Parathyroid scintigraphy in patients with primary hyperparathyroidism: 99mTc sestamibi SPECT and SPECT/CT

Simulated Fewer-Angle SPECT/CT Imaging Protocol for Parathyroid Adenoma

A new SPECT/CT protocol for parathyroid imaging detailing fewer image-angle acquisitions (fewer-angle SPECT/CT [FASpecT/CT]) was evaluated for identification of parathyroid adenoma. The motivation for validating this protocol was to be able to use it in the future to decrease patient imaging time in our clinic. Methods: This was a retrospective review of existing data performed as a simulated case control study evaluating 50 parathyroid SPECT/CT scans acquired using the standard 60-stop protocol and the tested 15-stop FASpecT protocol acquired using angular sampling software. Agreement on the final interpretations between imaging methods was evaluated using the McNemar test and the Cohen κ. Interrater reliability among the 3 readers was described for each method using the Fleiss κ interpreted as in the strength-of-agreement guidelines by Landis and Koch. Results: Of the 50 evaluated images, 45 (90%) had concordant final image interpretations between imaging methods. The sensitivity of FASpecT/CT relative to SPECT/CT was 17 of 19 (89.5%; 95% CI, 66.9%-98.7%), and the specificity was 28 of 31 (90.3%; 95% CI, 74.2%-98.0%). Additionally, there was statistically significant substantial agreement between protocols and among readers for each protocol. Conclusion: Adequate diagnostic-quality SPECT/CT images can be acquired using significantly fewer imaging stops given advances in camera quality and processing algorithms such as iterative reconstruction.

Preoperative imaging for hyperparathyroidism often takes upper parathyroid adenomas for lower adenomas

We retrospectively evaluated how accurately preoperative imaging localizes parathyroid adenoma in superior versus inferior parathyroids. Over 6 years, 104 patients with primary hyperparathyroidism underwent parathyroid surgery in a single centre. Of these, 103 underwent ultrasound, 97 [^99mTc]pertechnetate/MIBI SPECT/CT and 30 [¹⁸F]fluorocholine (FCH) PET/CT. One patient with a unilateral double adenoma was excluded from the analysis. Surgical findings with histopathologic confirmation of adenoma were used as the standard. Ultrasound misjudged 5 of 48 detected lower adenomas as upper, but 14 of 29 upper adenomas as lower (error rate 10 vs 48%, p = 0.0002). The corresponding error rates for [^99mTc]pertechnetate/MIBI SPECT/CT were 3 versus 55% (p = 0.000014), and for [¹⁸F]FCH PET/CT 17 versus 36% (p = 0.26). Our results suggest that about half of the superior parathyroid adenomas which are detected, are erroneously assigned to the inferior position by both ultrasound and SPECT/CT imaging whereas the opposite mistake is significantly less frequent with ultrasound and SPECT/CT.

The relationship between 18F-FCH uptake intensity and cell content in parathyroid lesions

PURPOSE

To investigate the relationship between cell content and histopathological features of parathyroid lesions and 18F-FCH uptake intensity on PET/CT images.

METHODS

Patients with primary hyperparathyroidism (age > 18) who were referred to 18F-FCH PET/CT were involved. All patients underwent parathyroidectomy. Correlation of SUVmax with following factors were statistically analysed: serum PTH, Ca, P levels and histopathological parameters, total absolute amounts of chief cell, oxyphyllic cell and clear cell components calculated by the multiplication of the volume of the parathyroid lesion and the percentage of each type of cell content (called as Absolute_chief, Absolute_oxyphyllic and Absolute_clear reflecting the total amount of each cell group).

RESULTS

A total of 34 samples from 34 patients (6M, 28F, mean age: 53.32 ± 15.15, min: 14, max: 84) who had a positive 18F-FCH PET/CT localizing at least one parathyroid lesion were involved. In the whole study group, SUVmax was found to be correlated with the greatest diameter and volume of the lesion and Absolute_chief (p = 0.004, p = 0.002 and p = 0.035, respectively). In the subgroup analysis of 28 samples with longest diameter > 1 cm, the correlation between SUVmax and Absolute_chief remained significant (p = 0.036) and correlation between SUVmax and volume and longest diameter became stronger (p = 0.011 and p > 0.001, respectively). No correlation was found between SUVmax and Absolute_oxyphyllic or Absolute_clear.

CONCLUSIONS

There might be a relationship between 18F-FCH uptake intensity and chief cell content in patients with parathyroid adenoma. Further studies with larger patient groups would be beneficial to support the data.

Brown Adipose Tissue Biodistribution and Correlations Particularities in Parathyroid Pathology Personalized Diagnosis

Brown adipose tissue (BAT) participates in the regulation of whole-body metabolism by producing a variety of adipokines. This study investigates into the BAT pattern and the clinical aspects of overweight and obese (OOB) vs. non-obese (NO) hyperparathyroidism (HPT) patients with the aim of assessing the impact of BAT and obesity on HPT. Parathyroid scans performed on 441 HPT patients between 2015 and 2020 were retrospectively analyzed in order to select the images with active BAT. Based on their BMI, the patients with active BAT were divided into OOB vs. NO. The results showed that BAT was present in cervical and supraclavicular regions, with a single localization especially among NO vs. multiple sites among OOB. The (total counts/pixels)_BAT/(total counts/pixels)_non-BAT ratio in the right cervical localization showed a significant difference between the groups with higher values in OOB. BMI, PTH, FT4, vitamin D, magnesium, creatinine, and urea had significant correlations with BAT ratios. The predictive values showed that right cervical ratios higher than 1.52 and right supraclavicular ratios lower than 1.15 indicated an increased probability of being OOB. The significant correlations between BAT activation in OOB vs. NO and HPT clinical parameters could be useful for developing potential treatments based on this tissue.

Analysis of the successful clinical treatment of 140 patients with parathyroid adenoma: A retrospective study

BACKGROUND

Parathyroid adenoma (PA) sometimes recurs after surgery, how to improve the surgical success rate of PA is the key to the treatment of this disease.

AIM

To investigate the clinical features, diagnosis, and surgical treatment of patients with PA.

METHODS

Patients who were pathologically confirmed with PA and had undergone surgery for the first time between January 2010 and December 2017 at the Beijing Shijitan Hospital affiliated to Capital Medical University were included in the study. The clinical features, localization diagnosis, and surgical treatment of these patients were analyzed.

RESULTS

Of the 140 patients, 32 were male and 108 were female; 132 cases had one adenoma, and 8 had two adenomas. In addition, 114 cases had clinical symptoms, among which 51, 28, 23, 8, and 4 had urinary system, skeletal system, digestive system, neuromuscular system, and neuropsychiatric symptoms, respectively, while 26 cases had no obvious symptoms. The median level of preoperative parathyroid hormone (PTH) was 201.0 pg/mL. The positive detection rate of technetium-99m sestamibi (Tc-99m MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT), ultrasound examination, and the combined use of Tc-99m MIBI SPECT/CT and ultrasound examination was 92.9%, 85.5%, and 96.4%, respectively. Open surgery was performed in all patients, and PTH was monitored during surgery. The success rate of surgery was 98.6%. After surgery, 21 cases developed hypocalcemia, 1 case developed temporary hoarseness, and 19 cases had transient hypoparathyroidism but there was no permanent hypoparathyroidism, postoperative hemorrhage, or hematoma in the surgical area.

CONCLUSION

For patients with clinically unexplained skeletal system, urinary system, and neuropsychiatric symptoms, the possibility of PA should be considered. Imaging examinations such as ultrasound and Tc-99m MIBI SPECT/CT could be integrated before surgery to obtain accurate localization diagnosis. Precise preoperative localization, intraoperative PTH monitoring, and delicate surgery to protect the integrity of the PA capsule ensure a minimally invasive and successful surgery.

Incidental Primary Intrathoracic Goiter: Dual-Isotope Scintigraphy and Early-MIBI SPECT/CT

Primary intrathoracic goiter is an uncommon congenital entity resulting from over decent ectopic thyroid tissue. As compared with secondary intrathoracic goiter, primary entities are discrete from orthotopic thyroid tissue and may lead to potentially serious complications such as malignancy and shortness of breath. Intrathoracic goiters have been described as showing mild or absent uptake of ^99m Tc-pertechnetate on planar scintigraphy. We present an incidental primary intrathoracic goiter found in a patient undergoing evaluation with multimodal scintigraphy and early ^99m Tc-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) for localization of parathyroid adenomas. The mass was inconspicuous on TcO ^4- scintigraphy but methoxyisobutylisonitrile-avid on early planar and SPECT/CT.

Incidental Detection of Mandibular Metastasis in Renal Cell Carcinoma on 99mTc-MIBI Scan

ABSTRACT

MIBI scintigraphy is the most widely used modality to identify parathyroid adenomas preoperatively. However, MIBI is also known to accumulate in multiple benign and malignant lesions. In renal cell carcinoma, 30% of the patients present with distant metastasis, commonly lungs and bone; however, jaw bone metastases are extremely rare (<1% of oral malignancies). Here we present a rare case of MIBI-avid mandibular metastasis in bilateral renal cell carcinoma on 99mTc-MIBI scintigraphy. Thus, we emphasize on careful interpretation of 99mTc-MIBI scans, which in addition to parathyroid adenomas can incidentally detect concurrent malignant lesions.

Usefulness of 99mTc-SESTAMIBI Scintigraphy in Persistent Hyperparathyroidism after Kidney Transplant

Purpose

^99mTc-labeled sestamibi scintigraphy combined with single-photon emission computed tomography (SPECT) has a high positive predictive value for localizing hyperfunctioning parathyroid lesions in primary hyperparathyroidism (pHPT) but relatively low sensitivity and specificity in secondary hyperparathyroidism (sHPT) and tertiary hyperparathyroidism (tHPT). The purpose of this study is to investigate the usefulness of ^99mTc-sestamibi scintigraphy in persistent hyperparathyroidism after kidney transplant (KT).

Methods

Retrospectively evaluated 50 patients who received parathyroidectomy after KT at a single medical center. The parathyroid lesion with the highest sestamibi uptake intensity of a patient was graded from 0 to 3. Uptake intensity was analyzed in correlation with parathyroid hormone (PTH), calcium, ionized calcium, phosphorus, and vitamin D.

Results

Per-patient analysis, 43 patients had hyperplasia, 6 patients had adenomas, and 1 patient had a carcinoma. Only 3 patients with hyperplasia did not demonstrate any sestamibi uptake in the parathyroid scans. Out of the 148 pathologically confirmed parathyroid lesions, SPECT/CT images were able to identify 89 lesions (60%) and planar images of 71 lesions (48%). The average of sestamibi uptake intensity was mild at grade 1.6. Uptake intensity showed a positive correlation with parathyroid hormone (PTH) level but not with phosphorus, calcium, ionized calcium, or vitamin D levels. The largest lesion showed a high positive predictive value, especially in lesions with a diameter over 1.0 cm.

Conclusions

Regardless of relatively low and less discrete uptake in KT patients, it well depicts the largest and the most hyperfunctioning lesion.

ACR Appropriateness Criteria® Parathyroid Adenoma

Hyperparathyroidism is defined as excessive parathyroid hormone production. The diagnosis is made through biochemical testing, in which imaging has no role. However, imaging is appropriate for preoperative parathyroid gland localization with the intent of surgical cure. Imaging is particularly useful in the setting of primary hyperparathyroidism whereby accurate localization of a single parathyroid adenoma can facilitate minimally invasive parathyroidectomy. Imaging can also be useful to localize ectopic or supernumerary parathyroid glands and detail anatomy, which may impact surgery. This document summarizes the literature and provides imaging recommendations for hyperparathyroidism including primary hyperparathyroidism, recurrent or persistent primary hyperparathyroidism after parathyroid surgery, secondary hyperparathyroidism, and tertiary hyperparathyroidism. Recommendations include ultrasound, CT neck without and with contrast, and nuclear medicine parathyroid scans. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Primary hyperparathyroidism caused by an ectopic parathyroid adenoma in an uncommon location: a case report

Primary hyperparathyroidism caused by an ectopic parathyroid adenoma in the mediastinum is a rare clinical condition. We present a 75-year-old male with primary hyperparathyroidism caused by an ectopic parathyroid adenoma in the mediastinum. This patient was initially referred to the clinic for suspected incidental hypercalcemia. Initial imaging showed two suspicious lesions: one adjacent to the thyroid gland and another in the mediastinum. Further investigations identified a sole mediastinal adenoma. The diagnosis was confirmed by normalization of parathyroid hormone levels after its surgical resection. Thoroughly diagnosing such cases can prove challenging and using a single modality such as ultrasonography, computed tomography, or nuclear imaging alone may not yield conclusive findings or can give false positive results. Our case demonstrates that a combination of several imaging modalities can lead to accurate localization of the cause of primary hyperparathyroidism. This will obviate the performance of unnecessary surgical procedures. In addition, the possibility of missing additional sources of ectopic secretions of the parathyroid hormone will be reduced.

Clinicopathological variables that correlate with sestamibi positivity in uniglandular parathyroid disease: a retrospective analysis of 378 parathyroid adenomas

PURPOSE

Technetium-99 m sestamibi parathyroid scintigraphy (MIBI scan) has been used to localize abnormal glands in patients with primary hyperparathyroidism to guide parathyroidectomy. This series aimed to identify the biochemical and histopathological correlates of MIBI scan findings in patients with parathyroid adenoma.

METHODS

A total of 378 patients with histologically and biochemically proven parathyroid adenoma were included. The results of MIBI scan, histopathological (gland volume and weight, oxyphil cell ratio), biochemical (blood and 24 h urine calcium, creatinine, glomerular filtration rate, parathormone, alkaline phosphate, and vitamin D3) variables were recorded. A positive uptake on the MIBI scan referred to a localized adenoma. Among histological variables, a cutoff of 30% was applied to define parathyroid adenomas with low (≤ 30%) and high (> 30%) oxyphil cell content. Statistical analyses were performed to assess the relationship among variables.

RESULTS

MIBI scan localized the adenoma in 306 patients. Parathyroid gland volume and weight, and oxyphil ratio were significantly higher in the MIBI scan-positive group. Among the biochemical variables, only PTH was found to be significantly increased in the MIBI scan-positive group. Binary logistic regression models identified statistically significant cutoffs for the gland volume (1700 mm³), gland weight (1.3 g) and PTH levels (170 pg/mL) that can be used to predict the MIBI scan positivity.

CONCLUSION

In addition to PTH levels, this series underscored the impact of cellular composition along with the parathyroid gland volume and weight, both of which correlate with sestamibi positivity in patients with benign uniglandular parathyroid disease.

Detectability of 18F-choline PET/MR in primary hyperparathyroidism

PURPOSE

We aimed to evaluate the power of 18F-fluorocholine (FCH) positron emission tomography/magnetic resonance (PET/MR) imaging in unlocalized primary hyperparathyroidism.

METHODS

Thirty-four patients were included. In 17/34 patients, PET/MR was performed immediately after a negative 18F-FCH PET/CT. Sensitivity, specificity, positive and negative predictive values were calculated for MR only (blinded to PET data) and PET only (blinded to MR data) findings.

RESULTS

18F-FCH PET/MR was positive in 26/34 (76%) patients. PET/MR was also positive in 12/17 (71%) patients with a negative PET/CT. Among 11/34 (32%) patients where 18F-FCH PET-only and MR-only results were discordant, MR was false positive in 7/11 patients (3/7 of the lesions were not 18F-FCH avid and in 4/7 of them PET and MRI pointed different locations. Postoperative histopathology revealed that 18F-FCH-positive ones were true positives). Sensitivity, specificity, PPV, NPV and accuracy of neck MR evaluated blinded to PET data were 80%, 50%, 70%, 64% and 68%, respectively, and all were calculated as 100% for PET/MR.

CONCLUSION

18F-FCH PET/MR is very effective in preoperative localization of parathyroid adenomas even if 18F-FCH PET/CT is negative. Neck MR alone is insufficient in detecting parathyroid adenomas but PET/MR combination helps in precise localisation.

The use of computed tomography as a first-line imaging modality in patients with primary hyperparathyroidism

BACKGROUND

The success of minimally invasive parathyroidectomy (MIP) relies on accurate localization of the abnormal parathyroid glands. Concordant findings on ultrasound (US) and ^99mTc-scintigraphy (sestamibi) are currently considered the 'gold standard'. Computed tomography (CT) has also recently been used in preoperative planning. We sought to assess the accuracy of CT for localization of abnormal parathyroid glands in such patients.

METHODS

An audit of 75 patients with primary hyperparathyroidism (PHPT) who underwent neck US and CT between 2017 and 2019 at our center as their first-line imaging.

RESULTS

All 75 patients underwent US and CT and 54 (72.0%) also had sestamibi. CT alone identified a potential target in all patients, of which the location was correct in 63 (84.0%). The overall combined sensitivity of US and CT was 88% (95% CI 78-94) and was higher than the combined sensitivity of US and sestamibi (65% [95% CI 53-76]; p < 0.001). Twenty-one patients (28.0%) had an ectopic gland, and the sensitivity of US and CT was 86% (95% CI 64-96) versus US and sestamibi (57% [95% CI 34-77]; p = 0.016). For adenomas < 1.0 g (n = 36; 48%), the accuracy of CT was 81% (95% CI 64-91) compared with 62% (95% CI 44-77) for US and sestamibi (p = 0.04). The correct preoperative diagnosis of multiglandular disease (n = 9; 12%) seemed to be the most difficult, with similar accuracy for US and sestamibi (40% [95% CI 14-73]) and US and CT (50% [95% CI 20-80]) (p > 0.99).

CONCLUSION

The combination of US and CT was able to correctly identify the location of the abnormal parathyroid in 88% of patients and, in comparison with US and sestamibi, had better diagnostic accuracy, especially for smaller and ectopic adenomas. This finding suggests that US and CT could be considered as a first-line imaging modality in patients with PHPT considered for MIP.

The EANM practice guidelines for parathyroid imaging

INTRODUCTION

Nuclear medicine parathyroid imaging is important in the identification of hyperfunctioning parathyroid glands in primary hyperparathyroidism (pHPT), but it may be also valuable before surgical treatment in secondary hyperparathyroidism (sHPT). Parathyroid radionuclide imaging with scintigraphy or positron emission tomography (PET) is a highly sensitive procedure for the assessment of the presence and number of hyperfunctioning parathyroid glands, located either at typical sites or ectopically. The treatment of pHPT is mostly directed toward minimally invasive parathyroidectomy, especially in cases with a single adenoma. In experienced hands, successful surgery depends mainly on the exact preoperative localization of one or more hyperfunctioning parathyroid adenomas. Failure to preoperatively identify the hyperfunctioning parathyroid gland challenges minimally invasive parathyroidectomy and might require bilateral open neck exploration.

METHODS

Over a decade has now passed since the European Association of Nuclear Medicine (EANM) issued the first edition of the guideline on parathyroid imaging, and a number of new insights and techniques have been developed since. The aim of the present document is to provide state-of-the-art guidelines for nuclear medicine physicians performing parathyroid scintigraphy, single-photon emission computed tomography/computed tomography (SPECT/CT), positron emission tomography/computed tomography (PET/CT), and positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with pHPT, as well as in those with sHPT.

CONCLUSION

These guidelines are written and authorized by the EANM to promote optimal parathyroid imaging. They will assist nuclear medicine physicians in the detection and correct localization of hyperfunctioning parathyroid lesions.

Non-functional water clear cell parathyroid carcinoma masquerading as medullary thyroid carcinoma

Parathyroid carcinoma is a rare neuroendocrine tumor. Non-functional parathyroid carcinomas are exceedingly rare neoplasms which generally present at an advanced disease stage, and occasionally can masquerade as medullary thyroid carcinoma.

Pediatric hyperparathyroidism: review and imaging update

Hyperparathyroidism, due to increased secretion of parathyroid hormones, may be primary, secondary or tertiary. Most pediatric patients with sporadic primary hyperparathyroidism will be symptomatic, presenting with either end-organ damage or nonspecific symptoms. In younger patients with primary hyperparathyroidism, there is a higher prevalence of familial hyperparathyroidism including germline inactivating mutations of the calcium-sensing receptor genes that result in either neonatal severe hyperparathyroidism or familial hypocalciuric hypercalcemia. Parathyroid scintigraphy and ultrasound are complementary, first-line imaging modalities for localizing hyperfunctioning parathyroid glands. Second-line imaging modalities are multiphase computed tomography (CT) and magnetic resonance imaging. In pediatrics, multiphase CT protocols should be adjusted to optimize radiation dose. Although, the role of these imaging modalities is better established in preoperative localization of hyperfunctioning parathyroid glands in primary hyperparathyroidism, the same principles apply in secondary and tertiary hyperparathyroidism. In this manuscript, we will review the embryology, anatomy, pathophysiology and preoperative localization of parathyroid glands as well as several subtypes of primary familial hyperparathyroidism. While most of the recent imaging literature centers on adults, we will focus on the issues that are pertinent and applicable to pediatrics.

Four-dimensional computed tomography protocol for preoperative evaluation of the parathyroid glands and its correlations with other imaging methods: a pictorial essay

Parathyroid adenoma is the most common cause of primary hyperparathyroidism. Advances in surgical techniques have made it possible to excise only the affected parathyroid gland in most cases. Imaging examinations play a fundamental role in the preoperative planning of parathyroidectomy. To localize the parathyroid glands, imaging tests such as scintigraphy, ultrasound, and, more recently, four-dimensional computed tomography (4D CT). The aim of this pictorial review was to illustrate the use of the 4D CT protocol in cases of parathyroid adenoma and to determine how well it correlates with other imaging methods, in order to improve understanding of the 4D CT method.

Role of 11C-Methionine PET/CT in 99mTc-Sestamibi-Negative Parathyroid Adenoma: A Case Report

We report a case of 16-year-old female primary hyperparathyroidism patient who underwent cervical ultrasonography and ^99mTc-sestamibi single photon emission computed tomography/computed tomography, both of which were negative for parathyroid adenoma. Subsequent ¹¹C-methionine positron emission tomography/CT showed positive focal uptake suggesting parathyroid adenoma, which then was confirmed pathologically.

Preoperative Localization for Primary Hyperparathyroidism: A Clinical Review

With increasing use of minimally invasive parathyroidectomy (PTx) over traditional bilateral neck exploration in patients with primary hyperparathyroidism (PHPT), accurate preoperative localization has become more important to enable a successful surgical outcome. Traditional imaging techniques such as ultrasound (US) and sestamibi scintigraphy (MIBI) and newer techniques such as parathyroid four-dimension computed tomography (4D-CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) are available for the clinician to detect the diseased gland(s) in the preoperative workup. Invasive parathyroid venous sampling may be useful in certain circumstances such as persistent or recurrent PHPT. We review the diagnostic performance of these imaging modalities in preoperative localization and discuss the advantages and weaknesses of these techniques. US and MIBI are established techniques commonly utilized as first-line modalities. 4D-CT has excellent diagnostic performance and is increasingly performed in first-line setting and as an adjunct to US and MIBI. PET and MRI are emerging adjunct modalities when localization has been equivocal or failed. Since no evidence-based guidelines are yet available for the optimal imaging strategy, clinicians should be familiar with the range and advancement of these techniques. Choice of imaging modality should be individualized to the patient with consideration for efficacy, expertise, and availability of such techniques in clinical practice.

Molecular Imaging in the Head and Neck: Diagnosis and Therapy

This article is a summary of the most up-to-date applications of radiopharmaceuticals to the diagnosis and therapy of benign and malignant diseases involving endocrine or neuroendocrine organs of the head and neck, focusing on radiotracers approved by the US Food and Drug Administration, such as I-123- and I-131-sodium iodide, F-18-fluorodeoxyglucose, Tc99m-sestamibi, as well as the more recently approved tracers Ga-68 DOTATATE and Lu-177 DOTATATE.

Rare Imaging Findings of Concomitant Presence of Multiple Parathyroid Adenomas and Carcinoma in a Chronic Kidney Disease Patient with Tertiary Hyperparathyroidism Detected on 99mTc-Sestamibi Single-Photon-Emission Computed Tomography/Computed Tomography Scintigraphy

Parathyroid carcinoma (PC) is a rare endocrine carcinoma. It is one of the rare causes for primary hyperparathyroidism. It is very uncommon in individuals with secondary or tertiary hyperparathyroidism. We report a rare case of 53-year-old male, a known case of chronic kidney disease on dialysis, who presented with fatigue and muscle cramps. Lab reports revealed elevated parathyroid hormone (PTH) and serum calcium levels. ^99mTc-Sestamibi single-photon-emission computed tomography/computed tomography scintigraphy showed 4 foci of increased tracer uptake with retention, suggestive of parathyroid adenomas, including two ectopic foci in the mediastinum. At surgery, the enlarged bilateral superior, left inferior parathyroid gland, and two calcified left superior mediastinal lesions were removed. Histopathology revealed parathyroid adenomas in the right superior, left inferior, supernumerary ectopic left superior mediastinum lesion and PC in the left superior parathyroid lesion. Intraoperative serum PTH became normal, and the patient is asymptomatic now.

Parathyroid Imaging

Primary hyperparathyroidism (PHPT) is a common endocrine abnormality, caused in most cases by a single parathyroid adenoma. Surgery remains the first-line curative therapy in PHPT. Imaging plays a vital role in presurgical localization of parathyroid adenomas. Ultrasound provides a safe and quick imaging modality free of ionizing radiation, but is operator dependent. Sestamibi scan offers comparable sensitivity to ultrasound, improved with concurrent tomographic imaging. 4DCT remains a problem-solving technique in challenging cases and after failed neck exploration. We present an overview of various parathyroid imaging modalities, including protocols and findings, in addition to relevant pearls and pitfalls.

Localization of Parathyroid Disease in Reoperative Patients with Primary Hyperparathyroidism

The localization of persistent or recurrent disease in reoperative patients with primary hyperparathyroidism presents challenges for radiologists and surgeons alike. In this article, we summarize the relevant imaging modalities, compare their accuracy in identifying reoperative disease, and outline their advantages and disadvantages. Accurate localization by preoperative imaging is a predictor of operative success, whereas negative or discordant preoperative imaging is a risk factor for operative failure. Ultrasound is a common first-line modality because it is inexpensive, accessible, and radiation-free. However, it is highly operator-dependent and less accurate in the reoperative setting than in the primary setting. Sestamibi scintigraphy is superior to ultrasound in localizing reoperative disease but requires radiation, prolonged imaging times, and reader experience for accurate interpretation. Like ultrasound, sestamibi scintigraphy is less accurate in the reoperative setting because reoperative patients can exhibit distorted anatomy, altered perfusion of remaining glands, and interference of radiotracer uptake. Meanwhile, four-dimensional computed tomography (4DCT) is superior to ultrasound and sestamibi scintigraphy in localizing reoperative disease but requires the use of radiation and intravenous contrast. Both 4DCT and magnetic resonance imaging (MRI) do not significantly differ in accuracy between unexplored and reoperative patients. However, MRI is more costly, inaccessible, and time-consuming than 4DCT and is inappropriate as a first-line modality. Hybrid imaging with positron emission tomography and computed tomography (PET/CT) may be a promising second-line modality in the reoperative setting, particularly when first-line modalities are discordant or inconclusive. Lastly, selective venous sampling should be reserved for challenging cases in which noninvasive modalities are negative or discordant. In the challenging population of reoperative patients with PHPT, a multimodality approach that utilizes the expertise of high-volume centers can accurately localize persistent or recurrent disease and enable curative parathyroidectomy.

Atypical presentations of parathyroid gland pathology: A pictorial review

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Adenoma, carcinoma and hyperplasia cause parathyroid gland enlargement.

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Mimics include thyroid nodules and cystic structures in the head and neck.

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Enlarged parathyroid glands can enhance variably following contrast administration.

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Hyperparathyroidism can present acutely with respiratory compromise.

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Syndromic associations.

Primary hyperparathyroidism is associated with significant morbidity and mortality. It is in this day and age, an eminently treatable condition which relies heavily on preoperative imaging to localise enlarged parathyroid glands. The imaging appearances of parathyroid gland enlargement are varied; this paper seeks to address some of its more unusual manifestations with an emphasis on its atypical enhancement patterns, mimics and associations. An enlarged glands may also present as an ‘incidentaloma’ in head and neck imaging performed for entirely different indications, or as part of sporadic or familial syndrome. Radiologists are in a good position to expedite the relevant investigations and curative treatment, and knowledge of the spectrum of imaging appearances is crucial.

Actual role of color-doppler high-resolution neck ultrasonography in primary hyperparathyroidism: a clinical review and an observational study with a comparison of 99mTc-sestamibi parathyroid scintigraphy

PURPOSE

Primary hyperparathyroidism (PHPT) is a frequent endocrine pathology that has surgical treatment as its only decisive measure. High-Resolution Neck Ultrasonography with color-Doppler (CDHR-NUS) and 99mTechnetium-SestaMIBI Parathyroid Scintigraphy (99mTc-MIBI PS) are the two instrumental exams more commonly used in the preoperatory localization of pathologic parathyroids. The aim of this observational study was to outline-in accordance with the latest scientific literature-the precise role of CDHR-NUS in the environment of PHPT, comparing it with that of Parathyroid Scintigraphy.

METHODS

136 patients operated on for PHPT and underwent CDHR-NUS and 99mTc-MIBI PS preoperatively. The CDHR-NUS was carried out by an expert medical sonographer. The results of the two methods were compared between each other and with the results of the operative act for the evaluation of accordance and diagnostic performances.

RESULTS

PHPT is prevalently due to monoglandular pathology (SGD). The parallel use of CDHR-NUS and of 99mTc-MIBI PS does not determine a significant increase in diagnostic accuracy. The preoperative accordance evaluation between the two methods does not exclude the presence of multiglandular pathology (MGD) with certainty.

CONCLUSIONS

CDHR-NUS is an accurate as well as cost-effective method; its role as a main and eventual unique preoperative localization method in patients affected by PHPT is confirmed. In the presence of expert medical sonographers, the sequential use of the two methods is retained correct and their use in parallel is neither justified nor cost-effective. The preoperative accordance evaluation between the two methods is neither necessary nor indispensable.

Two cases of spontaneous remission of primary hyperparathyroidism due to auto-infarction: different management and their outcomes

Spontaneous remission of primary hyperparathyroidism (PHPT) due to necrosis and haemorrhage of parathyroid adenoma, the so-called 'parathyroid auto-infarction' is a very rare, but previously described phenomenon. Patients usually undergo parathyroidectomy or remain under close clinical and biochemical surveillance. We report two cases of parathyroid auto-infarction diagnosed in the same tertiary centre; one managed surgically and the other conservatively up to the present time. Case #1 was a 51-year old man with PHPT (adjusted (adj.) calcium: 3.11 mmol/L (reference range (RR): 2.20-2.60 mmol/L), parathyroid hormone (PTH) 26.9 pmol/L (RR: 1.6-6.9 pmol/L) and urine calcium excretion consistent with PHPT) referred for parathyroidectomy. Repeat biochemistry 4 weeks later at the surgical clinic showed normal adj. calcium (2.43 mmol/L) and reduced PTH. Serial ultrasound imaging demonstrated reduction in size of the parathyroid lesion from 33 to 17 mm. Twenty months later, following recurrence of hypercalcaemia, he underwent neck exploration and resection of an enlarged right inferior parathyroid gland. Histology revealed increased fibrosis and haemosiderin deposits in the parathyroid lesion in keeping with auto-infarction. Case #2 was a 54-year-old lady admitted with severe hypercalcaemia (adj. calcium: 4.58 mmol/L, PTH 51.6 pmol/L (RR: 1.6-6.9 pmol/L)) and severe vitamin D deficiency. She was treated with intravenous fluids and pamidronate and 8 days later developed symptomatic hypocalcaemia (1.88 mmol/L) with dramatic decrease of PTH (17.6 pmol/L). MRI of the neck showed a 44 mm large cystic parathyroid lesion. To date, (18 months later), she has remained normocalcaemic. Learning points: Primary hyperparathyroidism (PHPT) is characterised by excess parathyroid hormone (PTH) secretion arising mostly from one or more autonomously functioning parathyroid adenomas (up to 85%), diffuse parathyroid hyperplasia (<15%) and in 1-2% of cases from parathyroid carcinoma. PHPT and hypercalcaemia of malignancy, account for the majority of clinical presentations of hypercalcaemia. Spontaneous remission of PHPT due to necrosis, haemorrhage and infarction of parathyroid adenoma, the so-called 'parathyroid auto-infarction', 'auto-parathyroidectomy' or 'parathyroid apoplexy' is a very rare in clinical practice but has been previously reported in the literature. In most cases, patients with parathyroid auto-infarction undergo parathyroidectomy. Those who are managed conservatively need to remain under close clinical and biochemical surveillance long-term as in most cases PHPT recurs, sometimes several years after auto-infarction.

American Head and Neck Society Endocrine Surgery Section update on parathyroid imaging for surgical candidates with primary hyperparathyroidism

Health care consumer organizations and insurance companies increasingly are scrutinizing value when considering reimbursement policies for medical interventions. Recently, members of several American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) committees worked closely with one insurance company to refine reimbursement policies for preoperative localization imaging in patients undergoing surgery for primary hyperparathyroidism. This endeavor led to an AAO-HNS parathyroid imaging consensus statement (https://www.entnet.org/content/parathyroid-imaging). The American Head and Neck Society Endocrine Surgery Section gathered an expert panel of authors to delineate imaging options for preoperative evaluation of surgical candidates with primary hyperparathyroidism. We review herein the current literature for preoperative parathyroid localization imaging, with discussion of efficacy, cost, and overall value. We recommend that planar sestamibi imaging, single photon emission computed tomography (SPECT), SPECT/CT, CT neck/mediastinum with contrast, MRI, and four dimensional CT (4D-CT) may be used in conjunction with high-resolution neck ultrasound to preoperatively localize pathologic parathyroid glands. PubMed literature on parathyroid imaging was reviewed through February 1, 2019.

PRE-OPERATIVE LOCALIZATION OF PARATHYROID ADENOMA: PERFORMANCE OF 4D MRI PARATHYROID PROTOCOL

Objective: Accurate pre-operative image localization is critical in the selection of minimally invasive parathyroidectomy as a surgical treatment approach in patients with primary hyperparathyroidism (PHPT). Sestamibi scan, ultrasound, computed tomography, and conventional magnetic resonance imaging (MRI) has varying accuracy in localizing parathyroid adenoma (PTA). Our group has previously shown that four-dimensional (4D) MRI is more accurate than conventional imaging in identifying single adenomas. In this study, we set out to determine if it is possible to accurately localize the quadrant of the adenoma using 4D MRI. Methods: We analyzed and matched the quadrants of PTA identified by pre-operative 4D-MRI with the operative findings during parathyroidectomy for PHPT at our institution during the study period. All resections were confirmed to be successful with an adequate decrease in intraoperative parathyroid hormone as defined by the Miami criterion. Results: A total of 26 patients with PHPT underwent pre-operative localization with the 4D MRI parathyroid protocol. Fourteen patients had true single-gland adenoma (SGA) and 12 patients had multi-gland disease (MGD). 4D MRI accurately identified all the SGA. Using this method, we were also able to localize the adenoma in the correct quadrant in 14 of the 18 patients with SGA. All 3 double adenomas were accurately identified using 4D MRI; however, MGD was only accurately identified 67% of the time. The 4D MRI had an overall 85% accuracy in distinguishing SGA from MGD. Conclusion: 4D MRI accurately identified single and double adenomas in their respective quadrants. However, accuracy was lower with MGD. Abbreviations: BNE = bilateral neck exploration; CT = computed tomography; IOPTH = intra-operative parathyroid hormone; MGD = multi-gland disease; MIBI = sestamibi; MIP = minimally invasive parathyroidectomy; MRI = magnetic resonance imaging; PHPT = primary hyperparathyroidism; PTA = parathyroid adenoma; PTH = parathyroid hormone; SGA = single-gland adenoma; SPECT = single photon emission computed tomography; 4D = four-dimensional.

99mTc-MIBI Uptake in a Benign Thymic Cyst

A 34-year-old man with end-stage renal failure status post rejection of a deceased donor kidney transplant presented with bone pain in the setting of elevated serum parathyroid hormone and calcium levels. A Tc-MIBI SPECT/CT was performed before planned subtotal parathyroidectomy. SPECT/CT imaging revealed a 1.9-cm anterior mediastinal lesion with radiotracer uptake on both the immediate and delayed images. Surgical pathology of the lesion showed a benign thymic cyst with no parathyroid component.

Highly specific preoperative selection of solitary parathyroid adenoma cases in primary hyperparathyroidism by quantitative image analysis of the early-phase Technetium-99m sestamibi scan

INTRODUCTION

Highly specific preoperative localizing test is required to select patients for minimally invasive parathyroidectomy (MIP) in lieu of traditional four-gland exploration. We hypothesized that Tc-99m sestamibi scan interpretation incorporating numerical measurements on the degree of asymmetrical activity from bilateral thyroid beds can be useful in localizing single adenoma for MIP.

METHODS

We devised a quantitative interpretation method for Tc-99m sestamibi scan based on the numerically graded asymmetrical activity on early phase. The numerical ratio value of each scan was obtained by dividing the number of counts from symmetrically drawn regions of interest (ROI) over bilateral thyroid beds. The final pathology and clinical outcome of 109 patients were used to perform receiver operating curve (ROC) analysis.

RESULTS

Receiver operating curve analysis revealed the area under the curve (AUC) was calculated to be 0.71 (P = 0.0032), validating this method as a diagnostic tool. The optimal cut-off point for the ratio value with maximal combined sensitivity and specificity was found with corresponding sensitivity of 67.9% (56.5-77.2%, 95% CI) and specificity of 75.0% (52.8-91.8%, 95% CI). An additional higher cut-off with higher specificity with minimal possible sacrifice on sensitivity was also selected, yielding sensitivity of 28.6% (18.8-38.6%, 95% CI) and specificity of 90.0% (69.6-98.8%, 95% CI).

CONCLUSIONS

Our results demonstrated that the more asymmetrical activity on the initial phase, the more successful it is to localize a single parathyroid adenoma on sestamibi scans. Using early-phase Tc-99m sestamibi scan only, we were able to select patients for minimally invasive parathyroidectomy with 90% specificity.

Absent 99mTc-MIBI Uptake in the Thyroid Gland during Early Phase of Parathyroid Scintigraphy in Patients with Primary and Secondary Hyperparathyroidism

BACKGROUND

Thyroid uptake of technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) during parathyroid scintigraphy can be affected by various conditions.

AIM

To evaluate the frequency of absent ^99mTc-MIBI uptake by the thyroid gland in the early phase of dual-phase parathyroid scintigraphy.

METHODS

The early planar images of dual phase Tc^99m MIBI parathyroid scintigraphy from 217 patients performed between 2014 and 2017 were retrospectively analysed. Patients were divided into two groups. The first group included 147 patients with primary hyperparathyroidism and the second group included 70 patients with chronic renal failure. Patient records, laboratory and ultrasonographic data were analysed in all patients. Descriptive statistic was used for data analysis.

RESULTS

Out of all patients in the first group, 18 patients (12.24%) showed absent thyroid uptake. Thyroidectomy was performed in 44.4% of these patients, and the rest of them had some thyroid disease. Only one patient had no thyroid or another chronic disease. In the second group, 8 patients (11.42%) presented with absent thyroid uptake of MIBI. Among them, 5 patients had no history of thyroid disease and had been on hemodialysis programme, and 3 patients had hypothyroidism.

CONCLUSION

Absent ^99mTc-MIBI uptake in the thyroid during the early phase of parathyroid scintigraphy is most frequently related to thyroid disease. A small proportion of patients with chronic renal failure can present with absent ^99mTc-MIBI uptake in the thyroid as well. The mechanism for this alteration is still unclear and needs further investigation.

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

CONTEXT

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.

OBJECTIVE

To examine the relationship between vitamin D deficiency and correct parathyroid tissue localization by four-pole thyroid quadrant analysis.

DESIGN

Retrospective study.

SETTING

Referral center.

PARTICIPANTS

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).

MAIN OUTCOMES

Quadrant localization using ^99mTc-sestamibi/SPECT.

RESULTS

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).

CONCLUSIONS

Vitamin D levels do not affect the accuracy of preoperative localization with sestamibi.

Brown tumor of the jaws as a manifestation of tertiary hyperparathyroidism: A literature review and case report

Brown tumor of the jaws is a manifestation of hyperparathyroidism consisting of osteolytic lesions that show proliferation of multinucleated giant cells in the maxilla and/or mandible. Differential diagnosis of these lesions from local central giant-cell granuloma is mandatory for the correct treatment of the patient. Radiographic and histopathological exams of the jaw lesion are not sufficient to determine the diagnosis, which requires laboratory tests including serum levels of calcium, alkaline phosphatase, parathyroid hormone (PTH) and phosphate, and radiographic examination of other bones as well, such as hand-wrist, pelvis, and femur. We present here a brief literature review focusing on the clinical and radiographic features, diagnostic criteria and treatment of brown tumor and also report a case of the disease affecting the jaw.

Proteomics Analysis of Tissue Samples Reveals Changes in Mitochondrial Protein Levels in Parathyroid Hyperplasia over Adenoma

BACKGROUND/AIM

To unveil the pathophysiology of primary hyperparathyroidism, molecular details of parathyroid hyperplasia and adenoma have to be revealed. Such details will provide the tools necessary for differentiation of these two look-alike diseases. Therefore, in the present study, a comparative proteomic study using postoperative tissue samples from the parathyroid adenoma and parathyroid hyperplasia patients was performed.

MATERIALS AND METHODS

Protein extracts were prepared from tissue samples (n=8 per group). Protein pools were created for each group and subjected to DIGE and conventional 2DE. Following image analysis, spots representing the differentially regulated proteins were excised from the and used for identification via MALDI-TOF/TOF analysis.

RESULTS

The identities of 40 differentially-expressed proteins were revealed. Fourteen of these proteins were over-expressed in the hyperplasia while 26 of them were over-expressed in the adenoma.

CONCLUSION

Most proteins found to be over-expressed in the hyperplasia samples were mitochondrial, underlying the importance of the mitochondrial activity as a potential biomarker for differentiation of parathyroid hyperplasia from adenoma.

99m-Technetium Sestamibi Uptake in a Gastric Schwannoma

We report the case of a 74-year-old woman with primary hyperparathyroidism who underwent 99m-technetium-sestamibi single photon emission computed tomography-computed tomography for preoperative localization of parathyroid adenoma. Unexpected focal sestamibi uptake was observed at a 5 cm submucosal tumor arising from the greater curve of the stomach. The patient underwent partial gastrectomy and the histological and immunohistochemical findings were consistent with the diagnosis of gastric schwannoma.

Hyperparathyroidism Caused by Coexisting Parathyroid Hyperplasia and Ectopic Parathyroid Adenomas

Tc sestamibi parathyroid scan was performed in a 35-year-old man with chronic renal failure to evaluate the cause of increased serum parathyroid hormone. Both early and delayed images showed intense activity overlapping the left upper pole of the thyroid, which was proven to be nodular parathyroid hyperplasia after parathyroidectomy. However, the levels of serum parathyroid hormone remained elevated postsurgically. A repeat sestamibi study revealed abnormal activity in the left upper mediastinum, which could also be subtly seen on initial sestamibi study. A retrosternal lesion was resected, which was confirmed as an ectopic parathyroid adenoma by pathological examination.

11C-Choline PET/CT for Detection and Localization of Parathyroid Adenomas

OBJECTIVE

The purpose of this study is to determine the efficacy of ¹¹C-choline PET/CT for the detection of parathyroid adenomas by retrospectively reviewing a large patient population.

MATERIALS AND METHODS

In this single-institution retrospective study, 7088 ¹¹C-choline PET/CT scans performed of 2933 men with prostate cancer from January 2005 through February 2016 were evaluated. Patients with suspected parathyroid adenomas were identified through a review of the electronic medical record and relevant imaging. Patient demographics, laboratory results, and lesion characteristics were noted. Pathologically proven parathyroid adenomas and lesions in patients with imaging or laboratory findings consistent with the diagnosis were considered positive.

RESULTS

Thirteen men (mean [± SD] age, 72 ± 7 years) with pathologically or laboratory-proven parathyroid adenomas were identified. All had abnormally elevated serum calcium and parathyroid hormone levels. All adenomas were tracer avid on ¹¹C-choline PET/CT (maximum standardized uptake value, 5.6 ± 3.0), with activity averaging 4.2 times that of the blood pool and 2.1 times that of the adjacent thyroid. One case of an ectopic adenoma was identified. Of the six pathologically confirmed cases, none displayed high-grade features such as capsular, vascular, or adjacent tissue invasion. Three additional patients with possible parathyroid adenomas at ¹¹C-choline PET/CT were ultimately found to have thyroid lesions on the basis of tissue diagnosis; however, none of these patients had abnormal calcium or parathyroid hormone levels.

CONCLUSION

In our patient population, ¹¹C-choline PET/CT identified parathyroid adenomas with high specificity. Prospective investigation is warranted to validate this result and delineate the utility of ¹¹C-choline PET/CT relative to other modalities.

Concomitant occurrence of primary hyperparathyroidism (PHPT) due to mediastinal parathyroid adenoma and sublingual thyroid gland: the role of parathyroid technetium-99m-MIBI scintigraphy

The concomitant appearance of a sublingual thyroid and primary hyperparathyroidism due to parathyroid mediastinal adenoma is not common. This co‐occurrence can lead to a misdiagnosis by morphological imaging methods alone. This case emphasizes the role of 99mTc‐MIBI scintigraphy in the detection of parathyroid ectopic adenoma in a patient with an ectopic thyroid gland. This more accurate location of parathyroid scintigraphy is of great benefit to the surgeon for surgical excision.

Multiple endocrine neoplasia type 1 with anterior mediastinal parathyroid adenoma: successful localization using Tc-99m sestamibi SPECT/CT

The most common manifestation of multiple endocrine neoplasia type 1 (MEN1) is hyperparathyroidism. Treatment of hyperparathyroidism in MEN patients is surgical removal of the parathyroid glands, however ectopic parathyroid gland is challenging for treatment. A 51-year-old female, the eldest of 3 MEN1 sisters, had hyperparathyroidism with ectopic parathyroid adenoma in the mediastinal para-aortic region, which was detected by technetium-99m (Tc-99m) sestamibi scintigraphy and single-photon emission computed tomography/computed tomography (SPECT/CT). She underwent total parathyroidectomy with video-assisted thoracoscopic surgery on an anterior mediastinal mass. Anterior mediastinal parathyroid adenoma in MEN1 patients is rare. Precise localization of an ectopic parathyroid gland with Tc-99m sestamibi SPECT/CT can lead to successful treatment of hyperparathyroidism. This is the first reported case in the literature of mediastinal parathyroid adenoma in MEN1 patient visualized by Tc-99m sestamibi SPECT/CT.

Hybrid-fusion SPECT/CT systems in parathyroid adenoma: Technological improvements and added clinical diagnostic value

Nuclear medicine traditionally employs planar and single photon emission computed tomography (SPECT) imaging techniques to depict the biodistribution of radiotracers for the diagnostic investigation of a range of disorders of endocrine gland function. The usefulness of combining functional information with anatomy derived from computed tomography (CT), magnetic resonance imaging (MRI), and high resolution ultrasound (US), has long been appreciated, either using visual side-by-side correlation, or software-based co-registration. The emergence of hybrid SPECT/CT camera technology now allows the simultaneous acquisition of combined multi-modality imaging, with seamless fusion of 3D volume datasets. Thus, it is not surprising that there is growing literature describing the many advantages that contemporary SPECT/CT technology brings to radionuclide investigation of endocrine disorders, showing potential advantages for the pre-operative locating of the parathyroid adenoma using a minimally invasive surgical approach, especially in the presence of ectopic glands and in multiglandular disease. In conclusion, hybrid SPECT/CT imaging has become an essential tool to ensure the most accurate diagnostic in the management of patients with hyperparathyroidism.

Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders.

METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology.

RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for ^99mTc-sestamibi parathyroid scintigraphy and ^99mTc-pertechnetate thyroid scintigraphy, ¹²³I- or ¹³¹I-radioiodine for staging of differentiated thyroid carcinoma, ¹¹¹In- and ^99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, ¹³¹I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and ¹²³I- or ¹³¹I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma.

CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy from CT, translating to improved diagnostic accuracy and meaningful impact on patient care.