Interpretation of 99mTc sestamibi parathyroid SPECT scan is improved when read by the surgeon and nuclear medicine physician together

Validation of a novel method for localization of parathyroid adenomas using SPECT/CT

Background

Accurate localization of parathyroid adenomas is of critical importance in surgical planning for minimally invasive parathyroidectomy. SPECT/CT is considered the investigation of choice but has limitations regarding localization of superior versus inferior adenomas. We proposed a novel method for localization using SPECT/CT by determining the anterior-posterior relationship of the adenoma to a horizontal line in the coronal plane through the tracheoesophageal groove. Our objective was to determine the accuracy, validity, and inter-rater reliability of this method.

Method

This was a retrospective review of patients who underwent parathyroidectomy for a single adenoma between 2010-2017. SPECT/CT images were reviewed by two staff Otolaryngologists, a Radiologist, an Otolaryngology fellow and Otolaryngology resident. Results were compared using intra-operative report as the gold standard.

Overall accuracy in determining superior/inferior and right/left adenomas was calculated, as well as Cohen's Kappa to determine agreement with operative report and inter-rater reliability. The performance was compared to that of the original radiology report.

Results

One hundred thirty patients met criteria and were included. Our method correctly identified the location of the adenoma in terms of both side and superior/inferior position in 80.4% [76 - 84%] of patients, which considerably outperformed the original radiology report at 48.5% [4-78%] accuracy. The agreement level between our method and operative report was high (Kappa=0.717 [0.691-0.743]), as was the inter-rater reliability (Kappa=0.706 [0.674-0.738]).

Conclusion

We report a novel method for localization of parathyroid adenomas using SPECT/CT which outperforms standard radiology reporting. This tool can be used by surgeons and radiologists to better inform and plan for minimally invasive parathyroidectomy.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Sporadic multiple parathyroid gland disease--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Sporadic multiglandular disease (MGD) has been reported in literature in 8-33 % of patients with primary hyperparathyroidism (pHPT). This paper aimed to review controversies in the pathogenesis and management of sporadic MGD.

METHODS

A literature search and review was made to evaluate the level of evidence concerning diagnosis and management of sporadic MGD according to criteria proposed by Sackett, with recommendation grading by Heinrich et al. and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled 'Hyperparathyroidism due to multiple gland disease: An evidence-based perspective'.

RESULTS

Literature reports no prospective randomised studies; thus, a relatively low level of evidence was achieved. Appropriate surgical therapy of sporadic MGD should consist of a bilateral approach in most patients. Unilateral neck exploration guided by preoperative imaging should be reserved for selected patients, performed by an experienced endocrine surgeon and monitored by intraoperative parathormone assay (levels of evidence III-V, grade C recommendation). There is conflicting or equally weighted levels IV-V evidence supporting that cure rates can be similar or worse for sporadic MGD than for single adenomas (no recommendation). Best outcomes can be expected if surgery is performed by an experienced parathyroid surgeon working in a high-volume centre (grade C recommendation). Levels IV-V evidence supports that recurrent/persistence pHPT occurs more frequently in patients with double adenomas hence in situations where a double adenoma has been identified, the surgeon should have a high index of suspicion during surgery and postoperatively for the possibility of a four-gland disease (grade C recommendation).

CONCLUSIONS

Identifying preoperatively patients at risk for MGD remains challenging, intraoperative decisions are important for achieving acceptable cure rates and long-term follow-up is mandatory in such patients.

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.

Surgical management of the patient with primary hyperparathyroidism

Abstract: 

The successful surgical management of primary hyperparathyroidism requires a surgeon with a clear understanding of both the embryology and anatomy of the parathyroid glands. While the majority of patients may only have a single diseased gland, there is no 100% confirmation that can be attained in the preoperative period. For this reason, even when imaging is suggestive of a single diseased gland, additional intraoperative adjuncts should be used. Intraoperative parathyroid hormone monitoring is the most commonly used adjunct. When preoperative localization is not possible, or intraoperative parathyroid hormone levels fail to meet criteria for successful resection, the patient requires a four gland exploration. Cure is not confirmed until normocalcemia is documented for at least 6 months after surgery.

Improved localization of sestamibi imaging at high-volume centers

OBJECTIVES/HYPOTHESIS

Sestamibi imaging can provide critical information regarding the location of suspected parathyroid adenomas. However, this modality can be challenging to perform and interpret reliably. The impact of experience on the localizing efficacy of sestamibi scanning was assessed.

STUDY DESIGN

Prospective analysis of a consecutive series of patients undergoing parathyroidectomy was undertaken after institutional review board approval was obtained.

METHODS

Patients undergoing parathyroid surgery from October 2003 through June 2011 were considered. Inclusion criteria represented primary surgery for primary hyperparathyroidism, in which a single adenoma was excised and cure obtained. Sestamibi scan results, performed at our institution and at outside imaging centers, were compared to intraoperative findings.

RESULTS

There were 389 parathyroidectomies performed; 188 patients met inclusion criteria. Fifty-four patients had sestamibi scans performed at outside institutions; 36 (67%) were localizing and 18 (33%) were nonlocalizing. Among localizing studies, half identified the correct quadrant and half recognized the correct side. At our institution, 147 patients underwent sestamibi imaging; 121 (82%) localized and 26 (18%) did not. Among localizing studies, the correct quadrant was reported in 64% and the correct side in 36%. Of the 147 scans performed at our institution, 13 represented repeat scans of patients with nonlocalizing outside scans. All 13 of these localized; six identified the correct quadrant and seven the side of the adenoma.

CONCLUSIONS

A high volume of experience may improve the yield of sestamibi imaging. Repeating this study at a high-volume center when it was nonlocalizing elsewhere may provide useful additional information.

Superiority of minimally invasive parathyroidectomy

Because greater than 80% of spontaneous cases of primary hyperparathyroidism are caused by a single adenoma, BCE of the neck, which has long been the approach of choice, is being replaced. Focused parathyroidectomy has been made possible by advances in preoperative parathyroid localization and IOPTH monitoring, which allows confirmation of cure and confirmation of the absence of MGD without visualizing all 4 parathyroids. Several techniques for focused parathyroidectomy exist, but open MIP through an incision of 2 to 3 cm with surgeon-administered locoregional anesthesia seems to improve on the already high success rate and low morbidity associated withimproe on bilateral exploration. In addition, MIP is associated with numerous secondary benefits such as decreased hospital cost, improved patient satisfaction, decreased operative time, and same-day discharge. Bilateral exploration will remain the standard of care for most patients with multigland or syndromic disease. Most patients with sporadic PHPT are candidates for MIP.

Sestamibi imaging for primary hyperparathyroidism: the impact of surgeon interpretation and radiologist volume

BACKGROUND

Preoperative localization is the first step towards minimally invasive targeted parathyroidectomy. While there are data emphasizing that surgeon experience optimizes operative outcomes, the role of the radiologist's experience in successful preoperative imaging is unclear. We hypothesized that the accuracy of sestamibi scanning for primary hyperparathyroidism is dependent upon surgeon interpretation and radiologist volume.

METHODS

Between January 2000 to August 2009, 1,255 patients underwent parathyroidectomy for hyperparathyroidism at our institution. Of these, 763 had sestamibi scans for primary hyperparathyroidism. All scans were reviewed by surgeons and radiologists blinded, and were correlated with the operative findings and pathological reports. Radiologists were grouped into high volume (>50 cases/year, HV-RAD) or low volume (<50 cases/year, LV-RAD) based upon a database of >6,000 parathyroid cases reported by 89 regional hospitals.

RESULTS

Of the 763 patients, 77 % were female and the mean age was 60 years. Mean baseline calcium and parathyroid hormone levels were 11.2 ± 0.03 mg/dl and 133 ± 3.27 pg/ml, respectively. The sensitivity of the surgeon (93 %) was higher than both HV (83 %) and LV (72 %) radiologists. Importantly, the positive predictive values were similar: 96 % for surgeon, 93 % for HV-RAD, and 98 % for LV-RAD. As a result, out of 99 scans which were correctly read by the surgeon but not by radiologist, 84 were read as negative by radiologist, 11 on the wrong side of the neck, and 4 on the same side but the wrong gland.

CONCLUSIONS

Surgeon interpretation and radiologist volume increase the likelihood of successful preoperative sestamibi parathyroid localization for primary hyperparathyroidism. We recommend that imaging be reviewed by experienced parathyroid surgeons rather than relying on radiological interpretation alone.

Chasing "shadows": discovering the subtleties of sestamibi scans to facilitate minimally invasive parathyroidectomy

BACKGROUND

With the advent of sestamibi scans, high-resolution ultrasonography (US), and intraoperative intact parathyroid hormone (PTH) measurements, minimally invasive parathyroidectomy (MIP) is considered the standard of care for patients with primary hyperparathyroidism (PHPT). Preoperative imaging, however, can be negative more than 20% of the time.

METHODS

We chose to examine one surgeon's experience with patients who presented with PHPT and negative or indeterminate preoperative imaging from July 1993 to September 2009. A retrospective review of a parathyroid surgery database and patient records was conducted to collect the following information: patient age and sex; calcium and PTH levels; sestamibi and US results; and operative reports. Each sestamibi scan had been re-reviewed preoperatively by the surgeon with a nuclear medicine physician. The study cohort included patients with negative or indeterminate sestamibi results and a negative or no US report in which the surgeon was able to identify a "shadow" or subtlety on sestamibi and plan an MIP.

RESULTS

A total of 126 patients had a negative or indeterminate sestamibi scan and a negative or no US report. "Shadows" or subtleties were found in 18 of 44 (41%) of the cases with a negative sestamibi and in 62 of 82 (76%) of cases with an indeterminate sestamibi scan. For these 80 cases a MIP was planned. In all, 7 of 80 (9%) were converted to a bilateral exploration. The remaining 46 patients underwent a planned bilateral exploration. Cure rates were comparable: 99% in the study group compared to 97% in the group who underwent a planned or converted bilateral exploration.

CONCLUSIONS

With careful preoperative re-review of a negative or indeterminate sestamibi scan and the identification of subtleties in patients with a negative preoperative US scan, a successful MIP can be performed 91% of the time with a 98% cure rate.

Intraoperative adjuncts for parathyroid surgery

In recent years, parathyroid surgery has evolved from traditional bilateral neck exploration to minimal invasive parathyroidectomy. This trend became possible due to preoperative localization imaging that guides the surgeon in the search for a parathyroid adenoma. Intraoperative adjuncts are complementary to preoperative localization and assist in localizing parathyroid glands, confirming parathyroid tissue and establishing a cure. Institutions and surgeons utilize different intraoperative adjuncts in different protocols with varying results. The purpose of this article is to review the available intraoperative adjuncts to parathyroid surgery and critically evaluate their utility, accuracy and their added value to the surgeon.

Minimally invasive parathyroidectomy

Minimally invasive parathyroidectomy (MIP) is an operative approach for the treatment of primary hyperparathyroidism (pHPT). Currently, routine use of improved preoperative localization studies, cervical block anesthesia in the conscious patient, and intraoperative parathyroid hormone analyses aid in guiding surgical therapy. MIP requires less surgical dissection causing decreased trauma to tissues, can be performed safely in the ambulatory setting, and is at least as effective as standard cervical exploration. This paper reviews advances in preoperative localization, anesthetic techniques, and intraoperative management of patients undergoing MIP for the treatment of pHPT.

4D parathyroid CT as the initial localization study for patients with de novo primary hyperparathyroidism

BACKGROUND

Preoperative localization of parathyroid tumors of primary hyperparathyroidism (pHPT) is required for minimally invasive parathyroidectomy (MIP). Parathyroid four-dimensional computed tomography (4DCT) has mainly been used as an adjunct to other imaging modalities in the remedial setting. 4DCT was evaluated as the initial localization study in de novo patients with pHPT.

MATERIALS AND METHODS

A total of 87 consecutive patients underwent parathyroidectomy for pHPT from August 2008 to November 2009. 4DCT was introduced as the preferred imaging modality instead of sestamibi with SPECT (SeS) in April 2009. Results of the imaging studies [4DCT, SeS, and ultrasonography (US)], operative and, pathologic findings, and biochemical measurements were evaluated.

RESULTS

In this study, 84% of patients (73 of 87) underwent an US, 59.8% (52 of 87) a SeS, and 38.0% (33 of 87) had a 4DCT. 4DCT had improved sensitivity (85.7%) over SeS (40.4%) and US (48.0%) to localize parathyroid tumors to the correct quadrant of the neck (P < 0.005) as well as to localize (lateralize) the parathyroid lesions to one side of the neck (93.9% for 4DCT vs. 71.2% for US and 61.5% for SeS; P < 0.005). 4DCT correctly predicted multiglandular disease (MGD) in 85.7% (6 of 7) patients, whereas US and SeS were unable to detect MGD in any case. All patients achieved cure based on intraoperative parathyroid hormone (PTH) measurements and normalization of intact PTH and S-Ca during follow-up.

CONCLUSIONS

4DCT provides significantly greater sensitivity than SeS and US for precise localization of parathyroid tumors of pHPT. Additionally, it correctly predicted MGD in a majority of patients.

Imaging of parathyroid glands

Preoperative imaging studies have an important role in facilitating successful localization of adenomas for surgeons. Their use has increased and parallels the recent growth of minimally invasive parathyroidectomy. Based on findings that scintigraphy is reported to have the highest accuracy for localization of adenomas when compared with anatomic imaging techniques, this article discusses the current role and limitations of imaging, with a focus on scintigraphy, in the evaluation of patients before surgery for hyperparathyroidism.

Effectiveness of "office"-based, ultrasound-guided differential jugular venous sampling (DJVS) of parathormone in patients with primary hyperparathyroidism

BACKGROUND

Pre-operative localization is the first step for focused parathyroidectomy. Surgeon-performed ultrasonography (SUS) is used often as a single method of localization; however, when equivocal, sestamibi (MIBI) scan is still indicated. Intra-operative differential jugular venous sampling (DJVS) is positive in 71-80% of patients. The purpose of this study is to evaluate the effectiveness of office based DJVS as the next method for localization when SUS is equivocal.

METHODS

Twenty-one patients with an equivocal SUS underwent office-based, SUS-guided DJVS. The samples were collected from the most inferior portion of each internal jugular vein and sent for standard parathormone (PTH) measurement. The side of the neck with the highest value of serum PTH was the initial side of exploration. DJVS lateralization was correlated retrospectively with operative findings.

RESULTS

In 17 of 21 (81%) patients, DJVS was correct in indicating the side of the abnormal gland. DJVS was incorrect in 2 and negative in 2 other patients. Bilateral neck explorations were performed in only 6 of 21 patients because of either multiglandular disease (3 patients), concomitant thyroidectomy (2 patients), or surgeon's judgment (1 patient). There were no complications from DJVS, and all patients became eucalcemic.

CONCLUSION

Office based DJVS is accurate and may eliminate the need for MIBI in patients with equivocal SUS. This simple technique can shorten the pre-operative evaluation of sporadic primary hyperparathyroidism.

Surgical management of primary hyperparathyroidism: state of the art

This article reviews the current state of the art regarding therapy for primary hyperparathyroidism. Clinical evaluation and indications for parathyroidectomy are described, followed by a review of surgical techniques currently being practiced and possible outcomes involved. Focused parathyroidectomy has become a successful alternative to conventional bilateral cervical exploration.

Ectopic mediastinal parathyroid adenoma: a cause of acute pancreatitis

A 38-year-old male was admitted to our hospital with epigastric pain, and he was confirmed to have acute exudative pancreatitis. After the episode of acute pancreatitis subsided, laboratory investigation revealed increased serum calcium (12.0 mg/dl), decreased serum phosphorus (2.7 mg/dl), and increased serum parathyroid hormone (intact) levels (131 pg/ml). A computed tomography (CT) scan of the neck did not reveal any mass lesions in the parathyroid gland. However, (99m)Tc sestamibi scintigraphy revealed that there was one functioning parathyroid gland in the upper mediastinum. Combined (99m)Tc sestamibi scintigraphy and CT scan confirmed the diagnosis of primary hyperparathyroidism in the mediastinum. Microscopic examination revealed the presence of a parathyroid adenoma (1.3 x 0.4 cm(2)) adjacent to the atrophic parathyroid gland in right thymus gland. We report the case of a patient diagnosed with primary hyperparathyroidism due to an ectopic mediastinal parathyroid adenoma. An ectopic mediastinal parathyroid adenoma may manifest as an episode of acute pancreatitis. Preoperative investigation to determine the exact location of an adenoma should include two types of imaging studies, preferably (99m)Tc sestamibi scintigraphy and CT of the neck and chest.

Negative preoperative localization leads to greater resource use in the era of minimally invasive parathyroidectomy

BACKGROUND

Successful preoperative localization plays an important role in patient selection for focused parathyroidectomy.

METHODS

The case records of 499 consecutive patients with presumed hyperparathyroidism who underwent neck exploration were reviewed. Positive imaging patients (n = 373) had a localizing study that clearly showed a single abnormal parathyroid gland whereas negative imaging patients (n = 44) failed to localize or had discordant imaging results.

RESULTS

Positive imaging patients were more likely to have a single adenoma (93.0% vs 72.1%; P < .001), and were less likely to require a bilateral exploration (8.1% vs 70.4%; P < .001). Negative imaging patients required more frozen sections (.9 +/- 1.3 vs .2 +/- .7; P < .001), and longer surgical time (77.3 +/- 52.5 min vs 48.4 +/- 34.6 min; P < .001). The cure rate was significantly higher in the positive imaging group (96.0% vs 87.1%; P < .03), with no difference in the incidence of complications (3.2% vs 2.3%; P value was not significant).

CONCLUSIONS

Patients with unsuccessful or discordant preoperative localization have a higher incidence of multigland disease, lower cure rate, and consume more institutional resources than patients with successful preoperative localization.

Nuclear imaging and minimally invasive surgery in the management of hyperparathyroidism

Primary hyperparathyroidism is the most common cause of hypercalcemia, and the treatment is primarily surgical. Because of biochemical screening, more patients now present with asymptomatic primary hyperparathyroidism, and consensus guidelines have been developed for the treatment of these patients. There is now considerable interest in minimally invasive approaches to the treatment of hyperparathyroidism. Sestamibi scanning as a localizing study, used in combination with anatomic imaging and intraoperative rapid parathyroid hormone assays, has enabled focused surgical approaches. Patients with localizing studies that indicate a single parathyroid adenoma are candidates for such approaches, including unilateral neck exploration, minimally invasive single-gland exploration, or endoscopic exploration instead of the traditional approach of bilateral neck exploration. Nuclear imaging is also critical to the successful management of patients with persistent or recurrent hyperparathyroidism.

Parathyroid imaging: technique and role in the preoperative evaluation of primary hyperparathyroidism

OBJECTIVE

This article discusses the commonly used techniques for imaging the parathyroid glands and their role in the preoperative evaluation of patients with primary hyperparathyroidism.

CONCLUSION

The importance of sonography and sestamibi scintigraphy in the preoperative evaluation of patients with primary hyperthyroidism has increased with the adoption of minimally invasive parathyroidectomy techniques at most medical centers. When the results of these studies are concordant, the cure rates of minimally invasive surgery equal those of traditional bilateral neck exploration.

Improved preoperative planning for directed parathyroidectomy with 4-dimensional computed tomography

BACKGROUND

Four-dimensional computed tomography (4D-CT) provides both functional and highly detailed anatomic information about parathyroid tumors. The purpose of this study was to compare 4D-CT with sestamibi imaging and ultrasonography as methods for the accurate preoperative localization of hyperfunctioning parathyroid glands before parathyroidectomy.

METHODS

A study of 75 patients with primary hyperparathyroidism was performed at a tertiary-care institution. Sestamibi imaging, ultrasonography, and 4D-CT were performed on each patient preoperatively. Results of the imaging studies were compared with operative findings, pathologic data, and biochemical measurements to assess the sensitivity and specificity of each of the imaging modalities.

RESULTS

4D-CT demonstrated improved sensitivity (88%) over sestamibi imaging (65%) and ultrasonography (57%), when the imaging studies were used to localize (lateralize) hyperfunctioning parathyroid glands to 1 side of the neck. Moreover, when used to localize parathyroid tumors to the correct quadrant of the neck (ie, right inferior, right superior, left inferior, or left superior), the sensitivity of 4D-CT (70%) was significantly higher than sestamibi imaging (33%) and ultrasonography (29%).

CONCLUSION

4D-CT provides significantly greater sensitivity than sestamibi imaging and ultrasonography for precise (quadrant) localization of hyperfunctioning parathyroid glands. This allows improved preoperative planning, particularly for the case of reoperation. In addition to the data that are provided, we present a novel classification scheme for use in parathyroid localization.

Technetium-99m-sestamibi subtraction scintigraphy vs. ultrasonography combined with a rapid parathyroid hormone assay in parathyroid aspirates in preoperative localization of parathyroid adenomas and in directing surgical approach

OBJECTIVE

To determine the sensitivity and positive predictive value (PPV) of subtraction scintigraphy (SS) vs. ultrasonography (US) of the neck combined with rapid intact parathyroid hormone (iPTH) assay in US-guided fine-needle parathyroid aspirates in preoperative localization of parathyroid adenomas and in directing surgical approach.

DESIGN

The results of SS for localization of parathyroid adenoma were determined in 121 patients with primary hyperparathyroidism (pHPT) and compared with findings at surgery and with the results of US alone (in patients without nodular goitre) and US in combination with the iPTH assay in US-guided fine-needle aspirates (FNAs) of suspicious parathyroid lesions (in patients with concomitant nodular goitre).

PATIENTS

All 121 patients had biochemically documented pHPT; all were referred for first-time surgery.

MEASUREMENTS

SS was performed with 99mTc-sestamibi and 99mTc-pertechnetate. High-resolution US of the neck was performed by a single endocrine surgeon and combined with US-guided FNAs of suspicious parathyroid lesions in all patients with nodular goitre (n = 43).

RESULTS

The sensitivity and PPV of SS were significantly higher in patients without vs. with goitre (89.3% and 95.7%vs. 74.3% and 76.5%, respectively; P < 0.001). The sensitivity and PPV of US were significantly higher in patients without vs. with goitre (96% and 97.3%vs. 67.7% and 71.9%, respectively; P < 0.001). The iPTH assay of US-guided FNAs of suspicious parathyroid lesions in patients with nodular goitre significantly improved both the sensitivity and PPV of US imaging (90.7% and 100%, respectively), allowing for an accurate choice of surgical approach in 118 (97.5%) of 121 patients. SS was more accurate than US alone in detection of ectopic parathyroid adenomas. However, US alone was characterized by a higher sensitivity in detection of small parathyroid adenomas (< 500 mg) at typical sites (P < 0.01).

CONCLUSIONS

Both the sensitivity and PPV of SS and US alone are comparable, with significantly less accurate results obtained in patients with goitre. In cases of equivocal results of US and/or in patients with concomitant goitre, an iPTH assay in US-guided FNAs of suspicious parathyroid lesions may be used to establish the nature of the mass, distinguish between parathyroid and nonparathyroid tissue (goitre, lymph nodes) and improve the accuracy of US parathyroid imaging, allowing for successful directing of surgical approach in a majority of patients.

Consequences of targeted parathyroidectomy guided by localization studies without intraoperative parathyroid hormone monitoring

BACKGROUND

After excision of an abnormal gland, the dynamics of intraoperative parathyroid hormone (PTH) levels signal whether or not more hypersecreting tissue is present. This quantitative assurance of operative success has led to targeted exploration of the hyperfunctioning gland(s). Some have questioned the need for intraoperative PTH monitoring (IPM) in the presence of positive nuclear scanning. The purpose of this study was to examine the accuracy of nuclear scans in correctly localizing and guiding the complete excision of all abnormal gland(s) in patients with sporadic primary hyperparathyroidism (SPHPT) and to demonstrate how IPM changed the operative management in these patients.

STUDY DESIGN

Five hundred nineteen consecutive patients with sporadic primary hyperparathyroidism had technetium 99-m-sestamibi scans (MIBI) as localization studies obtained before undergoing parathyroidectomy guided exclusively by IPM. All patients were either followed for more than 6 months, or their procedures were identified as operative failures. MIBI reports were correlated with operative findings, hormone dynamics, and postoperative outcomes.

RESULTS

Operative success was achieved in 506 of 519 patients (97%). MIBI correctly localized all involved glands in 411 patients (80%). Among the 105 patients (20%) with incorrect or negative scans, IPM changed the operative management in 86 of 105 (82%) by pointing out incomplete resection in patients with a single MIBI incorrect focus (21 of 28) or unrecognized multiglandular disease by scan (13 of 15); avoiding unnecessary exploration in patients with additional incorrect foci (20 of 21); and guiding the surgeon to successful excision or unilateral neck exploration in patients with negative MIBI (32 of 41).

CONCLUSIONS

MIBI as a single adjunct missed 87% of patients with multiglandular disease. Including patients with negative (8%) and incorrect (12%) MIBI, IPM changed the operative management in 17% of patients and led to operative success in 97%. We suggest that IPM should be used to guide parathyroid excision in every patient with sporadic primary hyperparathyroidism.