Abnormal Parathyroid Research Articles

Predictors of Surgeon-Performed Ultrasound Accuracy of Abnormal Parathyroid Gland Localization in Patients with Sporadic Primary Hyperparathyroidism

Predictors of Surgeon-Performed Ultrasound Accuracy of Abnormal Parathyroid Gland Localization in Patients with Sporadic Primary Hyperparathyroidism

Dual-Isotope 99mTc-MIBI/123I Parathyroid Scintigraphy in Primary Hyperparathyroidism

In patients with primary hyperparathyroidism, the preoperative imaging objective is to locate accurately and reliably uniglandular or multiglandular hyperfunctioning parathyroid, to guide surgery, particularly for minimally invasive method. Subtraction planar scintigraphy with dual-isotope (I/Tc-MIBI) is an efficient examination to specify abnormal parathyroid location, but without accurate anatomic reference. This lack should be avoided by a hybrid SPECT/CT image acquisition. We compared planar scans (neck and mediastinum parallel-hole, associated with anterior neck pinhole) to neck and mediastinum SPECT/CT, all with subtraction (I/Tc-MIBI) method, in exact location of abnormal parathyroid in 50 patients with sporadic primary hyperparathyroidism. Surgical and histological findings were used as the standard of comparison. Sensitivity is equivalent for the 2 protocols (86% and 75% for SPECT/CT and planar protocol, respectively, P = 0.15), but SPECT/CT was highly specific (specificity 100% and 90% for SPECT/CT and planar protocol, respectively, P = 0.04). In patients with concomitant thyroid disease, subtraction SPECT/CT appeared to be more sensitive than planar protocol (88% and 62% for SPECT/CT and planar protocol, respectively, P = 0.04). In preoperative assessment of primary hyperparathyroidism and to guide surgery, we propose to perform first subtraction SPECT/CT and to complete it with neck pinhole, only if tomoscintigraphy is negative.

Histopathological Changes of the Thyroid and Parathyroid Glands in HIV-Infected Patients

Objective. To study histopathology of the thyroid and parathyroid glands in HIV-infected African Americans in the United States. Methods. A retrospective review of 102 autopsy cases done by the Department of Pathology at Howard University Hospital from 1980 through 2007 was conducted. The histopathological findings of the thyroid and parathyroid glands were reviewed, both macroscopically and microscopically. A control group of autopsy patients with chronic non-HIV diseases was examined. Results. There were 71 males (70%) and 31 females (30%) with an average age of 38 years (range: 20–71 y). Thirteen patients with abnormal thyroid findings were identified. Interstitial fibrosis was the most common histological finding (4.9%), followed by thyroid hyperplasia (1.9%). Infectious disease affecting the thyroid gland was limited to 2.9% and consisted of mycobacterium tuberculosis, Cryptococcus neoformans, and cytomegalovirus. Kaposi sarcoma of the thyroid gland was present in only one case (0.9%). Parathyroid hyperplasia was the most common histological change noted in the parathyroid glands. Comparing the histological findings of cases and controls, we found a similar involvement of the thyroid, with a greater prevalence of parathyroid hyperplasia in HIV patients. Conclusion. Thyroid and parathyroid abnormalities are uncommon findings in the HIV-infected African American population.

Parathyroid nuclear scan. A focused review on the technical and biological factors affecting its outcome

Technetium Parathyroid Scintigraphy (TS) is the most popular noninvasive localization procedure in patients with primary hyperparathyroidism (PHPT). Awareness of various factors involved in technetium uptake helps understand the outcome of TS. We utilize a case of changing TS scans in a patient to review the literature on the various biological and technical factors involved in technetium uptake by the abnormal parathyroid tissue. A 56 year female was diagnosed with PHPT and osteopenia. An initial scan using (99m)Tc-Tetrofosmin showed no definite areas of abnormal parathyroid tissue. Patient refused surgical exploration, was started on Bisphosponates and subsequently monitored. Five years later she suffered fracture of her right wrist. A repeat TS using (99m)Tc-Sestamibi revealed hypervascular parathyroid lesion in the right lower neck. She underwent successful removal of a right lower parathyroid adenoma. Technical factors like the type of Tc isotope used, imaging techniques and biological factors like biochemical parameters (calcium, vitamin D levels), adenoma size, content of oxyphilic cells, vascularity can affect the outcome of the scan. Clinicians should be aware of technical and biological factors that could result in negative scan in parathyroid nuclear scintigraphy.

Intraoperative parathyroid hormone assay-cutting the Gordian knot.

Background:Hyperparathyroidism is treated by surgical excision of the hyperfunctioning parathyroid gland. In case of adenoma the single abnormal gland is removed, while in hyperplasias, a subtotal excision, that is, three-and-a-half of the four glands are removed. This therapeutic decision is made intraoperatively through frozen section evaluation and is sometimes problematic, due to a histological overlap between hyperplasia and the adenoma. The intraoperative parathyroid hormone (IOPTH) assay, propogated in recent years, offers an elegant solution, with a high success rate, due to its ability to identify the removal of all hyperfunctioning parathyroid tissue.Aim:To study the feasibility of using IOPTH in our setting.Materials and Methods:Seven patients undergoing surgery for primary hyperparathyroidism had their IOPTH levels evaluated, along with the routine frozen and paraffin sections.Results:All seven patients showed more than a 50% intraoperative fall in serum PTH after excision of the abnormal gland. This was indicative of an adenoma and was confirmed by histopathological examination and normalization of serum calcium postoperatively.Conclusion:The intraoperative parathyroid hormone is a sensitive and specific guide to a complete removal of the abnormal parathyroid tissue. It can be incorporated without difficulty as an intraoperative guide and is superior to frozen section diagnosis in parathyroid surgery.

Intraoperative risk management of hyperparathyroidism: Modeling and testing the parathyroid hormone’s evolution as a mean reverting stochastic processes

This paper describes and validates a stochastic model (Ornstein–Uhlenbeck process) for parathyroid hormone (PTH) levels. Rapid intraoperative parathyroid hormone assay supports the emergence of a minimally invasive approach to unilateral parathyroid exploration in the surgical treatment of hyperparathyroidism. The model’s goal is to verify whether a cure has been attained with excision of abnormal parathyroid tissue, based on intraoperative measurements, sparing the need for a bilateral exploration. The scarcity of PTH observations renders the classical methods of goodness-of-fit tests (GoFT) and cure criteria inadmissible or numerically challenging. The paper suggests a new approach to accomplish these goals given limited data. The GoFT strongly supports the model and consequently the induced cure criterion. This model will clarify the confusion in the literature regarding the required PTH decay representing a high likelihood of cure from hyperparathyroidism.

Incremental value and clinical impact of neck sonography for primary hyperparathyroidism: a risk-adjusted analysis

Despite the different preoperative imaging modalities available for parathyroid adenoma localization, there is currently no uniform consensus on the most appropriate preoperative imaging algorithm that should be routinely followed prior to the surgical management of primary hyperparathyroidism (PHPT). We sought to determine the incremental value of adding neck ultrasonography to scintigraphy-based imaging tests. In a single institution, surgically naive patients with PHPT underwent the following localization studies before parathyroidectomy: 1) Tc-99m sestamibi imaging with single photon emission computed tomography/computed tomography (SPECT/CT) or Tc-99m sestamibi imaging with SPECT alone, or 2) ultrasonography in addition to those tests. We retrospectively collected data and performed a multivariate analysis comparing group I (single study) to group II (addition of ultrasonography) and risk of bilateral (BNE) compared with unilateral (UNE) neck exploration. Our study included 208 patients. Group II had 0.45 times the odds of BNE versus UNE compared with group I (unadjusted odds ratio [OR] 0.45, 95% confidence interval [CI] 0.25-0.81, p = 0.008). When adjusting for patient age, sex, preoperative calcium level, use of intraoperative PTH monitoring, preoperative PTH level, adenoma size, and number of abnormal parathyroid glands, Group II had 0.48 times the odds of BNE versus UNE compared with group I (adjusted OR 0.48, 95% CI 0.23-1.03, p = 0.06). In a subgroup analysis, only the addition of ultrasonography to SPECT decreased the risk of undergoing BNE compared with SPECT alone (unadjusted OR 0.40, 95% CI 0.19-0.84, p = 0.015; adjusted OR 0.38, 95% CI 0.15-0.96, p = 0.043). The addition of ultrasonography to SPECT, but not to SPECT/CT, has incremental value in decreasing the extent of surgery during parathyroidectomy, even after adjusting for multiple confounding factors.

Do giant parathyroid adenomas represent a distinct clinical entity?

The size of abnormal parathyroid glands in patients with primary hyperparathyroidism (PHPT) is highly variable, but the clinical significance of giant glands is unknown. We reviewed 300 consecutive patients after parathyroidectomy for PHPT. We compared patients with giant parathyroid adenomas (weight ≥95th percentile) with the remaining patients. Giant adenomas were defined as weight ≥95th percentile or 3.5 g (median, 0.61; range, 0.05-29.93). Patients with giant adenomas had a greater mean preoperative calcium level, greater mean parathyroid hormone (PTH) level, and were less likely to have multiglandular or symptomatic disease. Giant adenomas were successfully localized on imaging in 87% of patients, which was not increased over other patients (82%). There were no differences between the groups in age, gender, gland location, or the incidence of persistent or recurrent hyperparathyroidism. Finally, giant glands had an increased incidence of symptomatic postoperative hypocalcemia, including 1 patient who required rehospitalization after removal of a giant gland. Giant parathyroid adenomas have a distinct presentation characterized by single gland disease and lower incidence of symptoms despite increased levels of calcium and PTH. Additionally, afterresection of a giant adenoma, patients are more likely to develop symptomatic hypocalcemia.

4D-CT for Preoperative Localization of Abnormal Parathyroid Glands in Patients with Hyperparathyroidism: Accuracy and Ability to Stratify Patients by Unilateral versus Bilateral Disease in Surgery-Naïve and Re-Exploration Patients

4D-CT is an emerging technique that uses high-resolution images, multiplanar reformats, and perfusion characteristics to identify abnormal parathyroid glands in patients with hyperparathyroidism. This study evaluates the accuracy of 4D-CT for localization and lateralization of abnormal parathyroid glands in preoperative planning for minimally invasive parathyroidectomy vs bilateral neck exploration at a tertiary referral center. Radiology, pathology, and operative reports were retrospectively reviewed for 208 patients with hyperparathyroidism who underwent 4D-CT and parathyroid surgery between May 2008 and January 2012. 4D-CT performance in localizing side and site was determined by use of surgical and pathologic findings as a reference. Of 208 patients, 155 underwent initial surgery and 53 underwent re-exploration parathyroid surgery. No lesions were found in 8 patients (3.8%). A total of 284 lesions were found in 200 patients; 233 were correctly localized by 4D-CT (82.0%). Of the 200 patients with parathyroid lesions, 146 underwent unilateral and 54 bilateral neck exploration. 4D-CT correctly identified unilateral vs bilateral disease in 179 (89.5%) of 200. 4D-CT correctly localized parathyroid lesions in 126 of the unilateral cases (86.3%). In the re-exploration cohort, 4D-CT correctly identified unilateral vs bilateral disease in 46 (95.8%) of 48. There was no statistically significant difference in subgroups stratified by surgery type (primary or subsequent) and number of scan phases (3 or 4) (P > .56). 4D-CT leverages modern high-resolution CT scanning and dynamic contrast enhancement to localize abnormal parathyroid glands in patients with hyperparathyroidism of any cause and can be used for planning minimally invasive parathyroidectomy vs bilateral neck exploration.

Thyroid Nodule Evaluation: Us-Fna And On-Site Cytology Assessment

Thyroid nodules are a very common endocrine problem, with an estimated 4% of the population having a palpable nodule and more than 50% having a nodule detectable by ultrasound (US). In each of the major clinical guidelines on the management of thyroid nodules (1–3), US is highlighted as a critical tool in selecting nodules requiring fine needle aspiration (FNA). In addition to using US to assess thyroid nodule characteristics, parathyroid abnormalities, and lymph nodes, US-guided FNA has essentially replaced the use of palpation FNA.

Minimally invasive parathyroidectomy provides a conservative surgical option for multiple endocrine neoplasia type 1–primary hyperparathyroidism

Many authors advocate routine subtotal parathyroidectomy or total parathyroidectomy and autotransplantation for patients with multiple endocrine neoplasia type 1 (MEN1). Many of these patients are young and recurrence may take decades. Four-gland parathyroid exploration carries a higher risk of complication than minimally invasive parathyroidectomy (MIP). The aim of this study was to assess the role of selective removal of only abnormal glands for MEN1 in the era of MIP. For this retrospective, cohort study we collected data on patients undergoing parathyroidectomy for MEN1 from an endocrine surgery database. We reviewed preoperative localization studies, operative findings, histopathology, and clinical outcomes. Twenty-six patients underwent parathyroidectomy for MEN1-associated hyperparathyroidism over the 23-year study period. Six of 10 (60%) patients in the total parathyroidectomy group and 4 of 10 (40%) patients in the subtotal parathyroidectomy group developed hypocalcemia. The subtotal and total parathyroidectomy groups both had a recurrence rate of 30% with a mean follow-up rate of 106 and 133months, respectively. The MIP group had no hypocalcemia or recurrence with a mean follow-up of 19months. MIP with excision of only documented abnormal parathyroid glands provides an acceptable outcome for patients with MEN1, avoiding the potential for permanent hypoparathyroidism in young patients. It is accepted that recurrent disease is inevitable in these patients; however, such recurrence may take decades to occur and may be able to be dealt with by a further focused procedure.

Radionuclide parathyroid imaging: a concise, updated review.

The hypercalcemia of hyperparathyroidism (HPT) can cause devastating effects to the patient and only surgical removal of the hyperfunctioning parathyroid tissue can definitely cure the disease. Radionuclide parathyroid imaging has no role in the diagnosis of hyperparathyroidism or in the selection of the type of treatment. However, once surgery is decided (99m)Tc-sestamibi scanning can localize abnormal parathyroid glands preoperatively. In primary HPT radionuclide assessment may occasionally be helpful before bilateral neck exploration, it can identify patients suitable for focused surgery and is a prerequisite of the minimally invasive radioguided parathyroidectomy. In secondary and tertiary HPT the clinical value of parathyroid scintigraphy remains debatable, but in persistent or recurrent disease this modality is a first line examination before reoperation. In conclusion, (99m)Tc-sestamibi assessment has a well defined clinical role in the surgical management of patients with primary hyperparathyroidism and in recurrent disease, but its usefulness in cases of secondary hyperparathyroidism is not clearly established.

Ultrasound-Guided Percutaneous Laser Ablation in Patients With Primary Hyperparathyroidism

Brief Description of the Purpose of the StudyTo assess the efficacy of ultrasound-guided percutaneous laser ablation (US-PLA) of abnormal parathyroid gland in patients with primary hyperparathyroidism (PHPT).MethodsThirty six patients with PHPH underwent 2-4 sessions of US-PLA for a single abnormal parathyroid gland, probably a parathyroid adenoma (PA), with the diode medical laser of 1030nm wavelength. PA were detected with ultrasound, proven with SPECT and exhibited high PTH (588-4929 pg/ml) in the needle washout after fine needle aspiration biopsy. The size of PA ranged from 3×9×7mm to 6×10×22mm. Follow-up period was 1month - 1 year after US-PLA.Main ResultsPA was not sonographically detected in 6 cases after US-PLA. The rest 30 cases demonstrated 4.5 times decrease in volume (from 0.32 ± 0.12 cm3 to 0.07 ± 0.01cm3) in 1 month after US-PLA. All detected PA were avascular with color and power Doppler imaging. Blood intact parathyroid hormone (iPTH) decreased 3.4 times in general from 183 ± 56 pg/ml to 53 ± 5 pg/ml and blood ionized calcium from 1.30 ± 0.06 mmol/l to 1.11 ± 0.06 mmol/l. The size of PA and iPHT level exhibited staged changes with increase during first days after US-PLA followed by their gradual decrease.Importance of the ConclusionsUS-PLA can be used as an alternative treatment modality in selected patients with PHPT. Brief Description of the Purpose of the StudyTo assess the efficacy of ultrasound-guided percutaneous laser ablation (US-PLA) of abnormal parathyroid gland in patients with primary hyperparathyroidism (PHPT). To assess the efficacy of ultrasound-guided percutaneous laser ablation (US-PLA) of abnormal parathyroid gland in patients with primary hyperparathyroidism (PHPT). MethodsThirty six patients with PHPH underwent 2-4 sessions of US-PLA for a single abnormal parathyroid gland, probably a parathyroid adenoma (PA), with the diode medical laser of 1030nm wavelength. PA were detected with ultrasound, proven with SPECT and exhibited high PTH (588-4929 pg/ml) in the needle washout after fine needle aspiration biopsy. The size of PA ranged from 3×9×7mm to 6×10×22mm. Follow-up period was 1month - 1 year after US-PLA. Thirty six patients with PHPH underwent 2-4 sessions of US-PLA for a single abnormal parathyroid gland, probably a parathyroid adenoma (PA), with the diode medical laser of 1030nm wavelength. PA were detected with ultrasound, proven with SPECT and exhibited high PTH (588-4929 pg/ml) in the needle washout after fine needle aspiration biopsy. The size of PA ranged from 3×9×7mm to 6×10×22mm. Follow-up period was 1month - 1 year after US-PLA. Main ResultsPA was not sonographically detected in 6 cases after US-PLA. The rest 30 cases demonstrated 4.5 times decrease in volume (from 0.32 ± 0.12 cm3 to 0.07 ± 0.01cm3) in 1 month after US-PLA. All detected PA were avascular with color and power Doppler imaging. Blood intact parathyroid hormone (iPTH) decreased 3.4 times in general from 183 ± 56 pg/ml to 53 ± 5 pg/ml and blood ionized calcium from 1.30 ± 0.06 mmol/l to 1.11 ± 0.06 mmol/l. The size of PA and iPHT level exhibited staged changes with increase during first days after US-PLA followed by their gradual decrease. PA was not sonographically detected in 6 cases after US-PLA. The rest 30 cases demonstrated 4.5 times decrease in volume (from 0.32 ± 0.12 cm3 to 0.07 ± 0.01cm3) in 1 month after US-PLA. All detected PA were avascular with color and power Doppler imaging. Blood intact parathyroid hormone (iPTH) decreased 3.4 times in general from 183 ± 56 pg/ml to 53 ± 5 pg/ml and blood ionized calcium from 1.30 ± 0.06 mmol/l to 1.11 ± 0.06 mmol/l. The size of PA and iPHT level exhibited staged changes with increase during first days after US-PLA followed by their gradual decrease. Importance of the ConclusionsUS-PLA can be used as an alternative treatment modality in selected patients with PHPT. US-PLA can be used as an alternative treatment modality in selected patients with PHPT.

Differences between sporadic and MEN related primary hyperparathyroidism; clinical expression, preoperative workup, operative strategy and follow-up

BackgroundPrimary hyperparathyroidism (PHPT) is most commonly sporadic (sPHPT). However, sometimes PHPT develops as part of multiple endocrine neoplasia (MEN) type 1 or 2A. In all, parathyroidectomy is the only curative treatment. Nevertheless, there are important differences in clinical expression and treatment.MethodsWe analyzed a consecutive cohort of patients treated for sporadic, MEN1-related, and MEN2A-related PHPT and compared them regarding clinical and biochemical parameters, differences in preoperative workup, operative strategies, findings, and outcome.ResultsA total of 467 patients with sPHPT, 52 with MEN1- and 16 with MEN2A-related PHPT were analyzed. Patients with sPHPT were older, more often female and had higher preoperative calcium and parathyroid hormone levels, when compared with MEN1 and MEN2A patients. Minimally invasive parathyroidectomy (MIP) was performed in 367 of 467 sPHPT patients (79%). One abnormal parathyroid was found in 426 patients (91%). Two or more in 35 patients (7%). In six patients (1%) no abnormal parathyroid gland was retrieved. Of 52 MEN1 patients, eight (15%) underwent a MIP and 44 patients (85%) underwent conventional neck exploration (CNE); with resection of fewer than 3½ enlarged glands in 21 patients (40%), subtotal parathyroidectomy (SPTX, 3-3½ glands) in seventeen (33%) and total parathyroidectomy with autotransplantation (TPTX) in six (12%). Eleven patients (21%) had persistent disease, 29 (56%) recurrent PHPT and nine (17%) permanent hypoparathyroidism, mostly after TPTX. Of 16 MEN2A patients, six (38%) underwent MIP, four (25%) CNE and six (38%) selective resection of the enlarged gland(s) during total thyroidectomy. Three patients (19%) suffered from persistent PHPT and two (13%) developed recurrent disease.ConclusionsSporadic PHPT, MEN1- and MEN2A-related PHPT are three distinct entities as is reflected preoperatively by differences in gender, age at diagnosis and calcium and PTH levels.MEN2A patients are very similar to sPHPT with respect to operative approach and findings. MIP is the treatment of choice for both. MIP has low rates of persistent and recurrent PHPT and a low complication rate. The percentage of multiglandular disease and recurrences are significantly higher in MEN1 patients, demonstrating the need for a different approach. We advocate treating these patients with CNE and SPTX.

副甲状腺の画像診断の進歩MIBI シンチグラフィ，CTを中心に

副甲状腺の画像診断の進歩MIBI シンチグラフィ，CTを中心に

Preoperative parathyroid harpoon localisation: a new technique helpful in reoperative patients with persistent hyperparathyroidism

Surgery for persistent primary hyperparathyroidism remains a major challenge for surgeons and these reoperative procedures require an experienced parathyroid surgeon. The goal of reoperative surgery is to excise the abnormal parathyroid gland(s) and limit exploration to help minimise the potential complications. At least two positive and concordant localising studies should be available before reoperation because the technical difficulties in these cases make an exact localisation necessary before surgery. We describe the placement of a metallic harpoon under ultrasonography guidance as a safe, simple and inexpensive technique for localisation of the enlarged gland prior to conservative surgery.

Comparison of five parathyroid scintigraphic protocols.

Objectives. We compared five parathyroid scintigraphy protocols in patients with primary (pHPT) and secondary hyperparathyroidism (sHPT) and studied the interobserver agreement. The dual-tracer method (99mTc-sestamibi/123I) was used with three acquisition techniques (parallel-hole planar, pinhole planar, and SPECT/CT). The single-tracer method (99mTc-sestamibi) was used with two acquisition techniques (double-phase parallel-hole planar, and SPECT/CT). Thus five protocols were used, resulting in five sets of images. Materials and Methods. Image sets of 51 patients were retrospectively graded by four experienced nuclear medicine physicians. The final study group consisted of 24 patients (21 pHPT, 3 sHPT) who had been operated upon. Surgical and histopathologic findings were used as the standard of comparison. Results. Thirty abnormal parathyroid glands were found in 24 patients. The sensitivities of the dual-tracer method (76.7–80.0%) were similar (P = 1.0). The sensitivities of the single-tracer method (13.3–31.6%) were similar (P = 0.625). All differences in sensitivity between these two methods were statistically significant (P < 0.012). The interobserver agreement was good. Conclusion. This study indicates that any dual-tracer protocol with 99mTc-sestamibi and 123I is superior for enlarged parathyroid gland localization when compared with single-tracer protocols using 99mTc-sestamibi alone. The parathyroid scintigraphy was found to be independent of the reporter.

The Rationale for performing MR Imaging before Surgery for Primary Hyperparathyroidism

Objective : The purpose of this study was to evaluate prospectively Magnetic Resonance Imaging (MRI) for the preoperative localization of hyperfunctioning parathyroid glands.Design : Prospective study of 58 consecutive patients with biochemically confirmed primary hyperparathyroidism whounderwent preoperative MRI.Setting : The setting is a referral centre.Patients : Fifty-six of the 58 consecutive patients (41 women, 17men) were studied by both preoperative MRI and 99mTC MIBI scintigraphy, and two by MRI alone. The same surgeon, using the information from both MRI and 99mTC MIBI, performed surgery in 58 patients, including 19 with a history of neck surgery. Initial interpretation of each MR study was done independently by one radiologist and the surgeon and then results were compared. At surgery, the operative duration, the precise anatomical location, weight, and dimensions as well as complete histopathological evaluations of all excised glands were recorded.Main outcome measure : In addition to the prospective assessment of MRI, this study compared performance of MRI with double-phase 99mTC MIBI scintigraphy for preoperative localization of hyperfunctioning parathyroid glands. Results : All patients became normocalcaemic after surgery. MRI and 99mTC MIBI imaging revealed 53 of 58 (91%) and 47 of 56 (84%) of abnormal glands, respectively. Sensitivities of MRI and 99mTC MIBI were respectively 94.3 and 88.0. Positive predictive values were 96.15 and 93.60. When MRI and 99mTC MIBI were interpreted together, the sensitivity and positive predictive values both raised to 98.10. Median operative duration was 30 minutes (ranges 20–300 minutes, mean 65).Conclusion : MRI has better sensitivity and positive predictive value than 99mTC MIBI scintigraphy for the detection of hyperfunctioning parathyroid glands. The combination of the two studies provides an additional increase in sensitivity and positive predictive value leading to a more precise anatomical localization of the abnormal parathyroid glands reducing both the extent of the surgical dissection and the operative duration.

Minimally Invasive Radioguided Parathyroidectomy

The surgical management of hyperparathyroidism has evolved over the last 20 years, transitioning from routine bilateral neck exploration to, frequently, a minimally invasive approach. Adjuncts which have made this transition possible include advancements in imaging techniques which allow the pre-operative localization of adenomatous glands, the rapid parathyroid hormone assay and the use of 99-m technetium sestamibi injections the day of surgery to allow for gamma probe detection of abnormal glands. The gamma probe can help with gland localization, which can be particularly useful in a re-operative field or with glands in ectopic locations. It is also helpful in confirming that excised tissue is abnormal parathyroid tissue, alleviating the need for frozen sections during surgery. In this chapter we discuss and review radioguided minimally invasive parathyroidectomy.

Systematic review of intravenous methylene blue in parathyroid surgery

Methylene blue is an intraoperative adjunct for localization of enlarged parathyroid glands. The availability of preoperative and other intraoperative localization methods, and the reported adverse effects of methylene blue make its routine use debatable. The aim of this study was to perform a systematic review of the use of methylene blue in parathyroidectomy. A systematic review of English-language literature in MEDLINE and Scopus databases on the use of intravenous methylene blue in parathyroid surgery was carried out. There were no randomized clinical trials. Thirty-nine observational studies were identified, of which 33 did not have a control arm. The overall median staining rate for abnormal parathyroid glands was 100 per cent. The median cure rates in the methylene blue and no-methylene blue arms were 100 and 98 per cent respectively. Neurotoxicity was reported in 25 patients, all of whom were taking serotonergic medication. Observational evidence suggests that methylene blue is efficacious in identifying enlarged parathyroid glands. Toxicity appears to be mild in the absence of concomitant use of serotonin reuptake inhibitors. The effectiveness of methylene blue in the context of currently used preoperative and intraoperative localization techniques has yet to be shown.