Localization of Parathyroid Adenomas By 99mTc-Sestamibi Scanning: Upper Neck Versus Lower Neck Lesions

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.

Factors related to a non-localising technetium 99m sestamibi scan result during parathyroid adenoma imaging in primary hyperparathyroidism

OBJECTIVES

The aim of this study is to investigate factors that are associated with having a non-localising ^99m Tc-sestamibi scan.

DESIGN

A retrospective study was performed on patients that underwent parathyroid surgery performed within a single institution between 2001 and 2018.

SETTING

Single tertiary centre for parathyroid surgery.

PARTICIPANTS

230 patients underwent surgery for primary hyperparathyroidism due to a solitary parathyroid adenoma and had preoperative ^99m Tc-sestamibi imaging.

MAIN OUTCOME MEASURES

Variables including age, gender, intra-operative location of parathyroid adenoma, adenoma weight and pre- and postoperative calcium and parathyroid hormone levels were investigated through univariate and multivariate analysis to identify any association with having a non-localising (negative) ^99m Tc-sestamibi scan result.

RESULTS

Multivariate analysis identified that right-sided adenomas (P = .038), superior adenomas (P = .042) and a lower preoperative PTH level (P = .034) were all individual factors associated with having a negative ^99m Tc-sestamibi scan result. Although the weight of the adenoma was significant on univariate analysis (P = .029), this was not demonstrated on multivariate analysis (P = .422).

CONCLUSION

Factors that were associated with having non-localising ^99m Tc-sestamibi scan were right-sided adenomas, superior adenomas and lower preoperative PTH level. Further large prospective multicentre studies are needed to further evaluate these initial findings.

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.

Primary Hyperparathyroidism: To Evaluate Benefit of Ultrasound and Tc99m-SESTAMIBI Scan in Localizing Abnormal Parathyroid Gland Before Surgery, in a Secondary Care Hospital

Introduction

Primary hyperparathyroidism is a common endocrine condition requiring parathyroidectomy for curative management. Localization of parathyroid gland by ultrasound and Tc99m-SESTAMIBI is important to opt for less invasive and comparatively lower complication risk surgery minimal invasive parathyroidectomy (MIP) instead of four-gland exploration surgery.

Aim

To evaluate ultrasound and Tc99m-SESTAMIBI in localization of abnormal parathyroid gland before surgery.

Method and materials

All patients of primary hyperparathyroidism (PHPT) that presented to a secondary care hospital (endocrinology department) from 2015-2019 were recruited retrospectively from electronic fusion system of hospital. Results of ultrasound parathyroid and Tc99m-SESTAMIBI done for localization of abnormal parathyroid gland were analyzed.

Results

Total PHPT patients recruited were 59, mean age 64.2 years, male 11 (18.64%) and female 48 (81.3%). Ultrasound parathyroid was done in 44 patients, Tc 99m-SESTAMIBI was done in 31, both tests were done in 31 patients. Combined concordant adenoma in both tests was seen in 11 (35%) cases which can opt for minimal invasive parathyroidectomy (MIP) with confidence whereas 65% of cases would require either four-gland exploration or further testing like single-photon emission computed tomography-computed tomography (SPECT-CT) or intraoperative parathyroid hormone measurement to opt for MIP.

Conclusion

Combined ultrasound parathyroid and Tc 99m-SESTAMIBI scan was useful in localization of parathyroid adenoma in 11 (35%) patients that can opt for MIP which is a lower complication risk surgery whereas 20 (65%) patients would need further investigation with SPECT-CT or intraoperative parathyroid hormone measurement or four-gland exploration surgery.

Recommendation

Third modality of investigation such as SPECT-CT or intraoperative parathyroid hormone measurement needs evaluation so that more patients can benefit from MIP instead of four-gland exploration surgery.

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.

Does levothyroxine administration impact parathyroid localization?

BACKGROUND

Proper localization is crucial in performing minimally invasive parathyroidectomy for primary hyperparathyroidism. Ultrasonography (US) and Tc-99m sestamibi (MIBI) scintigraphy are common methods used for localization. As the appearance and activity of the thyroid gland may impact parathyroid localization, the purpose of this study was to determine how exogenous use of the thyroid hormone, levothyroxine (LT), affects parathyroid localization.

METHODS

Adult patients with non-familial primary hyperparathyroidism who underwent initial parathyroidectomy from 2000-2014 were retrospectively identified. LT (+LT) and non-LT (-LT) patients were matched 1:3 based on age, gender, goiter status, and preoperative parathyroid hormone levels. Subgroup analysis was performed on patients previously treated with radioactive iodine and patients undergoing single adenoma resection.

RESULTS

Of the 1737 patients that met inclusion criteria, 286 were on LT at the time of their parathyroid localization scan. Use of LT did not impact the percentage of correct MIBI localization scans when compared with -LT patients (P = 0.83). Interestingly, use of LT significantly hindered localization by US in comparison with the -LT group (48.4 versus 62.2%, P < 0.01). When examining only patients where a single upper gland was removed, the +LT group was less likely to have a correct US compared with the -LT group (50 versus 72.8%, P < 0.01). However, there was no difference in US accuracy for patients who only had a single lower gland removed (P = 0.51).

CONCLUSIONS

Exogenous LT is associated with impaired parathyroid localization with US but not MIBI. Surgeons should be aware of localization efficiency for this subset of patients in the era of personalized medicine and cost effectiveness.

Endoscopic neck surgery

Endoscopic surgery in the neck was attempted in 1996 for performing parathyroidectomy. A similar surgical technique was used for performing thyroidectomy the following year. Most commonly reported endoscopic neck surgery studies in literature have been on thyroid and parathyroid glands. The approaches are divided into two types i.e., the total endoscopic approach using CO(2) insufflation and the video-assisted approach without CO(2) insufflation. The latter approach has been reported more often. The surgical access (port placements) may vary-the common sites are the neck, anterior chest wall, axilla, and periareolar region. The limiting factors are the size of the gland and malignancy. Few reports are available on endoscopic resection for early thyroid malignancy and cervical lymph node dissection. Endoscopic neck surgery has primarily evolved due to its cosmetic benefits and it has proved to be safe and feasible in suitable patients with thyroid and parathyroid pathologies. Application of this technique for approaching other cervical organs such as the submandibular gland and carotid artery are still in the early experimental phase.

Utility of Ultrasound-Guided Fine-Needle Aspiration of Parathyroid Adenomas for Localization Before Minimally Invasive Parathyroidectomy

OBJECTIVE

To determine the sensitivity and specificity of ultrasound (US)-guided fine-needle aspiration (FNA) and measurement of parathyroid hormone (PTH) in the aspirate (FNA/PTH) as a preoperative localization procedure.

METHODS

The study group consisted of 34 consecutive patients with primary hyperparathyroidism. The FNA/PTH estimations in these patients were compared with those from 13 proven thyroid nodules. All patients underwent US study of the neck, which suggested the presence of a solitary adenoma in 30 patients and of hyperplasia in 2; no adenoma or hyperplasia could be visualized in 2 patients. Thirty-two patients underwent FNA/PTH, which yielded a mean PTH level of 22,060.0 +/- 6,653.0 pg/mL. This result was significantly different (P<0.001) from the mean PTH level in 13 thyroid nodules (9.0 +/- 1.0 pg/mL).

RESULTS

On the basis of the FNA/PTH results, 28 patients with suspected adenomas underwent minimally invasive parathyroidectomy (MIP), and 2 patients are awaiting a surgical procedure. Of these 28 patients, 27 had more than a 50% decline in intraoperative PTH level after removal of the suspected adenoma, confirming surgical success. In 1 patient, multigland hyperplasia was discovered during the operation. The 2 study subjects with US findings of suspected hyperplasia underwent 4-gland surgical procedures. All patients treated surgically continued to have normal serum calcium levels 6 to 18 months postoperatively.

CONCLUSION

Primary hyperparathyroidism is caused most commonly by a solitary adenoma and less commonly by multigland hyperplasia of the parathyroid glands. Surgical resection is the only curative therapy. MIP has become a frequently used strategy, but there are limitations to current preoperative localization techniques. We conclude that US-guided FNA is a useful technique that facilitates MIP, with a high degree of specificity (95%) and sensitivity (91%).

Nonequivalent Results of Tetrofosmin and Sestamibi Imaging of Parathyroid Tumors

OBJECTIVE

To report the case of a patient with a large parathyroid carcinoma missed by dual-phase technetium Tc 99m tetrofosmin (TETRO) parathyroid scanning.

METHODS

We present the clinical findings, laboratory results, imaging studies, and surgical pathology report in a man with parathyroid carcinoma and review the literature regarding the use of TETRO scintigraphy in patients with hyperparathyroidism.

RESULTS

In an 83-year-old man with hyperparathyroidism, severe hypercalcemia developed in the context of nephrolithiasis. An in-office ultrasonographic evaluation of the neck revealed a partially calcified mass (2.3 by 1.3 by 1.6 cm) at the inferoposterior border of the left thyroid lobe. Technetium Tc 99m sestamibi (MIBI) scanning was requested and reported as "negative." In fact, TETRO scanning had been substituted for MIBI scanning by the management of the nuclear medicine facility. Before neck exploration, performance of dual-phase MIBI parathyroid scintigraphy revealed radionuclide retention in the left lower neck area at 120 minutes, in the same site as the ultrasonographically visualized mass. A limited left inferior parathyroidectomy was performed, and intraoperative parathyroid hormone levels declined from 254 pg/mL to 28 pg/mL 10 minutes after near-complete resection of the mass. Pathology evaluation of the surgical specimen revealed a 2,000-mg parathyroid carcinoma.

CONCLUSION

Although both agents incorporate the same technetium Tc 99m radionuclide, TETRO and MIBI parathyroid scanning are not equivalent in the detection of parathyroid tumors with use of the dual-phase technique. We do not recommend substitution of TETRO for MIBI as a cost-control measure in the evaluation of hyperparathyroidism.