Use of Preoperative Imaging in Primary Hyperparathyroidism

Localization of Ectopic Hyperparathyroidism: Ultrasound Versus 99mTc-sestamibi, 4-Dimensional Computed Tomography, and 11C-choline Positron Emission Tomography/Computed Tomography

OBJECTIVE

To investigate the usefulness of ultrasound (US) for the localization of ectopic hyperparathyroidism and compare it with 99mTc-sestamibi (99mTc-MIBI), 4-dimensional computed tomography (4D-CT), and 11C-choline positron emission tomography/ computed tomography (PET/CT).

METHODS

Of the 527 patients with surgically confirmed primary hyperparathyroidism, 79 patients with ectopic hyperparathyroidism were enrolled. The diagnostic performance of US, 99mTc-MIBI, US + MIBI, 4D-CT, and 11C-choline PET/CT was calculated, and the factors affecting the sensitivity of US and 99mTc-MIBI were analyzed.

RESULTS

Eighty-three ectopic parathyroid lesions were found in 79 patients. The sensitivity was 75.9%, 81.7%, 95.1%, 83.3%, and 100% for US, 99mTc-MIBI, US + MIBI, 4D-CT, and 11C-choline PET/CT, respectively. The difference in sensitivity among these different modalities did not achieve statistical significance (P > .05). The US sensitivity was significantly higher for ectopic lesions in the neck region than for those in the anterior mediastinum/chest wall (85.9% vs. 42.1%, P < .001). The 99mTc-MIBI and 4D-CT sensitivity was not significantly different between these two groups (84.1% vs. 94.6%, P = .193 and 81.3% vs. 85.7%, P = 1). The 11C-choline PET/CT sensitivity was 100% in both groups.

CONCLUSIONS

US is a valuable tool for the localization of ectopic hyperparathyroidism, especially for ectopic lesions in the neck region.

[Localization diagnostics and operative strategy for the first intervention in sporadic primary hyperparathyroidism]

Primary hyperparathyroidism (pHPT) is a frequent endocrine disease, the incidence of which is clearly increasing. In addition to the classical symptoms of bone pain, osteoporosis and renal calculi, nonspecific complaints, such as listlessness and exhaustion, anxiety states and depressive symptoms also often occur. The diagnosis is simple and is carried out by determination of calcium and parathormone (PTH) serum levels. The majority of parathyroid adenomas can be localized by ultrasound and Tc-99m-MIBI scintigraphy. The indications for surgery can normally already be identified by the laboratory biochemical detection. Surgery is the only curative treatment of pHPT and is normally successful. In addition to bilateral exploration, a focused parathyroidectomy can be planned. The success of surgery can be intraoperatively documented by the determination of intraoperative Quick PTH (IOPTH).

Parathyroidectomy trends and surgical trainee parathyroidectomy experience based on the Collaborative Endocrine Surgery Quality Improvement Program (CESQIP) database

BACKGROUND

The parathyroidectomy approach has shifted over the last few decades from routine bilateral to more commonly focused exploration. The purpose of this study is to assess the operative experience in parathyroidectomy for surgical trainees as well as overall parathyroidectomy trends.

METHODS

Data from the Collaborative Endocrine Surgery Quality Improvement Program (CESQIP) were analyzed between 2014 and 2019.

RESULTS

The overall distribution of focused versus bilateral parathyroidectomy remained stable (2014: 54 % focused and 46 % bilateral approach; 2019: 55 % focused and 45 % bilateral). Ninety three percent of procedures involved a trainee (fellow or resident) in 2014, this dropped to 74 % in 2019 (P < 0.005). Fellow involvement decreased significantly from 31 % to 17 % (P < 0.05) over the six-year period.

CONCLUSIONS

Resident exposure to parathyroidectomies mirrored that of practicing endocrine surgeons. This works highlights the opportunities to capture more information regarding the surgical trainee experience in endocrine surgeries.

Educational Review: Intraoperative Parathyroid Fluorescence Detection Technology in Thyroid and Parathyroid Surgery

BACKGROUND

Accurate parathyroid gland (PG) identification is a critical yet challenging component of cervical endocrine procedures. PGs possess strong near-infrared autofluorescence (NIRAF) compared with other tissues in the neck. This property has been harnessed by image- and probe-based near-infrared fluorescence detection systems, which have gained increasing popularity in clinical use for their ability to accurately aid in PG identification in a rapid, noninvasive, and cost-effective manner. All NIRAF technologies, however, cannot differentiate viable from devascularized PGs without the use of contrast enhancement. Here, we aim to provide an overview of the rapid evolution of these technologies and update the surgery community on the most recent advancements in the field.

METHODS

A PubMed literature review was performed using the key terms "parathyroid," "near-infrared," and "fluorescence." Recommendations regarding the use of these technologies in clinical practice were developed on the basis of the reviewed literature and in conjunction with expert surgeons' opinions.

RESULTS

The use of near-infrared fluorescence detection can be broadly categorized as (1) using parathyroid NIRAF to identify both healthy and diseased PGs, and (2) using contrast-enhanced (i.e., indocyanine green) near-infrared fluorescence to evaluate PG perfusion and viability. Each of these approaches possess unique advantages and disadvantages, and clinical trials are ongoing to better define their utility.

CONCLUSIONS

Near-infrared fluorescence detection offers the opportunity to improve our collective ability to identify and preserve PGs intraoperatively. While additional work is needed to propel this technology further, we hope this review will be valuable to the practicing surgeon.

Comparative utility of preoperative imaging in normocalcemic versus hypercalcemic primary hyperparathyroidism

BACKGROUND

Normocalcemic primary hyperparathyroidism (PHPT) has been shown to benefit from parathyroidectomy. PHPT may be localized preoperatively with various imaging modalities, but the utility of preoperative imaging in normocalcemic PHPT compared to hypercalcemic PHPT is not well defined.

METHODS

Retrospective review was performed on all PHPT patients who underwent parathyroidectomy from 2001 to 2019. Patients were stratified into normocalcemic and hypercalcemic groups. Patient and outcomes data were analyzed.

RESULTS

All 2218 patients in this database were included. 433 patients had normocalcemic PHPT (19.5%) and 1785 had hypercalcemic PHPT (80.5%). Among normocalcemic patients, equivalent cure rates were seen between patients with preoperative imaging versus those without (100% vs 99%). No differences in postoperative complications were demonstrated except for a slightly increase in transient hypocalcemia in patients without imaging.

CONCLUSIONS

Normocalcemic PHPT patients had equivalent cure and similar complication rates with or without preoperative imaging compared to hypercalcemic patients. Routine localization studies in normocalcemic PHPT may be safely omitted in favor of exploration with intraoperative adjuncts by experienced surgeons.

Advances in Endocrine Surgery

Recent changes in the landscape of endocrine surgery include a shift from total thyroidectomy for almost all patients with papillary thyroid cancer to the incorporation of thyroid lobectomy for well-selected patients with low-risk disease; minimally invasive parathyroidectomy with, and potentially without, intraoperative parathyroid hormone monitoring for patients with well-localized primary hyperparathyroidism; improvement in the management of parathyroid cancer with the incorporation of immune checkpoint blockade and/or targeted therapies; and the incorporation of minimally invasive techniques in the management of patients with benign tumors and selected secondary malignancies of the adrenal gland.

Accuracy of Parathyroid Adenoma Localization by Preoperative Ultrasound and Sestamibi in 1089 Patients with Primary Hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (pHPT) is well treatable surgically. Sonography (US) and sestamibi scintigraphy (MIBI) are used routinely, but it is unclear how valuable they are in determining Parathyroid glands' different locations. This study aimed to evaluate the prognostic value of US and MIBI in relation to the different localization of parathyroid adenomas in one of the largest study populations analyzed to date.

METHODS

1089 patients with pHPT who had treatment in one tertiary referral center between 2007 and 2016 were analyzed. Preoperative US and MIBI reports were compared with the parathyroid adenoma's intraoperative localization. All parathyroid glands were confirmed by histological diagnosis.

RESULTS

No gland was detectable in 22.5% and 27.7% of all patients, by US or by MIBI, respectively. In relation to the different adenoma locations, the sensitivity of US ranged from 21.3% (upper right) to 68.9% (lower left) and of MIBI ranged from 23.5% (upper right) to 72% (lower left). The specificity for US ranged from 85% (lower right) to 99.2% (upper right) and for MIBI ranged from 86.1% (lower right) to 99.1% (upper right. Positive predictive values for all gland sites were 54% and 59% for MIBI and US, respectively. The value increased for side-only prediction to 73% and 78%, respectively. Neither the parathyroid hormone level nor the calcium value level influenced the sensitivity or specificity of the two test methods.

CONCLUSIONS

The validity of preoperative US and MIBI depends crucially on the specific localization of adenomas. This should be considered when planning the extent of parathyroid surgery.

Advanced Computed Tomographic Localization Techniques for Primary Hyperparathyroidism: A Systematic Review and Meta-analysis

Importance

Emerging computed tomographic (CT) imaging techniques for the localization of primary hyperparathyroidism (PHPT) may be superior to the current imaging standard, thus necessitating a critical review and pooling of available evidence.

Objective

Primary hyperparathyroidism requires accurate imaging to guide definitive surgical management. Advanced techniques including 4-dimensional computed tomographic (4D-CT) scan have been investigated over the past decade. We sought to evaluate the efficacy of these emerging imaging techniques through pooled analysis of the existing evidence.

Data Sources

PubMed, Embase, and Web of Science databases were queried for original English articles without any restrictions on date.

Study Selection

We included comparative observational studies but excluded animal studies, case reports, and case series. Overall, 353 abstracts were screened independently by 2 investigators along with a third reviewer to resolve conflicts. A total of 26 full-text articles were included in this review.

Data Extraction and Synthesis

This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Data was independently extracted by 2 investigators and subsequently pooled into a meta-analysis using a random-effects model.

Main Outcomes and Measures

Measures of imaging diagnostic performance such as sensitivity, specificity, positive predictive value, and negative predictive value were the primary outcomes of interest.

Results

Overall, of 34 articles screened, 26 met criteria for qualitative synthesis, and 23 of these were appropriate for meta-analysis. Of the 26 studies included, there were 5845 patients, of which 4176 were women (79.2%). The average of mean ages reported in 23 studies was 60.9 years. Meta-analysis in all patients with PHPT revealed pooled sensitivity that was greater with 4D-CT (81%; 95% CI, 77%-84%; I2 = 88%) compared with the current first-line modality of sestamibi-single-photon emission CT (SPECT/CT) (65%; 95% CI, 59%-70%; I2 = 93%). For patients with recurrent PHPT requiring reoperation, 4D-CT pooled sensitivity was 81% (95% CI, 64%-98%; I2 = 93%) in contrast to 53% (95% CI, 35%-71%; I2 = 81%) for sestamibi-SPECT/CT. The overall quality of the 26 studies was moderate with a median (range) Methodological Index for Nonrandomized Studies score for all included studies of 15.5 (13-19).

Conclusions and Relevance

The findings of this systematic review and with meta-analyses of numerous studies from the past decade suggest that the 4D-CT can be more sensitive and specific than sestamibi-SPECT/CT in localizing PHPT. More research is needed to determine the clinical significance of this improvement in localization.

Increased 99mTc-Sestamibi Activity in Giant Cell Tumor of Bone

ABSTRACT

A 99mTc-sestamibi parathyroid scintigraphy was performed in a 27-year-old woman to evaluate possible hyperparathyroidism. The images did not identify any parathyroid abnormality. However, an intense activity was noted in the proximal left upper extremity, which was confirmed as giant cell tumor of the proximal left humerus by pathological examination.

Parathyroid Imaging: Past, Present, and Future

The goal of parathyroid imaging is to identify all sources of excess parathyroid hormone secretion pre-operatively. A variety of imaging approaches have been evaluated and utilized over the years for this purpose. Ultrasound relies solely on structural features and is without radiation, however is limited to superficial evaluation. 4DCT and 4DMRI provide enhancement characteristics in addition to structural features and dynamic enhancement has been investigated as a way to better distinguish parathyroid from adjacent structures. It is important to recognize that 4DCT provides valuable information however results in much higher radiation dose to the thyroid gland than the other available examinations, and therefore the optimal number of phases is an area of controversy. Single-photon scintigraphy with 99mTc-Sestamibi, or dual tracer 99mTc-pertechnetate and 99mTc-sestamibi with or without SPECT or SPECT/CT is part of the standard of care in many centers with availability and expertise in nuclear medicine. This molecular imaging approach detects cellular physiology such as mitochondria content found in parathyroid adenomas. Combining structural imaging such as CT or MRI with molecular imaging in a hybrid approach allows the ability to obtain robust structural and functional information in one examination. Hybrid PET/CT is widely available and provides improved imaging and quantification over SPECT or SPECT/CT. Emerging PET imaging techniques, such as 18F-Fluorocholine, have the exciting potential to reinvent parathyroid imaging. PET/MRI may be particularly well suited to parathyroid imaging, where available, because of the ability to perform dynamic contrast-enhanced imaging and co-registered 18F-Fluorocholine PET imaging simultaneously with low radiation dose to the thyroid. A targeted agent specific for a parathyroid tissue biomarker remains to be identified.

Recurrence after successful parathyroidectomy-Who should we worry about?

BACKGROUND

Preventing cervical reoperations is important-especially after parathyroidectomy. We sought to examine early predictors of recurrence of primary hyperparathyroidism after surgical cure.

METHODS

Adult patients with sporadic primary hyperparathyroidism treated with parathyroidectomy between September 1, 1997, and September 1, 2019, with confirmed eucalcemia at 6 months postoperatively were identified. Recurrence was defined as hypercalcemia (>10.2 mg/dL) with an elevated or nonsuppressed parathyroid hormone level on subsequent follow-up.

RESULTS

Parathyroidectomy was performed in 522 patients (median age, 62.1 years, 77% female) with the majority undergoing planned minimally invasive parathyroidectomy (85.4%, n = 446). After a median follow-up of 30.9 months, 13 patients (2.5%) recurred (median time to recurrence 50.2 months, interquartile range 27.9-66.5), all of whom underwent planned minimally invasive parathyroidectomy (n = 13/446, 2.9%). Recurrence was more common in those with higher (but still normal) 6-month calcium (10.1 vs 9.3 mg/dL, P < .001) or parathyroid hormone values (64 vs 46 pg/mL, P < .01). Multivariate analysis revealed that age >66.5 years, calcium ≥9.8mg/dL and parathyroid hormone ≥80 pg/mL at 6 months were associated with increased risk of recurrence. In addition, the presence of at least 1 preoperative imaging study that conflicted with intraoperative findings among minimally invasive parathyroidectomy patients (n = 446) was associated with increased risk of recurrence (hazard ratio 4.93, 95% confidence interval 1.25-16.53, P = .016).

CONCLUSION

Recurrence of sporadic primary hyperparathyroidism after initial surgical cure in the era of minimally invasive parathyroidectomy is 2.5%. Identification of those at risk for recurrence using 6-month serum calcium ≥9.8 mg/dL, parathyroid hormone ≥80 pg/mL, and/or potentially conflicting localization studies may inform surveillance strategies.