Factors contributing to negative parathyroid localization: an analysis of 1000 patients

Addressing the challenges of missed parathyroid glands in ultrasonography for secondary hyperparathyroidism: a retrospective observational study

Purpose

Preoperative localization plays an important role in secondary hyperparathyroidism (SHPT) surgery. The advantages of neck ultrasound (US) include high availability and low cost. However, the reported sensitivity of US is 54%-76%, and the reason for missed parathyroid glands (PGs) on US has been rarely addressed.

Methods

Fifty-four patients who were diagnosed with renal SHPT from September 2020 to March 2022 were included in this retrospective study. Preoperative localization included surgeon-oriented US and technetium 99m-sestamibi single-photon emission CT (SPECT)/CT.

Results

A total of 212 PGs were pathologically confirmed, resulting in a success rate of 96.2% (52 of 54). Using echo, 193 PGs (91.0%) were accurately localized, while 19 glands (9.0%) were not identified, including those in ectopic positions (n = 12, at thymus or intrathyroid or others), of small size (<1 cm, n = 6), or overlapping with an ipsilateral PG (n = 1). US accurately detected 4 PGs in 36 (66.7%) patients, while SPECT/CT localized 4 glands in 19 patients (35.2%). Although the number of US-detectable PGs was not associated with success rate, it showed a significant negative correlation with surgical time (rs = -0.459, P = 0.002).

Conclusion

US detected 4 glands in 66% of SHPT patients with a sensitivity of 90% for localization. Ectopic position and small size were the most common reasons for the failure to detect PG on US. Complete preoperative echo localization might shorten operating time.

4D SPECT/CT: A Hybrid Approach to Primary Hyperparathyroidism

Our rationale was to review the imaging options for patients with primary hyperparathyroidism and to advocate for judicious use of 4-dimensional (4D) SPECT/CT to visualize diseased parathyroid glands in patients with complex medical profiles or in whom other imaging modalities fail. We review the advantages and disadvantages of traditional imaging modalities used in preoperative assessment of patients with primary hyperparathyroidism: ultrasound, SPECT, and 4D CT. We describe a scheme for optimizing and individualizing preoperative imaging of patients with hyperfunctioning parathyroid glands using traditional modalities in tandem with 4D SPECT/CT. Using the input from radiologists, endocrinologists, and surgeons, we apply patient criteria such as large body habitus, concomitant multiglandular disease, multinodular thyroid disease, confusing previous imaging, and unsuccessful previous surgery to create an imaging paradigm that uses 4D SPECT/CT yet is cost-effective, accurate, and limits extraneous radiation exposure. 4D SPECT/CT capitalizes on the strengths of SPECT and 4D CT and addresses limitations that exist when these modalities are used in isolation. In select patients with complicated clinical parameters, preoperative imaging with 4D SPECT/CT can improve accuracy yet remain cost-effective.

The value of ultrasound in combination with 99mTc-MIBI imaging department of ultrasound medicine, for the diagnosis of ectopic parathyroid glands in the thyroid gland in patients with secondary hyperparathyroidism

To investigate the value of preoperative ultrasound combined with 99mTc-MIBI imaging for the diagnosis of ectopic intrathyroid parathyroid gland (ETPG) in patients with secondary hyperparathyroidism (SHPT). One hundred and eleven patients with SHPT who underwent total parathyroidectomy plus forearm transplantation from January 2015 to January 2022 in the Third Hospital of Hebei Medical University were selected. All patients underwent routine preoperative ultrasonography and 99mTc-MIBI imaging, and with pathological diagnosis as the gold standard, the clinical data of ETPG patients were selected, including clinical manifestations, laboratory tests, preoperative ultrasonography and 99mTc-MIBI imaging for localization and diagnosis, intraoperative exploration and postoperative pathology, and postoperative follow-up. To analyze the ultrasound manifestations of preoperative parathyroid hyperplasia and the results of 99mTc-MIBI imaging in patients with ETPG. Among 111 patients with SHPT, there were 5 patients with ETPG, 1 male and 4 females with a mean age of (45.00 ± 5.05) years, and 6 ectopic parathyroid glands were located in the thyroid gland. The incidence of ETPG was 4.5% (5/111), 4 were detected by ultrasound, 2 were not detected with a diagnostic accuracy of 66.7% (4/6), 3 were positive for 99mTc-MIBI imaging, 3 were negative with a diagnostic accuracy of 50.0% (3/6). Among them, one was not detected by ultrasound, but was positive for 99mTc-MIBI imaging, 2 with negative 99mTc-MIBI imaging, but all were detected by ultrasound, and one with negative 99mTc-MIBI imaging was detected by ultrasound but misdiagnosed as a thyroid nodule. A total of 5 ETPGs were detected by ultrasound combined with 99mTc-MIBI imaging, with a diagnostic accuracy of 83.3% (5/6). Patients' postoperative serum calcium and serum parathyroid hormone (PTH) levels were normalized or significantly decreased from preoperative levels. Ultrasound combined with 99mTc-MIBI imaging can achieve higher accuracy than either examination alone in the preoperative localization and diagnosis of ETPG in SHPT patients.

Sonographic Features of Atypical and Initially Missed Parathyroid Adenomas: Lessons Learned From a Single-Center Cohort

CONTEXT

Awareness of typical and atypical ultrasonographic (US) features of parathyroid adenomas (PAs) is crucial since US is the most widely used first-line imaging modality.

OBJECTIVE

The purpose of this study was to describe the atypical features of PAs on US and other possible factors leading to a false negative examination in a large single-center cohort.

MATERIALS AND METHODS

The US records of 457 PAs in 445 patients with biochemically proven primary hyperparathyroidism (PHPT) were evaluated in a prospectively maintained database. Atypical size, composition, shape, echogenicity, location, and vascular pattern on US were noted. For patients who previously had at least one negative US examination in referring centers, the main possible reason was defined accordingly.

RESULTS

The study group included 359 female and 86 male patients with PHPT. Typical sonographic features were observed in 231 PAs (51%), whereas 226 (49%) had at least one atypical US feature. The most common atypical features were atypical size (29%), followed by atypical echogenicity (19%), shape (8%), location (7%), and composition (7%), respectively. There were 122 initially missed PAs in all groups. The most frequent main atypical US features leading to false negative examinations were atypical size (22.1%) and atypical location (18.8%). Inexperience was third most common reason (16.3%) for false negative US examinations.

CONCLUSIONS

Almost half of PAs have at least one atypical feature on US. Awareness of the high prevalence of atypical US features could increase the accuracy of US examination and potentially decrease demand for more expensive second-line imaging modalities.

Primary Hyperparathyroidism: Outcomes of Repeated Imaging After Initial Negative Radiological Localization

BACKGROUND

Radiological localization imaging aids in the identification of abnormal parathyroid glands resulting in primary hyperparathyroidism (PHPT), thereby facilitating minimally invasive parathyroid surgery. Sometimes initial imaging may fail to identify the abnormal gland and imaging may therefore be repeated. This study explored patient outcomes of repeated parathyroid localization imaging, after initial negative gland localization, at a United Kingdom institution.

METHODOLOGY

Data was retrospectively collected and analyzed for patients with PHPT undergoing repeated imaging during a five-year period (2015-2020). The total number of episodes of scanning, types of scans performed, the time interval between scans and the imaging success of gland localization were recorded. We explored the reasons for repeated imaging and attempted to identify any factors that might predict subsequent positive radiological localization.

RESULTS

A total of 45 patients were identified who underwent repeated localizing imaging after first localizing imaging was negative. Of these, 39 did not undergo surgery despite repeat imaging being undertaken; 11 out of these 39 patients (28%) had subsequent positive localization scans. Again, a large proportion of patients were managed conservatively, despite the repeated sets of imaging being done. Patients undergoing three or four sets of repetitive imaging did not have imaging or surgical success.

CONCLUSION

A streamlined parathyroid pathway should be followed whereby patients should be triaged for suitability for surgery prior to repeated imaging. A second set of scans should be offered when patients are unsuitable for conservative management and are willing and fit to undergo surgery. There is no merit to repeating imaging more than twice.

Efficacy of surgeon-performed, intra-operative ultrasound scan for localisation of parathyroid adenomas in patients with primary hyperparathyroidism

BACKGROUND

In the UK, guidance recommends ultrasound scanning alone or in combination with sestamibi scintigraphy to guide surgery in patients with primary hyperparathyroidism. If an adenoma is localised on imaging, this can facilitate targeted or minimally invasive surgery. Surgeon-performed ultrasound scan on the operating table benefits from being performed on an anaesthetised patient with optimal positioning. The aim of this study was to investigate the efficacy of intra-operative, blinded, surgeon-performed ultrasound scan in localisation of parathyroid adenomas.

METHODS

Prospective data were collected on consecutive patients undergoing surgery for primary hyperparathyroidism at a single tertiary centre from November 2019 to June 2021. Patients underwent blinded, surgeon-performed ultrasound scan under general anaesthesia immediately prior to surgery. Localisation results from pre-operative imaging and surgeon-performed ultrasound scan were then compared with the intra-operative findings.

RESULTS

Forty-nine patients underwent surgery and were found to have single-gland disease. Sestamibi scintigraphy, radiologist-performed ultrasound scan and surgeon-performed ultrasound scan had sensitivities of 59.4, 43.75 and 73.8 per cent, respectively. Surgeon-performed ultrasound scan had a statistically significantly increased sensitivity compared with radiologist-performed ultrasound (p < 0.05).

CONCLUSION

Intra-operative, surgeon-performed ultrasound scan is effective in localising parathyroid adenomas and may be a useful adjunct to facilitate minimally invasive parathyroid surgery.

Use of dual energy computed tomography versus conventional techniques for preoperative localization in primary hyperparathyroidism: Effect of preoperative calcium and parathyroid hormone levels

BACKGROUND

We aimed to investigate the association of preoperative calcium and parathyroid hormone (PTH) levels with sensitivity and accuracy of dual energy computed tomography (DECT), single-photon emission CT with ^99mTc-sestamibi (CT-MIBI), and ultrasound (US) for pre-operative localization primary hyperparathyroid (PHP) patients.

METHODS

Patients undergoing parathyroidectomy for PHP at a tertiary care facility who underwent DECT, CT-MIBI and US between 2012 and 2021 were stratified by preoperative calcium and PTH levels.

RESULTS

Of 278 patients, those with high calcium and PTH levels had a higher sensitivity and accuracy with DECT (87.7%, 85.2%) compared to CT-MIBI (82.3%, 79.0%), and US (61.7%, 53.1%). DECT was more sensitive and accurate than other preoperative localization techniques in subgroups with normal PTH (DECT sensitivity 60.9%, accuracy 52.1%) and normal calcium levels (41.7%, 33.3%).

CONCLUSION

Preoperative calcium and PTH were associated with sensitivity and accuracy of pre-operative localization in PHP. DECT was sensitive and accurate for preoperative localization compared to other first-line imaging techniques.

Application value of contrast-enhanced ultrasound in preoperative localization of microwave ablation for primary hyperparathyroidism

BACKGROUND

Ultrasonography (US) and ^99m Technetium-sestamibi scintigraphy (^99m Tc-MIBI) are currently first-line imaging modalities to localize parathyroid adenomas with sensitivities of 80% and 84%, respectively. Therefore, finding other modalities to further improve the diagnostic accuracy for preoperative localization is critically needed.

PURPOSE

To evaluate the application value of contrast-enhanced ultrasound (CEUS) in the preoperative localization of microwave ablation (MWA) for primary hyperparathyroidism (PHPT).

METHODS

Between December 2012 and May 2021, 100 PHPT patients (34 males and 66 females; mean age, 56.31 ± 13.43 years; age range, 25-85 years) with 130 suspected parathyroid nodules were enrolled. US, CEUS, and ^99m Tc-MIBI were performed for the localization of pathological parathyroid glands. All patients were performed MWA under ultrasound guidance. All the suspected parathyroid nodules underwent core needle biopsy under ultrasound guidance during MWA to confirm the pathology. The diagnostic performance of all the imaging tests was analyzed in comparison with the pathological results.

RESULTS

A total of 130 nodules suspected to be of parathyroid origin from preoperative localization images were confirmed by pathological results, of which 116 were of parathyroid origin, and 14 were not of parathyroid origin. The sensitivity, specificity, accuracy, and the area under receiver operating characteristic curve of CEUS in the localization of pathological parathyroid glands were 100%, 92.86%, 99.23%, and 0.964, which were significantly higher than those of US (93.10%, 42.86%, 87.69%, and 0.680) and ^99m Tc-MIBI (81.90%, 42.86%, 77.69%, and 0.624) (p < 0.05). The sensitivity and accuracy of CEUS were 100% and 97.22%, which were higher than those of ^99m Tc-MIBI (65.62% and 63.89%) or US (75.00% and 72.22%) in patients with multiple parathyroid glands (p < 0.05). For smaller parathyroid adenomas (≤2 cm in diameter), the sensitivities of CEUS in locating hyperfunctioning parathyroid glands were 100%, which was significantly higher than that of ^99m Tc-MIBI (73.68% and 84.31%, p < 0.05).

CONCLUSIONS

CEUS is a valuable preoperative localization method for PHPT patients performed MWA, especially for the patients with smaller pathological parathyroid gland and multiple glandular lesions.

An Approach to a Patient With Primary Hyperparathyroidism and a Suspected Ectopic Parathyroid Adenoma

Primary hyperparathyroidism (PHPT) is characterized by hypercalcemia driven by excess parathyroid hormone (PTH) secretion. PHPT is a common endocrine condition with a prevalence of 1 to 7 cases per 1000 adults. PHPT typically presents in the fifth or sixth decade and shows significant female preponderance. Solitary hyperfunctioning parathyroid adenomas account for 85% to 90% of PHPT cases. The remaining 10% to 15% include cases of multiglandular disease (multiple adenomas or hyperplasia) and, rarely, parathyroid carcinoma (1%). Ectopic parathyroid adenomas may arise due to abnormal embryological migration of the parathyroid glands and can be difficult to localize preoperatively, making surgical cure challenging on the first attempt. The potential existence of multiglandular disease should be considered in all patients in whom preoperative localization fails to identify a target adenoma or following unsuccessful parathyroidectomy. Risk factors for multiglandular disease include underlying genetic syndromes (eg, MEN1/2A), lithium therapy, or previous radiotherapy. In addition to multifocal disease, the possibility of an ectopic parathyroid gland should also be considered in patients requiring repeat parathyroid surgery. In this article, we use illustrative clinical vignettes to discuss the approach to a patient with primary hyperparathyroidism (PHPT) and a suspected ectopic parathyroid adenoma.

Correlation of Preoperative Imaging Findings and Parathyroidectomy Outcomes Support NICE 2019 Guidance

CONTEXT

Preoperative localization studies are standard practice in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). The most common modalities are neck ultrasound (US) and sestamibi scanning. However, the nature of pHPT is changing, with imaging increasingly yielding negative results. Numerous studies suggest unlocalized disease is associated with poor outcomes, calling into question whether such patients are best treated conservatively.

OBJECTIVE

This study aims to correlate parathyroidectomy outcomes with preoperative imaging in a single, high-volume institution.

METHODS

Data from a prospectively maintained departmental database of operations performed from 2017 to 2019 were analyzed. All patients undergoing first-time surgery for sporadic pHPT were included. Data collected included patient demographics, preoperative imaging, surgical strategy, and postoperative outcomes.

RESULTS

A total of 609 consecutive parathyroidectomies were included, with a median age of 59 years (range 20-87 years). The all-comer cure rate was 97.5%; this was 97.9% in dual localized patients (those with positive US and sestamibi), compared to 95.8% in the dual unlocalized group (those with negative US and sestamibi) (P = 0.33). Unilateral neck exploration was the chosen approach in 59.9% of patients with double-positive imaging and 5.7% of patients with double-negative imaging (otherwise, bilateral parathyroid visualization was performed). There was no significant difference in postoperative complications between patients undergoing unilateral or bilateral neck exploration.

CONCLUSIONS

Patients with negative preoperative imaging who undergo parathyroidectomy are cured in almost 96% of cases, compared to 98% when the disease is localized. This difference does not reach statistical or clinical significance. These findings therefore support current recommendations that all patients with pHPT who are likely to benefit from operative intervention should be considered for parathyroidectomy, irrespective of preoperative imaging findings.

A mini-invasive approach is feasible in patients with primary hyperparathyroidism and discordant or negative localisation studies

Preoperative localisation of pathological glands in patients with primary hyperparathyroidism (PHP) is the mainstay for mini-invasive parathyroidectomy. Nevertheless, a not negligible number of patients presents discordant or negative neck ultrasound (US) and ^99mTc-Sestamibi (MIBI) scan. The aim of this study was to assess if a mini-invasive approach is feasible in this kind of patients. In this retrospective study were included patients that underwent parathyroidectomy for PHP. Patients were divided into two groups according to concordance of US and MIBI scan results. 242 patients were included: 183 had concordant preoperative studies, and 59 had discordant or negative studies. A mini-invasive approach was possible in 42 (72.9%) patients with unclear preoperative studies, whereas 12 (20.3%) additional patients required conversion to BNE. The incidence of persistent PHP was higher in patients with unclear preoperative studies (8.5% vs 2.7%), but this difference did not reach a statistical significance (p = 0.121). In patients with unclear preoperative studies, a negative result of intraoperative PTH allowed to avoid a persistent disease in 12 patients, while in 3 cases led to an unnecessary additional exploration. In patients with discordant preoperative studies a mini-invasive approach is feasible; in this setting, the use of intraoperative PTH is mandatory to reduce the incidence of persistent PHP.

Surgical results and the location of pathological glands in the treatment of primary sporadic hyperparathyroidism with negative preoperative 99mTc-sestamibi scintigraphy

INTRODUCTION

The primary hyperparathyroidism is a frequent disease whom the surgery is the only curative treatment. The preoperative location imaging techniques could help in the surgical management. Our objective was to analyze surgical results regarding the cure rate, etiology and location of the glands responsible for the primary hyperparathyroidism in patients with negative preoperative ^99mTc-sestamibi scintigraphy.

METHODS

Observational study in patients with the diagnosis of primary sporadic hyperparathyroidism with negative ^99mTc-sestamibi scintigraphy, operated consecutively in an endocrine surgery unit for 18 years. The cure rate, the intraoperatory PTH, the etiology and the pathological glands location were analyzed.

RESULTS

In the study were included 120 patients. After surgery 95% of patients (n = 114) presented cure criteria of hyperparathyroidism. 14.1% presented a multigland disease. 69% of the adenomas presented a typical perithyroid location, founding a percentage of 23.9% of ectopic adenomas in cervical location and a 7.1% in mediastinum.

CONCLUSIONS

The absence of uptake in the ^99mTc-sestamibi scintigraphy should not condition the surgical indication. The success with experienced surgeons is similar to patients with positive results. The surgical indication must be established by clinical and biochemistry criteria.

Hiperparatiroidismo primario por adenoma paratiroideo doble con glándulas paratiroides eutópica y ectópica

El hiperparatiroidismo primario (HPTP) es una afección producida por el exceso de secreción de hormona paratiroidea a partir de glándulas paratiroides que funcionan autárquicamente. Constituye la causa más común de hipercalcemia en la población. Por su embriología, las paratiroides son glándulas que pueden tener localizaciones ectópicas de forma frecuente. El HPTP se presenta en forma esporádica en el 90% de los casos, resultante en general de un adenoma único con expansiones monoclonales de una estirpe celular única. Menos frecuentemente (2-15%), se asocia con un segundo adenoma funcionante. La forma familiar (10%) se asocia a síndrome de neoplasias endócrinas múltiples (NEM) como NEM 1 y NEM 2A. Se presenta un caso de adenoma paratiroideo doble, con el segundo adenoma paratiroideo localizado en el mediastino, describiéndose los estudios preoperatorios y de localización glandular, así como los hallazgos operatorios.

Sestamibi Single-Positron Emission Computed Tomography/Diagnostic-quality Computed Tomography for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism: What clinicopathologic factors affect its accuracy?

PURPOSE

Sestamibi Single-Positron Emission Computed Tomography/Diagnostic-quality Computed Tomography (MIBI-SPECT/CT) is a common technology used for primary hyperparathyroidism (PHPT) localization in clinical practice. However, the clinicopathologic factors affecting the accuracy of MIBI-SPECT/CT and the potential limitations remain unclear.

METHODS

Retrospectively enrolled PHPT patients (n = 280) were analyzed from August 2017 to December 2019.

RESULTS

Of 96 patients with PHPT (mean age, 54 years; 63 females), 17 had discordance between MIBI-SPECT/CT and intraoperative findings. Among the 17 patients with discordance, 58.8% had major discordance, which occurred in most patients with multigland disease (MGD). Compared with concordant patients, discordant patients exhibited increased frequencies of autoimmune thyroid disease (29.4% vs 10.1%, p = 0.035), MDG (41.2% vs 3.8%, p = 0.035), higher PTH (296 pg/mL vs 146 pg/mL; p = 0.012),and lower phosphorus levels (0.77 mmol/L vs 0.90 mmol/L; p = 0.024). MDG (odds ratio [OR], 16.95; 95% CI 2.10-142.86), parathyroid lesion size of 12 mm or less (OR, 6.93; 95% CI 1.41-34.10), and a PTH level higher than 192.5 pg/mL (OR, 12.66; 95% CI 2.17-71.43) were independently associated with discordant MIBI-SPECT/CT results.

CONCLUSION

MGD was most strongly associated with discordance between MIBI-SPECT/CT and intraoperative findings followed by a PTH level higher than 192.5 pg/mL and parathyroid lesion size of 12 mm or less. Surgeons should recognize these potential limitations, which may improve the preoperative procedure by encouraging further localization imaging and promptly facilitate intraoperative troubleshooting.

Surgical management of MILD hyperparathyroidism

INTRODUCTION

There is no consensus for management of Mild primary hyperparathyroidism (MILD-pHP). Specific management has been suggested by some authors. We have compared the surgical management of the patients with MILD-pHP to those with Classic primary hyperparathyroidism (C-pHP) treated by surgery according to The Fourth International Workshop on pHP.

MATERIALS AND METHODS

Data of 173 patients who underwent a parathyroidectomy were reviewed and retrospectively analysed. Management of 32 patients with MILD-pHPT (18.5%) patients were compared to that of 141 (81.5%) patients with C-pHPT.

RESULTS

MILD-pHP group was more often discovered after non-fractured osteoporosis (21.9% vs 7.1%, p = 0.02) and surgery for chondrocalcinosis was more often carried out (6.3% vs 0%, p = 0.03) in the MILD-pHP group. A Mini-Invasive Parathyroidectomy (MIP) was carried out in 81.3% of cases, and 87.5% of patients had a single adenoma. The rate of multiglandular pathology was not different. Same day discharge was significantly higher in MILD-pHP group (37.5% vs 17.7%, p = 0.01). Success was obtained in 87.5% in the MILD-pHP group, there was no significant difference with the C-pHP group (92.9%, p = 0.48). There was no significant difference in the imaging performances. Imaging discordance was observed in 18.8% of cases in MILD-pHP and 33.6% in C-pHP (p = 0.38) without correlation with surgical failure.

CONCLUSION

This study suggests that, by selecting patients on the basis of concordant imaging and international recommendations, there is no difference in outcome between MILD-pHP and C-pHP treated surgically.

4DCT Scanning Technique for Primary Hyperparathyroidism: A Scoping Review

Objective

4DCT for the detection of (an) enlarged parathyroid(s) is a commonly performed examination in the management of primary hyperparathyroidism. Protocols are often institution-specific; this review aims to summarize the different protocols and explore the reported sensitivity and specificity of different 4DCT protocols as well as the associated dose.

Materials and Methods

A literature study was independently conducted by two radiologists from April 2020 until May 2020 using the Medical Literature Analysis and Retrieval System Online (MEDLINE) database. Articles were screened and assessed for eligibility. From eligible studies, data were extracted to summarize different parameters of the scanning protocol and observed diagnostic attributes.

Results

A total of 51 articles were included and 56 scanning protocols were identified. Most protocols use three (n = 25) or four different phases (n = 23). Almost all authors include noncontrast enhanced imaging and an arterial phase. Arterial images are usually obtained 25–30 s after administration of contrast, and less agreement exists concerning the timing of the venous phase(s). A mean contrast bolus of 100 mL is administered at 3-4 mL/s. Bolus tracking is not often used (n = 3). A wide range of effective doses are reported, up to 28 mSv. A mean sensitivity of 81.5% and a mean specificity of 86% are reported.

Conclusion

Many different 4DCT scanning protocols for the detection of parathyroid adenomas exist in the literature. The number of phases does not appear to affect sensitivity or specificity. A triphasic approach, however, seems preferable, as three patterns of enhancement of parathyroid adenomas are described. Bolus tracking could help to reduce the variability of enhancement. Sensitivity and specificity also do not appear to be affected by other scan parameters like tube voltage or tube current. To keep the effective dose within limits, scanning at a lower fixed tube current seems preferable. Lowering tube voltage from 120 kV to 100 kV may yield similar image contrast but would also help lower the dose.

Detection of parathyroid adenomas with multiphase 4DCT: towards a true four-dimensional technique

Background

Four-dimensional computed tomography (4DCT) is a commonly performed examination in the management of primary hyperparathyroidism, combining three-dimensional imaging with enhancement over time as the fourth dimension. We propose a novel technique consisting of 16 different contrast phases instead of three or four different phases. The main aim of this study was to ascertain whether this protocol allows the detection of parathyroid adenomas within dose limits. Our secondary aim was to examine the enhancement of parathyroid lesions over time.

Methods

For this prospective study, we included 15 patients with primary hyperparathyroidism and a positive ultrasound prior to surgery. We performed 4DCT with 16 different phases: an unenhanced phase followed by 11 consecutive arterial phases and 4 venous phases. Continuous axial scanning centered on the thyroid was performed over a fixed 8 cm or 16 cm coverage volume after the start of contrast administration.

Results

In all patients, an enlarged parathyroid lesion was demonstrated, and the mean lesion size was 13.6 mm. The mean peak arterial enhancement for parathyroid lesions was 384 Hounsfield units (HU) compared to 333 HU for the normal thyroid. No significant difference could be found. The time to peak (TTP) was significantly earlier for parathyroid adenomas than for normal thyroid tissue: 30.8 s versus 32.3 s (p value 0.008). The mean slope of increase (MSI) of the enhancement curve was significantly steeper than that of normal thyroid tissue: 29.8% versus 22.2% (p value 0.012). The mean dose length product was 890.7 mGy cm with a calculated effective dose of 6.7 mSv.

Conclusion

Our 4DCT protocol may allow better visualization of the pattern of enhancement of parathyroid lesions, as enhancement over time curves can be drawn. In this way, wash-in and wash-out of contrast in suspected lesions can be readily demonstrated. Motion artifacts are less problematic as multiple phases are available. Exposure to our proposed 4DCT technique is comparable to that for classic helical 4DCT. Careful selection of parameters (lowering kV and SNR) can help to further reduce the dose.

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.

Factors associated with negative 99mTc-MIBI scanning in patients with primary hyperparathyroidism

OBJECTIVE

The objective was to evaluate the clinical and biological factors associated with negative ^99mTc-MIBI scanning in patients with primary hyperparathyroidism (PHPT).

METHODS

A retrospective observational study was designed in 195 patients (mean age: 59.2 ± 13.0 years; 77% woman) with PHPT (calcium: 11,3 ± 1,1 mg/dl and PTH: 218 ± 295 pg/ml) studied in endocrinology setting between 2013 and 2020. An univariate and multivariate analysis was made to evaluate the clinical and biological factors associated with negative ^99mTc-MIBI scanning.

RESULT

50 patients (26%) with negative ^99mTc-MIBI scanning had lower PTH levels (146 ± 98 vs. 244 ± 334; p < 0,001), adenomas with smaller sonographic dimensions (maximum diameter: 1,2 ± 0,4 vs. 1,7 ± 0,9 cm; p = 0,001 and volume: 0,36 ± 0,43 vs. 1,7 ± 4,1 cm³; p < 0,001), localized more frequently in upper parathyroid glands (37% vs 14%; p = 0,005) and associated more frequently to thyroid nodules (72% vs 57%; p = 0,045) than patients with positive scanning. 116 patients were operated and parathyroid adenomas were smaller (maximum diameter: 1,3 ± 0,5 vs. 1,9 ± 1,1 cm; p = 0,008 and volume: 0,30 ± 0,20 vs. 1,2 ± 1,1 cm³; p < 0,001), less heavy (567 ± 282 vs. 1470 ± 1374 mgr.; p = 0,030) and were localized more frequently in upper situation (65% vs 16%; p < 0,001) than patients with positive scanning. In the multivariate analysis an independent association between negative ^99mTc-MIBI scanning and size of removed adenoma ≤1 cm (OR: 5,77; IC 95: 1,46-22,71) and upper adenoma localization were observed (OR: 8,05; IC 95%: 2,22-29,16).

CONCLUSIONS

One in four patients studied for PHPT had a negative ^99mTc-MIBI scanning and were independent associated with size of adenoma ≤1 cm and upper adenoma localization.

The feasibility of anterior 180° 99m Tc-sestamibi parathyroid SPECT/CT

OBJECTIVE

For ^99mTc-sestamibi parathyroid single photon emission computed tomography/computed tomography (SPECT/CT), the traditional full-arc 360° acquisition technique has been suggested but not the theoretically low tissue-attenuated anterior 180° method. We aimed to compare the diagnostic performances and target-to-background ratios of anterior 180° and 360° SPECT/CT imaging.

METHODS

Ninety-nine patients who underwent ^99mTc-sestamibi scintigraphy and received a surgical-pathological diagnosis of parathyroid adenoma or hyperplasia were enrolled. The SPECT/CT reconstructed images with anterior 180° and full-arc 360° data were interpreted by two physicians using a scoring scale, and the lesions were semi-quantified using target-to-background ratios for both image sets.

RESULTS

In total, 113 abnormal parathyroid lesions were identified on the SPECT/CT images. The agreements of interpretation between the two image sets and readers were very good (κ value: 0.83-1.00). The accuracies of summative interpretation for the anterior 180° and full-arc 360° SPECT/CT were 83.04% and 82.46%, respectively. The target-to-background ratios were significantly higher for the anterior 180° than the full-arc 360° images (P < 0.01).

CONCLUSIONS

The anterior 180° SPECT/CT technique, a time-saving method, can provide satisfactory diagnostic performance and superior lesion contrast compared with the full-arc 360° SPECT/CT technique in ^99mTc-sestamibi parathyroid imaging.

Surgical results and the location of pathological glands in the treatment of primary sporadic hyperparathyroidism with negative preoperative 99mTc-sestamibi scintigraphy

INTRODUCTION

The primary hyperparathyroidism is a frequent disease whom the surgery is the only curative treatment. The preoperative location imaging techniques could help in the surgical management. Our objective was to analyze surgical results regarding the cure rate, etiology and location of the glands responsible for the primary hyperparathyroidism in patients with negative preoperative 99mTc-sestamibi scintigraphy.

METHODS

Observational study in patients with the diagnosis of primary sporadic hyperparathyroidism with negative 99mTc-sestamibi scintigraphy, operated consecutively in an Endocrine Surgery Unit for 18 years. The cure rate, the intraoperatory parathyroid hormone (PTH), the etiology and the pathological glands location were analyzed.

RESULTS

In the study were included 120 patients. After surgery 95% of patients (n = 114) presented cure criteria of hyperparathyroidism. The 14.1% presented a multigland disease; 69% of the adenomas presented a typical perithyroid location, founding a percentage of 23.9% of ectopic adenomas in cervical location and a 7.1% in mediastinum.

CONCLUSIONS

The absence of uptake in the 99mTc-sestamibi scintigraphy should not condition the surgical indication. The success with experienced surgeons is similar to patients with positive results. The surgical indication must be established by clinical and biochemistry criteria.

Factors associated with negative 99mTc-MIBI scanning in patients with primary hyperparathyroidism

OBJECTIVE

The objective was to evaluate the clinical and biological factors associated with negative ^99mTc-MIBI scanning in patients with primary hyperparathyroidism (PHPT).

MATERIAL AND METHODS

A retrospective observational study was designed in 195 patients (mean age: 59.2±13.0years; 77% woman) with PHPT (calcium: 11.3±1.1mg/dl and PTH: 218±295pg/ml) studied in endocrinology setting between 2013 and 2020. An univariate and multivariate analysis was made to evaluate the clinical and biological factors associated with negative ^99mTc-MIBI scanning.

RESULTS

50 patients (26%) with negative ^99mTc-MIBI scanning had lower PTH levels (146±98 vs. 244±334; p<0.001), adenomas with smaller sonographic dimensions (maximum diameter: 1.2±0.4 vs. 1.7±0.9cm; p=0.001 and volume: 0.36±0.43 vs. 1.7±4.1cm³; p<0.001), localized more frequently in upper parathyroid glands (37% vs. 14%; p=0.005) and associated more frequently to thyroid nodules (72% vs. 57%; p=0.045) than patients with positive scanning. 116 patients were operated and parathyroid adenomas were smaller (maximum diameter: 1.3±0.5 vs. 1.9±1.1cm; p=0.008 and volume: 0.30±0.20 vs. 1.2±1.1cm³; p<0.001), less heavy (567±282 vs. 1470±1374mg; p=0.030) and were localized more frequently in upper situation (65% vs. 16%; p<0.001) than patients with positive scanning. In the multivariate analysis an independent association between negative ^99mTc-MIBI scanning and size of removed adenoma ≤1cm (OR: 5.77; 95% CI: 1.46-22.71) and upper adenoma localization were observed (OR: 8.05; 95% IC: 2.22-29.16).

CONCLUSIONS

One in four patients studied for PHPT had a negative ^99mTc-MIBI scanning and were independent associated with size of adenoma ≤1cm and upper adenoma localization.

Bilateral giant parathyroid adenoma in the absence of multiple endocrine neoplasia type 1

INTRODUCTION

Bilateral giant parathyroid adenoma in the absence of multiple endocrine neoplasia (MEN) type 1 is extremely rare and literature on this subject is limited.

CASE HISTORY

A 79-year-old man presented with acute kidney injury secondary to hypercalcaemia. Blood test results indicated primary hyperparathyroidism. Ultrasonography revealed bilateral parathyroid adenomas measuring 19.4mm x 19.5mm x 18.8mm (left) and 15.2mm x 18.3mm x 19.6mm (left) whereas on computed tomography, the measurements were 31mm x 20mm (left) and 30mm x 14mm (right). Intraoperatively, giant adenomas measuring 50mm x 25mm x 12mm (left, weighing 8.101g) and 48mm x 22mm x 10mm (right, weighing 7.339g) were identified and excised. Parathyroid hormone level dropped from 44.6pmol/l preoperatively to 8.9pmol/l postoperatively (normal range 1.3-7.6pmol/l). The patient was discharged with no complications.

CONCLUSIONS

We report a rare phenomenon where bilateral giant parathyroid adenoma occurred in the absence of MEN type 1. It highlights the importance of cross-sectional imaging in delineating the anatomy of adenomas as their size can be grossly underestimated by ultrasonography alone.

Diagnostic value of four-dimensional computed tomography and four-dimensional magnetic resonance imaging in primary hyperparathyroidism when first-line imaging was inadequate

INTRODUCTION

Accurate localisation of the abnormal hyperfunctioning gland with preoperative imaging has a critical role in parathyroid surgery to obtain a successful outcome. This study aimed to evaluate the diagnostic performance of second-line imaging and their contribution to the treatment success in primary hyperparathyroidism when the first-line methods were negative or discordant.

METHODS

Among the patients who underwent parathyroidectomy due to primary hyperparathyroidism, 33 who underwent four-dimensional computed tomography and/or four-dimensional magnetic resonance imaging because of negative or discordant first-line imaging results were included. Persistent and recurrent cases were excluded.

RESULTS

The majority of the patients were female (84.8%) and the mean age was 59.2 years. Seventeen patients had four-dimensional computed tomography and 25 had four-dimensional magnetic resonance imaging, respectively. Four-dimensional computed tomography and four-dimensional magnetic resonance imaging localised the culprit gland successfully in 52.9% and 84%, respectively. Twenty-five patients in whom single adenoma was detected underwent focused parathyroidectomy. The culprit gland was solitary in 32 cases and one patient had double adenoma. Normocalcaemia was achieved in all cases. Among the 29 patients who completed their postoperative sixth month success rate was 100%.

CONCLUSION

Four-dimensional magnetic resonance imaging had high accuracy with fast dynamic imaging in detecting parathyroid adenomas. When the first-line imaging methods were negative or inconclusive, four-dimensional magnetic resonance imaging should be considered primarily since it is cost effective in Turkey and emits no radiation.

Huge brown tumor of the rib in an unlocatable hyperparathyroidism patient with “self-recovered” serum calcium and parathyroid hormone: A case report

BACKGROUND

The brown tumor is a kind of complication of hyperparathyroidism (HPT). The ultimate therapy usually is the resolution of HPT. We herein report an unlocatable HPT patient who received resection of a huge brown tumor of the rib, and experienced “self-recovery” of serum calcium and parathyroid hormone.

CASE SUMMARY

A 34-year-old female patient who suffered from a gradually increasing mass of the left chest wall since 2007 came to our hospital for treatment. The patient had a history of serum Ca and parathyroid hormone (PTH) increasing since June 2015 and received zoledronic acid treatment for 17 mo. When she came to our hospital in November 2017 after discontinuing medical treatment for 3 mo, the serum Ca and PTH levels were within normal ranges. The patient had no imaging abnormalities of parathyroid ultrasound or ^99mTc-methoxyisobutyl isonitrile. Enhanced computed tomography revealed a local soft tissue mass of 96 mm × 113 mm with bone erosion of the left 8^th rib, and the mass presented irregular enhancement with an unclear boundary between the mass and spleen. The mass was thought to likely be caused by HPT, but a malignancy could not be ruled out. Resection of the mass was performed, and the pathology proved that the mass was a brown tumor. A diagnosis of unlocatable HPT was considered. Since the serum Ca and PTH levels were both normal pre- and post-operation, the patient did not receive exploratory surgery for HPT, and received regular follow-up.

CONCLUSION

The huge brown tumor of the rib and “self-recovered” serum PTH and Ca levels are relatively rare in HPT patients. An exploratory operation may be deferred for these patients, and long-term follow-up should be performed.

[A clinical case of combined differentiated thyroid cancer and primary hyperparathyroidism: the complexity of topical differential diagnosis]

In recent years, the understanding of the epidemiology, symptoms and strategies for managing patients with hyperparathyroidism has changed significantly. The most common cases in clinical practice are of sporadic primary hyperparathyroidism, which today ranks third in prevalence among endocrine diseases (the frequency of occurrence in the adult population is, on average, 12%). In primary hyperparathyroidism, solitary parathyroid adenoma is detected in up to 85% of all cases. The only treatment is radical surgical removal of pathologically altered parathyroid tissue. Early diagnosis and treatment of hyperparathyroidism makes it possible to avoid severe lesions of the skeletal bones and visceral organs. A diagnostically challenging clinical case of a combined onco-endocrine pathology in a 70-year-old patient is presented. The main difficulties in the initial diagnosis were associated with the absence of pathognomonic symptoms of the disease, which was often completely asymptomatic. The most urgent problem appears to be the topical diagnosis of pathologically altered parathyroid glands. Therefore, there is a need to develop an algorithm for the combining and sequential use of existing medical imaging methods.

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.

Serum Vitamin D Level Does not Affect The Sensitivity of Parathyroid Adenoma Localization Tests

The aim of the present study was to evaluate the predictive value of 25-hydroxyvitamin D, calcium and parathormone level, co-existence of thyroid nodule, thyroidectomy history and adenoma volume on the success of neck ultrasound (US) and technetium-99m sestamibi (MIBI) scan in primary hyperparathyroidism (PHP) patients. This study included 256 patients with PHP who underwent parathyroidectomy. 169 (%66) patients had vitamin D deficiency and 56 (%22) of patients had insufficiency. The sensitivity of US and MIBI studies showed no difference between vitamin D deficiency, insufficiency and replete groups (%80.5, %82 and %71 (p > 0.05) and %81, %84 and %71 respectively (p > 0.05)). Vitamin D level was not found to be an independent predictor of localization on either US or MIBI scan after adjusting for different variables (p > 0.05). Calcium level was found to be an independent predictor for US sensitivity (r²:0,033, p:0,032) and parathormone level for MIBI sensitivity (r²:0,05, p:0,025). The co-existence of nodular thyroid disease and history of thyroidectomy significantly decreased the sensitivity of US (%76 and %43). MIBI sensitivity was not impaired by nodular disease but the history of thyroidectomy also impaired the sensitivity of MIBI (%43). As a result vitamin D level does not affect the sensitivity of preoperative localization tests.

VEGFR-2 is downregulated in sestamibi-negative parathyroid adenomas

BACKGROUND

The purpose of this study was to determine the expression profile of several biomarkers in sestamibi-positive (n = 23) and sestamibi-negative (n = 6) parathyroid adenomas.

METHODS

A tissue microarray of parathyroid adenomas from 29 patients was constructed and slides were stained for several proteins involved in angiogenesis, inflammation, cell adhesion, cell cycle, apoptosis, and with markers of the sonic hedgehog, mTOR, Forkhead box O and WNT signal transduction pathways. Protein expression was determined using an image-analysis software (Spectrum Plus©, 38 Aperio).

RESULTS

Protein expression analysis revealed that the vascular endothelial growth factor receptor 2 (VEGFR2) score was significantly higher in the sestamibi-positive cohort compared to sestamibi-negative adenomas (P = .038). Other proteins were not differentially expressed between sestamibi-positive and sestamibi-negative adenomas.

CONCLUSION

It is hypothesized that VEGFR-2 overexpression in parathyroid adenomas increases vascular permeability resulting in a higher uptake of sestamibi.

Comparison between technetium-99m methoxyisobutylisonitrile scintigraphy and ultrasound in the diagnosis of parathyroid adenoma and parathyroid hyperplasia

Objective

The aim of this study was to evaluate the value of technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) imaging and ultrasound in preoperative localization of parathyroid adenoma (PA) and parathyroid hyperplasia (PH).

Participants and methods

A retrospective study of ^99mTc-MIBI double-phase scintigraphy (DPS) was performed in 187 hyperparathyroidism cases with pathologically diagnosed PA or PH. Of these patients, 167 cases underwent ultrasound, and 146 cases underwent ^99mTc-MIBI single-photon emission computed tomography/computed tomography (SPECT/CT). The sensitivity and diagnostic accuracy of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT were compared between PA and PH. Differences in ^99mTc-MIBI DPS, serum parathyroid hormone (PTH), serum calcium and phosphorus, as well as the weight and longest diameter of lesion between PA and PH were also compared.

Results

As per patient-based analysis, the sensitivity of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT was 90.70% (39/43), 95.56% (43/45), and 100.00% (30/30), respectively, for PA, and 93.55% (116/124), 90.85% (129/142), and 93.10% (108/116), respectively, for PH. There were no significant differences in sensitivity of these three imaging methods between PA and PH. However, per lesion-based analysis, the accuracy of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT in detecting PA was 78.43% (40/51), 86.79% (46/53) and 96.88% (31/32), respectively, and the accuracy of ^99mTc-MIBI DPS was higher than that of ultrasound (χ²=6.507, P=0.011), and for PH, it was 49.69% (160/322), 40.71% (171/420), and 43.80% (152/347), respectively. The accuracy of ultrasound was higher than that of ^99mTc-MIBI DPS (χ²=5.940, P=0.015). The accuracy of a combination of all three examinations of ultrasound+^99mTc-MIBI DPS, ultrasound+^99mTc-MIBI SPECT/CT, ^99mTc-MIBI DPS+SPECT/CT, and ultrasound+^99mTc-MIBI DPS+^99mTc-MIBI SPECT/CT was 51.51% (154/299), 53.85% (161/299), 50.17% (150/299), and 54.18% (162/299), respectively, which was higher than that of ultrasound (χ²=5.273, P=0.022; χ²=8.226, P=0.004; χ²=3.880, P=0.049; χ²=8.702, P=0.003, respectively). Serum levels of PTH and phosphorus were lower in patients with PA than in patients with PH (P<0.001), and serum calcium level, the weight, and the longest diameter of lesion and early uptake rate of ^99mTc-MIBI DPS were higher in patients with PA than in patients with PH (P<0.01). Serum PTH level is often less than 1000 pg/ml in PA, but usually more than 1000 pg/ml in PH.

Conclusion

Ultrasound, ^99mTc-MIBI DPS, and SPECT/CT all have a higher value in the diagnosis of PA than PH. ^99mTc-MIBI SPECT/CT should be optimal for detecting PA, and early SPECT/CT scan might be better than delayed scan. Compared with ^99mTc-MIBI DPS and SPECT/CT, ultrasound has a slight advantage in localization of PH lesions. The combination of ultrasound and ^99mTc-MIBI DPS or SPECT/CT imaging could improve the accuracy in localization of PH lesions and should be considered as the first-line method for detecting PH.

Correlation of surgeon-performed parathyroid ultrasound with the Perrier classification and gland weight

BACKGROUND

Ultrasound localisation of parathyroid glands correlates with gland weight. We hypothesise that gland identification is also dependent on anatomical location. Perrier et al. have described a uniform and reliable nomenclature for parathyroid locations. We aimed to correlate surgeon-performed ultrasound (SUS) with intra-operative Perrier classification and gland weight.

METHODS

Review of a prospectively maintained single operator SUS database of 194 patients referred with non-familial primary hyperparathyroidism (PHPT) at a tertiary centre between 2010 and 2015. Patients underwent MIBI localisation as well as on table SUS. Intra-operative pathological gland locations were classified according to the Perrier nomenclature.

RESULTS

Mean weight of pathological glands found and missed by SUS was 1.07 ± 0.1 g and 0.48 ± 0.08 g respectively (p = 0.0001, unpaired t test). The weight of glands identified was greater than that of missed glands for each of the Perrier locations (p < 0.001, Mann-Whitney). The proportion of pathological glands found at each Perrier location varied significantly (p < 0.0001, Chi Square); so we find proportionally more B-, D-, E- and F-type glands and miss more A- and C-type glands. The median weight of glands missed on SUS varied significantly across the Perrier groups (Kruskal-Wallis, p = 0.0034) and suggests that SUS can miss quite large glands (> 0.5 g) in locations B, C and F; whereas missed glands in locations A, D and E were all small (< 0.5 g).

CONCLUSION

Whilst gland identification correlates well with gland weight, anatomical location has a significant impact on failure of localisation irrespective of gland weight. For the surgeon operating on PHPT patients with negative US localisation, particular attention should be paid to locations C, D and A as these are the sites where pathological glands are most often missed on pre-operative US.

Management protocol for primary hyperparathyroidism in a single institution: utility of surgeon performed ultrasound

Background

We aimed to: (I) discover preoperative diagnostic studies, intraoperative techniques, and patient factors most predictive of cure within a single hospital system; (II) establish practice guidelines for surgical treatment of primary hyperparathyroidism to maximize outcomes based on this hospital system's performance.

Methods

A retrospective chart review was undertaken of all parathyroid-related procedures from 01/01/02 to 7/31/15 at the Veteran's Administration Hospital.

Results

Seventy-one patients were eligible and charts available for analysis. Preoperative studies most predictive of cure were a combination of sestamibi parathyroid scan and surgeon performed ultrasound (S-US). When studies did not agree, S-US was most often correct. Intraoperative parathyroid hormone (PTH) rapid assay was helpful in predicting cure, but added an average of 33 minutes to operating room time. Patients who had two corroborating preoperative localizing studies, one of which was S-US, that agreed with intraoperative findings, and who did not undergo intraoperative PTH confirmation enjoyed equal cure rates and shorter operating room times. Successful achievement of normal calcium was high at 95.8%. Vitamin D deficiency was prevalent in this patient population, prompting more aggressive preoperative investigation and replacement.

Conclusions

A management protocol was developed based on the findings of this study: (I) obtain two preoperative localization studies, one of which is surgeon-performed ultrasound; (II) obtain preoperative vitamin D levels and supplement as indicated; and (III) in select patients who have two strongly corroborating preoperative localization studies, one of which is surgeon performed ultrasound, and intraoperative findings are consistent with the localizing studies, intraoperative PTH (IOPTH) may not be necessary.

Better performance of four-dimension computed tomography as a localization procedure in normocalcemic primary hyperparathyroidism

INTRODUCTION

The multi-phase or four-dimensional computed tomography (4D CT) has emerged as a promising technique for preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism (PHPT), but little is known about its accuracy in patients with normocalcemic primary hyperparathyroidism (NPHPT).

METHODS

A total of 18 patients diagnosed with PHPT underwent three methods of preoperative localization (4D CT, TC-99-Sestamibi scintigraphy and ultrasonography). After surgery, the results of imaging were compared with operative findings, pathological and biochemical data to evaluate the sensitivity and of each localization procedure.

RESULTS

In NPHPT the sensitivity for identifying the parathyroid lesion, according to presentation of PHPT (hypercalcemic or normocalcemic), was better with 4DCT in comparison to USG and scintigraphy. In these patients, the sensitivity for lateralization was as follows: USG: 22% (95% CI 0-44.9), scintigraphy: 11.1% (95% CI 0-31.6), 4DCT: 55.6% (95% CI 23.1-88). In hypercalcemic patients the results were as follows: USG: 58.3% (95% CI 30.4-86.2), scintigraphy: 75% (95% CI 50.5-99.5), 4DCT: 75% (95% CI 50.5-99.5). There was a poor agreement between the three procedures in the identification of the parathyroid lesions, with Kappa coeficients of 0.292 and 0.01 for scintigraphy and 4DCT, respectively, in comparison to USG.

CONCLUSION

Our data showed that 4DCT had a better performance as a preoperative localization procedure of the parathyroid lesion in patients with NPHPT.

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.

Selective venous sampling supports localization of adenoma in primary hyperparathyroidism

Background

Selective venous sampling (SVS) is an invasive localization study for persistent or recurrent hyperparathyroidism.

Purpose

To assess the role of SVS in addition to non-invasive imaging for primary hyperparathyroidism (pHPT).

Material and Methods

This study was approved by the institutional review board and included 14 patients who underwent SVS and subsequent parathyroidectomy between January 2014 and April 2017 following a clinical diagnosis of pHPT. All patients underwent pre-SVS non-invasive imaging, including ultrasound, computed tomography (CT), and ^99mTc-MIBI scintigraphy, and sensitivity was assessed using the operative and pathological findings.

Results

In all but one case, a single parathyroid adenoma was responsible for the pHPT; the remaining case exhibited a chemical response following surgical removal of parathyroid tissue. The sensitivity (%) for ultrasound, CT, ^99mTc-MIBI scintigraphy, and SVS was 76.9, 84.6, 69.2, and 76.9, respectively. SVS yielded positive results in four patients with discordant results and one patient with non-detectable results on imaging. In seven patients, a significant increase in the intact parathyroid hormone level was recognized only in the thyroid veins. The procedure time was in the range of 52–183 min (median = 89.5 min).

Conclusion

The addition of SVS to a non-invasive imaging study would be helpful to locate the responsible lesion of pHPT with discordant or non-detectable results on imaging for initial surgical treatment as well.

Is Unilateral Neck Surgery Feasible in Patients with Sporadic Primary Hyperparathyroidism and Double Negative Localisation?

INTRODUCTION

Ultrasound and Tc99mMIBI scans are used to localise parathyroid tumours in sporadic primary hyperparathyroidism (pHPT). Intra-operative PTH (ioPTH) assay facilitates unilateral neck exploration (UNE). When both ultrasound and MIBI are negative, it is our policy to explore the left side of the neck and only proceed to bilateral neck exploration (BNE) when either a tumour is not found or when ioPTH does not fall to >50% of the highest pre-excision value. The aim of this study was to investigate the outcome of our approach to 'double negative' patients.

METHODS

A retrospective analysis of patients undergoing primary parathyroidectomy for pHPT. Data were obtained from a prospective surgical database and the hospital electronic patient record.

RESULTS

Between January 2004 and November 2014, 746 patients underwent a parathyroidectomy for pHPT. Those who did not have both pre-operative scans, ioPTH or a minimum of 6-month follow-up were excluded. Of 552 patients, 111 (20%) had double negative scans (group A), and in 441, either one or both scans were positive (group B). Median age was 61.5 years (range 10-88). Pre-operative PTH level was significantly lower in group A: 11.8 pmol/l (range 3.1-38.8) versus 14.9 pmol/l (range 2.8-101.6; P < 0.01). Median tumour weight was significantly lower in group A: 280 mg (range 50-3710) versus 573 mg (range 10-12,000; P < 0.01). Overall rate of multiple gland disease (MGD) was 11%; 24% in group A and 7% in group B (P < 0.01). Overall rate of UNE in Group A was 28% and converse to the rate in Group B (76%; P < 0.01). Sensitivity and specificity of ioPTH to detect MGD were 98 and 98% in Group A versus 98 and 100% in Group B. First-time cure rate was 92.7% in group A and 96.8% in group B (P < 0.05).

CONCLUSION

A double negative scan is associated with small tumours and higher rates of MGD. Despite these challenges, surgery is successful in this group of patients reinforcing the message that negative localisation is not a contraindication for parathyroidectomy. We demonstrated that it is feasible to offer unilateral neck surgery to 28% of patients with double negative scans. A randomised trial is needed to compare BNE with ioPTH/UNE in this select population.

Factors Associated With Discordance Between Preoperative Parathyroid 4-Dimensional Computed Tomographic Scans and Intraoperative Findings During Parathyroidectomy

Importance

Parathyroid 4-dimensional computed tomographic scans (4D-CTs) have emerged as an accurate and cost-effective initial localization study for patients with primary hyperparathyroidism. However, potential limitations and factors affecting the accuracy of preoperative 4D-CTs remain poorly defined.

Objectives

To characterize factors associated with missed parathyroid lesions on preoperative 4D-CTs and to investigate patterns of commonly observed errors.

Design, Setting, and Participants

A prospectively accrued patient database was analyzed from September 1, 2011, through October 31, 2016. The study was performed in a tertiary referral center. Consecutive patients with primary hyperparathyroidism undergoing preoperative 4D-CTs and subsequent parathyroidectomy were included in the study.

Main Outcomes and Measures

Discordance between preoperative 4D-CTs and intraoperative findings in the number and location of abnormal parathyroid lesions.

Results

Of 411 patients studied (mean [SD] age, 59 [14] years; 325 [79.1%] female), 123 (29.9%) had discordance between preoperative 4D-CTs and intraoperative findings. Among the 411 patients, 75 (18.2%) had major discordance, including incorrectly localized adenoma on the contralateral side of the neck, missed double adenoma, and absence of any abnormal lesion detected on 4D-CTs. Compared with concordant cases, discordant cases had higher frequencies of multigland disease (66.7% [82 of 123] vs 24.3% [70 of 288], P < .001) and multinodular goiter or thyroid nodule (40.7% [50 of 123] vs 29.2% [84 of 288], P = .02). Missed parathyroid lesions were smaller (mean [SD], 0.86 [0.29] vs 1.24 [0.50] cm; P < .001) and were more likely to be in the inferior position (65.4% [87 of 133] vs 38.1% [177 of 465], P < .001). Parathyroid lesion size of 10 mm or less (odds ratio [OR], 4.37; 95% CI, 2.24-8.54), multigland disease (OR, 7.63; 95% CI, 3.49-16.69), multinodular goiter or thyroid nodule (OR, 1.82; 95% CI, 1.01-3.28), and parathyroid lesion in the inferior position (OR, 6.82; 95% CI, 3.10-14.99) were independently associated with discordant 4D-CT results.

Conclusions and Relevance

Multigland disease was most strongly associated with discordance between preoperative 4D-CTs and intraoperative findings, followed by parathyroid lesion in the inferior position and parathyroid lesion size of 10 mm or less. Awareness of these potential pitfalls may allow surgeons to better leverage this new localization technique in preoperative planning and intraoperative troubleshooting.

Value of preoperative ultrasound-guided fine-needle aspiration for localization in Tc-99m MIBI-negative primary hyperparathyroidism patients

To evaluate the value of preoperative ultrasound-guided fine-needle aspiration (UG-FNA) of ultrasound-detected suspicious parathyroid nodules for localization in Tc-99m MIBI-negative primary hyperparathyroidism patients.From May 2008 to December 2016, Tc-99m MIBI-negative primary hyperparathyroidism patients with ultrasound-detected suspicious cervical nodules underwent UG-FNA. The sample obtained from the solid component of the nodule was subjected to cytological evaluation and immunohistochemical staining. The sample obtained from the cystic component of the nodule or solid nodules was subjected to parathyroid hormone determination. After aspiration, the nodules underwent surgical resection or follow-up.Fifteen nodules (5 cystic, 5 cystic and solid, and 5 solid) from 15 patients were subjected to UG-FNA. Aspirate samples were obtained from 12 of the nodules, and the parathyroid hormone (PTH) levels of these samples were markedly elevated (range: 302- >2500 pg/mL). The samples obtained from the solid components of the 4 cystic and solid and 4 solid nodules were subjected to cytological evaluation, and parathyroid cells were identified in 5 of them. Of these 5 cases, 4 were subjected to immunohistochemical staining, which revealed PTH positivity in the cell block. The UG-FNA results suggested that the suspicious nodules were all parathyroid lesions. The surgical pathology results of 13 cases confirmed the UG-FNA results; the follow-up of 2 cases did not reveal any significant change.The cytological evaluation, immunohistochemical staining, and aspirate fluid PTH determination of UG-FNA were helpful for preoperative localization in Tc-99m MIBI-negative primary hyperparathyroidism patients with ultrasound-detected suspicious parathyroid nodules and can be applied selectively or in combination. Aspirate sample PTH determination should be preferred for nodules with cystic components. Further prospective study with large population is needed to confirm our conclusions.

Unilateral Clearance for Primary Hyperparathyroidism in Selected Patients with Multiple Endocrine Neoplasia Type 1

Background

Primary hyperparathyroidism is the most common manifestation of multiple endocrine neoplasia type 1 (MEN1). Guidelines advocate subtotal parathyroidectomy (STP) or total parathyroidectomy with autotransplantation due to high prevalence of multiglandular disease; however, both are associated with a significant risk of permanent hypoparathyroidism. More accurate imaging and use of intraoperative PTH levels may allow a less extensive initial parathyroidectomy (unilateral clearance, removing both parathyroids with cervical thymectomy) in selected MEN1 patients with primary hyperparathyroidism.

Methods

We performed a retrospective cohort study at a high-volume tertiary medical center including patients with MEN1 and primary hyperparathyroidism, who underwent STP or unilateral clearance as their initial surgery from 1995 to 2015. Unilateral clearance was offered to patients who had concordant sestamibi and ultrasound showing a single enlarged parathyroid gland. For both the groups, we compared rates of persistent/recurrent disease and permanent hypoparathyroidism.

Results

Eight patients had unilateral clearance and 16 had STP. Subtotal parathyroidectomy patients were younger (37 vs 52 years). One patient in each group had persistent disease. One (13 %) unilateral clearance and five (31 %) STP patients had recurrent hyperparathyroidism after a mean follow-up of 47 and 68 months (p = 0.62). No unilateral clearance patients and two of 16 SPT patients had permanent hypoparathyroidism (p = 0.54).

Conclusions

Some MEN1 patients with primary hyperparathyroidism who have concordant localizing studies may be selected for unilateral clearance as an alternative to STP. For appropriately selected MEN1 patients, unilateral clearance can achieve similar results as STP and has no risk of permanent hypoparathyroidism, and may facilitate possible future reoperations.

Validation of selective use of intraoperative PTH monitoring in parathyroidectomy

BACKGROUND

The objective of this study was to validate our approach of treating primary hyperparathyroidism using sestamibi scan directed parathyroidectomy, without routine use of intraoperative parathyroid hormone measurements (ioPTH).

METHODS

We prospectively established a protocol limiting the use of ioPTH to patients with negative or equivocal sestamibi scans, and those who had risk factors for multi-gland disease. We then performed a retrospective review to determine our disease control rate.

RESULTS

128 patients underwent sestamibi-guided parathyroidectomy without (111/128 = 87%) or with (17/128 = 13%) ioPTH. The overall disease control (eucalcemia) rate was 95%. 3/111 (3%) of patients who had surgery without ioPTH measurements required re-exploration.

CONCLUSIONS

Selective use of ioPTH is an effective strategy. ioPTH is best reserved for patients who have non-localizing preoperative imaging, are at risk for multi-gland disease, or require revision surgery.

Influence of a negative sestamibi scan on the decision for parathyroid operation by the endocrinologist and surgeon

BACKGROUND

It has been observed that negative sestamibi scans may impact practice patterns in patients with primary hyperparathyroidism. However, there are no published data on the issue. The objective was to elucidate the influence of negative sestamibi scans on referrals by endocrinologists for parathyroidectomy and surgeon decision-making.

METHODS

All patients with primary hyperparathyroidism were identified within a region-wide health care system over a 2-year period. Data, including age, calcium, parathyroid hormone, renal function, bone density, and sestamibi scan results, were collected from the electronic medical record of all patients. The electronic referral system was used to track consultations with endocrinologists and surgeons. Multivariable logistic regression analysis was done to model factors involved in endocrinologist recommendations (referral or no referral to operation) and surgeon recommendations (parathyroidectomy or no parathyroidectomy).

RESULTS

A total of 539 patients with primary hyperparathyroidism were identified, and 452 were seen by endocrinologists. Of these, 260 patients had sestamibi scans done (120 negative and 140 positive), and 201 (77%) patients were referred to surgeons. Compared with positive sestamibi scans, negative sestamibi scans were independently associated with no referral to surgeons, after adjusting for presence of classic symptoms, age, fitness for operation, calcium, parathyroid hormone, glomerular filtration rate, and bone density (odds ratio = 0.36; 95% confidence interval 0.18-0.73). Surgeons saw an additional 54 patients referred from nonendocrinologists or primary care physicians and sestamibi scans were completed. Surgeons recommended parathyroidectomy in 236 of the 255 patients. Negative sestamibi scans were independently associated with no recommendation for operation (odds ratio = 0.32; 95% confidence interval 0.11-0.91). Surgeons initially scheduled and completed parathyroidectomies in 211/255 patients. Cure rate after operation was 98%, and this was not influenced by the sestamibi scan result.

CONCLUSION

Negative sestamibi scans influence decision making in the management of patients with primary hyperparathyroidism. Endocrinologists commonly order sestamibi scans, and if negative, they are less likely to refer patients to surgeons. Surgeons are also influenced by sestamibi scans, and if negative, they are less likely to recommend parathyroidectomy. Cure rate in sestamibi-negative patients is excellent after operation.

Shear wave elastography and parathyroid adenoma: A new tool for diagnosing parathyroid adenomas

OBJECTIVES

This study prospectively determines the shear wave elastography characteristics of parathyroid adenomas using virtual touch imaging quantification, a non-invasive ultrasound based shear wave elastography method.

METHODS

This prospective study examined 57 consecutive patients with biochemically proven primary hyperparathyroidism and solitary parathyroid adenoma identified by ultrasound and confirmed by at least one of the following: surgical resection, positive Technetium-99m Sestamibi Scintigraphy (MIBI) scan, or fine needle aspiration biopsy with positive PTH washout (performed only in MIBI negative patients). Vascularity and shear wave elastography were performed for all patients. Parathyroid adenoma stiffness was measured as shear wave velocity in meters per second.

RESULTS

The median (range) pre-surgical value for PTH and calcium were 58pg/mL (19, 427) and 10.8mg/dL (9.5, 12.1), respectively. 37 patients had positive MIBI scan. 20 patients had negative MIBI scan but diagnosis was confirmed with positive PTH washout. 42 patients underwent parathyroidectomy, and an adenoma was confirmed in all. The median (range) shear wave velocity for all parathyroid adenomas enrolled in this study was 2.02m/s (1.53, 2.50). The median (range) shear wave velocity for thyroid tissue was 2.77m/s (1.89, 3.70). The shear wave velocity of the adenomas was independent of adenoma size, serum parathyroid hormone concentration, or plasma parathyroid hormone concentration.

CONCLUSIONS

Tissue elasticity of parathyroid adenoma is significantly lower than thyroid tissue. B-mode features and distinct vascularity pattern are helpful tools in diagnosing parathyroid adenoma with ultrasound. Shear wave elastography may provide valuable information in diagnosing parathyroid adenoma.