Radionuclide scanning in parathyroid diseases

Esophageal schwannoma mimicking non-functional parathyroid adenoma on 99mTc-sestamibi imaging: a case report

Technetium-99m sestamibi single-photon emission computed tomography/computed tomography (99mTc-sestamibi SPECT/CT) is a mainstay of the pre-operative localization of parathyroid lesions. We report here the case of a 30 year-old woman with a fortuitously discovered 2 cm cervical mass for which a parathyroid origin was originally suspected due to its retro-thyroidal localization and a personal history of nephrolithiasis. Normal serum calcium and parathyroid hormone (PTH) levels excluded primary hyperparathyroidism, raising suspicion of a non-functional parathyroid adenoma, and SPECT/CT imaging showed that the mass was 99mTc-sestamibi-avid. Fine-needle aspiration (FNA) was performed; cytology was non-diagnostic but the needle washout was negative for thyroglobulin, calcitonin and PTH, arguing against a thyroidal or parathyroidal origin of the mass. Core needle biopsy revealed a schwannoma, ostensibly originating from the recurrent laryngeal nerve; upon surgical resection, it was finally found to arise from the esophageal submucosa. This case illustrates the fact that endocrinologists, radiologists, nuclear medicine, head and neck, and other specialists investigating patients with cervical masses should be aware that schwannomas need to be considered in the differential diagnosis of focal 99mTc-sestamibi uptake in the neck region.

Pearls of Parathyroidectomy: How to Find the Hard to Find Ones

The treatment of hyperparathyroidism through parathyroidectomy requires careful and complete preoperative evaluation. There are multiple imaging modalities and methods available to clinicians today to aid in identifying a pathological lesion; however, each has limitations that the clinician must understand. A systematic approach to patient evaluation, imaging, and surgical exploration is necessary to ensure accurate diagnosis and maximize the chances of minimally invasive and successful surgical removal.

Evaluation of Imaging Findings in Patients with Pretransplant and Posttransplant Tertiary Hyperparathyroidism

OBJECTIVES

Tertiary hyperparathyroidism, characterized by autonomous overproduction of parathyroid hormone, can be seen in patients with long-standing secondary hyperparathyroidism (pretransplant) or after renal transplant (posttransplant). Parathyroid scintigraphy and ultrasonography are the most commonly used imaging procedures for the preoperative localization of abnormal parathyroid glands. We aimed to evaluate imaging findings in pretransplant and posttransplant tertiary hyperparathyroidism.

MATERIALS AND METHODS

This study included 32 patients with pretransplant tertiary hyperparathyroidism and 20 patients with posttransplant tertiary hyperparathyroidism. On parathyroid scintigraphy with technetium-99m sestamibi, early-phase and latephase images were acquired. Images were evaluated for the presence and the number of active foci and the degree of uptake on the late-phase image. The existence of an autonomous gland was based on latephase retention and was scored from 0 to 2 (retention score). On ultrasonography, the criteria threshold for autonomy was the maximum length of the largest gland ≥10 mm (ultrasonography score).

RESULTS

On parathyroid scintigraphy, the most commonly observed pattern in the pretransplant group was positivity in ≥3 glands, and in the posttransplant group the most commonly observed pattern was positivity in 1 to 2 glands. In pretransplant and posttransplant groups, the criteria threshold for the presence of an autonomous parathyroid gland on parathyroid scintigraphy (grade 2 retention) was met in 26 (81%) and 9 (45%) patients and on ultrasonography in 25 (78%) and 10 (50%) patients, respectively. In the whole group of patients (n = 52), correlation existed between ultrasonography score and retention score. Glandular weight was correlated with both retention score and ultrasonography score.

CONCLUSIONS

Higher numbers of detectable glands and the presence of parathyroid autonomy were more common in the pretransplant group. This might be explained by parathyroid gland involution after transplant. The results may also suggest that factors other than autonomy are responsible for posttransplant tertiary hyperparathyroidism.

Phenomic Studies on Diseases: Potential and Challenges

The rapid development of such research field as multi-omics and artificial intelligence (AI) has made it possible to acquire and analyze the multi-dimensional big data of human phenomes. Increasing evidence has indicated that phenomics can provide a revolutionary strategy and approach for discovering new risk factors, diagnostic biomarkers and precision therapies of diseases, which holds profound advantages over conventional approaches for realizing precision medicine: first, the big data of patients' phenomes can provide remarkably richer information than that of the genomes; second, phenomic studies on diseases may expose the correlations among cross-scale and multi-dimensional phenomic parameters as well as the mechanisms underlying the correlations; and third, phenomics-based studies are big data-driven studies, which can significantly enhance the possibility and efficiency for generating novel discoveries. However, phenomic studies on human diseases are still in early developmental stage, which are facing multiple major challenges and tasks: first, there is significant deficiency in analytical and modeling approaches for analyzing the multi-dimensional data of human phenomes; second, it is crucial to establish universal standards for acquirement and management of phenomic data of patients; third, new methods and devices for acquirement of phenomic data of patients under clinical settings should be developed; fourth, it is of significance to establish the regulatory and ethical guidelines for phenomic studies on diseases; and fifth, it is important to develop effective international cooperation. It is expected that phenomic studies on diseases would profoundly and comprehensively enhance our capacity in prevention, diagnosis and treatment of diseases.

Functional imaging for hyperparathyroidism

Once hyperparathyroidism has been proven, the goal of parathyroid functional imaging is to identify one or more pathological glands in view of guiding a possibly targeted surgical procedure, while maximizing the chances for recovery. Currently, parathyroid radionuclide imaging is based on two techniques, parathyroid scintigraphy and ¹⁸F-fluorocholine - positron emission tomography (PET). The main radiopharmaceutical in scintigraphy is ^99mTc-sestamibi, which can be used alone, in the dual-phase parathyroid scan, or in comparison with a thyroid radiotracer, pertechnetate (NaTcO₄) or iodine 123 (dual-tracer method). The acquisitions can be planar and/or tomographic (SPECT). It is now recognized that the ^99mTc-sestamibi - iodine 123 dual-tracer method is more efficient than the dual-phase scan, while SPECT-CT improves the sensitivity and specificity of the scintigraphy. This imaging and cervical ultrasonography are considered to be the two first-line reference techniques in preoperative assessment of hyperparathyroidism. More recently developed, ¹⁸F-fluorocholine detected by PET-CT has shown excellent performance, at least equal to that of scintigraphy. Initially considered as a second-line technique, its advantages over scintigraphy have prompted some authors to suggest it as the only examination to be performed in preoperative assessment of hyperparathyroidism. That said, due to a lack of specificity in ¹⁸F-fluorocholine uptake, which has been observed on inflammatory lesions and, particularly, in the mediastinal lymph nodes, and given the absence of simultaneous comparison of thyroid function, this strategy remains contested, and possibly reserved for patients without any associated thyroid pathology; large-scale evaluation would be justified.

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.

Comparison between technetium-99m methoxyisobutylisonitrile scintigraphy and ultrasound in the diagnosis of parathyroid adenoma and parathyroid hyperplasia

Objective

The aim of this study was to evaluate the value of technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) imaging and ultrasound in preoperative localization of parathyroid adenoma (PA) and parathyroid hyperplasia (PH).

Participants and methods

A retrospective study of ^99mTc-MIBI double-phase scintigraphy (DPS) was performed in 187 hyperparathyroidism cases with pathologically diagnosed PA or PH. Of these patients, 167 cases underwent ultrasound, and 146 cases underwent ^99mTc-MIBI single-photon emission computed tomography/computed tomography (SPECT/CT). The sensitivity and diagnostic accuracy of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT were compared between PA and PH. Differences in ^99mTc-MIBI DPS, serum parathyroid hormone (PTH), serum calcium and phosphorus, as well as the weight and longest diameter of lesion between PA and PH were also compared.

Results

As per patient-based analysis, the sensitivity of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT was 90.70% (39/43), 95.56% (43/45), and 100.00% (30/30), respectively, for PA, and 93.55% (116/124), 90.85% (129/142), and 93.10% (108/116), respectively, for PH. There were no significant differences in sensitivity of these three imaging methods between PA and PH. However, per lesion-based analysis, the accuracy of ultrasound, ^99mTc-MIBI DPS, and SPECT/CT in detecting PA was 78.43% (40/51), 86.79% (46/53) and 96.88% (31/32), respectively, and the accuracy of ^99mTc-MIBI DPS was higher than that of ultrasound (χ²=6.507, P=0.011), and for PH, it was 49.69% (160/322), 40.71% (171/420), and 43.80% (152/347), respectively. The accuracy of ultrasound was higher than that of ^99mTc-MIBI DPS (χ²=5.940, P=0.015). The accuracy of a combination of all three examinations of ultrasound+^99mTc-MIBI DPS, ultrasound+^99mTc-MIBI SPECT/CT, ^99mTc-MIBI DPS+SPECT/CT, and ultrasound+^99mTc-MIBI DPS+^99mTc-MIBI SPECT/CT was 51.51% (154/299), 53.85% (161/299), 50.17% (150/299), and 54.18% (162/299), respectively, which was higher than that of ultrasound (χ²=5.273, P=0.022; χ²=8.226, P=0.004; χ²=3.880, P=0.049; χ²=8.702, P=0.003, respectively). Serum levels of PTH and phosphorus were lower in patients with PA than in patients with PH (P<0.001), and serum calcium level, the weight, and the longest diameter of lesion and early uptake rate of ^99mTc-MIBI DPS were higher in patients with PA than in patients with PH (P<0.01). Serum PTH level is often less than 1000 pg/ml in PA, but usually more than 1000 pg/ml in PH.

Conclusion

Ultrasound, ^99mTc-MIBI DPS, and SPECT/CT all have a higher value in the diagnosis of PA than PH. ^99mTc-MIBI SPECT/CT should be optimal for detecting PA, and early SPECT/CT scan might be better than delayed scan. Compared with ^99mTc-MIBI DPS and SPECT/CT, ultrasound has a slight advantage in localization of PH lesions. The combination of ultrasound and ^99mTc-MIBI DPS or SPECT/CT imaging could improve the accuracy in localization of PH lesions and should be considered as the first-line method for detecting PH.

Lesion based diagnostic performance of dual phase 99mTc-MIBI SPECT/CT imaging and ultrasonography in patients with secondary hyperparathyroidism

Background

We aimed to evaluate the diagnostic performance of ^99mTc-MIBI SPECT/CT and ultrasonography in patients with secondary hyperparathyroidism (SHPT), and explored the factors that affect the diagnostic performance.

Methods

^99mTc-MIBI SPECT/CT and ultrasonography were performed in 50 patients with SHPT within 1 month before they underwent surgery. Imaging results were confirmed by the pathology. Pearson correlation analysis was used to determine the correlation of PTH level with clinical data. The optimal cutoff value for predicting positive ^99mTc-MIBI results was evaluated by ROC analysis in lesions diameter.

Results

Forty-nine patients had a positive ^99mTc-MIBI imaging results and 39 patients had positive ultrasonography results. The sensitivities of ^99mTc-MIBI and ultrasonography were 98.00% and 78.00%, respectively. A total of 199 lesions were resected in 50 patients. Among them, 183 lesions were proved to be parathyroid hyperplasia. On per-lesion basis analysis, the sensitivity and specificity of ^99mTc-MIBI and ultrasonography were 59.34% and 75.00% vs 46.24% and 80.00%, respectively. The Pearson correlation analysis showed that the serum AKP and PTH level had a significant linear association (r = 0.699, P < 0.001). The lesion diameter was a statistically significant predictive factor in predicting positive ^99mTc-MIBI SPECT/CT. The optimal cutoff value for predicting positive ^99mTc-MIBI results evaluated by ROC analysis in lesions diameter was 8.05 mm.

Conclusion

Dual phase ^99mTc-MIBI SPECT/CT imaging had a higher sensitivity in patients with SHPT than ultrasonography. Therefore, using ^99mTc-MIBI positioning the lesion could be an effective method pre-surgical in patients with SHPT.

Sensitivity and Specificity of Dual-Isotope 99mTc-Tetrofosmin and 123I Sodium Iodide Single Photon Emission Computed Tomography (SPECT) in Hyperparathyroidism

Purpose

Despite recommendations for ^99mTc-tetrofosmin dual tracer imaging for hyperparathyroidism in current guidelines, no report was published on dual-isotope ^99mTc-tetrofosmin and ¹²³I sodium iodide single-photon-emission-computed-tomography (SPECT). We evaluated diagnostic accuracy and the impact of preoperative SPECT on the surgical procedures and disease outcomes.

Methods

Analysis of 70 consecutive patients with primary hyperparathyroidism and 20 consecutive patients with tertiary hyperparathyroidism. Imaging findings were correlated with surgical results. Concomitant thyroid disease, pre- and postoperative laboratory measurements, histopathological results, type and duration of surgery were assessed.

Results

In primary hyperparathyroidism, SPECT had a sensitivity of 80% and a positive predictive value of 93% in patient-based analysis. Specificity was 99% in lesion-based analysis. Patients with positive SPECT elicit higher levels of parathyroid hormone and higher weight of resected parathyroids than SPECT-negative patients. Duration of parathyroid surgery was on average, approximately 40 minutes shorter in SPECT-positive than in SPECT-negative patients (89±46 vs. 129±41 minutes, p=0.006); 86% of SPECT-positive and 50% of SPECT-negative patients had minimal invasive surgery (p = 0.021). SPECT had lower sensitivity (60%) in patients with tertiary hyperparathyroidism; however, 90% of these patients had multiple lesions and all of these patients had bilateral lesions.

Conclusion

Dual-isotope SPECT with ^99mTc-tetrofosmin and ¹²³I sodium iodide has a high diagnostic value in patients with primary hyperparathyroidism and allows for saving of operation time. Higher levels of parathyroid hormone and higher glandular weight facilitated detection of parathyroid lesion. Diagnostic accuracy of preoperative imaging was lower in patients with tertiary hyperparathyroidism.

Mediastinal hemorrhage due to ectopic parathyroid hyperplasia with long-term hemodialysis: report of a case

Secondary hyperparathyroidism can sometimes occur among long-term hemodialysis patients. We herein present the case of a 48-year-old female who underwent surgical resection to treat a mediastinal hemorrhage from an ectopic parathyroid. She had been receiving dialysis for the past 16 years due to renal failure. She visited the hospital due to chest pain, and a CT scan revealed a tumorous lesion in the anterior mediastinum. An increase in size of the tumorous lesion, accompanied by bilateral pleural fluid, was observed. Emergency surgery was performed due to a diagnosis of a mediastinal hemorrhage from the tumorous lesion, accompanied by a decrease in the Hb value. The pathological findings of the hematoma revealed parathyroid hyperplasia. This is a rare case report of an ectopic parathyroid developing hyperplasia which caused a mediastinal hemorrhage due to secondary hyperparathyroidism.

Nonadenomatous nonencapsulated thymic parathyroid tissue concomitant with primary hyperparathyroidism due to ectopic parathyroid adenoma

Primary hyperparathyroidism due to ectopic parathyroid adenoma is not infrequent. Primary hyperparathyroidism caused by unusual thymic nonadenomatous nonencapsulated parathyroid tissue has been reported before. Both can cause unsuccessful neck explorations. Here we presented for the first time a patient with hyperparathyroidism due to ectopic parathyroid adenoma concomitant to the presence of thymic nonadenomatous nonencapsulated parathyroid tissue.

The value of intraoperative PTH measurements in patients with mild primary hyperparathyroidism

PURPOSE

Intraoperative parathyroid hormone (ioPTH) measurement has facilitated a move to minimally invasive parathyroidectomy. Patients are referred for surgery earlier with milder hypercalcaemia and smaller tumours. Whilst previous research has shown that glands size can affect ioPTH kinetics in patients with multiple gland disease, the dynamics of ioPTH in patients with mild hyperparathyroidism (HPT) has not been studied. We therefore investigated the relationship between biochemical parameters and parathyroid adenoma weight, and determined the dynamics and accuracy of ioPTH assay in patients with milder hypercalcaemia undergoing parathyroidectomy.

METHODS

Patients undergoing parathyroidectomy for single gland disease from January 2004 to March 2011 were divided prospectively into two groups according to preoperative serum calcium: patients with a preoperative calcium ≥ 2.85 mmol/L (11.4 mg/dL) and <2.85 mmol/L were grouped as severe and mild hypercalcaemia, respectively. Correlation coefficients were calculated to assess the relationship between biochemical markers of calcium homeostasis and ioPTH measurements with respect to parathyroid gland weight.

RESULTS

There was a weak correlation of preoperative serum calcium (r = 0.248, r = 0.207), PTH (r = 0.392, r = 0.275), and baseline ioPTH (r = 0.516, r = 0.244) with parathyroid gland weight in severe (n = 113) and mild groups (n = 190), respectively. No correlation between the magnitude in ioPTH drop with parathyroid gland weight at 5 or 10 min post-excision for either group was observed. Success rates (post-operative normocalcaemia) were similar for each group (99.1 % severe, 98.9 % mild).

CONCLUSION

This prospective study provides evidence that ioPTH assay is a valuable tool in predicting adequate tissue removal in patients with milder and more severe hypercalcaemia due to single gland primary HPT.

Intraoperative Parathyroid Hormone Assay

Objectives. The aims were to: (1) evaluate whether failure of intraoperative parathyroid hormone (ioPTH) to decrease by the Miami criterion is a more specific indicator of multiglandular disease (MGD) than sestamibi scan and (2) determine an adequate cutoff value for decrease in ioPTH in MGD.

Study Design. Case series with chart review.

Setting. Louisiana State University Health Sciences Center–Shreveport.

Subjects and Methods. Review of subjects undergoing parathyroidectomy using ioPTH and sestamibi for suspected parathyroid adenoma between 2005 and 2009. Patients with MGD were identified by pathology and operative reports.

Results. Eighty-three subjects were identified (68 single adenomas, 11 double adenomas, and 4 multiple-gland hyperplasias). Sestamibi predicted MGD in only 4 of 15 cases (27%). Five of the 11 double adenomas (DAs) were identified during initial surgery; the rest required reoperation for cure. ioPTH was useful in predicting MGD in 7 of 10 cases (70%) when a postexcisional value was drawn after removal of the first enlarged gland. Using the Miami criterion of 50% decrease in ioPTH over 15 minutes would have resulted in 1 unnecessary neck exploration and 3 missed DAs. Requiring both a 50% decrease in ioPTH over 15 minutes and normalization of the postexcisional value would have missed only 1 DA and resulted in a single unnecessary neck exploration.

Conclusion. Sestamibi alone fails to identify MGD 73% of the time, but the success rate increases significantly when combined with ioPTH. The “50% and normal” criterion worked best to increase the success rate in our study population, but larger trials are needed to confirm the utility of this criterion.

Pathologic fractures: a neglected clinical feature of parathyroid adenoma

The pattern of clinical presentation of primary hyperparathyroidism (pHPT) has changed dramatically from a severe disease to an asymptomatic condition in Western countries. The story is completely different in Eastern countries. Bone and joint related sign and symptoms like bone pain and multiple fractures are common in these patients. Imaging and nuclear medicine studies will be helpful specially in patient who candidate for surgical removal of the abnormal parathyroid gland. Here, we present a 48-year-old man with multiple typical fractures in long bones and a single adenoma in his right inferior parathyroid gland. pHPT is a severe, symptomatic disease with serious complications and high morbidity in Iran. Advanced skeletal disease is the most common pattern of presentation.

Hyperparathyroidism in pregnancy: options for localization and surgical therapy

BACKGROUND

Hyperparathyroidism in pregnancy is a threat to the health of both mother and fetus. The mothers suffer commonly from nephrolithiasis, hyperemesis, or even hypercalcemic crisis. Untreated disease will commonly complicate fetal development and fetal death is a significant risk. Treatment options, including medical and surgical therapy, are debated in the literature.

METHODS

This is a case series comprising seven patients with primary hyperparathyroidism in pregnancy. Data collected included symptoms at diagnosis, biochemical abnormalities, pathologic findings, treatment regimes, and subsequent maternal and fetal outcomes.

RESULTS

Seven women, aged 20 to 39 years, presented with hyperparathyroidism during pregnancy. The earliest presented at 8 weeks and the latest at 38 weeks. Four of seven patients experienced renal calculi. Calcium levels were 2.7-3.5 mmol/l. All were found to have solitary parathyroid adenomas, of which two were in ectopic locations. Fetal complications included three preterm deliveries and one fetal death with no cases of neonatal tetany. Maternal and fetal complications could not be predicted based on duration or severity of hypercalcemia. Three patients were treated during pregnancy with surgery, and two of these had ectopic glands that required reoperations with a novel approach using Tc-99m sestamibi scanning during pregnancy to assist in localizing the abnormal gland. Four cases were treated postpartum with a combination of open and minimally invasive approaches after localization. No operative complications or fetal loss related to surgery were observed in this cohort.

CONCLUSIONS

Primary hyperparathyroidism in pregnancy represents a significant risk for maternal and fetal complications that cannot be predicted by duration of symptoms or serum calcium levels. Surgical treatment should be considered early, and a minimally invasive approach with ultrasound is best suited to mitigating risk to mother and fetus. Equally important, Tc-99m sestamibi imaging may be used safely for localization of the parathyroids after negative cervical explorations.

Virtual neck exploration: a new method for localizing abnormal parathyroid glands

BACKGROUND DATA

Computed tomography (CT) together with 99mTc-sestamibi single photon emission computed tomography (MIBI-SPECT) image fusion (CT-MIBI-SPECT image fusion) allows virtual exploration of the neck. The aim of this study was to evaluate whether CT-MIBI-SPECT image fusion is superior to MIBI-SPECT and CT in detecting abnormal parathyroid glands in patients with primary hyperparathyroidism.

METHODS

CT-MIBI-SPECT image fusion for preoperative localization was performed in 116 patients with primary hyperparathyroidism (pHPT). Both investigations were performed with reproducible fixation of the patient on a vacuum mattress. At a special work station the neck was virtually explored by viewing the CT images in all 3 dimensions. The MIBI-SPECT images were superimposed on underlying CT images. Only patients with single-gland disease were evaluated (pHPT: 112, persistent pHPT: 1, recurrent pHPT: 1, persistent secondary hyperparathyroidism: 1, tertiary HPT after kidney transplantation: 1). CT-MIBI-SPECT image fusion results were compared with those obtained with CT alone and MIBI-SPECT alone. The predicted positions were correlated with the intraoperative findings.

RESULTS

CT-MIBI-SPECT image fusion was able to predict the exact position of the abnormal gland in 102 (88%) of the 116 patients, whereas CT alone showed in 75 (65%) patients and MIBI-SPECT alone in 64 (55%) patients the exact position of the abnormal gland. Sixty-two patients underwent minimally invasive surgery, namely in 21 patients with a unilaterally focused approach and in 33 patients with a bilateral approach (27 of these underwent simultaneous thyroid resection). Sensitivity for CT-MIBI-SPECT image fusion was 88%, for CT alone 70%, and for MIBI-SPECT alone 59%. Specificity for CT-MIBI-SPECT image fusion was 99%, for MIBI-SPECT alone 95%, for CT alone 94%. Overall accuracy for CT-MIBI-SPECT image fusion was 97%, for CT alone 89%, for MIBI-SPECT 87%.

CONCLUSIONS

This study provides evidence that CT-MIBI-SPECT image fusion is superior to CT or MIBI-SPECT alone for preoperative localization of enlarged parathyroid glands in patients with single-gland primary hyperparathyroidism.

Preoperative 123I/99mTc-sestamibi subtraction SPECT and SPECT/CT in primary hyperparathyroidism

The trend toward focused surgical parathyroidectomy requires precise preoperative localization of parathyroid lesions in patients with hyperparathyroidism. The purpose of this study was to directly compare the diagnostic accuracy of (99m)Tc-sestamibi/(123)I subtraction SPECT with SPECT/CT for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism.

METHODS

A total of 61 consecutive surgical patients with primary hyperparathyroidism underwent both (123)I/(99m)Tc-sestamibi subtraction SPECT and SPECT/CT scans preoperatively, using a hybrid SPECT/CT instrument that combined a dual-detector SPECT camera with a 6-slice multidetector spiral CT scanner. Four hours after being given (123)I-sodium iodide orally, each patient received (99m)Tc-sestamibi intravenously, followed immediately by a simultaneous, dual-isotope SPECT scan of the neck and upper chest. Then, without moving the patient, we performed a non-contrast-enhanced CT scan of the same body region. Normalization and subtraction of the (123)I SPECT images from the (99m)Tc SPECT images were performed. The subtraction SPECT and the coregistered fused SPECT/CT studies were interpreted separately, with images scored on a 5-point scale. Surgical and histopathologic findings were used as the standard of comparison.

RESULTS

Surgery was successful in 57 patients (solitary parathyroid adenoma in 48 patients, double parathyroid adenomas in 6 patients, and 10 hyperplastic parathyroid glands in 3 patients). The sensitivities of SPECT (50/70 = 71%) and SPECT/CT (49/70 = 70%) were similar (P = 0.779). The specificity of SPECT/CT (26/27 = 96%) was significantly greater than that of SPECT (13/27 = 48%; P = 0.006). The receiver-operating-characteristic area under the curve of SPECT/CT (0.833) was significantly greater than that of SPECT (0.632; P < 0.001).

CONCLUSION

SPECT/CT is significantly more specific than dual-isotope subtraction SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism.

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.

Cervical thymectomy for intrathymic parathyroid adenomas during minimally invasive parathyroidectomy

BACKGROUND

The development of an intrathymic parathyroid adenoma is common, and thymectomy is a significant component of the parathyroid surgeon's technical armamentarium. Over the last decade, minimally invasive parathyroidectomy (MIP) has become the standard technique for removal of an abnormal parathyroid gland, and the requirement for thymectomy should remain unchanged during the era of minimally invasive techniques. The aim of this paper was to assess the feasibility and outcomes of cervical thymectomy for intrathymic parathyroid adenomas during MIP.

METHODS

This is a retrospective case series. The study group comprised all patients undergoing parathyroidectomy in the University of Sydney Endocrine Surgical Unit during a 5-year period (January 2001 to December 2005). Patients undergoing MIP and open parathyroidectomy with a concomitant cervical thymectomy were compared.

RESULTS

A total of 840 patients underwent parathyroid surgery for primary hyperparathyroidism (PHPT) during this period. A total of 30 MIP procedures with concurrent thymectomy were performed, and 99 open bilateral neck explorations with cervical thymectomy were performed. Of the MIP thymectomy group, there were 25 female and 5 male patients; the average age was 57 years (range, 22 to 82). A mean length of 34 mm of thymus was extracted via the minimally invasive approach (range, 8 to 85 mm). In 5 cases, only fatty tissue was identified histologically, and, in 5 cases, a small supernumerary parathyroid gland was identified in the histologic specimen. Only 1 patient suffered temporary, recurrent laryngeal nerve palsy; there were no cases of postoperative hemorrhage requiring return to the operating room.

CONCLUSIONS

Cervical thymectomy for removal of intrathymic parathyroid adenomas can be performed during lateral focused mini-incision MIP with a safety and efficacy equivalent to open bilateral neck explorations.

Remedial surgery for primary hyperparathyroidism

Remedial parathyroid surgery is a complex undertaking for even the most experienced parathyroid surgeon. It involves a careful preoperative evaluation, including the confirmation of the initial diagnosis of primary HPTH, use of the appropriate localization studies, knowledge of the details of the previous exploration, and surgical re-exploration, including the use of intraoperative localization adjuncts, such as the rapid intraoperative PTH assay (Fig. 6). Althoughthe success rate of remedial explorations can be as high as 98%, complication rates are higher than in initial cervical explorations for parathyroid disease.

Scandinavian Quality Register for Thyroid and Parathyroid Surgery: audit of surgery for primary hyperparathyroidism

BACKGROUND AND AIM

Scandinavian Quality Register for Thyroid and Parathyroid Surgery is an on-line web-based database with the aim to improve the quality of thyroid and parathyroid surgery. Preliminary data from surgery for primary hyperparathyroidism are reported here.

MATERIALS AND METHODS

Fifteen departments registered 806 operations, with 639 women (79.7%) and 167 men. The median age of the patients was 62 years.

RESULTS

Approximately 95.4% of the patients had sporadic disease and first time operation was performed in 93.8% of the patients. Localization examinations were performed in 524 patients (65%); sestamibi scintigraphy in 413 patients, with a true positive adenoma localization in 64.4% and ultrasound in 293 patients with adenoma localization in 61.1%. Bilateral neck exploration was performed in 66.8%, unilateral exploration in 16.1%, and focused minimal invasive surgery in 17.1%. In 301 patients planned for limited parathyroid exploration, conversion to bilateral neck surgery occurred in 11%. The cure rate, based on short follow-up, was 91.9%. Postoperative hypocalcemia occurred in 11.4% of the patients, and was associated with reoperation, concomitant thyroid operation, and the weight of excised parathyroid tissue.

CONCLUSION

Localization examinations are performed in 2/3 of the patients, but limited neck exploration was performed in only approximately 1/3 of the operations. The cure rate was lower and postoperative hypocalcemia was more frequent than expected.

Sestamibi scanning and outcomes in minimally invasive parathyroidectomy

OBJECTIVE

To determine whether preoperative sestamibi scanning facilitates the desired outcome of successful completion of minimally invasive parathyroidectomy (MIP) and also to analyze the results in patients with underlying concurrent thyroid disease.

METHODS

We undertook a retrospective analysis by review of medical records of 133 parathyroidectomies for sporadic primary hyperparathyroidism with preoperative sestamibi scanning during a 26-month period at our medical center.

RESULTS

Of the 133 patients with preoperative sestamibi scanning, 106 were candidates for MIP, and 86 had positive scans showing a localized focus of uptake. MIP, with use of intraoperative parathyroid hormone level monitoring, was successfully completed in 70 patients; the other 16 patients required conversion to bilateral neck exploration. Another 20 patients with negative sestamibi scans (no localized focus of uptake) also underwent MIP. The surgeon used ultrasonography or subtle, nondiscrete sestamibi scan findings to decide on this approach. In this group, 65% of patients had successful completion of MIP, in comparison with 81% (95% confidence interval, 72% to 89%) in the group with positive scans (P = 0.13). Subgroup analysis of patients with underlying concomitant thyroid abnormalities showed successful completion of MIP in 39 of 51 (76%), in comparison with 31 of 35 patients (89%) without thyroid abnormalities (P = 0.16).

CONCLUSION

In patients with sporadic primary hyperparathyroidism, finding a localized focus of uptake on a preoperative sestamibi scan facilitates successful completion of MIP. In patients with underlying thyroid disease, positive sestamibi scans are still useful in completing MIP, but more patients in this group require conversion to bilateral neck dissection.

Negative Imaging Studies for Primary Hyperparathyroidism Are Unavoidable: Correlation of Sestamibi and High-Resolution Ultrasound Scanning with Histological Analysis in 150 Patients

BACKGROUND

Preoperative localization studies with Tc99m-sestamibi have become an integral step in the preoperative assessment of patients with primary hyperparathyroidism (PHPT). This enables scan-directed minimally invasive parathyroidectomy (MIP) to be the preferred treatment for PHPT in many units. This study aimed to identify factors that lead to negative imaging studies in patients with PHPT.

METHODS

Over a 3-year period consecutive unselected patients with PHPT underwent Tc99m-sestamibi scanning and high-resolution ultrasound (US) scanning by the same radiologist. When localization studies were concordant, patients underwent MIP. Those patients with negative imaging studies underwent bilateral neck exploration. Histology slides were independently reviewed and the proportion of chief cells and oxyphil cells within each adenoma was estimated.

RESULTS

One hundred and fifty-eight patients underwent localization studies (38 men and 120 women, aged 61.8 +/- 15.2 years). Sestamibi scans were negative in 52 (32%) and positive in 106 (68%) patients. There was a higher incidence of hyperplasia in the group of patients with negative sestamibi scans (4 out of 52 vs. 4 out of 103, P < 0.05, chi2 test). In patients with negative sestamibi scans the majority of adenomas were formed predominantly from chief cells (26 out of 36) while the majority of patients with adenomas composed predominantly of oxyphil cells had positive scans (21 out of 23) (P < 0.05, chi2 test). The weight of parathyroid adenomas was higher when sestamibi scans were positive (median: 1,180 vs. 517 mg, P < 0.05, Student's t-test).

CONCLUSION

Successful preoperative localization of parathyroid adenomas using Tc99m-sestamibi scanning is influenced by the cytological predominance of individual tumors. Negative scans might therefore be unavoidable in a subgroup of patients.

Surgeon-performed ultrasonography as the initial and only localizing study in sporadic primary hyperparathyroidism

BACKGROUND

With a secure diagnosis of hyperparathyroidism, preoperative localization of abnormal glands is the initial step toward limited parathyroidectomy. Nuclear scanning and ultrasonography done by third parties are costly. We investigated whether ultrasonography performed by the operating surgeon (SUS) could be the initial and only preoperative localization study in patients with sporadic primary hyperparathyroidism.

STUDY DESIGN

Two hundred twenty-six patients underwent preoperative SUS and Sestamibi scans before limited parathyroidectomy guided by quick intraoperative parathyroid hormone assay. SUS findings were noted before the surgeon had access to the scan results. Charge for localization by nuclear scan was 1,315 dollars and 204 dollars for SUS. Successful localization was determined by operative findings, intraoperative hormone dynamics, and postoperative calcium levels.

RESULTS

SUS correctly localized all the offending glands in 173 of 226 (77%) successfully treated patients. In 53 patients, SUS showed no parathyroid gland (n = 32), did not recognize multiglandular disease (n = 5), and showed an incorrect location of the abnormal gland (n = 16). In these patients, the technetium-99m-sestamibi scans successfully identified all abnormal tissue in 30 of 53 (57%). Localization using both methods was correct in 203 of 226 (90%) patients. Accuracy of SUS and scans used separately was equal. With use of quick intraoperative parathyroid hormone assay, successful parathyroidectomy was accomplished in 223 of 226 (99%), unilateral exploration in 88%, and overnight stay avoided in 78% of patients.

CONCLUSIONS

With equal accuracy, SUS is more convenient, less expensive, and noninvasive when compared with scans. Sestamibi should be used when the SUS is negative or equivocal. SUS should be the initial localizing test in the treatment of sporadic primary hyperparathyroidism.

Radionuclide imaging of the parathyroid glands

The parathyroid glands, which usually are situated behind the thyroid gland, secrete parathyroid hormone, or PTH, which helps maintain calcium homeostasis. Primary hyperparathyroidism results from excess parathyroid hormone secretion. In secondary hyperparathyroidism, the normal PTH effect on bone calcium release is lost. Serum PTH rises, causing generalized hyperplasia. In tertiary hyperparathyroidism, a complication of secondary hyperparathyroidism, normal feedback mechanisms governing PTH secretion are lost, parathyroid gland sensitivity to PTH decreases, and the threshold for inhibiting PTH secretion increases. 99mTc sestamibi, or MIBI, the current radionuclide study of choice for preoperative parathyroid localization, can be performed in various ways. The "single-isotope, double-phase technique" is based on the fact that MIBI washes out more rapidly from the thyroid than from abnormal parathyroid tissue. However, not all parathyroid lesions retain MIBI and not all thyroid tissue washes out quickly, and subtraction imaging is helpful. Many MIBI avid thyroid lesions also accumulate pertechnetate and iodine, and subtraction reduces false positives. Single-photon emission computed tomography provides information for localizing parathyroid lesions, differentiating thyroid from parathyroid lesions, and detecting and localizing ectopic parathyroid lesions. The most frequent cause of false-positive MIBI results is the solid thyroid nodule. Other causes include thyroid carcinoma, lymphoma, and lymphadenopathy. False-negative results occur because of several factors. Lesion size is important. Cellular function also may be important. Parathyroid tissue that expresses P-glycoprotein does not accumulate MIBI. Parathyroid adenomas that express either P-glycoprotein or the multidrug resistance related protein MRP are less likely to accumulate MIBI. MIBI scintigraphy is less sensitive for detecting hyperplastic parathyroid glands. In secondary hyperparathyroidism, MIBI uptake is more closely related to cell cycle than to gland size. Mitochondria-rich oxyphil cells presumably account for MIBI uptake in parathyroid lesions. Fewer oxyphil cells, and hence fewer mitochondria, may explain both lower uptake and rapid washout of MIBI from some lesions. MIBI is also less sensitive for detecting multigland disease than solitary gland disease.

Surgeon-Performed Ultrasound Improves Localization of Abnormal Parathyroid Glands

With a secure diagnosis of hyperparathyroidism, preoperative localization of abnormal glands is the initial step toward limited parathyroidectomy (LPX). We investigated whether ultrasonography in the hands of the surgeon (SUS) could improve the localization of abnormal parathyroids when sestamibi scans (MIBI) were negative or equivocal. One hundred eighty patients with sporadic primary hyperparathyroidism (SPHPT) underwent preoperative SUS and MIBI scans before LPX guided by intraoperative parathormone assay. When the sestamibi scans were negative, SUS was used to localize the parathyroid, distinguish parathyroid from thyroid tissue, and to guide the intraoperative jugular venous sampling for differential elevation of parathyroid hormone (PTH). Operative findings, intraoperative hormone dynamics, and postoperative calcium levels determined successful localization. MIBI was negative or equivocal in 36/180 (20%) patients: 1) showed no parathyroid gland in 22 patients, 2) suggested an incorrect location for the abnormal gland in 9, and 3) was insufficient in recognizing multiglandular disease in 5. In these 36 patients, the addition of SUS led to the successful identification of the abnormal tissue in 19/36 (53%). In the remaining 17 patients with negative/equivocal scans, the parathyroid could not be clearly visualized by SUS. In these patients, SUS facilitated LPX by aiding preoperative transcutaneous jugular venous sampling for differentially elevated PTH (n = 3) and identifying questionable thyroid nodule versus parathyroid tissue (n = 1). Overall, SUS was useful in 23/36 (67%) patients with nonlocalizing MIBI scans, thus improving the rate of localization from 80 per cent to 93 per cent ( P < 0.01). Surgeon-performed cervical ultrasonography improved the localization of abnormal parathyroids by MIBI scan, adding to the success of limited parathyroidectomy.

A Case of Thoracic Hemorrhage due to Ectopic Parathyroid Hyperplasia With Chronic Renal Failure

We report a case of secondary hyperparathyroidism in a 53-year-old man who had thoracic hemorrhage originating from an ectopic thymic parathyroid gland tumor. He was on long-term hemodialysis treatment and had persistent secondary hyperparathyroidism caused by 3 swollen parathyroid glands around the thyroid gland and a mediastinal ectopic parathyroid gland tumor. Parathyroidectomy and removal of the mediastinal tumor were planned. Preoperative chest x-ray and a computed tomographic scan obtained just before surgery showed left pleural effusion. Furthermore, diagnostic thoracentesis yielded hemorrhagic exudative fluid. Thoracoscopy confirmed the presence of a mediastinal tumor lesion that was bleeding into the thoracic cavity. The tumor was resected using thoracoscopic surgery, and ectopic thymic parathyroid gland hyperplasia associated with hemorrhage was pathologically diagnosed. A postoperative diagnostic chest computed tomographic scan and technetium 99m 2-methoxyisobutyl isonitrile scintigraphy showed successful removal of the ectopic parathyroid gland tumor. Subsequently, the secondary hyperparathyroidism could be clinically controlled by medical treatment, and total parathyroidectomy has been postponed indefinitely. We consider that hemorrhage from the ectopic parathyroid gland tumor resulted in thoracic bleeding. To our knowledge, this is the first case report of secondary hyperparathyroidism with thoracic hemorrhage originating from an ectopic mediastinal parathyroid gland.

The surgeon's armamentarium to the surgical treatment of primary hyperparathyroidism

Parathyroidectomy cures the vast majority of patients with primary hyperparathyroidism (HPT). While bilateral neck exploration has been the mainstay of therapy, recent advances in technology have revolutionized the field making a focused approach to parathyroidectomy a reality. The development of accurate pre-operative localization with sestamibi scanning, effective unilateral, endoscopic and video-assisted techniques, and rapid intra-operative parathyroid hormone (PTH) testing have made it possible to cure patients with the least amount of surgical dissection possible. In this paper, we will explore the role of focused parathyroidectomy in the surgical treatment of primary HPT.

???Shine Through??? on Dual Tracer Parathyroid Scintigraphy: A Potential Pitfall in Interpretation

Dual tracer scintigraphy has become the procedure of choice for preoperative localization of parathyroid adenomas. The typical protocol used by most laboratories is to initially perform a Tc-99m sestamibi (MIBI) study with early and delayed (2-3 hours) washout phase images. This is followed by a thyroid-specific Tc-99m pertechnetate study. A potential pitfall exists if the delayed phase of the initial MIBI study shows an intense, abnormal focus of retention. This focus may interfere with interpretation of the subsequent pertechnetate study because of a "shine through" effect. To differentiate a parathyroid adenoma from a thyroid adenoma, it may be necessary to repeat the thyroid-specific pertechnetate scan on a separate day after the dual tracer study.

Unilateral surgery for hyperparathyroidism: indications, limits, and late results--new philosophy or expensive selection without improvement of surgical results?

We assessed the "late" results after unilateral parathyroidectomy (PTX) performed for selected indications. From October 1998 throughout March 2001 we operated on 454 patients for hyperparathyroidism (HPT). A positive unifocal (99m)tc-MIBI scan was required for the unilateral approach to be used. Intact parathormone (PTH) measurements were done intraoperatively. Postoperative calcium and PTH serum levels of unilaterally operated patients were checked. Follow-up has been 16.2 months (range 6-40 months). Of the 454 patients, 336 (74.0%) were not eligible for the unilateral approach; and 125 (27.5%) of the 454 patients had renal HPT. Among the 329 patients with primary HPT, 125 (38.0%) were excluded for well established reasons, and in 77 other cases (23.5%) preoperative imaging results did not allow the unilateral approach. Altogether, 126 patients (38.3%) with primary HPT were selected for the unilateral approach. Of the 126 unilateral operations, 8 (6.3%) had to be converted to a bilateral procedure. Among the 118 patients with a unilateral approach, 3 patients have been reoperated for overlooked contralateral disease, and 13 dropped out of the study. A total of 102 postoperative calcium and PTH serum late levels are known: 90 (88.2%) patients had normal levels; 10 (9.8%) had a high PTH level, and 2 (1.9%) had high ionized calcium levels. The failure rate in selected cases was 4.2% (5/118) (three were reoperated, and two had a supranormal postoperative ionized Ca level). Even with stringent indications, the late results of unilateral surgery (95.8% cure rate) barely matched those of conventional bilateral surgery (97.6% cure rate). The economic impact of such a surgical strategy should be clarified.

[Surgery of hyperparathyroidism and of its potential recurrence in the MEN I setting]

Hyperparathyroidism (HPT) in the setting of multiple endocrine neoplasia type 1 (MEN I) is almost constant and occurs often early in the course of the disease. Underlying pathology is almost always multiglandular because of its genetic origin, and therefore, in case of less than subtotal parathyroidectomy, recurrence rate amounts to 20-40%. Operative strategy aims to find and check all parathyroid glands including possible supernumerary one(s) found in 30% of patients and to perform a subtotal parathyroidectomy. Combined transcervical thymectomy is a mandatory part of the procedure. Moreover HPT triggers the secretion of associated gastrinomas and its cure can thus delay the timing of duodenopancreatic surgery. In case of recurrent HPT, preoperative work-up yields to image the parathyroid remnant and possible supernumerary gland(s). Reoperation aims to remove all parathyroid tissue. Cryopreservation can be useful in case of permanent long-lasting symptomatic hypoparathyroidism.

Intraoperative testing for parathyroid hormone: a comprehensive review of the use of the assay and the relevant literature

OBJECTIVE

The rapid intraoperative parathyroid hormone assay is transforming the parathyroidectomy procedure. We present a review of the literature on the use of the assay as an adjunct to surgery. To our knowledge, this is the first review of the literature to encompass and compare all known primary studies of this assay in parathyroidectomy patients.

DATA SOURCES

Articles were collected by searching MEDLINE databases using relevant terminology. The references of these articles were reviewed for additional studies. Supplementary articles pertinent to the parathyroidectomy procedure, preoperative parathyroid localization studies, and intraoperative parathyroid hormone assay development also were examined.

STUDY SELECTION AND DATA EXTRACTION

One hundred sixty-five references were analyzed and categorized separately into groups.

DATA SYNTHESIS

The primary studies of intraoperative data on patients undergoing parathyroidectomy were compared when possible. Studies were analyzed by type of assay used, where performed, turnaround time, and efficiency of use. Reviews of the types of parathyroid surgery and preoperative localization were included for educational purposes.Conclusions.-The intraoperative parathyroid hormone assay is a useful adjunct to preoperative imaging and parathyroid surgery because of its unique ability to detect an occult residuum of hyperfunctioning parathyroid tissue. Use of this assay will obviate the need for frozen section in most routine cases. The test facilitates minimally invasive parathyroidectomy for single parathyroid adenomas, which, in turn, improves cost-effectiveness and cosmetic outcome. Its use in patients with known preoperative multiglandular disease is promising but requires further study.

Tc-99m-MIBI scintigraphy for recurrent hyperparathyroidism after total parathyroidectomy with autograft

The aim of this study is to assess the sensitivity of Tc-99m-MIBI for the pre-operative localization of hyperfunctioning parathyroid glands in patients with persistent or recurrent hyperparathyroidism (HPT) after total parathyroidectomy (PTX) with autograft.

PATIENTS AND METHODS

Tc-99m-MIBI scintigraphy was performed on 7 patients (3 men and 4 women; aged 32 to 62) on hemodialysis with persistent or recurrent HPT after PTX due to secondary hyperparathyroidism. Tc-99m-MIBI of 370 MBq was injected intravenously. Double-phase planar images were acquired at 15 min and 120 min-postinjection. SPECT images of the chest in an early phase were also obtained.

RESULTS

All patients underwent surgery after scintigraphy. The enlarged parathyroid grafts were removed in 4 patients. An unusual location of parathyroid hyperplasia was found in 2 patients. In one patient, the abnormal graft coexisted with an ectopic parathyroid in the mediastinal region. Tc-99m-MIBI was able to identify all hyperfunctioning parathyroids correctly (100% sensitivity). In one case, a focus of the increased uptake in SPECT was considered as a false positive. The remnant of ectopic parathyroid in the mediastinum was only detected by SPECT images.

CONCLUSION

Tc-99m-MIBI parathyroid scintigraphy is useful for the pre-operative localization of persistent or recurrent HPT following total PTX with autograft.

Impact of Hypercalcemia and Parathyroid Hormone Level on the Sensitivity of Preoperative Sestamibi Scanning for Primary Hyperparathyroidism

Technetium 99m sestamibi scanning (MIBI) can direct unilateral parathyroidectomy. However, the clinical application remains variable with sensitivities ranging from 55 to 100 per cent. We examined whether patient factors including serum calcium (Ca) and parathyroid hormone (PTH) levels impact the sensitivity of MIBI. We completed a retrospective review of 102 patients with primary hyperparathyroidism and mild hypercalcemia who underwent preoperative MIBI. All patients underwent bilateral neck explorations with abnormalities confirmed by histopathology. MIBI sensitivity was correlated with preoperative Ca and PTH levels using univariate and logistic regression analysis. The mean preoperative Ca was 11.0 mg/dL and the mean PTH was 158 pg/mL. More than 95 per cent of patients with Ca greater than 11.3 mg/dL had a positive scan as compared with 60 per cent of those with lesser values ( P = 0.0024). Similarly a serum PTH level greater than 160 pg/mL correlated with positive scans in 93 per cent as opposed to 57 per cent in those with lower levels ( P = 0.006). Using a scan-directed approach 65 of 74 patients would have undergone unilateral exploration; this would yield a 7.7 per cent operative failure rate because of contralateral multigland disease. Lower Ca and PTH levels seem to correlate with reduced sensitivity of MIBI. Increasing acceptance of surgery for hyperparathyroidism with minimal hypercalcemia may make MIBI less attractive without ancillary diagnostic measures such as rapid parathormone assays.

Surgical considerations and controversies in thyroid and parathyroid surgery

The techniques of thyroid surgery have been fully elucidated in several surgical texts and atlases. This article discuss surgical pearls of thyroid and parathyroid surgery. We discuss preoperative, intraoperative, and postoperative considerations and controversies for both procedures.

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.