Pre-operative localisation in primary hyperparathyroidism

OUP accepted manuscript

Chronic kidney disease mineral and bone disorder may persist after successful kidney transplantation. Persistent hyperparathyroidism has been identified in up to 80% of patients throughout the first year after kidney transplantation. International guidelines lack strict recommendations about the management of persistent hyperparathyroidism. However, it is associated with adverse graft and patient outcomes, including higher fracture risk and an increased risk of all-cause mortality and allograft loss. Secondary hyperparathyroidism may be treated medically (vitamin D, phosphate binders and calcimimetics) or surgically (parathyroidectomy). Guideline recommendations suggest medical therapy first but do not clarify optimal parathyroid hormone targets or indications and timing of parathyroidectomy. There are no clear guidelines or long-term studies about the impact of hyperparathyroidism therapy. Parathyroidectomy is more effective than medical treatment, although it is associated with increased short-term risks. Ideally parathyroidectomy should be performed before kidney transplantation to prevent persistent hyperparathyroidism and improve graft outcomes. We now propose a roadmap for the management of secondary hyperparathyroidism in patients eligible for kidney transplantation that includes the indications and timing (pre- or post-kidney transplantation) of parathyroidectomy, the evaluation of parathyroid gland size and the integration of parathyroid gland size in the decision-making process by a multidisciplinary team of nephrologists, radiologists and surgeons.

[Preoperative diagnostic value of 99mTc- MIBI SPECT/CT imaging combined with semiquantitative analysis in hyperparathyroidism and factors affecting its efficacy]

OBJECTIVE

To evaluate the diagnostic efficacy of technetium-99m methoxyisobutylisonitrile single photon emission/ computed tomography (^99mTc- MIBI SPECT/CT), ^99mTc- MIBI double- phase scintigraphy (DPS) DPS and ultrasound (US) in preoperative localization of hyperparathyroidism (HPT) and explore the factors affecting the diagnostic efficacy of ^99mTc-MIBI SPECT/CT.

METHODS

We retrospectively analyzed the data of 104 patients with HPT undergoing surgical resection between January, 2015 and July, 2019. Preoperative ^99mTc-MIBI imaging was performed in all the patients, and 82 patients also received US examination preoperatively. Semi-quantitative analysis was used to draw the region of interest and calculate the lesion/ ipsilateral deltoid muscle (T/NT) uptake ratio. The sensitivity and detection performance of ^99mTc-MIBI SPECT/CT, DPS and US in the diagnosis of HPT patients were compared, and the correlations of the T/NT ratios of parathyroid adenoma (PA) and parathyroid hyperplasia (PH) with the expression levels of COX-2 and Bcl-2 were analyzed.

RESULTS

The diagnostic sensitivity of ^99mTc- MIBI SPECT/CT, DPS and US for HPT was 95.19% (99/104), 91.3% (95/104) and 81.71% (67/82), respectively, demonstrating a significantly higher diagnostic sensitivity of ^99mTc-MIBI SPECT/CT than US (χ²=9.59, P=0.008). For PH lesions, ^99mTc-MIBI SPECT/CT had the highest diagnostic sensitivity, followed by DPS and then by US (P < 0.05), but their sensitivity did not differ significantly for PA (P>0.05). The T/NT ratio in fatty hyperplastic glands was significantly lower than that in fat-free hyperplastic glands (P=0.009). In PA, Bcl-2 expression was significantly lower in false negative lesions than in true positive lesions (P=0.046), but Cox-2 expression did not show such a difference (P>0.05). In PH lesions, the expressions of Bcl-2 and Cox- 2 did not differ significantly between false negative than true positive lesions (P>0.05).

CONCLUSIONS

^99mTc-MIBI SPECT/CT has a high sensitivity for HPT localization, and the T/NT ratio is positively correlated with the lesion volume. An increased expression of Bcl-2 in PA lesions and a decreased cell fat content in PH lesions can facilitate the detection of HPT glands by ^99mTc-MIBI SPECT/CT.

Effectiveness of the Gamma Probe in Childhood Parathyroidectomy: Retrospective Study

Background There are few reports about parathyroidectomy due to secondary hyperparathyroidism in patients with end-stage renal failure in the literature. We aimed to evaluate the surgical treatment methods and the results of patients who were operated for secondary hyperparathyroidism with end-stage renal disease in our center. Method Sixteen patients with the diagnosis of secondary hyperparathyroidism were treated surgically in our center. Demographical data, laboratory findings, and imagining methods were all examined. The effect of the Technetium 99m methoxyisobutylisonitrile (Tc-99m-MIBI) probe sensitive to gamma rays detection was also evaluated to locate and identify all the parathyroid glands during the operation. Results Eleven of the patients underwent intravenous (IV) Tc-99m MIBI preoperatively and a gamma probe was detected during surgery. The gamma probe was not used in five patients. Four parathyroid glands were removed in eight (72.7%) out of 11 patients with gamma probes and three parathyroid glands were found in three patients. Total parathyroidectomy and parathyroid autoimplantation were made to eight patients who had removed four glands, subtotal parathyroidectomy was done for the other patients. On a comparison of laboratory findings before and after the surgery, there was a significant relationship between the decrease of serum parathyroid hormone and calcium levels (p<0.05). Conclusion Total parathyroidectomy and parathyroid autoimplantation is the most efficient and safe mode of management for secondary parathyroidism patients. During the surgery, using a probe sensitive to gamma rays detection may also help the surgeon. Thus, unnecessary dissections to prevent the presence of atypical parathyroid glands are prevented.

Video-assisted thoracoscopic surgery for ectopic mediastinal parathyroid adenoma

Background

Primary hyperparathyroidism (PHPT), caused by an ectopic mediastinal parathyroid adenoma, is uncommon. In the past, when the adenoma was not accessible from the neck, median sternotomy was advocated for safe and successful parathyroidectomy. Video‐assisted thoracoscopic surgical (VATS) parathyroidectomy represents a modern alternative approach to this problem.

Methods

Information on patients undergoing VATS was obtained from a specific database, including clinical presentation, biochemistry, preoperative imaging, surgical approach and patient outcomes. A comprehensive literature review was undertaken to draw comparisons with other publications.

Results

Over a 2‐year period, nine patients underwent VATS parathyroidectomy for sporadic PHPT. Five patients had persistent PHPT following previous unsuccessful parathyroidectomy via cervicotomy, and four had had no previous parathyroid surgery. The median duration of surgery was 90 (range 60–160) min. Eight patients were cured biochemically, with no major complications. One patient required conversion to a median sternotomy for removal of a thymoma that had resulted in false‐positive preoperative imaging.

Conclusion

With appropriate preoperative imaging, multidisciplinary input and expertise, VATS parathyroidectomy is an effective, safe and well tolerated approach to ectopic mediastinal parathyroid adenoma.

Accuracy of Neck Ultrasonography in Predicting the Size and Location of Parathyroid Adenomas

OBJECTIVES

Ultrasonography (US) is a reliable tool for the preoperative localization of parathyroid adenomas (PTAs). The aim of this study was to evaluate the accuracy of US for estimating both the size and the location of PTAs and the effect of operator expertise.

STUDY DESIGN

Retrospective cohort study.

SETTING

A single tertiary medical center.

SUBJECTS AND METHODS

All patients who underwent parathyroidectomy for primary hyperparathyroidism between 1996 and 2012 were included. The estimated PTA localization and size by preoperative ultrasound were compared with the intraoperative findings and pathology report.

RESULTS

The cohort included 410 patients. US correctly localized the adenoma in 76% of cases with a sensitivity of 76.2% and a positive predictive value of 86.8%. Measurements were least accurate for adenomas measuring <1 cm in diameter (24%). Scans made by a single senior operator specializing in the neck had a higher accuracy rate than scans made by multiple operators, with a significant difference for small adenomas ( P < .001).

CONCLUSIONS

US is an accurate and sensitive tool for evaluating PTA size and location. Neck US is less accurate for small adenomas (<1 cm). In these cases particularly, the experience and expertise of the US operator may play an important role.

A rural perspective on minimally invasive parathyroidectomy: optimal preoperative imaging and patient outcomes

BACKGROUND

Our retrospective review of prospectively collected data evaluated the efficacy of minimally invasive parathyroidectomy (MIP) and compared preoperative imaging modalities in a rural referral centre.

METHODS

Patients with a diagnosis of primary hyperparathyroidism underwent surgeon-performed ultrasound (SUS) and technetium-99 m sestamibi (MIBI). Radiologist-performed ultrasound (RUS) was sought when the diagnosis remained in doubt. Four-dimensional computed tomography (4DCT) first replaced RUS in mid-2014, then MIBI as a frontline modality in 2015. MIP was conducted if possible and bilateral neck exploration (BNE) when localization remained doubtful. Treatment was evaluated by histopathology and serum parathyroid hormone and calcium levels at 6 weeks.

RESULTS

A total of 122 of 165 (73.9%) glands were removed by MIP and 43 of 165 (26.1%) by BNE. Of 15 cases with non-localizing preoperative investigations, one patient had a negative BNE. A total of 160 of 165 (97.0%) patients underwent a successful operation, with five (3.0%) suffering persistent post-operative hypercalcaemia. SUS had a sensitivity of 79.4% (131/165) and a positive predictive value (PPV) of 97.0% (131/135). MIBI had a sensitivity of 60.0% (81/135) and a PPV of 95.3% (81/85). RUS produced a sensitivity of 65.5% (76/116) and PPV of 98.7% (76/77). When used as a second-line modality, 4DCT had a sensitivity of 76.9% (10/13) and PPV of 100%. The sensitivity and PPV were 85.7% (18/21) and 94.7% (18/19) after 4DCT's promotion to first-line use.

CONCLUSION

MIP can be safely performed in rural centres of adequate volume. We recommend that operations be guided by SUS with routine use of an adjunctive modality. Our study has seen 4DCT replace MIBI in this regard.

ROLE OF IMAGING TESTS FOR PREOPERATIVE LOCATION OF PATHOLOGIC PARATHYROID TISSUE IN PATIENTS WITH PRIMARY HYPERPARATHYROIDISM

OBJECTIVE

Primary hyperparathyroidism (PHPT) can be cured by parathyroidectomy, and the preoperative location of enlarged pathologic parathyroid glands is determined by imaging studies, especially cervical ultrasonography and scintigraphy scanning. The aim of this retrospective study was to evaluate the use of preoperative cervical ultrasonography and/or parathyroid scintigraphy in locating pathologic parathyroid tissue in a group of patients with PHPT followed in the same endocrine center.

METHODS

We examined the records of 61 patients who had undergone parathyroidectomy for PHPT following (99m)Tc-sestamibi scintigraphy scan and/or cervical ultrasonography. Scintigraphic and ultrasonographic findings were compared to histopathologic results of the surgical specimens.

RESULTS

Ultrasonography detected enlarged parathyroid glands in 87% (48/55) of patients with PHPT and (99m)Tc-sestamibi scintigraphy in 79% (37/47) of the cases. Ultrasonography was able to correctly predict the surgical findings in 75% (41/55) of patients and scintigraphy in 72% (34/47). Of 7 patients who had negative ultrasonography, scintigraphy correctly predicted the surgical results in 2 (29%). Of 10 patients who had negative scintigraphy, ultrasonography correctly predicted the surgical results in 4 (40%). When we analyzed only patients with solitary eutopic parathyroid adenomas, the predictive positive values of ultrasonography and scintigraphy were 90% and 86%, respectively.

CONCLUSION

Cervical ultrasonography had a higher likelihood of a correct positive test and a greater predictive positive value for solitary adenoma compared to (99m)Tc-sestamibi and should be used as the first diagnostic tool for preoperative localization of affected parathyroid glands in PHPT.

ABBREVIATIONS

Ca = calcium IEDE = Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione PHPT = primary hyperparathyroidism PTH = parathyroid hormone.

Comparison of Tc-99m pertechnetate images with dual-phase Tc 99m MIBI and SPECT images in primary hyperparathyroidism

BACKGROUND

The purpose of this study was to evaluate the value of Tc-99m pertechnetate planar, dual-phase MIBI and MIBI-SPECT images in the determination and localization of parathyroid lesions.

MATERIALS AND METHODS

In this study, 38 patients who underwent operation for primary hyperparathyroidism were included. Tc-99m pertechnetate planar-pinhole imaging of the neck and then MIBI planar and SPECT images in supine position was performed. Late SPECT images were acquired 120 minutes after the injection. Early and late MIBI images were quantitatively evaluated.

RESULTS

Of the 38 patients, 30 of them had adenoma, 2 patients had hyperplasia and 6 of them were normal on planar images. Thirty-four of 38 patients were positive on SPECT images. SPECT images of the patients with positive results were matched with pathology results.

CONCLUSION

As a result, Tc-99m pertechnetate planar-pinhole, Tc-99m MIBI planar and SPECT images are useful for localization of parathyroid lesions especially in multinodular thyroid gland. However, US or CT images are necessary for more accurate localization and Tc-99m pertechnetate images are useful for interpreting and comparing with the early and late MIBI images.

Strategy of operative treatment of hyperparathyroidism using US scan and (99m)Tc-MIBI SPECT/CT

We evaluated the efficacy of technetium-sestamibi ((99m) Tc-MIBI) SPECT/CT for planning parathyroidectomy in cases with primary hyperparathyroidism (pHPT), comparing with planar scintigraphy and ultrasound (US), in an aim to establish the proper surgical strategy according to the preoperative imaging studies. A retrospective review of consecutive 75 pHPT patients who had been operated on was conducted. The results of preoperative imaging modalities and the operative finding were analyzed. Seven cases were found to have multiple hyperplastic glands, and no responsible gland was found in three cases. Four cases underwent only US scan for preoperative imaging. Remaining 61 cases were found to have single adenoma, and were included in the evaluation of localization imaging. US scan, (99m) Tc-MIBI planar scan and (99m) Tc-MIBI SPECT/CT showed accurate localization in 77.0% (47/61), 75.4% (46/61) and 88.5% (46/52) of the evaluable cases, respectively. US and (99m) Tc-MIBI planar scan demonstrated consistent result in 42 cases (68.9%), and those cases showed accurate localization in 90.5% (38/42). When both US and (99m) Tc-MIBI SPECT/CT was consistent, all 37 lesions had been correctly indicated. No clinico-pathological features were suggested to influence in demonstrating the localization, other than only (99m) Tc-MIBI SPECT/CT exhibited 100% sensitivity in ectopic glands. Combination of US and (99m) Tc-MIBI SPECT/CT certainly contributes to the planning of minimally invasive operation in cases with pHPT by indicating correct localization of single adenoma.

Causes of discordant or negative ultrasound of parathyroid glands in treatment naïve patients with primary hyperparathyroidism

OBJECTIVES

To describe causes of discordant or negative parathyroid ultrasound and to assess factors influencing them.

MATERIALS AND METHODS

Retrospective review of patients who underwent parathyroidectomy between 2000 and 2012 was done. Imaging findings were compared with operative findings and pathology to identify discrepant (n=60; 32 negative, 28 incorrect) parathyroid ultrasounds.

RESULTS

Fifty (83.3%) patients had parathyroid adenoma, of which 10 (16.6%) were ectopic and three were double adenomas; 8 (13.3%) had multigland hyperplasia and two had parathyroid carcinoma. Discrepant reports were due to incorrect localisation in 8 (13.3%); difficulty in differentiating thyroid from parathyroid lesion in 12 (20%); large and small size in two and three patients, respectively; overcall in 5 (8.3%) and satisfaction of search in 7 (11.7%) patients. There was significant correlation between presence of multi-nodular goitre and incorrect reports (χ(2)=4.112, p=0.04). Experience of ultrasound operators performing initial and second look ultrasound was significantly different (p<0.0001). Second look ultrasound was concordant with surgical findings in 39(65%) patients; 21 (66%) patients with initially negative ultrasound and four out of five extra-mediastinal ectopic lesions. Ten patients with negative initial ultrasound had elongated parathyroid lesion. Scintigraphy was concordant in 44 (73.3%) patients and nine were ectopic.

CONCLUSION

Second look ultrasound performed by experienced operator for negative or discordant initial ultrasound of parathyroid is a useful strategy which will improve the accuracy of parathyroid ultrasound. Being able to differentiate thyroid from parathyroid lesion is a factor which will influence performance of parathyroid ultrasound.

Efficacy of ⁹⁹mTc-sestamibi SPECT/CT for minimally invasive parathyroidectomy: comparative study with ⁹⁹mTc-sestamibi scintigraphy, SPECT, US and CT

PURPOSE

We evaluated the efficacy of (99m)Tc-sestamibi SPECT/CT for planning minimally invasive parathyroidectomy (MIP), comparing with dual phase (99m)Tc-sestamibi scintigraphy, (99m)Tc-sestamibi SPECT and conventional imaging (US and CT).

METHODS

Thirty-one patients (M:F = 10:21, range 35-78 years old) who showed high serum parathyroid hormone (intact PTH) level were included. (99m)Tc-sestamibi scintigraphy was performed 15 and 150 min after injection of (99m)Tc-sestamibi (555 MBq), and (99m)Tc-sestamibi SPECT/CT was obtained just after the delayed scan. Comparison study between imaging modalities was done by patient-based and lesion location-based analysis. The location of the lesion was confirmed by the operative finding. An operation was performed in 24 patients. Seven patients had normal (99m)Tc-sestamibi SPECT/CT, and followed for more than 6 months after SPECT/CT.

RESULTS

Among 24 patients, parathyroid adenoma was detected in 19 patients and the other 5 had parathyroid hyperplasia (total 35 lesions). (99m)Tc-sestamibi scintigraphy detected abnormal uptake in 15 patients with 24 lesions. Conventional imaging identified abnormal findings in 17 patients with 27 lesions. SPECT detected abnormal findings in 18 patients with 27 lesions. SPECT/CT identified abnormal findings in 24 patients with 35 lesions. SPECT/CT demonstrated 100 % sensitivity in a patient-based analysis. SPECT/CT exhibited significantly better sensitivity than (99m)Tc-sestamibi scintigraphy, SPECT and conventional imaging (p < 0.05). All lesion location was correctly identified to perform MIP. The final clinical diagnosis of 7 normal SPECT/CT patients was secondary hyperparathyroidism on 6 months follow-up.

CONCLUSIONS

We correctly identified the precise location of parathyroid adenomas or hyperplasia by (99m)Tc-sestamibi SPECT/CT which was helpful to perform MIP.

The impact of surgeon-based ultrasonography for parathyroid disease on a British endocrine surgical practice

INTRODUCTION

Surgeon-based ultrasonography (SUS) for parathyroid disease has not been widely adopted by British endocrine surgeons despite reports worldwide of accuracy in parathyroid localisation equivalent or superior to radiology-based ultrasonography (RUS). The aim of this study was to determine whether SUS might benefit parathyroid surgical practice in a British endocrine unit.

METHODS

Following an audit to establish the accuracy of RUS and technetium sestamibi (MIBI) in 54 patients, the accuracy of parathyroid localisation by SUS and RUS was compared prospectively with operative findings in 65 patients undergoing surgery for primary hyperparathyroidism (pHPT).

RESULTS

The sensitivity of RUS (40%) was below and MIBI (57%) was within the range of published results in the audit phase. The sensitivity (64%), negative predictive value (86%) and accuracy (86%) of SUS were significantly greater than RUS (37%, 77% and 78% respectively). SUS significantly increased the concordance of parathyroid localisation with MIBI (58% versus 32% with RUS).

CONCLUSIONS

SUS improves parathyroid localisation in a British endocrine surgical practice. It is a useful adjunct to parathyroid practice, particularly in centres without a dedicated parathyroid radiologist, and enables more patients with pHPT to benefit from minimally invasive surgery.

Intrathyroid adenomas in primary hyperparathyroidism: are they frequent enough to guide surgical strategy?

BACKGROUND

Ectopic parathyroid adenoma, including intrathyroid adenoma, is a common cause of failed parathyroid operations. The aim of this study was to evaluate the operative strategy/outcome in patients with primary hyperparathyroidism (pHPT), with special regard to intrathyroid adenomas.

METHOD

The authors performed an analysis of all patients receiving operative treatment for pHPT from 2003 through 2005. The operative strategy consisted of systematic perithyroid exploration followed by extended cervical exploration in cases where the adenoma was not found initially. In cases of persistent, high intraoperative parathyroid hormone levels, hemithyroidectomy was performed on the side with higher suspicion of intrathyroid adenoma or with more extended thyroid changes.

RESULTS

During the study, 115 patients received surgical treatment for sporadic pHPT. A single parathyroid adenoma (normal parathyroid position) was found in 95 patients (82.6%), ectopic single adenoma was found in 7 patients (6.1%), and double adenomas were found in 10 (8.7%) patients. Operative failure occurred in 3 cases (2.6%). In all, 4 of 7 ectopic single adenomas were intrathyroidal and were removed by hemithyroidectomy according to the authors' standard protocol.

CONCLUSION

The strategy of (a) cervical exploration, (b) extended cervical exploration, and (c) hemithyroidectomy was highly successful for removing undetectable intrathyroid parathyroid adenomas during primary intervention, thereby reducing the risks associated with reintervention.

PET and Parathyroid

In parathyroid disease, classical scintigraphic techniques remain the first choice for localizing hyperfunctional parathyroid glands in primary known hyperparathyroidism and in case of secondary, tertiary, and recurrent hyperparathyroidism. When classical scintigraphic techniques are not diagnostic, however, (11)C-methionine seems to offer a good imaging alternative.

Scintigraphic techniques in primary hyperparathyroidism: from pre-operative localisation to intra-operative imaging

INTRODUCTION

Primary hyperparathyroidism (PHPT) is an increasingly diagnosed disease worldwide. In most cases, PHPT is related to the presence of a solitary parathyroid adenoma (PA). Fifty percent or more of newly diagnosed PHPT patients are asymptomatic, and there is debate among endocrinologists and endocrine surgeons about whether or not such patients should be treated.

LOCALIZATION

Usually, in a PHPT patient with a solitary PA that is well localised pre-operatively, a parathyroidectomy with limited or minimally invasive neck exploration is offered. The diffusion of minimally invasive neck exploration procedures is a consequence of the significant improvement in the accuracy of pre-operative imaging (mainly scintigraphic) techniques; these techniques have changed the surgical strategy to PHPT, from the wide traditional bilateral neck exploration to limited neck exploration.

REVIEW

The present review considers developments during the past 10-15 years with regard to both the accuracy of pre-operative localising imaging techniques and intra-operative minimally invasive procedures in order to provide endocrinologists and endocrine surgeons with further information about the newly available diagnostic and therapeutic tools for use in PHPT patients with a solitary PA.

Ultrasonography in detection of single and multiple abnormal parathyroid glands in primary hyperparathyroidism: comparison with radionuclide scintigraphy and surgery

BACKGROUND

Among the parathyroid imaging techniques, ultrasonography (USG) has the advantage of convenience, easy availability and low cost.

OBJECTIVE

To study the role of USG in localization (side and/or site) of abnormal parathyroid glands in primary hyperparathyroidism (PHPT) and to compare with radionuclide scintigraphy and the 'gold standard', surgery.

METHODS

Forty-six consecutive patients undergoing USG of the anterior neck for a diagnosis of PHPT in whom a nuclear scan (technetium-99m sestamibi and/or thallium-201/technetium-99m pertechnetate scintigraphy) was also performed, were studied. The results of imaging were independently interpreted and correlated with reference to surgical findings.

RESULTS

Forty-six patients had 52 abnormal parathyroid glands on surgical exploration and surgery was successful in all but one. Forty-one patients had a single adenoma, four had multigland disease and one had a paraganglioma. USG correctly localized the abnormal gland in 30 (73%) and scintigraphy was positive in 40 (98%) out of 41 patients with a single adenoma as confirmed on surgical exploration. Scintigraphy showed a positive concordant test in all 30 patients with a single abnormal gland detected on USG and picked up 10 out of 11 abnormal glands where USG was negative. The sensitivity and positive predictive value of USG for detecting a single abnormal gland was 73% and 100%, respectively, whereas the sensitivity and positive predictive value for scintigraphy was 98%. In patients with multigland disease, USG missed 3 (30%) out of 10 and scintigraphy missed 6 (60%) out of 10 abnormal parathyroid glands as confirmed on surgical exploration (P < 0.05). However, in two patients who had ectopic parathyroid gland, both the modalities localized the lesion in one (paraganglioma), whereas in the other neither test was helpful (left retro-esophageal).

CONCLUSION

USG is a convenient, affordable and useful modality to localize abnormal enlarged parathyroid glands in the majority of patients with PHPT. However, when USG is negative, scintigraphy is complementary to it.

Two Hundred Consecutive Parathyroid Ultrasound Studies by a Single Clinician: The Impact of Experience

OBJECTIVE

To assess the ability of ultrasound studies, performed by an experienced clinician, to predict surgical findings and provide precise anatomic localization of abnormal parathyroid glands.

METHODS

We retrospectively examined 200 consecutive parathyroid ultrasound studies performed by a single experienced clinician in our unit. All patients subsequently underwent parathyroidectomy, with histopathologic confirmation of abnormal parathyroid tissue. The correlation between the ultrasound and surgical findings was assessed.

RESULTS

Of the 200 study patients, 197 (98.5%) were cured of their disease at the initial operation. Ultrasound studies correctly predicted the surgical findings in 88% of patients, including 168 of 180 (93%) with single gland disease and 7 of 20 (35%) with multiple gland disease (MGD). In all cases in which a single adenoma was identified, precise information regarding its location relative to adjacent anatomic structures was provided. In 92% of these cases, anatomic details correlated closely with surgical findings. Ectopic and descended superior adenomas were most frequently missed. Patients with two nonlocalizing studies (scintigraphy and ultrasonography) had a >50% likelihood of having MGD.

CONCLUSION

In experienced hands, parathyroid ultrasonography is a highly sensitive technique that provides both localization of enlarged parathyroid glands and precise anatomic detail. Thus, in this study, focused parathyroidectomy was possible in 76.5% of patients. MGD remains difficult to diagnose preoperatively. Nonlocalizing studies should alert the surgeon to a high probability of MGD and prompt the performance of 4-gland exploration.

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.

Ultrasound of the thyroid and parathyroid glands

Ultrasound plays a prominent role in the management of thyroid disease and parathyroid adenomas. It can detect clinically impalpable thyroid nodules and characterize them as cystic, solid, or complex. Determining that a nodule is definitively benign or malignant is difficult, and so when indicated an ultrasound-guided fine-needle aspiration can be performed. In the follow-up of patients with thyroid cancer, ultrasound can be used alone or in conjunction with computed tomography (CT)/magnetic resonance imaging (MRI) to detect recurrent disease. Recurrences can be confirmed using ultrasound to guide fine-needle aspirations. To locate parathyroid adenomas, ultrasound is often used in conjunction with sestamibi scanning. If both studies agree on the location of the adenoma, the surgeon can perform focused surgery for its removal. In patients in whom the studies do not agree or in whom they do not detect the adenoma, further evaluation with CT or more preferably MRI is indicated.

Ultrasonography for preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism: comparison with (99m)technetium sestamibi scintigraphy

OBJECTIVE

To determine the utility of ultrasonography for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism, and to compare this method with (99m)technetium sestamibi scintigraphy.

DESIGN

The results of ultrasonography for localization of enlarged parathyroid glands were determined in 120 consecutive patients with primary hyperparathyroidism and compared with findings at surgery (n = 86) and with the results of (99m)technetium sestamibi scintigraphy (n = 99).

PATIENTS

All patients had biochemically documented primary hyperparathyroidism based on elevated serum calcium and 'intact' parathyroid hormone measured by immunoassay. Patients with prior parathyroid surgery or secondary hyperparathyroidism were excluded.

MEASUREMENTS

High-resolution ultrasonography was performed by a single observer. (99m)Technetium sestamibi scintigraphy was performed using early and delayed (2-h) views, and correlated with simultaneous thyroidal 123I uptake in most patients.

RESULTS

Ultrasonography detected putative enlarged parathyroid glands in 92 of 120 unselected patients (77%). It correctly predicted surgical findings in 64 of 86 patients undergoing surgery (74%), including 61 of 72 patients with solitary eutopic parathyroid adenomas (84%), but only two of eight patients with solitary ectopic adenomas, and only one of six patients with multigland parathyroid disease. Sestamibi scintigraphy was positive in 87 of 99 unselected patients (88%), a higher proportion than ultrasonography (P < 0.05), reflecting superior sensitivity for the detection of ectopic parathyroid adenomas. For 74 patients undergoing parathyroid surgery who underwent both imaging tests there was no statistically significant difference between ultrasonography and sestamibi scintigraphy in ability to correctly predict surgical findings (74%vs. 82%, respectively) or in positive predictive value (93%vs. 90%, respectively). However, sestamibi scintigraphy was clearly more sensitive for ectopic parathyroid adenomas, providing correct localization in 8/8 cases. When one test was negative, testing with the second method was usually positive, improving the likelihood of a positive result to 98% when both tests were employed.

CONCLUSIONS

Ultrasonography can be a sensitive and accurate method for preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism, comparable in overall utility to sestamibi scintigraphy. These results suggest that a strategy of initial testing with one or the other method, followed by the alternate imaging test if the first test is negative, would provide correct parathyroid imaging in most patients without prior parathyroid surgery.

Minimally invasive surgery for solitary parathyroid adenomas in patients with primary hyperparathyroidism: role of US with supplemental CT

PURPOSE

To determine the role of ultrasonography (US) with supplemental computed tomography (CT) in patients with primary hyperparathyroidism who undergo minimally invasive surgery instead of conventional neck exploration.

MATERIALS AND METHODS

US and CT were performed in 61 consecutive patients with primary hyperparathyroidism (part 1) to identify and localize solitary adenomas for resection by means of minimally invasive surgery and to provide a surgical road map. In part 2, involving 33 consecutive patients, CT was performed only when no solitary adenoma was identified with US or for road map information. Minimally invasive surgery was considered successful when serum calcium levels normalized and remained stable.

RESULTS

In part 1, 46 definite solitary adenomas were found with US and two additional ones with CT. Minimally invasive surgery was successful in 45 patients and failed once. In part 2, US helped identify 23 solitary adenomas, and CT helped to find one. Minimally invasive surgery was successful in 22 patients and failed in two. Combined results in 94 patients demonstrated successful minimally invasive surgery in 67 (71%), with 64 of them selected with US alone (95% CI: 61, 80). The sensitivity of US in the diagnosis of solitary adenoma was 78% (95% CI: 67%, 86%), with a positive predictive value of 96% (95% CI: 88%, 99%).

CONCLUSION

US examination of patients with primary hyperparathyroidism allowed successful selection for minimally invasive surgery in more than two-thirds of the cases, with additional CT useful chiefly for surgical road mapping.

Color Doppler sonography in the detection of parathyroid adenomas

BACKGROUND

Various diagnostic modalities have been utilized to aid in the detection of abnormal parathyroid tissue; however, its localization is not always easy. The purpose of this study was to determine whether the evaluation of potential hemodynamic changes in thyroid arteries could aid in the detection of parathyroid adenomas.

METHODS

Twenty-eight patients with laboratory evidence of hyperparathyroidism were examined with color Doppler sonography. Data were collected for the superior and inferior thyroid arteries separately. These findings were compared with data for a control group of 14 healthy subjects.

RESULTS

Retrospective analysis of the data indicated that peak systolic velocities in the inferior thyroid arteries ipsilateral with the parathyroid adenomas were significantly higher than in normal controls (p <.001). Peak velocity values in the superior thyroid arteries ipsilateral with parathyroid adenomas located in the upper position were also significantly increased compared with those in control subjects (p <. 02). Conversely, peak velocities in the inferior and superior thyroid arteries contralateral with the adenomas, as well as velocities in the superior thyroid arteries ipsilateral with lower position adenomas, did not differ significantly from those in control subjects. The localization of both side and level site of the adenomas presented an accuracy of 86.6%, sensitivity reached 96. 5%, and specificity 83.1%.

CONCLUSION

Our results suggest that color Doppler sonography can be used to improve diagnostic accuracy in detecting parathyroid adenomas.

Preoperative evaluation of patients with primary hyperparathyroidism: role of high-resolution ultrasound

Unilateral parathyroid exploration with adenoma removal and identification of a normal parathyroid gland is an accepted surgical approach for the treatment of patients with primary hyperparathyroidism. This study prospectively evaluated the ability of high-resolution sonography to localize adenomas preoperatively and the effect of this localization on operative time and cost in 37 previously untreated patients undergoing surgical treatment for primary hyperparathyroidism. The sensitivity and positive predictive value of the sonographic examination were 84% and 90%, respectively. A true positive sonographic examination decreased surgical time by an average of 40 minutes and reduced operative charges by $564, including the cost of the test ($156). In experienced hands high-resolution sonography can be a cost-effective means of localizing parathyroid adenomas where unilateral exploration is considered an accepted surgical approach.

Recent advances in parathyroid imaging

Although no existing imaging procedure is as effective as an experienced surgeon for locating abnormal parathyroid glands in patients without previous neck surgery, preoperative parathyroid localization is considered essential for patients undergoing reoperations. The need for parathyroid imaging in patients undergoing an initial exploration remains controversial. Scintigraphy with (99m)Tc-sestamibi has largely replaced (99m)Tc-pertechnetate/(201)Tl chloride subtraction scintigraphy for parathyroid imaging because of its superior sensitivity and false-positive rate. Positron emission tomography, another technique recently applied to parathyroid imaging, is of uncertain value at present.

[Parathyroid adenoma encapsulated in a thyroid adenoma: an anatomical curiosity]

We describe a primitive hyperparathyroid in a old woman due to a parathyroid adenoma localized by Technetium 99m, Thallium 201 scintigraphy within the thyroid gland. During surgery, this adenoma was found inside a thyroid adenoma. It is the second case reported on the literature in a such localization. We underline the interest of the scintigraphy Technetium 99m, Thallium 201, for the detection of ectopic parathyroid adenoma.

Parathyroid localization prior to primary exploration

The success of parathyroid surgery is based on accurate localization of normal and abnormal parathyroid glands, knowledge of the pathologic conditions, and meticulous dissection during removal of the abnormal glands. Although parathyroid localization is essential in cases requiring re-exploration, there is considerable controversy regarding the indications for localization studies prior to primary exploration, since the success rate for surgery exceeds 90% to 95%. However, in specific circumstances, including diagnostic problems, technical considerations, and high-risk patient factors, preoperative parathyroid localization assists the operating surgeon even during the primary cervical exploration. The purpose of this paper is to define these specific circumstances and discuss the appropriate studies.

Ultrasonic detection of parathyroid adenomas

High-resolution real time sonography was used to evaluate patients with suspected primary hyperparathyroidism. A total of 12 consecutive patients was scanned pre-operatively. The sensitivity of the procedure was 92% and the specificity 97%. In our hospital sonography is the procedure of choice for localizing enlarged parathyroid glands prior to surgical exploration.