents a diagnostic challenge in localization and differentiating it from a thyroid nodule. We report here three distinct cases of PHPT where preoperative imaging findings were compared with surgical and histopathological findings. Case 1 was a typical true IP adenoma, as diagnosed by preoperative sestamibi and ultrasound, and confirmed at surgery and subsequent histopathology. Case 2 was diagnosed by sestamibi and ultrasound as bilateral lower pole IP adenomas which turned out to be thyroid nodules at surgery. Postsurgery, the serum PTH levels dropped only partially and PHPT persisted. Revision surgery was performed, and a right inferior parathyroid adenoma was removed, after which PTH was normalized. Case 3 had a preoperative sestamibi diagnosis of left inferior parathyroid. Preoperative ultrasound suggested a left thyroid nodule/IP along with an associated contralateral right inferior parathyroid nodule. Surgery and subsequent histopathology confirmed left follicular adenoma and right inferior parathyroid adenoma. We discuss the limitations of preoperative imaging modalities in these cases along with their learning outcomes. It is very essential that all the involved clinicians, radiologists, and surgeons are well aware of the diagnostic features and pitfalls associated with IPs so as to enable a correct diagnosis and appropriate surgical or medical management.

Comparative Diagnostic Performance of Ultrasonography and 99mTc-Sestamibi Scintigraphy for Parathyroid Adenoma in Primary Hyperparathyroidism; Systematic Review and Meta- Analysis

Objective:Ultrasonography (US) and parathyroid scintigraphy (PS) with 99mTc-MIBI are common methods for preoperative localization of parathyroid adenomas but there discrepancies exist with regard to diagnostic accuracy. The aim of the study was to compare PS and US for localization of parathyroid adenoma with a systematic review and meta-analysis of the literature.Methods:Pub Med, Scopus (EMbase), Web of Science and the reference lists of all included studies were searched up to 1st January 2016. The search strategy was according PICO characteristics. Heterogeneity between the studies was accounted by P < 0.1. Point estimates were pooled estimate of sensitivity, specificity and positive predictive value of SPECT and ultrasonography with 99% confidence intervals (CIs) by pooling available data. Data analysis was performed using Meta-DiSc software (version 1.4).Results:Among 188 studies and after deletion of duplicated studies (75), a total of 113 titles and abstracts were studied. From these, 12 studies were selected. The meta-analysis determined a pooled sensitivity for scintigraphy of 83% [99% confidence interval (CI) 96.358 -97.412] and for ultra-sonography of 80% [99% confidence interval (CI) 76-83]. Similar results for specificity were also obtained for both approache.Conclusion:According this meta- analysis, there were no significant differences between the two methods in terms of sensitivity and specificity. There were overlaps in 99% confidence intervals. Also features of the two methods are similar.

Accuracy of 2-Phase Parathyroid CT for the Preoperative Localization of Parathyroid Adenomas in Primary Hyperparathyroidism.

Minimally invasive parathyroidectomy requires accurate preoperative localization of suspected adenomas, and multiphase CT allows adenoma characterization while providing detailed anatomic information. The purpose of this study was to assess the feasibility of a protocol using only arterial and venous phases to localize pathologic glands in patients with primary hyperparathyroidism. We identified 278 patients with primary hyperparathyroidism who had undergone 2-phase CT with surgical cure. All scans were read prospectively by board-certified neuroradiologists. A neuroradiology fellow retrospectively reviewed images and reports and classified suspected adenomas on the basis of anatomic location. Accuracy was determined by comparing imaging results with surgical findings. The ability of 2-phase CT to localize adenomas to 1 of 4 neck quadrants and lateralize them to the correct side was assessed. Accuracy of identifying multigland disease was also evaluated. In patients with single-gland disease, the sensitivity and specificity of 2-phase CT to correctly localize the quadrant were 55.4% and 85.9%, respectively. The sensitivity and specificity of correct lateralization were 78.8% and 67.8%, respectively. The sensitivity and specificity to identify multigland disease were 22.9% and 79.5%, respectively. While the 2-phase CT protocol in this study demonstrates lower accuracy compared with reports of other techniques, its lower radiation compared with 3- and 4-phase techniques may make it a feasible alternative for preoperative parathyroid localization. Further prospective studies are needed to identify patients for whom this technique is most suitable.

Location of Parathyroid Adenomas in Primary Hyperparathyroidism: Where to look?

ABSTRACTPurposePreoperative localization studies for parathyroid adenomas are very essential to perform minimal invasive parathyroidectomy (MIP) with decreased operative time and potential complications. Although most of these studies based on radiological imaging, intraoperative assessment provides the most accurate anatomical description of the location of parathyroid adenomas. In this study, we aim to evaluate the surgical variations of locations of parathyroid adenomas in patients performed parathyroid surgery for primary hyperparathyroidism (PHPT).Materials and methodsBetween January 2010 and December 2013, 243 patients (201 women/42 men) who underwent parathyroid surgery due to phPT were included. A total of 254 parathyroid adenomas were detected. Demographic features, preoperative work-up, surgical approach, types of procedures and postoperative complications were noted. Locations of parathyroid adenomas were recorded from operative notes. Statistical analysis was performed using t-test and chi-square. continuous data are expressed as mean ± standard deviation.ResultsWith regard to the most frequently observed, location of adenomas were as follows; right inferior (n = 89, 37.7%), left inferior (n = 78, 33%), right superior (n = 44, 18.6%), left superior (n = 25, 10.5%) and ectopic locations (n = 18). Ectopic adenomas were mostly located in the thymus (n = 9) and intrathyroidal tissue (n = 6) at a rate of 83%. Postoperative hypocalcemia (11%) was mostly seen in those with parathyroid adenoma located around the inferior lobes of the thyroid (86%) and undergoing bilateral neck exploration (75%).ConclusionThe most of the parathyroid adenomas were found in orthotopic position and located around the lower pole of the thyroid gland. Ectopic adenomas were mostly located in thymus or intrathyroidal. Postoperative hypocalcemia was also higher in those with parathyroid adenoma located around the inferior lobe of the thyroid.How to cite this articleYazici P, Mihmanli M, Bozdag E, Aygun N, Uludag M. Location of Parathyroid Adenomas in Primary Hyperparathyroidism: Where to look? World J Endoc Surg 2015;7(1):1-5.

4D‐CT for Localization of Nonlocalizing Parathyroid Adenomas in Primary Hyperparathyroidism

Objectives: (1) Present the application of 4-dimensional (4D) computed tomography (CT) in preoperative localization of parathyroid adenomas that do not localize with technetium-99 (Tc-99) single-photon emission computed tomography (SPECT)/CT or ultrasound. (2) Present indications for 4D-CT use. (3) Understand radiologic dosimetry issues of 4D-CT. Methods: A retrospective review of over 15 consecutive patients at an academic medical center with primary hyperparathyroidism who underwent preoperative 4D-CT after nonlocalizing preoperative ultrasound and Tc-99 SPECT-CT scans between November 2013 and June 2014. This was a mixture of patients presenting for their first operations and others requiring revision surgery. Intraoperative radioguided parathyroidectomy results, excised gland weight, patient demographics, and parathyroid hormone levels were recorded. Sensitivity, specificity, and positive and negative predictive values of 4D-CT for preoperative adenoma localization were calculated. Results: 4D-CT resulted in successful localization and biochemical cure in all primary or revision cases in which it was utilized. Radiation doses from 4D-CT will be presented and compared to radiologic dosimetry from SPECT-CT. Conclusions: 4D-CT offers a sensitive and specific modality for preoperative parathyroid adenoma localization which is useful in cases where ultrasound and SPECT-CT sestamibi are nonlocalizing.

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism

AimTo evaluate the usefulness of 11C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase 99mTc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. Material and methodsA prospective study that included 14 patients (mean age: 65.5±9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8±108pg/mL and serum calcium 10.8±0.9mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2–3h after injection of 740MBq (20mCi) of 99mTc-sestamibi. MET was obtained 10 min and 40 min after injection of 740MBq (20mCi) of 11C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. ResultsMIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. ConclusionMIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative.

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism

To evaluate the usefulness of (11)C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase (99m)Tc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. A prospective study that included 14 patients (mean age: 65.5 ± 9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8 ± 108 pg/mL and serum calcium 10.8 ± 0.9 mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2-3h after injection of 740 MBq (20 mCi) of (99m)Tc-sestamibi. MET was obtained 10 min and 40 min after injection of 740 MBq (20 mCi) of (11)C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. MIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. MIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative.

Radiofrequency ablation of parathyroid adenoma in primary hyperparathyroidism

We present a case of a 32-year-old woman with hyperparathyroidism, treated with ultrasound-guided percutaneous radiofrequency ablation (RFA). RFA, assisted by saline injection inferomedial to the parathyroid, is a safe technique that prevents burn injury to the nerve. The saline injection technique shifted the parathyroid gland laterally, so that the distance between the nerve and the parathyroid gland was sufficient to prevent burn injury. The completeness of tissue ablation was evaluated based on Doppler ultrasound imaging and serum intact parathyroid hormone (iPTH) level immediately after RFA. There were no complications associated with RFA. Serum iPTH levels normalized during follow-up for 20months. It was possible to perform RFA for primary parathyroid adenoma safely using a saline injection technique.