Abnormal Parathyroid Tissue Research Articles

Expression of the Calcium-Sensing Receptor on Normal and Abnormal Parathyroid and Thyroid Tissue

IntroductionCurrent imaging techniques have several limitations in detecting parathyroid glands. We have investigated the calcium-sensing receptor (CaSR) as a potential target for specifically labeling parathyroid glands for radiologic detection. For accurate imaging it is vital that a large differential expression exists between the target tissue and adjacent structures. We sought to investigate the relative abundance of the CaSR in normal and abnormal parathyroid tissue, as well as normal and abnormal thyroid. MethodsExisting clinical specimens were selected that represented a wide variety of pathologically and clinically confirmed malignant and benign thyroid and parathyroid specimens. Sections were stained for the CaSR using immunohistochemistry and scored for intensity and abundance of expression. (H score = intensity scored from 0 to 3 multiplied by the % of cells at each intensity. Range 0-300). ResultsAll parathyroid specimens expressed the CaSR to a high degree. Normal parathyroid had the highest H score (271, s.d. 25.4). Abnormal parathyroid specimens were slightly lower but still much higher than normal thyroid (H score 38.3, s.d. 23.3). Medullary thyroid cancer also expressed the CaSR significantly higher than normal thyroid (H score 182, s.d. 69.1, P < 0.001) but below parathyroid levels. Hürthle cell carcinoma expressed the CaSR to a lesser degree but higher than normal thyroid (H score 101, s.d. 46.4, P = 0.0037). ConclusionsThe CaSR is differentially expressed on parathyroid tissue making it a feasible target for parathyroid imaging. False positives might be anticipated with medullary and Hürthle cell cancers.

SAT191 Primary Hyperparathyroidism With Low-Normal Parathyroid Hormone Levels: Phosphorus Can Be The Key

Abstract Disclosure: D. He: None. T. Tavdy: None. Y. Tomer: None. D. Kalbi: None. V. Tabatabaie: None. Background: Primary hyperparathyroidism (PHPT) is characterized by the inappropriate secretion of PTH that leads to hypercalcemia. In patients with PHPT, 80-90% have PTH levels above the normal range and 10-20% have inappropriately “normal” PTH levels, most often in the high-normal range1. PTH levels below or in the lower end of the normal range prompt investigation of non-PTH mediated causes of hypercalcemia. We present a case of PHPT with low-normal PTH levels, and discuss how phosphorus levels guided our diagnosis of an underlying parathyroid adenoma. Clinical Case: An 83-year-old woman was found to have hypercalcemia with corrected calcium ∼13 mg/dL (8.5 - 10.5 mg/dL) and PTH of 36.7 pg/mL (20.0 - 80.0 pg/mL). Phosphorus was consistently low, ranging from 2.1 to 2.4 mg/dL (2.5 - 4.5 mg/dL). PTHrP was 18 pg/mL (11-20 pg/mL). 25-hydroxy vitamin D was 24.5 ng/mL (30-60 ng/mL). 1,25-dihydroxy vitamin D was 36 pg/mL (18-72 pg/mL). Serum and urine protein electrophoresis were normal. HTLV-1/2 antibody was negative. TSH was 1.15 uU/mL (0.30 - 4.20 uU/mL). The patient had no history of ingesting lithium or thiazide diuretics. Suspecting PHPT, the patient underwent a nuclear medicine parathyroid scan which showed abnormal parathyroid tissue in the left thyroid lobe. In the setting of volume overload, management of the patient’s persistent hypercalcemia of greater than 12 mg/dL (8.5 - 10.5 mg/dL) began initially with a dose of pamidronate 60 mg and gentle hydration followed by furosemide. Corrected calcium improved to 12.3 mg/dL (8.5 - 10.5 mg/dL). Given the patient’s decreased functional status (bedbound) and high surgical risk, after discussion with the patient and her family, a decision was made to proceed with medical management and not with parathyroidectomy. She was treated with cinacalcet 30 mg twice daily. The goal calcium of &amp;lt; 1 unit over the upper limit of normal (11.5 mg/dL) was achieved on day of discharge of the patient back to her nursing home. Conclusion: In patients with hypercalcemia, low serum phosphorus can point to a PTH- or PTHrP-mediated process. Inappropriate secretion of PTH or PTHrP results in high serum calcium and low phosphorus levels by increasing bone resorption and renal calcium reabsorption, and decreasing renal phosphorus reabsorption. This case shows that in patients with hypercalcemia and concomitant hypophosphatemia with normal PTHrP, PHPT should still be considered as a potential etiology, even in the setting of a low-normal PTH level. In our patient, the presence of a parathyroid adenoma was demonstrated with a conclusive parathyroid scan.

FRI688 Efficacy Of 4D CT Scan And Tc-99m-MIBI-SPECT/CT For The Preoperative Localization Of Abnormal Parathyroid Glands In Patients With Primary Hyperparathyroidism

Abstract Disclosure: E. Zareva: None. V. Rivera-Hernandez: None. S. Salpekar: None. J. Moyo: None. M. Bilbatua: None. Z. Lauer: None. A. Zare: None. P. Kaur: None. M. Deshmukh: None. Background: Primary hyperparathyroidism is a common endocrine disorder that often requires surgical intervention for a cure. Accurate localization of abnormal parathyroid glands is critical for successful surgical treatment. NM Parathyroid scan with single-photon emission computed tomography(Tc99m-MIBI-SPECT/CT) is considered the gold standard, but other options like ultrasound, CT, MRI, and PET have been used. Accurate preoperative imaging has become even more critical with the development of focused surgical approaches. This study aims to evaluate the accuracy of Tc99m-MIBI-SPECT/CT and 4D CT scan in localizing abnormal parathyroid glands in our institution. Objectives: To evaluate and compare the efficacy of 4D CT scan and Tc99m-MIBI-SPECT/CT for the preoperative localization of abnormal parathyroid glands in patients with primary hyperparathyroidism in a single health network. Methods and Design: We collected data on 100 patients with biochemically confirmed primary hyperparathyroidism regarding age, sex, image modalities such asTc99m-MIBI-SPECT/CT and 4D CT before surgery, and the surgical pathology results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for both imaging modalities. Results: A total of 100 patient charts were reviewed, including 77 females and 23 males (3.35:1 female to male ratio),with an average age of 65.9 years (standard deviation 12.59). 90 patients had undergone surgical resection. 54 (60%) of them were diagnosed as parathyroid adenoma; 30 (33.3%) as parathyroid hyperplasia; 1 (1.1%) malignant parathyroid carcinoma; 5 (5.5%) were normal. 84 patients underwent Tc99m-MIBI-SPECT/CT and97 patients - 4D CT. 4D CT scan had a sensitivity of 90.36% (95% CI,81.89%-95.75%) and specificity of 50.00% (95% CI, 6.76%-93.24%) and outperformed Tc99m-MIBI-SPECT/CT which had a sensitivity of 45.71% (95% CI,33.74%-58.06%) and specificity of 80.00% (95% CI, 28.36%-99.49%). 4D CT had a positive predictive value (PPV) of 97.40% (95% CI, 90.93%-99.68%) and a negative predictive value (NPV) of 20.01% (95% CI, 2.52%-55.62%) compared toTc99m-MIBI-SPECT/CT which had PPV of 96.95% (95% CI, 84.22%-99.92%) and NPV of9.57% (95% CI, 2.68%-22.68%). 4D CT also had higher accuracy (85.5%; 95% CI,79.87%-94.35%) compared to Tc99m-MIBI scan (48.01%; 95% CI,36.32%-59.86%). Conclusion: Diagnostic imaging plays a crucial role in the management of primary hyperparathyroidism. Among the patients who had Tc99m-MIBI-SPECT/CT, less than half had positive scans suggestive of abnormal parathyroid tissue. This highlights the need for additional imaging methods for patients with negative scans. 4D CT is widely used in our institution and is more effective than Tc99m-MIBI-SPECT/CT in the preoperative localization of abnormal parathyroid glands. Presentation: Friday, June 16, 2023

Role of 18Fluorocholine Positron Emission Tomography/Computed Tomography in the Localization of Culprit Lesions in Patients of Persistent/Recurrent Primary Hyperparathyroidism: A Prospective Study in COVID Times.

Recurrent/persistent primary hyperparathyroidism in patients who have undergone previous parathyroidectomy is a challenging condition. Imaging is important for localizing the parathyroid adenoma for re-exploration and 18F-Fluorocholine (18F-FCH) positron emission tomography/computed tomography (PET/CT) seems ideal for this purpose. This prospective study attempted to ascertain the utility of 18F-FCH PET/CT as an investigation in preoperative localization of abnormal parathyroid tissue in recurrent/persistent primary hyperparathyroidism while comparing it with 99mTc-Sestamibi dual-phase scintigraphy with early single-photon emission CT (SPECT)/CT and neck ultrasonography (USG). Twenty patients with biochemical features of recurrent/persistent primary hyperparathyroidism were enrolled into this study. They underwent neck USG, 99mTc-Sestamibi dual-phase scintigraphy with early SPECT/CT and 18F-FCH PET/CT for localization of parathyroid lesions. Six patients underwent surgical resection of the detected lesions, 3 were awaiting surgery, and 11 were managed conservatively. One patient died due to COVID. The calculated positive predictive values on a per-lesion basis of neck USG, 99mTc-sestamibi scintigraphy and early SPECT/CT and 18F-FCH PET/CT in the cohort of the 5 operated patients were 75% (3/4), 71.4% (5/7), and 71.4% (5/7), respectively. On a per-patient basis, the lesion detection rate was 100% for 99mTc-sestamibi scan and FCH PET (5/5) and 80% on neck USG (4/5). 18F-FCH PET/CT is a highly accurate imaging modality for the detection of parathyroid lesions in patients with recurrent/persistent primary hyperparathyroidism.

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

Successful surgical treatment for primary hyperparathyroidism requires accurate localization of abnormal parathyroid tissue in terms of location and number. Imaging is important for localizing the parathyroid adenoma, and there has been significant interest in 18F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) for this purpose. This study attempted to ascertain the utility of 18F-FCH PET/CT as a first-line investigation in preoperative localization of abnormal parathyroid tissue in primary hyperparathyroidism, in comparison with 99mTc-sestamibi dual-phase scintigraphy with early single-photon emission computed tomography (SPECT)/CT and neck ultrasonography. Fifty-five patients with biochemical features of primary hyperparathyroidism were enrolled in this study. They underwent neck ultrasonography, 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT, and 18F-FCH PET/CT for localization of parathyroid lesions. Thirty-three patients underwent surgical resection of the detected lesions. For two patients, clinical and biochemical follow-up was used as a gold standard. A total of 40 lesions were resected in the 33 patients who underwent surgery. A further two lesions were localized in two patients with clinical and biochemical follow-up as the gold standard. Of these 42 lesions, 41 were detected in preoperative imaging and 1 lesion was noted intraoperatively and resected. 41/42 lesions were detected by 18F-FCH PET/CT (detection rate: 97.6%), 33/42 by 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT (detection rate: 78.5%), and 30/42 by neck ultrasonography (detection rate: 71.4%). Detection rates on 18F-FCH PET/CT were superior to both 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT and neck ultrasonography in preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism.

Tricks of the trade: Techniques for preoperative localization in reoperative parathyroidectomy

BackgroundReoperative parathyroidectomy for recurrent/persistent primary hyperparathyroidism (PHPT) has high rates of failure. The goal of this study was to analyze our experience with imaging and parathyroid vein sampling (PAVS) for recurrent/persistent PHPT. MethodsWe performed a retrospective cohort study (2002–2018) of patients with recurrent/persistent PHPT undergoing reoperative parathyroidectomy. ResultsAmong 181 patients, the most common imaging study was sestamibi (89.5%), followed by ultrasound (75.7%). CT had the highest rate of localization (70.8%) compared to sestamibi (58.0%) and ultrasound (47.4%). PAVS was performed in 25 patients, and localized in 96%. Ultrasound and sestamibi both demonstrated 62% PPV for operative pathology, compared to 41% in CT. PAVS was 95% sensitive with 95% PPV for predicting the correct side of abnormal parathyroid tissue. ConclusionsWe recommend a sequential imaging evaluation for reoperative parathyroidectomy, with sestamibi and/or ultrasound followed by CT. PAVS should be considered if non-invasive imaging fails to localize.

Multi-modality parathyroid imaging: A shifting paradigm.

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis, rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach. Hence, the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration. The common causes include solitary parathyroid adenoma, multiple parathyroid adenomas, parathyroid hyperplasia and parathyroid carcinoma. It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging. The various imaging modalities available include high resolution ultrasound of the neck, nuclear imaging studies, four-dimensional computed tomography (4D CT) and magnetic resonance imaging. Contrast enhanced ultrasound is a novel technique which has been recently added to the armamentarium to differentiate between parathyroid adenomas and its mimics. Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

PSUN76 Massive Four-Gland Parathyroid Hyperplasia: The Case of the Missing Glands

Abstract Introduction Parathyroid adenoma (PA) and parathyroid hyperplasia (PH) are common causes of primary hyperparathyroidism (PHPT) for which the only definitive treatment is surgical removal. Surgery is often preceded by imaging for localization, including by ultrasound (US), Sestamibi scan (MIBI), positron emission tomography/computer tomography (PET/CT), and four-dimensional computed tomography (4D-CT). While it is common for parathyroid pathology to not be visualized on imaging, non-visualization is more typical of adenomas and hyperplasia of smaller size. Clinical Case A 65-year-old male without history of kidney dysfunction or family history of parathyroid disease was referred to surgery for parathyroidectomy to manage longstanding PHPT. Serology showed a parathyroid hormone (PTH) level of 581 pg/mL (reference range: 12-65 pg/mL) and calcium of 11.8 mg/dL (reference range: 8.6-10.5 mg/dL). Preoperative parathyroid localization US revealed a large well-defined 1.5 cm PA. The patient underwent parathyroidectomy, which detected a large right inferior parathyroid gland, confirmed with pathology to be an atypical parathyroid adenoma weighing 1800 mg. Postoperative PTH level was 550 pg/mL and calcium was 12.6 mg/dL. MIBI did not display any definite parathyroid adenoma or ectopic parathyroid tissue. Further evaluation with PET/CT did not demonstrate any evidence of metabolically active residual or ectopic parathyroid adenoma or metastatic disease, and repeat US showed did not reveal evidence of any abnormal parathyroid tissue. Ultimately, 4D-CT detected a multiglandular parathyroid with a 1.8×1.4×3.0 cm right superior adenoma weighing approximately 3931 mg, 1.2×0.8×2.1cm left superior adenoma weighing approximately 1048 mg, and a 0.3×0.4×0.4cm left superior adenoma weighing approximately 25 mg. The patient underwent re-exploration parathyroidectomy with removal of the right superior adenoma weighing 3105 mg and left superior adenoma weighing 1100 mg. The remaining left inferior gland was biopsied and the majority of it was implanted into the arm. Repeat serology one week post-operatively showed improvement of PTH level to 5 pg/mL and of calcium to 8.9 mg/dL and serology one year post-operatively showed a PTH level of 82 pg/mL and a calcium of 9.4 mg/dL. Conclusion We present a patient with massive four-gland PH who initially presented with findings more typical of PA, but ultimately had additional hyperplasic glands that were identified after removal of the adenomatous gland. These glands were unusually large to be seen in PH and yet still be undetected on multiple imaging modalities; no previously reported non-ectopic hyperplastic glands of this size have been documented that were not detected on US or MIBI. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Successful localization of abnormal parathyroid tissue with ultrasound-guided methylene blue dye injection before surgery for metastatic or recurrent thyroid cancers and parathyroid adenomas

ObjectivesA surgery to be performed on a previously operated neck includes difficulties such as increased risk of complications and prolonged operation time. The aim of the present study is to analyze the benefit of pre-anesthetic ultrasound-guided injection of methylene blue into parathyroid adenomas and abnormal lymph nodes to simplify their safe and satisfactory extraction. MethodsWe analyzed the case series records of 14 patients who were operated for reoperative neck surgery due to recurrent thyroid cancer (8 patients) and parathyroid adenoma (6 patients) and in the technique; 0.2 ml of a 1:5 dilution of 1 % methylene blue solution was injected directly onto the target during real-time ultrasound guidance before the operating room. ResultsIn adenomas, ultrasound-guided methylene blue injection was successfully applied in all cases, an average of 33.1 min before entering the operating room (range = 28–38 min). There were no complications related to dye injection. For patients with recurrent thyroid tumors, preoperative ultrasound-guided methylene blue injection was successfully applied in all patients, on average 27.5 min before entering the operating room (range = 20–35 min). No complications occurred due to dye injection. The blue stained lesion was easily identified during surgery. ConclusionsWe analyzed the feasibility of the injection process, the certainty of defining pathological lymph nodes, and the complications of the procedure. Preoperative administration of methylene blue preserved its intraoperative efficacy and maintained the easy the detection of reoperative or primary pathologies. The present study suggest that methylene blue dye injection is a safe, sufficient, and quietly effective method for identifying recurrent tumors and parathyroid adenomas in scarred reoperative neck surgeries. Our cases had comparatively short operative times and lower complication rates.

A cost-utility analysis of 18F-fluorocholine–positron emission tomography imaging for localizing primary hyperparathyroidism in the United States

BackgroundPrimary hyperparathyroidism historically necessitated bilateral neck exploration to remove abnormal parathyroid tissue. Improved localization allows for focused parathyroidectomy with lower complication risks. Recently, positron emission tomography using radiolabeled 18F-fluorocholine demonstrated high accuracy in detecting these lesions, but its cost-effectiveness has not been studied in the United States. MethodsA decision tree modeled patients who underwent parathyroidectomy for primary hyperparathyroidism using single preoperative localization modalities: (1) positron emission tomography using radiolabeled 18F-fluorocholine, (2) 4-dimensional computed tomography, (3) ultrasound, and (4) sestamibi single photon emission computed tomography (SPECT). All patients underwent either focused parathyroidectomy versus bilateral neck exploration, with associated cost ($) and clinical outcomes measured in quality-adjusted life-years gained. Model parameters were informed by literature review and Medicare costs. Incremental cost-utility ratios were calculated in US dollars/quality-adjusted life-years gained, with a willingness-to-pay threshold set at $100,000/quality-adjusted life-year. One-way, 2-way, and threshold sensitivity analyses were performed. ResultsPositron emission tomography using radiolabeled 18F-fluorocholine gained the most quality-adjusted life-years (23.9) and was the costliest ($2,096), with a total treatment cost of $11,245 or $470/quality-adjusted life-year gained. Sestamibi single photon emission computed tomography and ultrasound were dominated strategies. Compared with 4-dimentional computed tomography, the incremental cost-utility ratio for positron emission tomography using radiolabeled 18F-fluorocholine was $91,066/quality-adjusted life-year gained in our base case analysis, which was below the willingness-to-pay threshold. In 1-way sensitivity analysis, the incremental cost-utility ratio was sensitive to test accuracy, positron emission tomography using radiolabeled 18F-fluorocholine price, postoperative complication probabilities, proportion of bilateral neck exploration patients needing overnight hospitalization, and life expectancy. ConclusionOur model elucidates scenarios in which positron emission tomography using radiolabeled 18F-fluorocholine can potentially be a cost-effective imaging option for primary hyperparathyroidism in the United States. Further investigation is needed to determine the maximal cost-effectiveness for positron emission tomography using radiolabeled 18F-fluorocholine in selected populations.

A Challenging Diagnosis of Primary Hyperparathyroidism in an Adolescent Female

Background: Hypercalcemia secondary to primary hyperparathyroidism (PHPT) is less common in children than adults. Single parathyroid adenoma is commonly the cause of primary hyperparathyroidism in children. Clinical Case: We present a 15-year-old female with one-week history of abdominal pain despite taking over the counter antacids. Her initial work up by her primary care provider revealed serum calcium of 11.8 mg/dL (9.0–11.5) and creatinine of 0.8 mg/dL (0.4–1.2). A week later, she presented to the emergency department with same complaint. In ED, she was found to have hypercalcemia (12.8 mg/dl) with elevated parathyroid hormone (PTH) at 78.5 pg/mL (15–65). Her random urine calcium creatinine ratio was high at 2.1. Her 25OHD was 25 ng/mL (30–100). She had negative urine pregnancy test but had trace ketones, leukocyte esterase, blood and bacteria. CBC and CMP were otherwise unremarkable. She continued to complain abdominal pain with nausea, decrease appetite, fatigue, and general muscle weakness. There was no known family history of calcium or metabolic bone disorders. Her vital signs and physical exam were normal. Subsequent labs showed mild improvement of calcium between (11–12.3 mg/dL), PTH between 54.5 and 77 pg/mL, normal thyroid function. Ionized calcium was mildly elevated 6.0 mg/dL (4.5–5.3) but her repeat 25OHD was low at18 ng/mL. Serum phosphorus levels were relatively normal with lowest level of 2.5 mg/dL (2.7–4.5). Gliadin Deamidated IgA was detectable 15 U/mL (< 15.0 U/). Ultrasound of abdomen was significant for nonspecific mild hepatomegaly; kidneys were normal in size and appearance. Ultrasound of thyroid was significant for probably intrathyroid parathyroid, measuring 6 x 8 x 8 mm. Tc-Sestamibi scan did not confirm a parathyroid adenoma. Genetic testing for MEN-1 was negative. FHH- related genes (i.e. CASR) was positive for p.R990G variant resulting in a mild gain of function of the calcium-sensing receptor. Although previous Tc-Sestamibi scan was unremarkable, an over read of it raised a concern for questionable uptake in the left superior lobe. SPEC-CT demonstrated possible abnormal parathyroid tissue in the upper pole of the left thyroid. FNA of the left thyroid nodule confirmed likely intrathyroidal parathyroid adenoma. Subsequent follow up and treatment, including parathyroidectomy, was done by another institution. She underwent a left parathyroidectomy with normalization of serum calcium and PTH levels post operatively (10.1 mg/dl and 8 pg/mL, respectively) and has complete resolution of her previous abdominal and gastrointestinal symptoms. Conclusion: PHPT is uncommon in children and adolescents and is typically associated with a single parathyroid adenoma. High index of suspicion is key for early diagnosis of PHPT despite a negative Tc-Sestamibi initially.

Use of Indocyanine Green and Fluorescence Angiography in Parathyroid Surgery: A Feasibility Study

Background. Indocyanine green (ICG) with near-infrared (NIR) fluorescence is an established method for assessing vascularity in various clinical settings. We hypothesized that parathyroid adenomas, with increased capillary networks, may demonstrate a fluorescence which could aid intraoperative identification and confirmation of the abnormal parathyroid tissue. Methods. This prospective case-control study compared patients with primary hyperparathyroidism undergoing parathyroidectomy (cases) to normal parathyroid in thyroidectomy patients (controls). After exposing the parathyroid gland, ICG was injected and the fluorescence of parathyroid and thyroid was recorded and graded in comparison to the surrounding tissue and vasculature (0 = nonfluorescent and 5 = vasculature). Results. The intensity of parathyroid fluorescence was more in cases (4 ± 2) than controls (2 ± 1) when graded intraoperatively (P = .001). Thyroid fluorescence did not differ (3 vs 3, P = .072); however, parathyroid fluorescence was more intense than thyroid in cases (parathyroid = 4 ± 2 and thyroid = 3 ± 1, P = .018). Conclusions. ICG fluorescence in diseased parathyroid was more intense than normal parathyroid and thyroid, suggesting the ICG/NIR technology may be a useful intraoperative tool for identification of abnormal parathyroid.

Incremental Value of Sestamibi SPECT/CT Over Dual-Phase Planar Scintigraphy in Patients With Primary Hyperparathyroidism and Inconclusive Ultrasound.

Background: We evaluated the incremental value of [99mTc]sestamibi single photon-emission computed tomography (SPECT)/computed tomography (CT) over planar imaging for localization of abnormal parathyroid tissue in patients with primary hyperparathyroidism.Methods: Forty-six patients with biochemical evidence of hyperparathyroidism and inconclusive ultrasound underwent sestamibi dual-phase planar scintigraphy and SPECT/CT for preoperative localization of parathyroid adenoma. Imaging findings were compared with histopathological data. Decision tree analysis was performed to evaluate the value of SPECT/CT over planar scintigraphy for classifying patients with or without hyperfunctioning parathyroid tissue. The added value of SPECT/CT was also evaluated by decision curve analysis.Results: Planar scintigraphy was positive for presence of hyperfunctioning parathyroid in 52% of patients, with sensitivity of 63% and specificity of 100%. SPECT/CT was positive in 80% of patients with sensitivity of 97% and specificity of 100%. At decision tree analysis, after an initial split on planar imaging results, no further split was performed in patients with positive results, while those with negative results were further stratified by SPECT/CT. At decision curve analysis, the model including SPECT/CT was associated with the highest net benefit compared to the model including only planar technique and to a strategy considering that all patients should be treated.Conclusion: Sestamibi SPECT/CT provides incremental value over dual-phase scintigraphy in preoperative localization of hyperfunctioning parathyroid tissue in subjects with inconclusive ultrasound. Hybrid technique allows a better identification of pathological lesion to perform minimally invasive surgery and showed the highest net benefit, improving selection of surgical approach.

Recurrent and Persistent Hyperparathyroidism

Persistent and recurrent hyperparathyroidism is defined. Key components of preoperative planning including imaging modalities are discussed. Indications for surgery and emerging techniques to aid identification of abnormal parathyroid tissue in the reoperative neck are described. This review contains 2 figures, 2 tables and 22 references Key Words: indocyanine green fluorescence angiography, methylene blue injection, near-infrared autofluorescence imaging, parathyroid cryopreservation, parathyromatosis, persistent hyperparathyroidism, recurrent hyperparathyroidism, selective parathyroid hormone venous sampling

Recurrent and Persistent Hyperparathyroidism

Persistent and recurrent hyperparathyroidism is defined. Key components of preoperative planning including imaging modalities are discussed. Indications for surgery and emerging techniques to aid identification of abnormal parathyroid tissue in the reoperative neck are described. This review contains 2 figures, 2 tables and 22 references Key Words: indocyanine green fluorescence angiography, methylene blue injection, near-infrared autofluorescence imaging, parathyroid cryopreservation, parathyromatosis, persistent hyperparathyroidism, recurrent hyperparathyroidism, selective parathyroid hormone venous sampling

Pre-operative localization of abnormal parathyroid tissue by 99mTc-sestamibi in primary hyperparathyroidism using four-quadrant site analysis: an evaluation of the predictive value of vitamin D deficiency.

Accurate preoperative localization of abnormal parathyroid tissue aids importantly in minimally invasive parathyroidectomy in patients with primary hyperparathyroidism. Vitamin D deficiency may possibly influence the success and characteristics of pre-operative localization because it is associated with more active disease and possibly larger adenomas. This could increase the sensitivity of the sestamibi to identify abnormal parathyroid tissue, but earlier reports are conflicting. Vitamin D deficiency could also influence the nature of preoperative localization because it could lead to multi-gland stimulation of parathyroid tissue giving an appearance of multi-gland disease, which may lower accuracy of preoperative localization with sestamibi. To examine the relationship between vitamin D deficiency and correct parathyroid tissue localization by four-pole thyroid quadrant analysis. Retrospective study. Referral center. A total of 138 patients were divided into three groups according to the level of 25OHD; <20 ng/mL (vitamin D deficient), ≥20 to <30 ng/mL (vitamin D insufficient) and ≥30 ng/mL (vitamin D replete). Quadrant localization using 99mTc-sestamibi/SPECT. Among those with single-gland disease, the proportion of patients with correct quadrant localization were 60.0, 68.3 and 63.5% (p = 0.778), and the accuracy of sestamibi was 89.3, 90.6 and 89.9% for the deficient, insufficiency and replete groups, respectively. Among those with multi-gland disease, the proportion of patients with correct quadrant localization were 50.0, 25.0 and 18.2% (p = 0.619) while the accuracy was 50.0, 50.0 and 45.5%, respectively. Multi-gland disease did not occur more frequently in any of the three groups (p = 0.296). Vitamin D levels do not affect the accuracy of preoperative localization with sestamibi.

Nuclear Medicine Methods for Evaluation of Abnormal Parathyroid Glands in Patients with Primary and Secondary Hyperparathyroidism.

Considered rare disease in the past, primary hyperparathyroidism (PHPT) has dramatically increased in incidence over the past thirty years with the introduction of routine calcium measurements; it is now approximately 42 per 100 000 persons. By far, the most common lesion found in patients with PHPT is the solitary parathyroid adenoma, occurring in 85%-90% of patients, while in the rest 10%- 15% primary hyperplasia of the parathyroid glands is present. Currently, the most widely used surgical approach is minimally invasive parathyroidectomy which is associated with less post-surgery complications and shorter operation time. To be successful this procedure needs to rely on a precise preoperative localization of the abnormal parathyroid glands, hence preoperative parathyroid imaging gained so large importance. The rationale for locating abnormal parathyroid tissue prior to surgery is that the glands can be notoriously unpredictable in their location. There is a general consensus that the best imaging procedure identifying abnormal parathyroid glands is the preoperative scintigraphy with 99mTc-sestamibi or 99mTc-tetrofosmin. It is characterized with high sensitivity and specificity exceeding those of ultrasound, CT or MRI. Combining scintigraphy with the other imaging techniques increases the precision for topic localization.

Erratum to: Dual Pathologies of Parathyroid Adenoma and Papillary Thyroid Cancer on Fluorocholine and Fluorodeoxyglucose PET/CT.

[This corrects the article DOI: 10.1007/s13139-017-0488-3.].

ANALYSIS OF FACTORS AFFECTING OUTCOME OF ULTRASOUND-GUIDED RADIOFREQUENCY HEAT ABLATION FOR TREATMENT OF PRIMARY HYPERPARATHYROIDISM IN DOGS.

Radiofrequency (RF) parathyroid ablation is a noninvasive treatment for hyperparathyroidism in dogs. There are no published data assessing factors associated with RF parathyroid ablation success or failure in order to guide patient selection and improve outcome. The purpose of this retrospective analytical study was to determine whether imaging findings, biochemical data, or concurrent diseases were associated with RF heat ablation treatment failure. For inclusion in the study, dogs must have had a clinical diagnosis of primary hyperparathyroidism, undergone cervical ultrasound and RF ablation of abnormal parathyroid tissue, and must have had at least 3 months of follow-up information available following the date of ultrasound-guided parathyroid ablation. Dogs were grouped based on those with recurrent or persistent hypercalcemia and those without recurrent or persistent hypercalcemia following therapy. Parathyroid nodule size, thyroid lobe size, nodule location, and presence of concurrent disease were recorded. Recurrence of hypercalcemia occurred in 9/32 dogs that had ablation of abnormal parathyroid tissue (28%) and one patient had persistent hypercalcemia (3%) following parathyroid ablation. Nodule width (P = 0.036), height (P = 0.028), and largest cross-sectional area (P = 0.023) were larger in dogs that had recurrent or persistent hypercalcemia following ablation. Hypothyroidism was more common in dogs with recurrent disease (P = 0.044). Radiofrequency ablation was successful in 22/32 (69%) dogs. Larger parathyroid nodule size and/or concurrent hypothyroidism were associated with treatment failure in dogs that underwent ultrasound-guided RF parathyroid nodule ablation.

Intraoperative ex vivo parathyroid aspiration: A point-of-care test to confirm parathyroid tissue

Exvivo aspiration of a parathyroid gland with intraoperative parathyroid hormone determination is a method for intraoperative confirmation of parathyroid tissue. The aim of this study was to describe the use and applicability of this technique at a single, high-volume institution. This is a retrospective review of patients who underwent parathyroidectomy and exvivo aspiration of suspected, abnormal parathyroid tissue for intraoperative parathyroid hormone level (pg/mL). Sensitivity and specificity were calculated for aspirate intraoperative parathyroid hormone levels which were compared with the baseline serum aspirate intraoperative parathyroid hormone obtained prior to parathyroid excision in each patient. Of 921 tissue aspirates, 847 (92%) were confirmed as parathyroid on histopathology, with a mean±standard deviation aspirate intraoperative parathyroid hormone of 3,838±1,615 pg/mL. The 847 aspirates included 833 (98%) with aspirate intraoperative parathyroid hormone levels greater than the serum aspirate intraoperative parathyroid hormone and 14 (2%) with aspirate intraoperative parathyroid hormone levels less than the serum aspirate intraoperative parathyroid hormone; 74 (8%) aspirates were not parathyroid tissue, with a mean aspirate intraoperative parathyroid hormone level of 25±12.7 pg/mL. An aspirate intraoperative parathyroid hormone ≥1.5 times the serum aspirate intraoperative parathyroid hormone represented the optimal threshold for confirmation of parathyroid tissue. Intraoperative exvivo aspiration of presumed parathyroid gland is a sensitive and specific point-of-care method to confirm the presence of parathyroid tissue. An aspirate intraoperative parathyroid hormone ≥1.5 times greater than the baseline serum aspirate intraoperative parathyroid hormone minimizes the likelihood of misidentifying parathyroid tissue.