Pre-operative sestamibi-technetium subtraction scintigraphy in primary hyperparathyroidism: experience with 156 consecutive patients

Update on the current management of persistent and recurrent primary hyperparathyroidism after parathyroidectomy

Primary hyperparathyroidism (pHPT) is the third most common endocrine disease. The surgical procedure aims for permanent cure, but recurrence has been reported in 4%-10% of pHPT patients. Preoperative localization imaging is highly valuable. It includes ultrasound, computed tomography (CT), single-photon-emission CT, sestamibi scintigraphy and magnetic resonance imaging. The operation has been defined as successful when postoperative continuous eucalcemia exists for more than the first six months. Ongoing hypercalcemia during this period is defined as persistence, and recurrence is defined as hypercalcemia after six months of normocalcemia. Vitamin D is a crucial factor for a good outcome. Intraoperative parathyroid hormone (PTH) monitoring can safely predict the outcomes and should be suggested. PTH ≤ 40 pg/mL or the traditional decrease ≥ 50% from baseline minimizes the likelihood of persistence. Risk factors for persistence are hyperplasia and normal parathyroid tissue on histopathology. Risk factors for recurrence are cardiac history, obesity, endoscopic approach and low-volume center (at least 31 cases/year). Cases with double adenomas or four-gland hyperplasia have a greater likelihood of persistence/ recurrence. A 6-mo calcium > 9.7 mg/dL and eucalcemic parathyroid hormone elevation at 6 mo may be associated with recurrence necessitating long-term follow-up. 18F-fluorocholine positron emission tomography and 4-dimensional CT in persistent and recurrent cases can be valuable before reoperation. With these novel advances in preoperative imaging and localization as well as intraoperative PTH measurement, the recurrence rate has dropped to 2.5%-5%. Six-month serum calcium ≥ 9.8 mg/dL and parathyroid hormone ≥ 80 pg/mL indicate a risk of recurrence. Negative sestamibi scintigraphy, diabetes and elevated osteocalcin levels are predictors of multiglandular disease, which brings an increased risk of persistence and recurrence. Bilateral neck exploration was considered the gold-standard diagnostic method. Minimally invasive parathyroidectomy and neck exploration are both effective surgical techniques. Multidisciplinary diagnostic and surgical management is required to prevent persistence and recurrence. Long-term follow-up, even up to 10 years, is necessary.

"Before skin incision" high-resolution ultrasound in primary hyperparathyroidism: a new imaging tool for surgeons?

PURPOSE

Various diagnostic methods have been utilized for localizing pathologic parathyroid glands to consequently provide the possibility of avoiding bilateral neck dissection in cases of primary hyperparathyroidism. Scintigraphy, combined with ultrasound, became established as the standard method of localization in the 2000s. The aim of this study was to evaluate the role of the "before skin incision" surgeon-performed ultrasound in determining the improvement in the diagnostic accuracy in a large case series.

METHOD

The method used in this research is a retrospective observational study (study period: between 1-2014 and 12-2020) comparing two patient groups before (control group: 31 patients) and after (study group: 70 patients) the introduction of the ultrasonography surgical protocol: combined preoperative and "before skin incision" surgeon-performed ultrasound.

RESULTS

The sensitivity of the combined preoperative "before skin incision" surgeon-performed ultrasound was 97%, and the positive predictive value was 93% in regard to detecting the number of diseased glands and the appropriate anatomic location (right versus left, upper versus lower). The sensitivity of the parathyroid scan (Tc-MIBI-scintigraphy) was 74%, and the positive predictive value was 92%. The duration of surgery was significantly shorter in the test group (84.7 vs. 66.4 min; Mann‒Whitney U: 0.006). No differences were detected between the two groups in regard to avoiding intraoperative or postoperative complications.

CONCLUSION

The combination of the preoperative "before skin incision" surgeon-performed ultrasound could improve the efficiency of the preoperative location and anatomic classification using the standard literature-suggested diagnostic methods.

The Value of Preoperative and Intraoperative Ultrasound in the Localization of Intrathyroidal Parathyroid Adenomas

AIM

Intrathyroidal parathyroid adenoma (IPA) is rare and may easily be mistaken for thyroid nodule in ultrasonography. The aim of this study was to investigate the characteristic features of IPA and explore the value of preoperative and intraoperative ultrasound in the diagnosis and localization of IPA.

METHODS

13 of 216 patients who were found to have intrathyroidal parathyroid lesions underwent parathyroidectomy in our hospital because of PHPT. According to the relationship between parathyroid adenoma and thyroid gland, parathyroid adenoma was divided into extra-thyroid type or intra-thyroid type (partial or complete) and the results were compared with surgical and histopathological reports as gold standard. The sonographic features of intrathyroidal parathyroid lesions were analyzed retrospectively.

RESULTS

A total of 12 intrathyroidal lesions showed profoundly hypoechoic solid nodules with well-defined border, abundant blood flow and polar feeding vessels originating from the superior or inferior thyroid artery (92.3%, 12/13). These nodules were finally confirmed as IPA (or IPAC) after surgery. Polar feeding vessel was not detected in one case of parathyroid hyperplasia confirmed by pathology (7.7%, 1/13). 12 cases were diagnosed and localized on ultrasonography before operation and 10 cases were localized on Tc-99m MIBI SPECT/CT.

CONCLUSIONS

The color Doppler ultrasound findings of IPA were confirmed as profoundly hypoechoic nodules with clear boundary and abundant internal blood flow. The presence of polar feeding vessels which originate from thyroid artery were identified as characteristic features of US for IPA. Preoperative and intraoperative ultrasound could be helpful in the localization and treatment of intrathyroidal parathyroid diseases.

Efficacy of ultrasonography and Tc-99m MIBI SPECT/CT in preoperative localization of parathyroid adenomas causing primary hyperthyroidism

Background

Primary hyperparathyroidism (PHPT) results from an excess of parathyroid hormone (PTH) produced from an overactive parathyroid gland. The study aimed to explore the sonographic features of parathyroid adenomas and assess the diagnostic performance of ultrasonography (US) and Tc-99m MIBI SPECT/CT for preoperative localization of parathyroid adenomas.

Methods

A total of 107 patients were enrolled in this retrospective study who had PHPT and underwent parathyroidectomy. Of the 107 patients, 97 performed US and Tc-99m MIBI SPECT/CT examinations for preoperative localization of parathyroid nodules. The sensitivity and accuracy of each modality were calculated.

Results

In this study, residual parathyroid sign and polar vascular sign were identified as characteristic US features of parathyroid adenomas. These manifestations were closely related to the size of the abnormal parathyroid lesions. Among the 108 parathyroid nodules from 97 patients with PHPT, the sensitivity and accuracy of US for locating the parathyroid nodules were significantly higher than those of Tc-99m MIBI SPECT/CT (93.0% vs. 63.0% and 88.0% vs. 63.0% respectively; ²=26.224, 18.227 respectively, P<0.001). The differences between US+Tc-99m MIBI SPECT/CT and Tc-99m MIBI SPECT/CT-alone were statistically significant (²=33.410, 21.587 respectively, P<0.001), yet there were no significant differences in the sensitivity or accuracy between US+Tc-99m MIBI SPECT/CT and US-alone (²=0.866, 0.187 respectively, P=0.352 and 0.665).

Conclusions

US shows significantly better sensitivity and accuracy for localization of parathyroid adenomas than Tc-99m MIBI SPECT/CT. However, US combined with Tc-99m MIBI SPECT/CT is of great clinical value in the preoperative localization of parathyroid nodules in patients with PHPT.

Localization of Parathyroid Disease in Reoperative Patients with Primary Hyperparathyroidism

The localization of persistent or recurrent disease in reoperative patients with primary hyperparathyroidism presents challenges for radiologists and surgeons alike. In this article, we summarize the relevant imaging modalities, compare their accuracy in identifying reoperative disease, and outline their advantages and disadvantages. Accurate localization by preoperative imaging is a predictor of operative success, whereas negative or discordant preoperative imaging is a risk factor for operative failure. Ultrasound is a common first-line modality because it is inexpensive, accessible, and radiation-free. However, it is highly operator-dependent and less accurate in the reoperative setting than in the primary setting. Sestamibi scintigraphy is superior to ultrasound in localizing reoperative disease but requires radiation, prolonged imaging times, and reader experience for accurate interpretation. Like ultrasound, sestamibi scintigraphy is less accurate in the reoperative setting because reoperative patients can exhibit distorted anatomy, altered perfusion of remaining glands, and interference of radiotracer uptake. Meanwhile, four-dimensional computed tomography (4DCT) is superior to ultrasound and sestamibi scintigraphy in localizing reoperative disease but requires the use of radiation and intravenous contrast. Both 4DCT and magnetic resonance imaging (MRI) do not significantly differ in accuracy between unexplored and reoperative patients. However, MRI is more costly, inaccessible, and time-consuming than 4DCT and is inappropriate as a first-line modality. Hybrid imaging with positron emission tomography and computed tomography (PET/CT) may be a promising second-line modality in the reoperative setting, particularly when first-line modalities are discordant or inconclusive. Lastly, selective venous sampling should be reserved for challenging cases in which noninvasive modalities are negative or discordant. In the challenging population of reoperative patients with PHPT, a multimodality approach that utilizes the expertise of high-volume centers can accurately localize persistent or recurrent disease and enable curative parathyroidectomy.

The diagnostic value of parathyroid hormone washout in primary hyperparathyroidism patients with negative or equivocal 99 m Tc-MIBI results

BACKGROUND AND OBJECTIVES

The accurate identification of hyper functioning parathyroid gland is needed for definitive surgical treatment in primary hyperparathyroidism. Ultrasonography and 99mTechnetium sestamibi scintigraphy are the two most used methods with varying sensitivities. This study aimed to assess the value of parathyroid hormone (PTH) assay in preoperative ultrasound guided fine needle aspiration (FNA)-PTH washout fluid to verify the correct localisation of lesions with negative or inconclusive scintigraphy results.

METHODS

We evaluated data of 28 lesions in 21 patients who underwent US-guided parathyroid fine-needle aspiration (FNA) with PTH washout, retrospectively. The PTH washout results and the reports of parathyroid surgery and imaging studies were reviewed.

RESULTS

Of operated 28 lesions 23 had positive and 5 had negative washout results. The median FNA-PTH washout was 2315.5 pg/ ml (min-max: 12.3-6978 pg/ ml). The calculated sensitivity of FNA-PTH washout was 85.7% and the specifity was 28.6%. The positive and negative predictive values were 78.3% and 40.0%, respectively.

CONCLUSIONS

FNA-PTH can be used to establish the nature of the lesion, discriminate parathyroid gland from thyroid lesions or cervical lymph nodes, improving the surgical outcomes. It can be used to localise parathyroid lesions preoperatively when negative or discordant ultrasound and scintigraphy findings are obtained.

Update in Parathyroid Imaging

Primary hyperparathyroidism (PHPT) is characterized by excessive, dysregulated production of parathyroid hormone (PTH) by 1 or more abnormal parathyroid glands. Minimally invasive surgical techniques have created a need for more precise localization of the parathyroid lesion by imaging. A variety of imaging protocols and techniques have been used for this purpose, but no one modality is clearly superior. Nuclear medicine scintigraphy and ultrasound imaging are established modalities, although multiphase or 4-dimensional computed tomography is an emerging modality with several advantages. This review provides a background regarding PHPT and key anatomy, and discusses these alternative parathyroid imaging modalities with updates.

Parathyroid surgery: correlation between pre-operative localization studies and surgical outcomes

OBJECTIVE

Pre-operative imaging techniques have enabled minimally invasive parathyroid surgery to supersede the traditional approach to hyperparathyroidism (HPT) surgery, which included cervical exploration. Cervical ultrasound (US) and sestamibi scan (MIBI) are commonly performed, but the results of these localization tests do not always match. This study correlated surgical outcomes with pre-operative localization findings, including matched positive US and MIBI studies, one positive study (US or MIBI), conflicting studies or negative results.

DESIGN

Retrospective medical record review.

PATIENTS

A hundred and sixty nine consecutive patients who underwent parathyroidectomy from January 2005 to December 2012.

MEASUREMENTS

Correlation between surgical outcomes and pre-operative localization tests.

RESULTS

All patients (134F/35M, 59·6 ± 13·5 years of age) had primary HPT. US and MIBI localization studies matched in 76%, whereas 10·7% had positive MIBI only and 8·3% US only. Studies were negative in 3·6% and contradictory in 1·8%. Minimally invasive parathyroidectomy was performed in 87% of the matched group and 89% of the MIBI-only group. Surgical success rate, defined as postoperative normalization of calcium and PTH levels, was similar in patients with a single positive study (MIBI or US) vs double-matched studies (MIBI and US). Patients were followed up for 6 weeks. Overall, pathology was consistent with adenoma in 95%.

DISCUSSION

Parathyroidectomy success rate was similar in patients with primary HPT and MIBI-only or US-only positive localization studies compared to those with matched US/MIBI studies. The results support a clinical algorithm in which positive results from one imaging technique, either MIBI or US, are sufficient to refer a patient for parathyroid surgery.

Accuracy of 2-Phase Parathyroid CT for the Preoperative Localization of Parathyroid Adenomas in Primary Hyperparathyroidism

BACKGROUND AND PURPOSE

Minimally invasive parathyroidectomy requires accurate preoperative localization of suspected adenomas, and multiphase CT allows adenoma characterization while providing detailed anatomic information. The purpose of this study was to assess the feasibility of a protocol using only arterial and venous phases to localize pathologic glands in patients with primary hyperparathyroidism.

MATERIALS AND METHODS

We identified 278 patients with primary hyperparathyroidism who had undergone 2-phase CT with surgical cure. All scans were read prospectively by board-certified neuroradiologists. A neuroradiology fellow retrospectively reviewed images and reports and classified suspected adenomas on the basis of anatomic location. Accuracy was determined by comparing imaging results with surgical findings. The ability of 2-phase CT to localize adenomas to 1 of 4 neck quadrants and lateralize them to the correct side was assessed. Accuracy of identifying multigland disease was also evaluated.

RESULTS

In patients with single-gland disease, the sensitivity and specificity of 2-phase CT to correctly localize the quadrant were 55.4% and 85.9%, respectively. The sensitivity and specificity of correct lateralization were 78.8% and 67.8%, respectively. The sensitivity and specificity to identify multigland disease were 22.9% and 79.5%, respectively.

CONCLUSIONS

While the 2-phase CT protocol in this study demonstrates lower accuracy compared with reports of other techniques, its lower radiation compared with 3- and 4-phase techniques may make it a feasible alternative for preoperative parathyroid localization. Further prospective studies are needed to identify patients for whom this technique is most suitable.

(99m)Technetium Sestamibi-(123)Iodine Scintigraphy Is More Accurate Than (99m)Technetium Sestamibi Alone before Surgery for Primary Hyperparathyroidism

Objectives. Studies comparing outcome of single-^99mTc-methoxyisobutylisonitrile (^99mTc-sestamibi) and dual-tracer ^99mTc-sestamibi scintigraphy in combination with ¹²³I before primary surgery of primary hyperparathyroidism (PHPT) are scarce. Methods. We compared ^99mTc-sestamibi/¹²³I and ^99mTc-sestamibi in a single-centre retrospective series of 269 PHPT patients. The results were related to laboratory, surgical and histological findings. Results. ^99mTc-sestamibi/¹²³I and ^99mTc-sestamibi were positive in 206 (76.6%) and 111 (41.3%) of 269 patients, respectively (P < 0.001). Accuracies for ^99mTc-sestamibi/¹²³I and ^99mTc-sestamibi were 63.4% and 34.9%, respectively (96% CI, P < 0.001). Prevalence of multiglandular disease was 15.2%. In multiglandular disease, ^99mTc-sestamibi/¹²³I and ^99mTc-sestamibi revealed 43.8 and 22.1% of pathological glands, respectively (P < 0.001). Cure rate was similar for patients with (191/206; 92.7%) and without (59 of 63; 93.7%) a positive ^99mTc-sestamibi/¹²³I finding. Duration of targeted surgery (one or two quadrants) was 21 and 15 minutes shorter than bilateral neck exploration, respectively (both P < 0.001). Higher serum calcium (P = 0.014) and PTH (P = 0.055) concentrations and larger tumours (P < 0.001) characterized the 206 patients with a positive preoperative scan who were cured by removal of a single adenoma. Conclusions. ^99mTc-sestamibi/¹²³I scintigraphy is more accurate than ^99mTc-sestamibi before surgery of PHPT. However, outcome of surgery is not determined by scintigraphy alone.

Dynamic Parathyroid Computed Tomography (4DCT) Facilitates Reoperative Parathyroidectomy and Enables Cure of Missed Hyperplasia

BACKGROUND

Four-dimensional computed tomography (4DCT) is an emerging imaging modality in the evaluation of primary hyperparathyroidism (PHPT). We assessed the role of 4DCT in patients presenting for reoperative parathyroidectomy.

METHODS

A prospective database of patients with persistent or recurrent PHPT undergoing reoperative parathyroidectomy during the years 2006-2014 was analyzed. Patients treated before versus after the advent of 4DCT were compared for operative eligibility, operative success, operative time, and concordance of imaging results with surgical findings.

RESULTS

Ninety patients were included in the study (61 before 4DCT, 29 after 4DCT). The post-4DCT group had a higher rate of surgical concordance with imaging results (63 vs. 90 %, p < 0.01) and shorter operative time (114 vs. 76 min, p < 0.05). The operative success rate was not different (87 vs. 86 %). A similar pattern was observed in the subset of sestamibi-negative patients, with post-4DCT patients having a higher rate of surgical concordance (12 vs. 83 %, p < 0.0001) and shorter operative time (181 vs. 89 min, p < 0.05). Among patients ultimately found to have parathyroid hyperplasia, 4DCT correctly identified multiple enlarged glands in 80 % (4 of 5) and correctly lateralized one or more glands in 100 % (5 of 5) of cases, facilitating successful subtotal parathyroidectomy in the reoperative setting.

CONCLUSIONS

4DCT enables successful and efficient reoperative parathyroidectomy. These benefits extend to difficult cases, including sestamibi-negative patients and those with missed hyperplasia.

A comparative study of pre-operative imaging methods in patients with primary hyperparathyroidism: ultrasonography, 99mTc sestamibi, single photon emission computed tomography, and magnetic resonance imaging

AIM

This study compares the accuracy rates achieved in ultrasonography (US), 99mTc-sestamibi (MIBI), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) as imaging methods used in the pre-operative localization of the enlarged parathyroid glands.

SUBJECTS AND METHODS

For the purposes of this study, US, MIBI, SPECT, and MRI were performed on 98 patients with primary hyperparathyroidism (pHPT). All patients underwent parathyroidectomy.

RESULTS

Pre-operative localization of an abnormal parathyroid gland was successfully performed in 82 of the cases scanned with US (83.7%), while the result was 66 in the cases scanned with MIBI (67.3%), 71 of the cases were successfully localized with SPECT (72.4%), while MRI revealed the diseased gland in only 60 of the total cases (61.2%). In MIBI-positive and -negative patients there was a statistically significant difference among cases in terms of adenoma volume (1.30±1.51 vs 0.58±0.91, p<0.05). Sensitivity, specificity and diagnostic accuracy values were 87.2%, 25.0%, and 83.0%; 70.2%, 50.0%, and 69.4%; 75.5%, 50.0%, and 74.5%; 63.8%, 50.0%, and 63.3% for US, MIBI, SPECT, and MRI, respectively. The respective values for sensitivity, specificity, and diagnostic accuracy were 94.9%, 25.0%, and 91.1% when US was combined with MIBI.

CONCLUSIONS

Combining US and MIBI as imaging methods for pre-operative imaging of pHPT often produces more satisfactory results. While the accuracy of US is relatively low in the ectopic localizations, the size of the lesion can be an important factor in the accuracy achieved with MIBI.

The role of colour Doppler ultrasonography in the preoperative localization of parathyroid adenomas

The aim of the present study was to evaluate the diagnostic accuracy and imaging patterns of colour Doppler ultrasonography (US) and compare it with grayscale US, 99m-Tc methoxyisobutylisonitrile (MIBI) scans, and combined US and MIBI scans in the preoperative diagnosis of parathyroid adenomas in patients with primary hyperparathyroidism (pHPT). From June 2007 to June 2011, 36 consecutive patients (seven men and 29 women) with pHPT underwent grayscale US, colour Doppler ultrasonography (CDUS), and 99m-Tc MIBI scans prior to parathyroidectomy with traditional unilateral neck dissection. All 36 patients with pHPT underwent parathyroidectomy at our university hospital. According to histopathology results, the sensitivity, specificity, and accuracy of MIBI and US scan were 88%, 94%, and 91%, and 70%, 100%, and 85%, respectively. The overall sensitivity and specificity of combined US and MIBI was 97% and 100% respectively. The overall sensitivity, specificity, and accuracy of CDUS in the correct diagnosis of parathyroid adenoma were 97%, 100%, and 98.6%, respectively. The sensitivity and specificity of US in the detection of parathyroid adenoma and differentiating it from other cervical masses reached up to 97% and 100%, respectively, by combining CDUS with grayscale evaluations of parathyroid adenoma.

Localization of Small Parathyroid Adenomas Using Modified 4-Dimensional Computed Tomography/Ultrasound

Objective. To investigate whether parathyroid gland weight has an impact on the accuracy of preoperative localization of parathyroid adenomas with modified 4 dimensional computed tomography/ultrasound. And to determine if the weight of parathyroid adenomas can be calculated accurately based on the dimensions of the gland on the CT images.

Study Design. Case series with chart review.

Setting. Tertiary care hospital.

Subjects and Methods. One hundred forty-two patients who had a preoperative modified 4-dimensional computed tomography/ultrasound and underwent parathyroidectomy for hyperparathyroidism due to a parathyroid adenoma between 1998 and 2009. Charts were reviewed to identify (1) the sensitivity and specificity for localization of parathyroid adenomas according to gland weight and (2) correlation between preoperative estimate of parathyroid weight and the surgical weight of the parathyroid gland.

Results. Modified 4-dimensional computed tomography/ultrasound displayed 92% sensitivity for localizing adenomas weighing <150 mg to the correct side of the neck (95% confidence interval [CI], 65%-99%), 100% sensitivity for glands weighing 150 to 500 mg (95%-100%), and 98% sensitivity for glands weighing >500 mg (92%-100%). For localization to the correct quadrant of the neck, sensitivity was 75% (95% CI, 47%-91%) for glands weighing <150 mg, 89% (79%-95%) for those weighing 150 to 500 mg, and 94% (85%-97%) for glands weighing >500 mg. A positive correlation was seen between the preoperative weight estimate based on imaging and the operative weight of the gland, with a Pearson correlation coefficient of 0.96.

Conclusion. Modified 4-dimensional computed tomography/ultrasound can closely predict the weight of parathyroid glands preoperatively and has good sensitivity for localization of adenomas, even in glands weighing less than 150 mg.

Limitations of Tc99m-MIBI-SPECT imaging scans in persistent primary hyperparathyroidism

Background

In primary hyperparathyroidism (PHPT) the predictive value of technetium 99m sestamibi single emission computed tomography (Tc99m-MIBI-SPECT) for localizing pathological parathyroid glands before a first parathyroidectomy (PTx) is 83–100%. Data are scarce in patients undergoing reoperative parathyroidectomy for persistent hyperparathyroidism. The aim of the present study was to determine the value of Tc99m-MIBI-SPECT in localizing residual hyperactive parathyroid tissue in patients with persistent primary hyperparathyroidism (PHPT) after initial excision of one or more pathological glands.

Method

We retrospectively evaluated the localizing accuracy of Tc99m-MIBI-SPECT scans in 19 consecutive patients with persistent PHPT who had a scan before reoperative parathyroidectomy. We used as controls 23 patients with sporadic PHPT who had a scan before initial surgery.

Results

In patients with persistent PHPT, Tc99m-MIBI-SPECT accurately localized a pathological parathyroid gland in 33% of cases before reoperative parathyroidectomy, compared to 61% before first PTx for sporadic PHPT. The Tc99m-MIBI-SPECT scan accurately localized intra-thyroidal glands in 2 of 7 cases and a mediastinal gland in 1 of 3 cases either before initial or reoperative parathyroidectomy.

Conclusions

Our data suggest that the accuracy of Tc99m-MIBI-SPECT in localizing residual hyperactive glands is significantly lower before reoperative parathyroidectomy for persistent PHPT than before initial surgery for sporadic PHPT. These findings should be taken in consideration in the preoperative workup of patients with persistent primary hyperparathyroidism.

Parathyroid localization with modified 4D-computed tomography and ultrasonography for patients with primary hyperparathyroidism

OBJECTIVES

In this article, we report our decade-long experience in using modified 4D-computed tomography in combination with ultrasonography (Mod 4D-CT/US) to localize abnormal parathyroid glands in patients with primary hyperparathyroidism.

STUDY DESIGN

Retrospective medical record review at a university-based academic medical center.

METHODS

Patients with primary hyperparathyroidism who underwent a Mod 4D-CT/US and parathyroidectomy between January 1998 and May 2009 were included in the study. Results from preoperative localization studies were compared with operative findings, pathologic data, and biochemical measurements to assess the sensitivity and specificity as well as the positive and negative predictive values of Mod 4D-CT/US.

RESULTS

Mod 4D-CT/US demonstrated 94% sensitivity and 96% specificity when these imaging studies were used to lateralize the hyperfunctioning parathyroid glands to one side of the neck. In regard to localizing abnormal parathyroid glands to a specific quadrant of the neck (i.e., right-left; superior-inferior), the sensitivity and specificity of Mod 4D-CT/US was 82% and 93%, respectively. Mod 4D-CT/US had a 92% positive predictive value for single-gland disease and 75% for multigland disease. The negative predictive value for single and multigland disease (MGD) were 73% and 92%, respectively.

CONCLUSIONS

Mod 4D-CT/US provides excellent sensitivity and specificity in terms of localizing abnormal parathyroid glands to the correct side and quadrant in patients with primary hyperparathyroidism, and it correctly identifies many patients with MGD.

The role of selective venous sampling in the management of persistent hyperparathyroidism revisited

INTRODUCTION

Localization studies are mandatory prior to revision surgery in patients with persistent hyperparathyroidism in order to improve surgical outcome and reduce the risk of lengthy explorations. However, in this case, noninvasive localization studies are reported to have a poor sensitivity. The aim of our study is to determine the accuracy of selective venous sampling (SVS) for parathyroid hormone (PTH) in localizing residual hyperactive parathyroid glands in patients with persistent or recurrent hyperparathyroidism.

PATIENTS AND METHODS

We retrospectively evaluated the localizing accuracy of 20 PTH SVS performed prior to revision surgery in 18 patients with persistent or recurrent primary hyperparathyroidism (n=11) or autonomous (tertiary) hyperparathyroidism (n=7). Tc99m-methoxy-isobutyle-isonitrile (MIBI)-single photon emission computed tomography (SPECT) was also performed in all patients prior to revision surgery. Operative and pathological data were obtained from hospital records.

RESULTS

The SVS was able to accurately localize 15 of the 20 pathological glands removed at revision surgery, representing a sensitivity of 75%. This sensitivity is significantly higher than that of Tc99m-MIBI-SPECT, which was only 30% (P=0.012).

CONCLUSION

Our findings demonstrate that SVS is a valuable localization study in patients with persistent or recurrent hyperparathyroidism, with a sensitivity significantly higher than that of Tc99m-MIBI-SPECT. Our data suggest that SVS represents a useful addition to the preoperative workup of these patients prior to revision surgery.

Surgical treatment of mediastinal parathyroid adenoma: rationale for intraoperative parathyroid hormone monitoring

BACKGROUND

Recent publications have recommended parathyroidectomy guided solely by preoperative imaging. However, when the parathyroid adenoma is located deep in the mediastinum, the surgeon often encounters difficulties to localize and completely remove all hyperfunctioning parathyroid tissues. Thus, we hypothesized that patients with mediastinal adenoma differ substantially from cervical cases and require a specific strategy. The aim of this study was to evaluate the efficacy of intraoperative serum parathyroid hormone monitoring (ioPTH) used to guide completeness of targeted mediastinal parathyroidectomy.

METHODS

In a 10-year period, 33 patients underwent targeted mediastinal parathyroidectomy with ioPTH for primary sporadic hyperparathyroidism. A greater than 50% drop in ioPTH was considered confirming successful resection. If ioPTH failed to decline adequately, the operation was extended to complete cervical exploration. We analyzed the impact of ioPTH on the final surgical outcome.

RESULTS

In 26 patients the adenoma was correctly identified and removed at targeted mediastinal parathyroidectomy. In 7 patients lack of adequate ioPTH drop after targeted mediastinal parathyroidectomy triggered continued exploration, providing success at complete cervical exploration in 6 patients. In 1 patient this strategy failed owing to an undiagnosed lesion in the posterior mediastinum. Use of ioPTH decreased the failure rate from a potential 21.2% without ioPTH to 3% in the actual series.

CONCLUSIONS

Mediastinal parathyroid adenoma represents a distinct subset of primary hyperparathyroidism and requires a specific diagnostic and therapeutic approach. In these cases ioPTH monitoring is a reliable and effective method to confirm curative resection. It is an important adjunct predictor of postoperative successful outcome, which allows a low failure rate and avoids unnecessary reoperations.

Beneficial effect of endocrinologist-performed ultrasonography on preoperative parathyroid adenoma localization

OBJECTIVE

To evaluate whether endocrinologist-performed ultrasonography improves the localization of parathyroid adenomas in patients with primary hyperparathyroidism.

METHODS

We performed a retrospective analysis of consecutive patients with primary hyperparathyroidism due to a single adenoma who underwent surgery at the Dokuz Eylul University Hospital in Izmir, Turkey, between January 2000 and January 2008. Data regarding the localization of adenomas were obtained from surgical reports. Neck ultrasonography was performed in all patients as first-line imaging. Parathyroid ultrasonography was performed by a staff radiologist between January 2000 and December 2004. Beginning January 2005, parathyroid ultrasonography was performed blindly by an endocrinologist in addition to the staff radiologist. In the case of discordant preoperative localization between the endocrinologist- and radiologist-performed ultrasonography, surgery was performed according to the technetium Tc 99m sestamibi (MIBI) scan and endocrinologist-performed ultrasonography localization results.

RESULTS

A total of 156 patients with primary hyperparathyroidism due to a single adenoma were included. Of the 156 patients, 139 also underwent MIBI scan. Ultrasonography localized 102 parathyroid adenomas (65%). The accuracy of the ultrasonography was improved in patients who underwent endocrinologist-performed ultrasonography. Endocrinologist-performed ultrasonography localized the adenoma correctly in 19 patients for whom the staff radiologist had reported a negative or unsuccessful localization. When ultrasonography results were combined with the MIBI scan findings, parathyroid adenomas were again more likely to be localized in patients who underwent operation after January 2005 and thus had endocrinologist-performed ultrasonography.

CONCLUSION

Our results suggest that endocrinologist-performed ultrasonography improves the preoperative localization of parathyroid adenoma.

Localization of parathyroid adenomas by sonography and technetium tc 99m sestamibi single-photon emission computed tomography before minimally invasive parathyroidectomy: are both studies really needed?

OBJECTIVE

The purpose of this study was to determine the utility of radiologist-performed sonography as the principal modality for parathyroid localization before minimally invasive parathyroidectomy.

METHODS

Both sonography and technetium Tc 99m sestamibi single-photon emission computed tomography (SPECT) are commonly performed during imaging evaluation of patients with primary hyperparathyroidism (HPTH). Sonographic examinations ordered during the study period were performed by 1 author (M.E.T.), and results were immediately reported. Findings of a subsequent Tc 99m sestamibi study were recorded blinded to the sonographic results. The sensitivity and specificity of sonography and Tc 99m sestamibi SPECT were assessed with the use of surgery and pathology reports as a reference standard. The 2007 global Medicare reimbursement rates were used to assess the costs of preoperative localization.

RESULTS

Parathyroidectomy was performed in 144 of 172 patients evaluated by both modalities. The sensitivity, specificity, and positive predictive value of sonography for identifying abnormal parathyroid glands were 74%, 96%, and 90%, respectively. Sonography correctly localized a single adenoma or suggested multiglandular disease in 112 of 144 patients (78%). The sensitivity, specificity, and positive predictive value of SPECT were 58%, 96%, and 89%. Technetium 99m sestamibi SPECT correctly predicted an adenoma or multiglandular disease in 88 of 144 patients (61%). Five patients with negative sonographic findings were shown to have uniglandular disease on Tc 99m sestamibi SPECT. Selective use of Tc 99m sestamibi SPECT (ie, when sonographic findings were negative or equivocal) would have decreased the cost of imaging by 53%.

CONCLUSIONS

Radiologist-performed sonography may potentially be used as a principal imaging modality for patients with HPTH. Selective use of Tc 99m sestamibi in cases with negative or equivocal sonographic findings can decrease the cost of imaging before parathyroid resection considerably.

Focused approach to parathyroidectomy

Minimally invasive parathyroidectomy is performed after preoperative parathyroid localization-usually with high-quality sestamibi scans and/or ultrasonography-often under cervical block anesthesia during which a limited exploration is performed. The rapid intraoperative parathyroid hormone assay is then employed to confirm an adequate resection and cure of primary hyperparathyroidism. This article discusses imaging, anesthesia, results, and the surgical management of patients undergoing minimally invasive parathyroidectomy.

Parathyroid exploration in the reoperative neck: improved preoperative localization with 4D-computed tomography

BACKGROUND

Reoperation for hyperparathyroidism (HPT) carries an increased risk for morbidity and failure to cure. Accurate preoperative localization minimizes operative risk but is often difficult to achieve in the reoperative setting. Four-dimensional computed tomography (4D-CT) is an emerging technique that uses functional parathyroid anatomy for precise preoperative localization. We evaluated 4D-CT as a tool for localization of hyperfunctioning parathyroid tissue in the reoperative setting.

STUDY DESIGN

A prospective endocrine database was queried to identify 45 patients who underwent reoperative parathyroidectomy after preoperative localization using 4D-CT. The patients were categorized into 1 of 3 groups: group 1 included those who had previous neck surgery for non-HPT conditions; group 2 included those who had undergone a previously unsuccessful neck exploration for HPT; and group 3 included patients with HPT who had a previous neck exploration with resection of at least 1 hypercellular parathyroid.

RESULTS

The sensitivity of 4D-CT for localization was 88% compared with 54% for sestamibi imaging. Four-dimensional CT more often correctly localized (p=0.0003) and lateralized (p=0.005) hyperfunctional parathyroid tissue than sestamibi did. Four-dimensional CT successfully localized hyperfunctional parathyroid tissue in 18 (82%) of 22 group 1 patients, 10 (91%) of 11 group 2 patients, and 8 (67%) of 12 group 3 patients. Three patients were lost to followup. At a mean followup of 9.8 months, 39 (93%) of 42 patients were surgically cured and 3 patients (7%; 2 in group 3) had persistent HPT.

CONCLUSIONS

Four-dimensional-CT is an ideal tool for preoperative localization of hyperfunctioning parathyroid tissue in the reoperative setting. Localization and successful reoperation are most difficult in patients who have undergone an earlier operation that included resection of at least one hypercellular parathyroid suggesting multigland disease.

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.

Optimizing preoperative imaging in primary hyperparathyroidism

BACKGROUND

Scintigraphy of the hyperfunctioning parathyroid glands using technetium 99m ((99m)Tc)-methoxyisobutylisonitrile ((99m)Tc-MIBI) is an established and highly sensitive preoperative localization tool whose importance has been further increased by advances in minimally invasive surgery . The goal of the present prospective study was to determine the benefit of optimized imaging in a consistent patient population.

METHODS

Eighty-four patients with first presentations of primary hyperparathyroidism were investigated with (99m)Tc-MIBI scintigraphy, thyroid scintigraphy, and cervical ultrasonography. The evaluation algorithm consisted of (a) evaluation of the planar images alone, (b) additional evaluation of single-photon emission computed tomography (SPECT), (c) additional evaluation of thyroid gland scintigraphy, and (d) additional evaluation of ultrasound. All patients subsequently underwent parathyroidectomy. The intraoperative and the histologic findings were correlated with the results of the scintigraphic imaging.

RESULTS

The sensitivity of planar parathyroid scintigraphy was 74% and could be increased to 91% by the additional investigations. The difference was statistically significant (p<0.05). At the same time, a small increase in specificity from 96% to 99% was seen.

CONCLUSIONS

Prior to minimally invasive treatment of hyperparathyroidism, we recommend combined localization studies consisting of sequential (99m)Tc-MIBI scintigraphy, additional SPECT plus thyroid gland scintigraphy, plus high-resolution cervical ultrasonography.

Sensitivity and Utility of Parathyroid Scintigraphy in Patients with Primary Versus Secondary and Tertiary Hyperparathyroidism

INTRODUCTION

Parathyroid scintigraphy (PS) may be used to localize hyperactive parathyroid glands preoperatively. Performance of PS in the setting of secondary and tertiary hyperparathyroidism (HPT) is not well quantified. The performance of PS in secondary/tertiary HPT versus primary HPT may reflect physiologic as well as radiopharmaceutical kinetic differences between multigland hyperplasia versus adenoma. The aim of this study was to review the performance of PS in secondary/tertiary HPT with a comparison to that for primary HPT. Moreover, we evaluated (1) the sensitivity of PS in detecting enlarged glands, and (2) PS detectability as a function of gland weight.

METHODS

We performed a retrospective review of the Mayo Clinic database from 2000 to 2004. We identified 40 patients with secondary or tertiary HPT as well as a matched control group of 40 patients with primary HPT who had had preoperative PS and underwent parathyroid surgery.

RESULTS

Parathyroid scintigraphy correctly localized all enlarged glands in 88% of patients in the primary HPT group. PS correctly identified both the number and locations of all hyperplastic glands in only 28% of the secondary/tertiary HPT patients. PS failed to identify one enlarged gland in 23% of the patients and two or more enlarged glands in 40% of the patients. PS correctly detects the largest gland in 88% of the patients with secondary and tertiary HPT. The mean gland weight detectable by PS was 612 +/- 120 mg for primary HPT. In secondary/tertiary HPT, glands detected by PS had a mean weight of 950 +/- 109 mg, whereas the mean weight was 276 +/- 34 mg for undetected glands (P < 0.002).

CONCLUSIONS

Parathyroid scintigraphy is a sensitive study for localizing parathyroid glands preoperatively in primary HPT patients. Its sensitivity is low in secondary and tertiary HPT patients. Thus PS has limited value as a preoperative localization study in secondary/tertiary HPT patients.

Randomized clinical trial comparing scan-directed unilateral versus bilateral cervical exploration for primary hyperparathyroidism due to solitary adenoma

Background

It was shown in a previous retrospective study that scan-directed unilateral cervical exploration for primary hyperparathyroidism (HPT) can be carried out without an increase in the incidence of persistent or recurrent hypercalcaemia. This randomized clinical trial was conducted to test the hypothesis that focused unilateral operation leaves the patient no more vulnerable to persistent HPT than standard bilateral neck exploration.

Methods

Patients with HPT routinely underwent preoperative dual-isotope subtraction scintigraphy in an attempt to localize the presumed solitary parathyroid adenoma. Individuals with a positive scan (one residual focus of activity following subtraction) were deemed suitable for focused unilateral cervical exploration. At operation, if a single tumour was identified at the site suggested by the scan, the patient was randomized to unilateral or bilateral neck exploration.

Results

Between April 1998 and December 2003, 190 patients underwent first-time cervical exploration for HPT. Of these, 100 qualified for randomization. Fifty-four patients were randomized to unilateral neck exploration and 46 to bilateral operation. All 100 patients were cured following operation, as assessed by return of the serum calcium level to normal. Two patients randomized to bilateral exploration were found to have an unsuspected additional enlarged parathyroid on the contralateral side.

Conclusion

Scan-directed unilateral cervical exploration for HPT does not significantly increase the incidence of persistent hypercalcaemia compared with standard bilateral operation.

Hyperparathyroidism but a negative sestamibi scan: a clinical dilemma

BACKGROUND

The outcomes of patients with biochemically confirmed hyperparathyroidism but a negative Tc-99 Sestamibi scan are unclear. We examined the outcomes and quality of life of patients having surgery and those who had medical therapy.

METHODS

Patients having a diagnosis of hyperparathyroidism with confirmed elevated calcium and parathormone levels, yet negative sestamibi scans were identified. The RAND SF-36 Health Survey was administered via mail to these patients. The patient's charts were then reviewed to verify treatments and to determine outcomes.

RESULTS

Ninety-five patients fitting the criteria were identified. Twenty patients completed all aspects of the study. Ten of the respondents had undergone parathyroidectomy, and 10 had not. The surgical patients scored more favorably in all 8 of the measured parameters than patients treated medically. The differences in 3 domains, physical functioning, pain, and social functioning, were statistically significant.

CONCLUSIONS

Our findings suggest that surgical therapy confers a better quality of life and is superior to medical therapy in the treatment of primary hyperparathyroidism, even in patients having a negative sestamibi scan.

A systematic review of the diagnosis and treatment of primary hyperparathyroidism from 1995 to 2003

OBJECTIVE

To systematically review the current preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism.

STUDY DESIGN

A systematic literature review.

RESULTS

Of the 20,225 cases of primary hyperparathyroidism reported, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and parathyroid carcinomas (CAR) occurred in 88.90%, 5.74%, 4.14%, and 0.74% of cases respectively. Tc 99m -sestamibi and ultrasound were 88.44% and 78.55% sensitive, respectively, for SA, 44.46% and 34.86% for MGHD, and 29.95% and 16.20% for DA, respectively. Postoperative normocalcemia was achieved in 96.66%, 95.25%, and 97.69% of patients offered minimally invasive radio-guided parathyroidectomy (MIRP), unilateral, and bilateral neck exploration (BNE). Intraoperative PTH assays (IOPTH) were helpful in approximately 60% of bilateral neck exploration conversion (BNEC) surgeries.

CONCLUSION

The overall prevalence of multiple gland disease (MGD and DA) was lower than often suggested by conventional wisdom. Furthermore, preoperative imaging was less accurate than it is often perceived for accurately imaging MGD. MIRP and UNE were more successful in achieving normocalcemia than is typically quoted. IOPTH was a helpful but not "fool-proof" adjunct in parathyroid exploration surgery.

SIGNIFICANCE

These results support a greater role for the treatment of primary hyperparathyroidism using less invasive approaches. EMB rating: B-3.

Thyroid evaluation in patients with primary hyperparathyroidism

We evaluated the efficacy of preoperative high-resolution ultrasonography (US) for diagnosing possible concomitant thyroid disease which affects the surgical management in patients with primary hyperparathyroidism (pHPT). One hundred and nine patients with sporadic pHPT underwent US with or without ultrasound-guided fine-needle aspiration biopsy (US-FNAB). Diagnosis of concomitant thyroid nodules by US and US-FNAB were compared with the histopathological findings. Of the 109 patients, 19 (17.4%) had malignant thyroid nodules, 26 (23.9%) had benign thyroid nodules alone, and 12 (11.0%) had diffuse goiter. The sensitivity, specificity, and accuracy of diagnosing 72 thyroid nodules were 91.3%, 91.8%, and 91.7% for US, 57.9%, 94.3%, and 81.5% for US-FNAB, and 95.7%, 91.8%, and 93.1% for combined US and US-FNAB, respectively. True positive/false negative ratio of US-FNAB diagnosis was significantly lower in nodules of 5-9 mm than nodules of 10 mm or more. Four unexpected thyroid cancers existed at a different site in 3 of the 39 patients with palpable thyroid disease. Five thyroid cancers were histopathologically confirmed in 5 (7.1%) of 70 patients without palpable thyroid disease. Eight (88.9%) of the 9 non-palpable thyroid cancers were accurately diagnosed by combined US and US-FNAB. Preoperative US is useful for evaluation of possible concomitant thyroid disease, especially for prediction of malignancy.

Sestamibi scan-directed parathyroid surgery: potentially high failure rate without measurement of intraoperative parathyroid hormone

The present study evaluated sestamibi scan-directed parathyroidectomy with intraoperative parathyroid hormone (PTH) assessment (ioPTH). The preoperative sestamibi scintigraphies were compared with the intraoperative findings for 103 patients undergoing first exploration for sporadic primary hyperparathyroidism (pHPT). Data were collected prospectively. Ninety-nine patients (96%) were cured. Patients with persistent pHPT (n = 4) all had an incorrect scintigram as well as an insufficient decline of ioPTH. At operation, 90 patients (87%) had solitary parathyroid adenoma; 12 patients had multiglandular disease. In one patient no enlarged parathyroid gland was found. Overall 77 of 118 abnormal glands (65%) were correctly identified by sestamibi scintigraphy. The sensitivity for localizing a single parathyroid adenoma was 80%. Patients with incorrect scintigrams had a higher proportion of upper pole adenomas than patients with correct scans. High glandular weight and high level of serum PTH were important factors for detectability. Sestamibi scintigraphy did not predict multiglandular disease. However, the use of ioPTH identified 8 of the 9 patients with a positive scan (a solitary focus) and multiglandular disease. In contrast, false-negative ioPTH led to four unnecessary bilateral explorations in the 63 patients with a scan-identified adenoma. With the help of ioPTH, a focused parathyroidectomy was accomplished in 43% of scan-negative patients with a solitary adenoma. In conclusion, sestamibi scintigraphy is an acceptable method for localizing a solitary parathyroid adenoma. However, the technique alone does not reliably predict multiglandular disease. Potentially the failure rate in scan-directed parathyroidectomy could increase, with up to 10% of patients without ioPTH.

Imaging for primary hyperparathyroidism--what beginners should know

For patients with primary hyperparathyroidism surgical removal of the hyperfunctioning parathyroid gland is curative. With advances in minimally invasive surgery, accurate pre-operative localization of the hyperfunctioning parathyroid tissue is essential to aid successful surgical treatment. The onus of identifying this hyperfunctioning parathyroid tissue therefore falls on imaging techniques such as high-resolution ultrasound, radionuclide imaging, computed tomography and magnetic resonance imaging. This article is not an exhaustive review, and its main aim is to familiarize the general radiologist, trainee radiologists and clinicians with the basics of various imaging techniques and their roles in practical management of patients with primary hyperparathyroidism.

Unilateral neck exploration for primary hyperparathyroidism

Focused unilateral cervical exploration is a controversial alternative to conventional bilateral neck exploration for primary hyperparathyroidism (HPT) due to solitary adenoma. Development of preoperative localization techniques, notably isotope scintigraphy and small-part, real-time ultrasonography, has increased preoperative parathyroid tumor identification. Critics of scan directed unilateral neck exploration argue it may overlook enlarged parathyroid glands on the unexplored side, increasing the incidence of persistent and recurrent hypercalcemia. Our experience of this operation and prolonged follow-up of patients, however, confirm that it does not increase risk of persistent or recurrent HPT if a strict selection protocol is observed. This ensures the confident further development of minimally invasive surgical procedures for HPT based on the principle of a focused exploration following preoperative localization of the parathyroid adenoma.

Current issues in hyperparathyroidism

There has been a shift in the referral patterns in recent years that has resulted in increasing numbers of patients being referred to surgeons with a diagnosis of hypercalcemia rather than primary hyperparathyroidism. The surgeon must perform a thorough history, including medications, and laboratory assessment, including serum calcium and parathyroid hormone measurements. A 24-hour urinary calcium excretion should be routinely ordered to exclude FHH. After the diagnosis of primary hyperparathyroidism is made, preoperative localization studies will benefit 78% to 90% of patients, with sestamibi scan being the most commonly used.