Parathyroid Adenoma Research Articles

Primary hyperparathyroidism presenting as slipped capital femoral epiphysis; a case report and literature review

Primary hyperparathyroidism associated with slipped capital femoral epiphysis (SCFE) is rare. We report a case of a 14-year-old girl who presented with limping of gait and was diagnosed to have bilateral SCFE and underwent screw fixation of both hips. She had pain involving multiple joints and tenderness on further evaluation and was found to have biochemical hyperparathyroidism. The patient was initially managed medically, and further investigations revealed a parathyroid lesion in the right superior location. Workup for multiple endocrine neoplasia was negative. She underwent right superior parathyroid adenoma excision, and post-operatively, she was cured of the disease. On follow-up, she is asymptomatic, and her calcium is within normal limits. A literature review showed that SCFE is associated with severe hyperparathyroidism in adolescents.

Heterogeneous parathyroid near-infrared autofluorescence patterns are associated with single adenomas in primary hyperparathyroidism.

Primary adenoma (PA) and multi-gland hyperplasia (MGH) account for 85% and 15% of primary hyperparathyroidism (PHPT) cases, respectively. Near-infrared autofluorescence (NIRAF) enhances intraoperative parathyroid identification. We hypothesized that PA would display a more heterogeneous NIRAF pattern compared to MGH. Patients undergoing surgery for sporadic PHPT were categorized based on the presence of PA or MGH. To quantify heterogeneity, we utilized ratios of (1) mean parathyroid gland (PG) NIRAF over background NIRAF (mean ratio), (2) minimum and (3) maximum PG NIRAF over mean PG NIRAF (minimum and maximum ratios). Additionally, a heterogeneity score was quantified using mean ratio (mean PG NIRAF over background NIRAF), and overall NIRAF (mean NIRAF of eight random 15 × 15 pixel areas). A point was assigned to ratios <0.8 or >1.2. Images were quantified by ImageJ software. Mann-Whitney test was performed for all comparisons. Of 78 patients, 63 had a single PA and 15 had MGH, totaling 102 PGs. There was no difference between their mean ratios. PA had a lower minimum ratio compared to that of MGH (0.86 ± 0.01 vs. 0.93 ± 0.01, p = 0.001) and a brighter maximum ratio (1.21 ± 0.02 vs. 1.12 ± 0.01, p = 0.0008). PA also scored higher on their heterogeneity scores compared to MGH (1.27 ± 0.23 vs. 0.33 ± 0.15, p = 0.001). Single parathyroid adenomas display a more heterogeneous autofluorescence pattern compared to that of multi-gland hyperplasia. Intraoperative characterization of PGs by real-time NIR imaging patterns may be a beneficial adjunct during parathyroid surgery.

The unexpected effect of parathyroid adenoma on inflammation.

Primary hyperparathyroidism (PHPT) is an endocrinological disease that affects systemic inflammation. This study is aimed to investigate the preoperative and postoperative effect of PHPT on systemic inflammation. A total of 203 patients who were successfully operated for PHPT and 98 healthy controls were included in the study. The blood tests of the patients in the last month preoperatively and in the postoperative 6th month were compared. In addition, preoperative and postoperative tests were compared with the healthy control group. When the preoperative neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic inflammation index (SII) values of the patients who were operated for parathyroid adenoma were compared with the control group (p values were < 0.05, 0.01, 0.19, < 0.05), the NLR, PLR, and SII values were significantly lower in the patient group with parathyroid adenoma than in the control group. When the preoperative and postoperative 6th month NLR, PLR, LMR, and SII values of the patients were compared (p values: 0.026, 0.56, 0.023, 0.016, respectively), there was a significant increase in NLR and SII values after excision, while a significant decrease was observed in the LMR value. When the postoperative 6th month NLR, PLR, LMR, SII values were compared with the healthy control group (p values: 0.22, 0.29, 0.19, 0.29, respectively), no significant difference was observed between all values. We found that the immune system was suppressed in PHPT and this returned to normal levels after a successful surgery.

Robotic parathyroidectomy is a feasible technique for primary hyperparathyroidism

PurposeFocused parathyroidectomy is the gold standard treatment modality for primary hyperparathyroidism, which allows accurate preoperative localization. Robotic parathyroidectomy has emerged as a feasible procedure for focused parathyroidectomy. This study aimed to report the experiences of gasless robotic transaxillary parathyroidectomy for primary hyperparathyroidism in a single center.MethodsWe assessed the data obtained from patients who underwent gasless robotic parathyroidectomy with the transaxillary approach between December 2013 and August 2022 and were diagnosed with primary hyperparathyroidism at our institute. The data included clinical, biochemical, and pathological features and operation time.ResultsOf the 12 patients, 11 were women and one was a man. The median age of the patients was 44.5 years (range: 15–65 years). The median preoperative maximum mass diameters on ultrasonography and neck computed tomography were 1.2 ± 0.5 and 1.1 ± 0.6 cm, respectively. The median size of the postoperative maximum mass diameter in gross pathology was 1.3 ± 0.4 cm. The location of the enlarged parathyroid was left superior in five patients, right inferior in four, left inferior in three, and no right superior in one. In the final pathological examination, all cases were parathyroid adenomas. Only one case experienced a postoperative bleeding complication. At six months from surgery, average of an axillary scar length was 5.85 cm, and an average width was 0.21 cm. The mean operative time was 113 ± 48 min. The mean robot docking and console times were 9 ± 5 and 47 ± 52 min, respectively.ConclusionsRobotic transaxillary parathyroidectomy is a feasible technique in select patients with primary hyperparathyroidism and preoperatively localized disease. The gasless robotic transaxillary approach provides procedural safety as well as superior cosmetic results without a neck scar.

When parathyroid adenoma meets osteopathia striata, rarest amalgam of bony dysplasia with brown tumors: a case report

BackgroundOsteopathia is a benign entity characterized by linear densities along the diaphysis and metaphysis of the longitudinal axes of the long bone. Parathyroid adenoma is a non-malignant parathyroid gland tumor characterized by increased parathormone levels, causing defecting calcium levels leading to multiple brown tumors, renal calculi, bone pains, polyuria, and arrhythmias in the patient. The coexistence of parathyroid adenoma with osteopathia striata has not been reported yet in the literature. To our knowledge, this is the first case of its kind.Case presentationAn 18-year-old male patient presented to our institution with the complaint of genu valgum deformity in his right knee and was admitted for corrective surgery. While undergoing a preoperative evaluation, we came across multiple focal, lytic lesions in his radiographs and an atypical finding of osteopathia striata in his long bones. Further examination led us to the findings of cranial sclerosis and acro-osteolysis of distal phalanges. The tumor, whose catalyst was unclear, directed us toward an ultrasonographic analysis of the patient’s neck, leading us to a solitary parathyroid adenoma.ConclusionsRadiological examinations played a very crucial role in the diagnosis of this condition. Though the reason behind osteopathia and the parathyroid lesion in this patient remains unknown, this presentation remains an exceptional and never-reported case of parathyroid adenoma and associated brown tumors in a patient with osteopathia striata.

Accuracy of Four-Dimensional Computed Tomography and Different Imaging Modalities in Primary Hyperparathyroidism.

Background This study aimed to compare the accuracy of different imaging modalities in the preoperative localization of parathyroid pathology in primary hyperparathyroidism. Methodology This prospective study enrolled 70 patients who were biochemically diagnosed with primary hyperparathyroidism between 2021 and 2022 at our center. Patients underwent scanning using three imaging modalities, namely, Tc99m sestamibi scan (sestamibi), parathyroid ultrasonography, and four-dimensional computed tomography (4DCT). A descriptive analysis was performed to determine and compare the respective localizing sensitivities. Results The most common site of parathyroid adenoma (PA) was the left inferior parathyroid gland, seen in 28 (40%) patients. Three patients had false-positive imaging studies with no parathyroid pathology identified surgically or on histological examination. The median levels of parathyroid hormone decreased significantly (p < 0.001) after the surgery, with a median of 24.3 (1.90-121). Furthermore, 4DCT accomplished a sensitivity of 97.14% for diagnosing the side and 94.03% for overall localization of PA. This sensitivity was superior to the sensitivity of ultrasonography and sestamibi scan to detect the side and quadrant of the adenoma. 4DCT was significantly higher in sensitivity when compared to the combination of ultrasound and sestamibi (p < 0.001). Conclusions 4DCT yielded the highest sensitivity in localizing parathyroid pathology from the imaging modalities studied with the lowest false-negative rate. Using ultrasound with 4DCT could be the most cost-effective combination for detecting primary hyperparathyroidism.

Update in imaging tests used for the localization of parathyroid pathology

Preoperative localization of parathyroid pathology, generally a parathyroid adenoma, can be difficult in some cases due to the anatomical variants that these glands present. The objective of this review is to analyse the different imaging techniques used for preoperative localization of parathyroid pathology (scintigraphy, ultrasound, CT, MRI and PET).There is great variability between the different tests for the preoperative localization of parathyroid pathology. The importance of knowing the different diagnostic options lies in the need to choose the most suitable test at each moment and for each patient for an adequate management of primary hyperparathyroidism (PHP) with surgical criteria.

Tertiary Hyperparathyroidism Presenting as Multifocal Brown Tumors: A Case Report

Brown Tumor (BT) of the bone is a rare manifestation of hyperparathyroidism (HPTH), an unusual reactive bone lesion attributed to disturbed bone remodeling, from long-standing increase in parathyroid hormone level (PTH). Historically, BTs were described with primary HPTH but due to early diagnosis of this entity, and improved survival in patients with end-stage renal disease (ESRD) especially those on renal replacement therapy (RRT), more cases of BT are now described in this population, and less in PHPTH. Thus, it is mostly the consequence of untreated secondary or tertiary HPTH whose major culprits are chronic kidney disease (CKD) and ESRD. The management of brown tumors related to chronic renal failure consists primarily of its prevention through the use of phosphate binders, vitamin D analogues, and calcimimetics with surgical parathyroidectomy reserved as the final resort in refractory cases. Herein, we present the case of a 24-year-old female patient with ESRD on intermittent hemodialysis (IHD) who developed recent onset facial tumefaction. Blood work revealed markedly elevated PTH at more than 5000 pg/ml, upper borderline hypercalcemia, and hyperphosphatemia. Further investigations with chest computed tomography (CT) and Technetium-99m (99mTc)- Sestamibi scan nuclear imaging showed multiple ribs lytic lesions as well as features of extensive BT and parathyroid adenomas. Thereafter, the patient was sent for parathyroidectomy after which the patient developed hungry bone syndrome.

Comparing accuracy of machine learning approaches to identifying parathyroid adenomas: Lessons and new directions

PurposeThe purpose of this investigation is to understand the accuracy of machine learning techniques to detect biopsy-proven adenomas from similar appearing lymph nodes and factors that influence accuracy by comparing support vector machine (SVM) and bidirectional Long short-term memory (Bi-LSTM) analyses. This will provide greater insight into how these tools could integrate multidimensional data and aid the detection of parathyroid adenomas consistently and accurately. MethodsNinety-nine patients were identified; 93 4D-CTs of patients with pathology-proven parathyroid adenomas were reviewed; 94 parathyroid adenomas and 112 lymph nodes were analyzed. A 2D slice through the lesions in each phase was used to perform sequence classification with ResNet50 as the pre-trained network to construct the Bi-LSTM model, and the mean enhancement curves were used to form an SVM model. The model characteristics and accuracy were calculated for the training and validation data sets. ResultsOn the training data, the area under the curve (AUC) of the Bi-LSTM was 0.99, while the SVM was 0.95 and statistically significant on the DeLong test. The overall accuracy of the Bi-LSTM on the validation data set was 92 %, while the SVM was 88 %. The accuracy for parathyroid adenomas specifically was 93 % for the Bi-LSTM and 83 % for the SVM model. ConclusionEnhancement characteristics are a distinguishing feature that accurately identifies parathyroid adenomas alone. The Bi-LSTM performs statistically better in identifying parathyroid adenomas than the SVM analysis when using both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes. Summary statementThe Bi-LSTM more accurately identifies parathyroid adenomas than the SVM analysis, which uses both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes, performs statistically better.

Morphological criteria for sporadic multiple parathyroid gland disease

Background. There are no specific morphological signs for sporadic multiglandular disease (MGD) in primary hyperparathyroidism (PHPT). The aim of the study. To study the structure of the morphological substrate of primary, secondary and tertiary hyperparathyroidism and to assess the effectiveness of morphological criteria in the diagnosis of sporadic multiglandular disease in primary hyperparathyroidism. Methods. The study included 69 patients; 18 patients with PHPT and sporadic multiglandular disease (npreparation = 31) formed the main group, 51 patients (npreparations = 104) – the comparison group. The comparison group was divided into 3 subgroups: 1) patients with PHPT and solitary parathyroid gland (PTG) lesions – 26 patients (npreparations = 26); 2) patients with secondary hyperparathyroidism (SHPT) – 15 patients (npreparations = 48); 3) patients with tertiary hyperparathyroidism (TGPT) – 10 patients (npreparations = 30). Results. The morphological structure of the comparison groups is homogeneous: group 1 is represented by parathyroid adenoma (26 (100 %)), groups 2 and 3 – by hyperplasia (48 (100 %) and 30 (100 %), respectively). Most of the PTG specimens of the main group are represented by hyperplasia (25 (80 %)), and in 1/5 cases – by adenomas (6 (19.4 %)). Sporadic multiglandular disease in PHPT was characterized by a predominant frequency of detecting the absence of a capsule and a rim of unchanged tissue, as well as the presence of adipocytes (pχ2 &lt; 0.01). Components of the PTG morphological structure make it possible to identify changes specific to the sporadic multiglandular disease in PHPT, with a diagnostic efficiency of 76.5–90.3 %. Conclusion. Sporadic multiglandular disease in any clinical variant of hyperparathyroidism is characterized by a high prevalence of hyperplasia – 80 % in PHPT and 100 % in SHPT and TGPT. The following morphological criteria for sporadic multiglandular disease in PHPT have been established: the presence of adipocytes in the PTG parenchyma (diagnostic efficiency (DE) – 90 %)); absence of a capsule (DE = 78 %) and a rim of unchanged gland tissue (DE = 76 %).

Preoperative identification of small parathyroid adenomas-better done by fluorocholine positron emission tomography/computed tomography.

Preoperative localization imaging studies are crucial for safe and successful parathyroidectomy in patients with primary hyperparathyroidism (pHPT), especially in focused approaches. A common imaging sequence is ultrasound followed by scintigraphy. These techniques, but not 18F-fluorocholine positron emission tomography/computed tomography (PET/CT), show lower detection rates in multiglandular disease (MGD), which is associated with smaller adenomas. In this study, we evaluate the accuracy of these modalities in small parathyroid adenomas (PAs) and discuss the potential sequence of preoperative localization diagnostics. Patients undergoing parathyroidectomy for pHPT were retrospectively categorized into small adenoma (specimen diameter <10 mm) and large adenoma. The groups were compared for accuracy of preoperative imaging studies, short-term and long-term outcomes. Among 147 patients retrospectively analyzed in this study, 38 small PAs were found. Preoperative correct quadrant prediction for small adenomas was significantly lower for ultrasound (P=0.03) and single-photon emission computed tomography/CT (SPECT/CT) (P<0.01) but not for choline PET/CT. While PET/CT was performed significantly more often in small PAs (P<0.01), it showed highly significant superiority over the other imaging modalities in accurate preoperative localization in both small (P<0.0001) and large PAs (P<0.01). There was no difference in calcium and parathyroid hormone (PTH) levels at latest follow-up with slightly more recurrences in small adenomas (P=0.08). Choline PET/CT showed a better diagnostic yield especially for small and multiple adenomas and was better in prediction of the correct localization. It could therefore serve as a second-line imaging modality.

Abstract #1561754: Correlation of Preoperative Localization of Parathyroid Adenoma With Imaging Findings and Surgical Outcome

Abstract #1561754: Correlation of Preoperative Localization of Parathyroid Adenoma With Imaging Findings and Surgical Outcome

Adequacy of parathyroid CT coverage for localisation of parathyroid adenomas: clinical audit

Adequacy of parathyroid CT coverage for localisation of parathyroid adenomas: clinical audit

흉선에서 발생한 이소성 부갑상선 선종 1예

Primary hyperparathyroidism (PHPT) is a common endocrine disorder with elevated serum parathyroid hormone levels. In most cases, the disease involves a single parathyroid adenoma, followed by parathyroid hyperplasia. Parathyroid glands are rare, but can be present in a variety of locations because it migrates long distance during fetal period. Therefore, the incidence of ectopic parathyroid adenoma is rare and it is not easy to diagnose ectopic parathyroid adenomas and to specify the location before surgery. Recently, we diagnosed ectopic parathyroid adenoma at the thymus and treated successfully. So, we report this case with literature review.

Minimally Invasive Parathyroidectomy using Intraoperative Ultrasonography in Parathyroid Adenoma Patients with a History of Total Thyroidectomy

A 65-year-old patient who underwent total thyroidectomy 10 years ago was suspected of having a parathyroid adenoma, and minimally invasive parathyroidectomy was planned. Preoperative ultrasonography(USG) and 99mTc MIBI scan indicated a left lower parathyroid lesion. In the first operation, intraoperative parathyroid hormone monitoring (IOPTH) was not possible due to hospital circumstances. Although no adenomatous lesion was found in the expected surgical field, surgery was completed after removing lesions around the left lower parathyroid gland. However, post-surgery, parathyroid hormone did not decrease at all, so a second operation was performed with IOPTH preparation. In the second operation, intraoperative ultrasonography was performed, and a suspected adenoma lesion was removed from the left upper lesion. He has been under follow-up for 3 years without complications. Surgeon-peformed intraoperative USG and preoperative scintigraphy had advantages in determining the localization of parathyroid lesion even withiout IOPTH.

A Novel Adult Case of Recurrent Acute Pancreatitis Caused by Hypercalcemia With Concurrent Manifestation of Posterior Reversible Encephalopathy Syndrome Revealing Undiagnosed Primary Hyperparathyroidism due to an Underlying Parathyroid Adenoma.

Hypercalcemia-induced posterior reversible encephalopathy syndrome (PRES) is a rare entity primarily associated with iatrogenic vitamin D/calcium overdose, malignancy, or, infrequently, primary hyperparathyroidism. We present a novel case of an adult male from rural India who experienced recurrent acute pancreatitis caused by hypercalcemia with concurrent manifestation of PRES. Diagnostic evaluation revealed markedly elevated serum calcium levels and parathyroid hormone concentrations, consistent with primary hyperparathyroidism. Imaging studies identified a parathyroid adenoma near the right thyroid lobe, subsequently surgically excised. This case underscores the importance of considering primary hyperparathyroidism as an underlying cause of PRES, especially in the absence of acute arterial hypertension or autonomic dysfunction. Early recognition and intervention are essential in mitigating the morbidity and mortality of PRES.

Normocalcemic hyperparathyroidism after successful parathyroidectomy for single parathyroid adenoma: Prevalence, etiological factors, predictive markers, treatment and evolution

Background and objectivePostparathyroidectomy normocalcemic hyperparathyroidism (PPNCHPPT) is a frequent situation for which we have no information in our country. The objective is to know our prevalence of PPNCHPPT, the associated etiological factors, the predictive markers, the treatment administered and the evolution. Patients and methodRetrospective observational cross-sectional study on 42 patients. Twelve patients with PPNCHPPT and 30 without PPNCHPPT are compared. ResultsHPPTNCPP prevalence: 28.6%. Etiological factors: vitamin D deficiency: 75%; bone remineralization: 16.7%; renal failure: 16.7%; hypercalciruria: 8.3%. No change in the set point of calcium-mediated parathormone (PTH) secretion was observed, but an increase in the preoperative PTH/albumin-corrected calcium (ACC) ratio was observed. Predictive markers: PTH/ACC ratio (AUC 0.947; sensitivity 100%, specificity 78.9%) and PTH (AUC 0.914; sensitivity 100%, specificity 73.7%) one week postparathyroidectomy. Evolution: follow-up 30 ± 16.3 months: 50% normalized PTH and 8.3% had recurrence of hyperparathyroidism. Patients with PPNCHPPT less frequently received preoperative treatment with bisphosphonates and postoperative treatment with calcium salts. ConclusionsThis is the first study in our country that demonstrates a mean prevalence of PPNCHPPT, mainly related to a vitamin D deficiency and a probable resistance to the action of PTH, which can be predicted by the PTH/ACC ratio and PTH a week post-intervention and often evolves normalizing the PTH. We disagree with the etiological effect of hypercalciuria and the change in the PTH/calcemia regulation set point, and we acknowledge the scant treatment administered with calcium salts in the postoperative period.

Treating intra-thyroid parathyroid adenoma by radiofrequency is a valuable alternative to hemithyroidectomy

Background Parathyroid adenoma (PA) is the most common cause of primary hyperparathyroidism (PHPT). One infrequent scenario (0.7%–6%) is represented by intra-thyroid PA (I-PA), an ectopic variant of the parathyroid gland included in the thyroid parenchyma. Radiofrequency (RF) of I-PA seems to be an excellent alternative to hemithyroidectomy for these patients. The present study aimed to report three cases of PHPT and I-PA treated with RF at two institutions. Materials and methods These two institutions share guidelines for thyroid RF. At both institutions, cases with surgical indication and difficult PA localization are discussed during thyroid multidisciplinary meetings involving all disciplines involved in managing these cases. RF was performed using a Viva RF System generator (STARMED). Ultrasound contrast evaluation was performed using a SonoVue (Bracco). All patients were followed-up by an expert endocrinologist. Results Three cases had indications for treating I-PA. All patients were proposed to undergo RF rather than hemithyroidectomy, and accepted this option. RF of I-PA was performed with a power of 30–50 W and delivering a total between 0.02 and 0.69 Kcal. The active treatment lasted just more than 1 min. Post-treatment follow-up revealed PTH and calcium normalization. Conclusion This study showed highly encouraging results in favor of treating I-PA with RF.

Absolute and Relative Washout Rates Associated With Parathyroid Adenoma.

Background Parathyroid adenoma is a benign parathyroid gland tumor that causes excessive parathyroid hormone production, leading to primary hyperparathyroidism. High serum calcium levels characterize it. Accurate diagnosis and localization of adenomas are crucial for effective surgical management. Computed tomography is a fundamental imaging technique used to identify and characterize parathyroid adenomas. This study aimed to provide a comprehensive overview of the absolute and relative contrast washout rates of parathyroid adenoma and the thyroid gland, and compare enhancement patterns to establish the absolute and relative washout rates of parathyroid adenoma. Materials & methods This retrospective study analyzes the CT findings of 33 patients with histopathologically proven parathyroid adenomas. All patients with 4D CT scans have been included with no exclusion criteria. The mean attenuation was measured in Hounsfield units for the parathyroid adenoma and thyroid gland in the non-enhancing, arterial, venous, and delayed phases, depending on the region of interest. All statistical analyses were performed using SPSS (IBM Corp., Armonk, NY, USA). Student's t-test was used to evaluate the differences in measurements between the parathyroid adenoma and thyroid tissue. One-way ANOVA was used to evaluate the difference in calculations between the parathyroid adenoma and thyroid tissue. P-values <0.001 were considered statistically significant. Results The most common location of parathyroid adenomas is inferior to the thyroid gland. The average pre-contrast attenuation of the parathyroid adenoma is 61.8 ± 15.5 HU compared to 105.5 ± 15.2 HU of the thyroid gland. The arterial attenuation of the parathyroid adenoma is 170.3 ± 40.7 HU, relatively comparable to the thyroid gland arterial attenuation, which is 188.0 ± 9.6 HU. The venous and delayed-phase attenuation of the parathyroid adenoma were 146.8 ± 37.5 and 96.8 ± 26.7 HU, respectively,and 178.8 ± 20.2 HU and 149.3 ± 15.2 HU for the thyroid gland, respectively. The calculated absolute and relative arterial washout rates for the parathyroid adenoma were 69.4 ± 13.4% and 43.2 ± 8.0%, respectively, as compared to 46.4 ± 9.9% and 20.6 ± 6.7% for the thyroid gland. The calculated absolute and relative venous washout rates for the parathyroid adenoma were 58.0 ± 21.4% and 33.0 ± 13.7%, respectively, as compared to 37.2 ± 17.2% and 15.9 ± 9.6% for the thyroid gland. Conclusions Parathyroid adenoma demonstrated a significantly higher washout rate than the thyroid gland tissue. Absolute arterial washout ≥69% and relative arterial washout ≥43% indicate parathyroid adenoma. Moreover, absolute venous washout ≥58% and relative venous washout ≥33% can be considered diagnostic factors for parathyroid adenoma. Further, pre-contrast attenuation of <60 Hounsfield units has a substantial predictive value for parathyroid adenoma in addition to the described washout rate. Increased awareness of the washout rate can increase the success rate of four-dimensional computed tomography interpretation.

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.