Parathyroid Localization Research Articles

REGULARITIES OF DEVELOPMENT AND FORMATION OF EMBRYOTOPOGRAPHY OF THE THYROID AND PARATHYROID GLANDS IN HUMAN EMBRYOS OF 7-9 WEEKS OF GESTATION

The article describes the peculiarities of development and formation of variants of external shape and localization of thyroid and parathyroid glands in human embryos of 7-9 weeks of gestation.Aim of the study. The objective of the study was to fi nd the regularities of development and formation of embryotopographic relations between the thyroid and parathyroid glands during 7-9 weeks of the human intrauterine development. Material and methods. The study was carried out using a complex of morphological methods on 42 samples of human embryos without external signs of anatomical deviations or developmental defects. The specimens were taken from the museums of the Department of Human Anatomy of M. H. Turkevytch and the Department of Anatomy, Clinical Anatomy and Operative Surgery of the Bukovinian State Medical University.Results and discussion. In embryos with parietococcygeal length (PCL) of 14,0-17,0 mm intensive organogenesis processes of thyroid gland occur: separation of gland lobes, loss of connection with aortic arch and establishment of close correlations with laryngeal rudiment and vagus nerves. Therefore, the thyroid gland becomes semicircular. In embryos with 18,0-24,0 mm PCL there is a separation of the isthmus from the lateral lobes of the thyroid. Initially it is caused by intensive growth of the cricoid arch. Gradually the gland becomes H-shaped and fragmentation of the caudal part of the thyroglossal duct occurs. When the PCL reaches 29.5-31.0 mm, folliculogenesis begins and the thyroid gland becomes horseshoe- shaped. 9-week embryos show clear individual variations in the external shape of the thyroid gland: semicircular, H-shaped, and horseshoe. Areas of undiff erentiated epithelial tissue are found in the thyroid parenchyma, especially in its center.Conclusions. The conducted study has shown that during the 7-9 weeks of intrauterine development the structural organization of the thyroid and parathyroid rudiments becomes more complicated. Tight embryotopographic relations are established between them. Vascularization intensifi es and the connective tissue capsules of the thyroid and parathyroid glands are formed. At the same time their linear dimensions increase rapidly.

Primary hyperparathyroidism with intrathyroidal location of parathyroid adenoma

Primary hyperparathyroidism is a common endocrine disease with high morbidity and mortality from all causes. The disease can be asymptomatic and for a long time remain undiagnosed, which leads to untimely surgical treatment, increases the risks of development and progression of severe disabling complications and worsens patients prognosis. In clinical practice there are certain difficulties in diagnosing this pathology. One of the urgent problems is the search for the source of parathyroid hormone hyperproduction, especially in case of atypical location of paraаdenoma. The most common atypical locations of altered parathyroid glands are thymus, retroor paraesophageal space, retropharyngeal space, mediastinum and thyroid gland. The frequency of intrathyroidal masses of parathyroid glands, in the thyroid parenchyma or under its capsule, ranges on average from 2 to 3%, but according to some authors can reach 18–22%. With such localization of paraadenomas there is a need for their differential diagnosis, first of all, with nodular formations of the thyroid gland. In addition, the absence of additional laboratory studies parathormone and calcium blood levels does not allow timely suspicion of the disease, and cytologic examination of the material obtained by fine-needle aspiration puncture biopsy does not allow reliable differentiation of the altered parathyroid gland. This article presents a clinical case of a patient with primary hyperparathyroidism with intrathyroidally located parathyroid adenoma, for a long time long identified as a “nodular goiter,” and provides a brief review of the methods that identify an intrathyroidally located parathyroma. Despite the abundance of diagnostic methods in visualization of intrathyroidal parathyroid glands, today the most appropriate seems to be expert ultrasound examination with assessment of the parathyroid hormone level in a washout after fine-needle aspiration, supplemented, if necessary, by scintigraphy and single-photon emission computed tomography combined with computed tomography or multispiral computed tomography.

Machine learning-derived clinical decision algorithm for the diagnosis of hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism.

To train and validate machine learning-derived clinical decision algorithm (MLCDA) for the diagnosis of hyperfunctioning parathyroid glands using preoperative variables to facilitate surgical planning. This retrospective study included 458 consecutive primary hyperparathyroidism (PHPT) patients who underwent combined 4D-CT and sestamibi SPECT/CT (MIBI) with subsequent parathyroidectomy from February 2013 to September 2016. The study cohort was divided into training (first 400 patients) and validation sets (remaining 58 patients). Sixteen clinical, laboratory, and imaging variables were evaluated. A random forest algorithm selected the best predictor variables and generated a clinical decision algorithm with the highest performance (MLCDA). The MLCDA was trained to predict the probability of a hyperfunctioning vs normal gland for each of the four parathyroid glands in a patient. The reference standard was a four-quadrant location on operative reports and pathology. The accuracy of MLCDA was prospectively validated. Of 16 variables, the algorithm selected 3 variables for optimal prediction: combined 4D-CT and MIBI using (1) sensitive reading, (2) specific reading, and (3) cross-product of serum calcium and parathyroid hormone levels and outputted an MLCDA using five probability categories for hyperfunctioning glands. The MLCDA demonstrated excellent accuracy for correct classification in the training (4D-CT + MIBI: 0.91 [95% CI: 0.89-0.92]) and validation sets (4D-CT + MIBI: 0.90 [95% CI: 0.86-0.94]. Machine learning generated a clinical decision algorithm that accurately diagnosed hyperfunctioning parathyroid glands through classification into probability categories, which can be implemented for improved preoperative planning and convey diagnostic certainty. Question Can an MLCDA use preoperative variables for the diagnosis of hyperfunctioning parathyroid glands to facilitate surgical planning? Findings The developed MLCDA demonstrated excellent accuracy for correct classification in the training (0.91 [95% CI: 0.89-0.92]) and validation sets (0.90 [95% CI: 0.86-0.94]). Clinical relevance Using standard preoperative variables, an MLCDA for diagnosing hyperfunctioning parathyroid glands can be implemented to improve preoperative parathyroid localization and included in radiology reports forsurgical planning.

Preoperative visualization of parathyroid pathology in patients with primary hyperparathyroidism using PAT/KT: a retrospective study

INTRODUCTION: Topical diagnosis of pathologically altered parathyroid glands in patients with primary hyperparathyroidism is a challenge both for specialists of radial diagnostics and for planning the scope of surgical intervention. The choice of diagnostic modality for localization of parathyroid glands depends on the availability of the method for a particular medical center. PET/CT is a promising method to determine the localization of parathyroid adenomaOBJECTIVE: To analyze the experience of using PET/CT with 11C-methionine and PET/CT with 11C-choline for preoperative diagnosis of parathyroid pathology in patients with primary hyperparathyroidism.MATERIALS AND METHODS: 72 patients diagnosed with PHPT and underwent surgical treatment were included in the study. Before surgical intervention all patients underwent laboratory and instrumental investigations in the scope of: blood tests for PTH, TTH, ionized calcium, calcitonin, 25(OH)D, creatinine, phosphorus, ultrasound of the neck, computer tomography of the neck with intravenous bolus contrasting.RESULTS: PET/CT showed the highest rates of DA in the patient group before primary surgery — 90.9%, compared with ultrasound (89.6%) and CT with IV contrast (84.9%). In the group of solitary adenomas of ectopic MTCS, PET/CT also had a higher DA — 92.8% than the other modalities. In patients with relapsed or persistent disease, the informativity rates of CT with intravenous contrast and PET/CT were similar (Se — 100%, Sp — 94.1%, DT — 96.2%).DISCUSSION: The algorithm for preoperative evaluation of patients to identify the location of pathologic parathyroid glands now includes imaging with two modalities: Neck ultrasound and radionuclide imaging: planar scintigraphy (washout/subtraction), SPECT, SPECT-CT. If the results are questionable, a CT scan of the neck with contrast or PET/CT is performed as a second step. None of the modalities has 100% diagnostic accuracy. Our study demonstrated the superiority of PET/CT over ultrasound and CT w/in contrast in a group of patients scheduled for primary surgical treatment. In a small group of patients, high informative rates of PET/CT and CT with contrast were demonstrated before reoperation, confirming the great potential of these techniques in these patients.CONCLUSION: PET/CT with 11C-methionine and PET/CT with 11C-choline have high diagnostic accuracy in patients with primary hyperparathyroidism before reoperation. PET/CT and CT with contrast showed similarly high diagnostic accuracy for the diagnosis of parathyroid adenoma with persistence or recurrence of the disease in patients with primary hyperparathyroidism.

The role of anatomical and functional orientation in identification of parathyroid glands for patients with parathyroidectomy.

To investigate diagnostic approaches for preoperative localization of secondary hyperparathyroidism, as well as to give surgeons with precise parathyroid gland localization and imaging so that surgery can be performed safely. The clinical data of 710 patients with secondary hyperparathyroidism who underwent surgery in our center from October 2009 to October 2023 were retrospectively analyzed. The changes in calcium, phosphorus, and parathyroid hormone levels were observed to ascertain the anatomical location and number of parathyroid glands. Among the 710 patients, 55 underwent total parathyroidectomy, the others underwent total parathyroidectomy with autotransplantation. In total, 2,658 parathyroid glands were removed, with 43 glands being removed in 35 reoperation cases. The median parathyroid hormone level at 6 months postoperatively was 13.40 (interquartile range, 7.00-29.80) pg/mL. The detection rates of the parathyroid glands before first and repeat surgeries were higher using 99mTc-MIBI SPECT/CT fusion imaging than ultrasound (P<0.05). The sensitivity of combined preoperative 99mTc-MIBI SPECT/CT and ultrasound was 92.31%, higher than that of either 99mTc-MIBI SPECT/CT fusion imaging or ultrasound alone (P < 0.05). The incidence of ectopic parathyroid glands was 23.8%, and the incidence of ectopic left lower parathyroid glands was 13.2%. The left lower parathyroid gland was the most prone to ectopia. 99mTc-MIBI SPECT/CT fusion imaging, paired with high-frequency ultrasound, can be utilized to diagnose SHPT preoperatively. The most common ectopia site is the left lower parathyroid gland, which is located primarily in the thymus and superior mediastinum. Understanding the functional anatomical distribution of the parathyroid glands is critical for developing effective surgical methods for secondary hyperparathyroidism.

Intraoperative parathyroid hormone assay benefits surgery for primary hyperparathyroidism when preoperative localisation is negative or not performed.

Parathyroid localisation is now routine before first-time surgery for patients with primary hyperparathyroidism (PHPT). The aim of this study was to investigate the contribution of intraoperative parathyroid hormone (PTH) (ioPTH) in patients in whom localisation was either not undertaken or negative for a tumour. This was a retrospective study of patients undergoing first-time parathyroidectomy for PHPT in a regional endocrine centre. Data were collected prospectively (Microsoft Excel) and the all-Wales electronic patient record portal was used to retrieve missing data. Statistical analysis appropriate for nonparametric data was undertaken, with statistical significance reached when p<0.05. Between 1 July 2002 and 31 December 2022, 1,490 patients underwent a first-time parathyroidectomy for PHPT. Of this cohort, 1,133 patients had at least one positive imaging modality; the study group consisted of 343 patients that had negative imaging, and 13 that had no preoperative localisation. Patients with MEN-1 (n=26), an incorrect diagnosis (n=4), or less than six months follow-up (n=6) were excluded. Of the remaining 321, 106 patients underwent surgery without ioPTH (Group A), 215 cases with ioPTH (Group B). In Group B there were more women (170 female/45 male; 79% vs 67 female/37 male; 63% p=0.002, chi-squared), lower calcium (median [range] 2.77 [2.63-3.24] mmol/l; vs 2.85 [2.60-4.52] p=0.001) and lower PTH (12.0pmol/l [3.4-39.5] vs 14.4 [3.9-97.0] p=0.001) and smaller weights of resected tissue (320mg [50-9,000] vs 454 [46-8,280] p=0.02) (Student's t-test). The rate of multiple gland disease was similar (Group A 29%; Group B 27%). The rate of normocalcaemia at 6 months was significantly higher when ioPTH was used (Group B 202/215; 94% vs Group A 90/106; 85%) (p=0.014, chi-square test). The sensitivity and specificity of ioPTH was 98.5% [confidence interval (CI) 96.2-99.6] and 91.2% [80.7-97.0] (positive predictive value 99.9%, CI 93.6-100.0). Despite milder hyperparathyroidism and smaller tumour weight, the outcome in patients in whom ioPTH was used was superior, with failure rates 2.5-fold higher in the cohort where ioPTH was not utilised. The results of this study demonstrate that ioPTH is a valuable adjunct for the surgeon in cases where localisation has failed or not been undertaken.

Incidental synchronous intrathyroidal parathyroid carcinomas and papillary thyroid microcarcinoma with compressive neck mass and primary hyperparathyroidism: case report and literature review

BackgroundParathyroid carcinoma (PC) is a rare malignancy, often diagnosed incidentally through postoperative pathological examination. The occurrence of nodular goiter, intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma (PA), and papillary thyroid microcarcinoma (PTMC) is extremely uncommon, which prompted us to report our case experience.Case presentationWe describe a 67-year-old male who presented with a cervical mass causing tracheal compression, which prompted him to seek medical advice. Based on preoperative auxiliary examination results from color Doppler ultrasound, SPECT parathyroid imaging, and blood tests, he was initially diagnosed with a suspected parathyroid adenoma and nodular goiter. Excision of the right lobe and isthmus of the thyroid, and left superior parathyroid gland was conducted, which were sent to intraoperative frozen pathological examination. During intraoperative observation, adhesion around the right thyroid lobe was discovered. Consequently, right central area lymph node dissection was performed due to suspicion of an aggressive malignant tumor. Histology and immunohistochemistry analysis revealed incidental intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma, classical papillary thyroid microcarcinoma, and nodular goiter.ConclusionParathyroid carcinoma should be highly suspected when extremely high levels of PTH and severe hypercalcemia are present, which cannot be simply explained by a preoperatively localized parathyroid adenoma, especially when suspicious malignant adhesion is found during intraoperative exploration. In cases where multifocal thyroid nodules are associated with increased uptake of 99Tc-sestamibi, the possibility of coexisting carcinomas should be considered, not only for thyroid malignancy but also for the potential presence of intrathyroidal parathyroid carcinoma.

Comparing early and delayed [99mTc]Tc-MIBI SPECT/CT parathyroid scans: agreement, confidence levels, and clinical predictive factors

BackgroundParathyroid scan is an important imaging modality for localizing hyperfunctioning parathyroid tissue in patients with hyperparathyroidism. Unfortunately, whether early or delayed timing is the optimal protocol for [99mTc]Tc-MIBI SPECT/CT parathyroid remains under debate. This study aimed to evaluate the agreement and compare the confidence levels of physicians when interpreting early and delayed [99mTc]Tc-MIBI SPECT/CT parathyroid scans. Additionally, it sought to identify clinical factors that related to positive scan result. We conducted a prospective study where the early and delayed [99mTc]Tc-MIBI SPECT/CT was separately interpreted as either positive or negative. Furthermore, these interpretations were categorized based on whether they fell within more or less confidence levels of the readers and were correlated with clinical information.ResultsWe enrolled 39 patients with hyperparathyroidism with 158 possible locations of parathyroid glands. The per-location agreement between the early and delayed scans was moderate (concordant rate: 80.3%, Kappa = 0.558), and the per-patient agreement was slight (concordant rate: 71.8%, Kappa = 0.093). The confidence of interpretation was significantly higher for the delayed scans. Calcium supplementation, low serum parathyroid hormone levels, and low serum phosphate levels were associated with positive early scans. High calcium level and high parathyroid hormone levels were associated with positive delayed scans.ConclusionsOur study highlights the impact of the timing of SPECT/CT in [99mTc]Tc-MIBI parathyroid scans. The different confidence levels between early and delayed scans, along with clinical factors, imply that various factors affect parathyroid scan interpretation, and individualized scanning protocols adjusted for specific settings may be needed to optimize the successful localization of hyperfunctioning parathyroid tissue.

Dual-tracer subtraction scintigraphy combined with SPECT/CT in preoperative patients with primary hyperparathyroidism.

Abstract.

Advances in the application of auxiliary imaging techniques in parathyroid diseases

Hypoparathyroidism is one of the main complications after total thyroidectomy, severely affecting patients’ quality of life. How to effectively protect parathyroid function after surgery and reduce the incidence of hypoparathyroidism has always been a key research area in thyroid surgery. Therefore, precise localization of parathyroid glands during surgery, effective imaging, and accurate surgical resection have become hot topics of concern for thyroid surgeons. In response to this clinical phenomenon, this study compared several different imaging methods for parathyroid surgery, including nanocarbon, indocyanine green, near-infrared imaging techniques, and technetium-99m methoxyisobutylisonitrile combined with gamma probe imaging technology. The advantages and disadvantages of each method were analyzed, providing scientific recommendations for future parathyroid imaging. In recent years, some related basic and clinical research has also been conducted in thyroid surgery. This article reviewed relevant literature and provided an overview of the practical application progress of various imaging techniques in parathyroid surgery.

Primary hyperparathyroidism: diagnostic features and surgical outcomes.

Primary hyperparathyroidism is characterized by elevated plasma calcium levels due to inappropriate secretion of parathyroid hormone (PTH) in most cases by an adenomatous or hyperplastic parathyroid. We present a retrospective analysis of a large cohort of patients operated on of parathyroidectomy in our center analyzing their diagnostic characteristics, intraoperative match and surgical outcomes. We included patients with benign parathyroid disease who underwent parathyroidectomy associated or not with hemi- or total thyroidectomy at the Sant'Anna University Hospital of Ferrara between September 2003 and September 2022. In our study 371 patients fulfilled the inclusion criteria. The most widely used preoperative imaging method was ultrasound, followed by 99mTc-sestamibi scintigraphy. In most cases, preoperative imaging correctly localized the affected parathyroid. Considering the intraoperative site of the pathologically affected parathyroid, the majority of pathological parathyroids were located in the lower districts of the neck and a smaller percentage in the upper, intermediate, and ectopic sites. Postoperative complications were infrequent. The main challenge in parathyroid surgery lies in the difficulty in localizing the pathological parathyroid at the surgical site, which can lengthen the surgical time by increasing comorbidities. Currently, the results on pathological parathyroid localization are good. Technology needs to be developed toward greater diagnostic accuracy and minimally invasive surgical approaches.

Contribution of CT scan to patient's radiation exposure in parathyroid SPECT/CT scintigraphy

IntroductionDual phase technetium-99mTc-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography with computed tomography (SPECT/CT) may be the most accurate conventional imaging approach for localization of enlarged parathyroid gland (EPG). The imaging is based on the radiopharmaceutical (RP) retention in EPG compared to washout from normal thyroid and normal parathyroid glands. This study aimed to estimate and optimize the contribution of computed tomography (CT) scan and scan range to effective dose (ED) in dual-phase MIBI SPECT/CT parathyroid scintigraphy. MethodsThe study included seventy-four patients; thirty-seven with reduced and thirty-seven with extended CT scan range. The ED caused by the CT scan was calculated using Dose Length Product (DLP) data and estimated using the Imaging Performance Assessment of CT scanners (ImPACT) calculator. ResultsFor all patients, the contribution of CT to the ED in a combined SPECT/CT examination was 2.62 ± 0.29 mSv (48%). The contribution of CT to the total ED was 1.8 ± 0.18 mSv (33%) when using reduced and 3.44 ± 0.23 mSv (64%) when using extended scan range. The DLP and ED were statistically significantly different between the reduced and extended CT scan range (p < 0.001) in the first and second phases. The individual organ dose was reduced from 8% to 94%. ConclusionThe hybrid SPECT/CT improves the interpretation of nuclear medicine images and also increases the radiation dose to the patient. An adequately defined CT scan range on SPECT/CT imaging, can significantly reduce a patient's ED. Implications for practiceThe research findings showed that knowledge of anatomy, pathology and technology can provide optimising diagnostic procedures and reduce patient ED after SPECT/CT scans.

Four-Dimensional Computed Tomography for Parathyroid Adenoma Localization: A Pre-Operative Imaging Protocol.

Primary hyperparathyroidism (PHPT) affects approximately 0.86% of the population, with surgical resection as the treatment of choice. A 4D computed tomography (CT) is a highly effective tool in localizing parathyroid adenomas; however, there is currently no defined role for 4D CT when stratified against ultrasonography (USG) and nuclear medicine Technetium Sestamibi SPECT/CT (SES) imaging. Retrospective Study. University Hospital. All patients who underwent parathyroidectomy for PHPT between 2014 and 2019 at a single institution were reviewed. Patients who had a 4D CT were included. We compared outcomes of 4D CT as a second line imaging modality to those of USG and SES as first line modalities. An imaging algorithm was proposed based on these findings. There were 84 patients identified who had a 4D CT after unsuccessful first line imaging. A 4D CT localized parathyroid adenoma to the correct quadrant in 64% of cases, and to the correct laterality in 75% of cases. Obese patients had significantly lower rates of adenoma localization with USG (33.4%), compared to non-obese patients (67.5%; P = .006). In determining multigland disease the sensitivity of 4D CT was 86%, while the specificity was 87%. A 4D CT has impressive rates of accurate localization of parathyroid adenomas; however due to the radiation exposure involved, it should remain a second line imaging modality. PHPT patients should first be evaluated with USG, with 4D CT used if this is unsuccessful and patients are greater than 40 years old, have a high BMI, or are having revision surgery.

Preoperative diagnosis of parathyroid gland pathology in patients with persistent or recurrent primary hyperparathyroidism: a retrospective study

INTRODUCTION: Localization of abnormal parathyroid glands in persistent or relapsed patients with primary hyperparathyroidism presents problems for surgeons before repeated surgery. There is no clear standard for the choice of diagnostic modality for localization of PG in this group of patients.OBJECTIVE: To search for the optimal diagnostic protocol of the parathyroid pathology preoperative diagnosis in patients with primary hyperparathyroidism with persistent or recurrent disease.MATERIALS AND METHODS: 55 patients diagnosed with persistence or recurrence of PHPT who underwent repeated surgical treatment were included in the study. Before surgical intervention all patients underwent laboratory and instrumental investigations in the volume of: blood tests for PTH, TTH, ionized calcium, 25(OH)D, creatinine, phosphorus, neck ultrasound, parathyroid scintigraphy by washout method, dual-isotope subtractive scintigraphy of parathyroid glands (early and delayed phases), SPECT of parathyroid glands (with uptake correction), computed tomography of the neck with intravenous bolus contrast.RESULTS: CT and planar subtraction dual-isotope scintigraphy showed the highest DA in the overall group (persistence and recurrence) (78% and 78%), with the DA of these methods differing slightly (88% and 92%) and overall accuracy being higher for CT (90% and 87%). Neck ultrasound showed the lowest rates among all methods (DA — 46%, DS — 80%, OA — 67%). Planar scintigraphy (washout) and SPECT were comparable in their informativeness: DA — 67% and 65%, DS — 96% and 98%, OA — 85% and 86%.DISCUSSION: The most commonly used current diagnostic search algorithm before reoperation is visualization of the thyroid gland by two modalities: Neck ultrasound and parathyroid scintigraphy (washout/subtraction) or SPECT-CT. In doubtful cases, the second step is computed tomography of the neck with contrast or PET/CT. It is extremely difficult to choose one optimal diagnostic method, as none of them has 100% diagnostic accuracy. In addition, each study has limitations, and the availability of some modalities is limited. In our study, the location of pathologically altered thyroid was correctly recognized in 90% of cases by CT with contrast and in 87% of cases by planar subtraction dual-isotope scintigraphy. The informativeness of neck ultrasound showed the lowest values of all modalities. SPECT and planar washout scintigraphy took an intermediate position in terms of diagnostic accuracy.CONCLUSION: Isolated ultrasonography of the neck has low diagnostic accuracy in patients with primary hyperparathyroidism with persistent or recurrent disease. We recommend the combination of US with contrast-enhanced computed tomography of the neck or US with dual isotope subtraction scintigraphy of the parathyroid glands, which have the same diagnostic accuracy. SPECT and planar washout scintigraphy can be used for the diagnosis of abnormal parathyroid glands in persistent or recurrent patients with primary hyperparathyroidism when more informative techniques are unavailable. When the techniques were combined, the combination of ultrasound/CT with contrast and ultrasound/planar subtraction dual isotope scintigraphy showed the best results with DA of 85% and 86%.

Evaluation of Imaging Findings in Patients with Pretransplant and Posttransplant Tertiary Hyperparathyroidism.

Tertiary hyperparathyroidism, characterized by autonomous overproduction of parathyroid hormone, can be seen in patients with long-standing secondary hyperparathyroidism (pretransplant) or after renal transplant (posttransplant). Parathyroid scintigraphy and ultrasonography are the most commonly used imaging procedures for the preoperative localization of abnormal parathyroid glands. We aimed to evaluate imaging findings in pretransplant and posttransplant tertiary hyperparathyroidism. This study included 32 patients with pretransplant tertiary hyperparathyroidism and 20 patients with posttransplant tertiary hyperparathyroidism. On parathyroid scintigraphy with technetium-99m sestamibi, early-phase and latephase images were acquired. Images were evaluated for the presence and the number of active foci and the degree of uptake on the late-phase image. The existence of an autonomous gland was based on latephase retention and was scored from 0 to 2 (retention score). On ultrasonography, the criteria threshold for autonomy was the maximum length of the largest gland ≥10 mm (ultrasonography score). On parathyroid scintigraphy, the most commonly observed pattern in the pretransplant group was positivity in ≥3 glands, and in the posttransplant group the most commonly observed pattern was positivity in 1 to 2 glands. In pretransplant and posttransplant groups, the criteria threshold for the presence of an autonomous parathyroid gland on parathyroid scintigraphy (grade 2 retention) was met in 26 (81%) and 9 (45%) patients and on ultrasonography in 25 (78%) and 10 (50%) patients, respectively. In the whole group of patients (n = 52), correlation existed between ultrasonography score and retention score. Glandular weight was correlated with both retention score and ultrasonography score. Higher numbers of detectable glands and the presence of parathyroid autonomy were more common in the pretransplant group. This might be explained by parathyroid gland involution after transplant. The results may also suggest that factors other than autonomy are responsible for posttransplant tertiary hyperparathyroidism.

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.

A new histopathological location of parathyroid gland with high possibility of unintended parathyroidectomy.

Unintended parathyroidectomy occasionally happens despite meticulous capsular dissection and the histopathological location of removed parathyroid glands were traditionally classified as extracapsular, subcapsular, and intrathyroidal location. This study aimed to investigate the new histopathological location of parathyroid gland with high possibility of unintended parathyroidectomy that was difficult to be found with naked eye despite capsular dissection. This study investigated unintended parathyroidectomy that occurred in 743 patients who received thyroid surgery by reviewing pathology reports and slides. The histopathological location of unintentionally removed parathyroid glands was classified as intracapsule and extracapsule, and the intracapsular glands were further classified as completely buried in the thyroid parenchyme, partially buried, and subcapsular locations. The incidence of unintended parathyroidectomy was 12.8%. Among the 103 unintentionally removed parathyroid glands, 74 (71.8%) were found intracapsular and 29 were extracapsular. Among the intracapsular glands, 57 (55.4%) parathyroid glands were found in difficult locations such as completely buried (40.8%) and partially buried (14.6%). The partially buried parathyroid gland can act as a risk factor for unintended parathyroidectomy comparable to intrathyroidal parathyroid gland despite the surgeon's best effort with meticulous capsular dissection. However, continued advances in visualizing technique such as autofluorescence imaging may lower the chance of incidentally removed partially buried parathyroid glands in the future.

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.

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. 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. 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%. 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.

Minimal invaziv paratiroidektomi. Tek merkez deneyimi.

Objective: Among endocrine diseases, primary hyperparathyroidism ranks third in frequency after diabetes mellitus and thyroid diseases &#x0D; The aim of this study is to present the results of parathyroid adenoma surgery and the effectiveness of imaging methods in detecting parathyroid adenomas in our tertiary surgical clinic, where parathyroid surgery is frequently performed.&#x0D; Methods: Between January 2019 and March 2023, records of patients who underwent surgery in our clinic due to parathyroid adenoma were retrospectively scanned. Patient demographics, blood parameters, preoperative imaging results, surgical findings, and postoperative pathological examination results were recorded.&#x0D; Results: A total of 98 patients were included in the study. During surgery, it was observed that parathyroid adenomas were most commonly located in the right inferior position (48 patients, 49%) and secondarily in the left inferior position (30 patients, 30.6%).&#x0D; When examining the diagnostic accuracy rates of preoperative imaging studies in the localization of pathological parathyroid glands, it was found that the location of right inferior parathyroid adenomas was most accurately detected both in ultrasound examination and scintigraphic imaging results (30.6% and 36.7%, respectively). Parathyroid adenomas located adjacent to the isthmus were found to be least accurately detected both in ultrasound examination and scintigraphic imaging results (1% and 0%, respectively).

Are 99mTC-Sestamibi Single Photon Emission Computed Tomography Scan Results Associated to the Parathyroid Cell Type in Primary Hyperparathyroidism?

Introduction99mTC-sestamibi scintigraphy (SPECT-CT) is a common imaging modality for parathyroid localization in primary hyperparathyroidism (PHPT). Prior studies have suggested that the cellular composition of parathyroid adenomas influences SPECT-CT imaging results. Other biochemical and anatomical factors may also play a role in false negative results. Therefore, after controlling for confounding variables, we sought to determine whether the histologic composition of parathyroid adenomas is associated to SPECT-CT results in patients with single gland disease causing PHPT. MethodsA retrospective review of patients with PHPT due to confirmed single gland disease was performed over a 2-y period. A 1:1 propensity score matching was done between patients with positive and negative SPECT-CT results with regard to demographical, biochemical, and anatomical characteristics followed by blinded pathologic examination of cell composition in the matched pairs. ResultsFive hundred forty two patients underwent routine four gland exploration and 287 (53%) patients were found to have a single adenoma. Of those, 26% had a negative SPECT-CT result. There were significant differences between groups with regards to biochemical profile, gland location, and gland size. All of which became nonsignificant after propensity score matching. Adenomas were primarily composed of chief cells, with no difference between groups (95% versus 97%, P = 0.30). In the positive SPECT-CT group, chief cells were the dominant cell type in 68% of the cases, followed by mixed type (13%), oxyphil cells (12%), and clear cells (7%). This was similar to the negative SPECT-CT group (P = 0.22). ConclusionsWhile certain patient’s clinical characteristics are associated with SPECT-CT imaging results, histologic cell type is not significantly associated.