Thallium-pertechnetate subtraction scanning in the preoperative localization of an ectopic undescended parathyroid gland

Although bilateral exploration is highly effective in the treatment of primary hyperparathyroidism, minimally invasive parathyroidectomy has evolved into the procedure of choice when a single parathyroid lesion can be localized preoperatively. In this article, we discuss the utilization of thallium-pertechnetate subtraction scanning (TPSS) after technetium Tc-99m sestamibi scintigraphy failed to localize an ectopic parathyroid adenoma. Subsequently, radioguided resection of an undescended parathyroid adenoma inferior to the left submandibular gland was performed with surgical cure after a single procedure. This case report illustrates the importance of TPSS as a second-line modality in preoperative adenoma localization, thereby using minimally invasive techniques to successfully treat this patient's primary hyperparathyroidism.     

Diagnosis of hyperparathyroidism

AIM: To preoperatively localize enlarged parathyroid glands in patients with hyperparathyroidism (HPT). METHODS: Besides clinical and biochemical workup, high-resolution ultrasonography (US) is the most commonly used imaging method.Additionally,Tc-99m-MIBI scintigraphy in subtraction or biphasic technique, computed tomography (CT) and magnetic resonance imaging (MRI) are used. RESULTS: US fails to detect a minimum of 10% of enlarged parathyroid glands,most commonly due to ectopic location, or difficult examination conditions, such as nodular goiter or previous surgery. If attempted US localization is unsuccessful, multiphase scintigraphy, using Tc-99m-sestamibi, can help to locate ectopic adenomas in the mediastinum. With SPECT, ademomas can be found which escape detection on planar scans due to their small size.With combined use of US and scintigraphy, a correct localization of parathyroid adenomas is possible in up to 90%. CT and MRI are of limited value due to their low specificity. CONCLUSION: For newly diagnosed hyperparathyroidism, high-resolution US is the method of choice for localizing parathyroid adenomas.If ultrasound fails to detect a lesion, Tc-99m-MIBI scintigraphy is recommended. In patients scheduled for re-operation for recurrent or persistent HPT, a preoperative detection of a parathyroid adenoma should be attempted whenever possible, in order to minimize the extent of surgery. The role of CT or MRI is mainly to help to better anatomically localize a suspected adenoma previously detected with scintigraphy.     

Preoperative localization and radioguided parathyroid surgery.

Clinical or subclinical hyperparathyroidism is one of the most common endocrine disorders. Excessive secretion of parathyroid hormone is most frequently caused by an adenoma of >or=1 parathyroid gland. Unsuccessful surgery with persistent hyperparathyroidism, due to inadequate preoperative or intraoperative localization, may be observed in about 10% of patients. The conventional surgical approach is bilateral neck exploration, whereas minimally invasive parathyroidectomy (MIP) has been made possible by the introduction of (99m)Tc-sestamibi scintigraphy for preoperative localization of parathyroid adenomas. In MIP, the incision is small, dissection is minimal, postoperative pain is less, and hospital stay is shorter. Localization imaging techniques include ultrasonography, CT, MRI, and scintigraphy. Parathyroid scintigraphy with (99m)Tc-sestamibi is based on longer retention of the tracer in parathyroid than in thyroid tissue. Because of the frequent association of parathyroid adenomas with nodular goiter, the optimal imaging combination is (99m)Tc-sestamibi scintigraphy and ultrasonography. Different protocols are used for (99m)Tc-sestamibi parathyroid scintigraphy, depending on the institutional logistics and experience (classical dual-phase scintigraphy, various subtraction techniques in combination with radioiodine or (99m)Tc-pertechnetate). MIP is greatly aided by intraoperative guidance with a gamma-probe, based on in vivo radioactivity counting after injection of (99m)Tc-sestamibi. Different protocols used for gamma-probe-guided MIP are based on different timing and doses of tracer injected. Gamma-probe-guided MIP is a very attractive surgical approach to treat patients with primary hyperparathyroidism due to a solitary parathyroid adenoma. The procedure is technically easy, safe, with a low morbidity rate, and has better cosmetic results and lower overall cost than conventional bilateral neck exploration. Specific guidelines should be followed when selecting patients for gamma-probe-guided MIP.     

Preoperative localization of enlarged parathyroid glands with ultrasonically guided fine needle aspiration for parathyroid hormone assay

For preoperative localization of enlarged parathyroid glands, several imaging techniques have been used. In this study we demonstrate the feasibility of using ultrasonography with fine needle aspiration for parathyroid hormone assay as a preoperative localization procedure in 21 patients with primary hyperparathyroidism. A single adenoma was found in 18 patients while 3 patients had multiglandular disease. Ultrasonically guided fine needle biopsy was possible in 11 cases. In 8 of these aspirates, a high parathyroid hormone content was found. In all 8 cases the localization was confirmed at surgery. We conclude that the efficiency to preoperatively localize enlarged parathyroid glands is enhanced by fine needle aspiration.     

The usefulness of Tc-99m tetrofosmin scintigraphy in the diagnosis and localization of hyperfunctioning parathyroid glands

PURPOSE: The aim of the work was to study the diagnostic value of Tc-99m tetrofosmin to localize anomalous parathyroid glands in patients with hyperparathyroid disease. METHODS: We studied 31 patients, 19 with primary and 12 with secondary hyperparathyroid disease. Five of these patients were renal graft recipients. All patients underwent surgery. Each patient was injected with 555 to 740 MBq (15 to 20 mCi) Tc-99m tetrofosmin. Subsequently, radionuclide images were acquired 15 and 120 minutes after injection using a low-energy, all-purpose, parallel-hole collimator. Pertechnetate thyroid scintigraphy was obtained in nine cases (24 to 48 h later) when the thyroid activity made it difficult to identify the parathyroid glands. RESULTS: All cases showed tracer uptake as early as 15 minutes after injection. In the group of patients with primary hyperparathyroid disease, 15 showed focal uptake in a parathyroid gland, and surgery revealed an adenoma in the same location. In one patient with hyperplasia, scintigraphy identified only two of four diseased glands. In the three remaining cases, scintigraphy showed focal uptake in the lower parathyroid gland, whereas at surgery the abnormal gland was located in the upper pole. In the secondary hyperparathyroidism group, seven patients showed diffuse tracer uptake in two or more glands, and histologic analysis confirmed hyperplasia in all of them. Five cases showed focal uptake, with three evaluated after surgery (uptake in the only remaining gland); one of them was a renal graft recipient, and the remaining patient had chronic renal failure and was receiving hemodialysis. CONCLUSIONS: Our results suggest that Tc-99m tetrofosmin may be a suitable tracer for preoperative detection and screening of anomalous parathyroid glands. The earlier images at 15 minutes were better than those at 120 minutes. Tc-99m tetrofosmin is cleared more slowly from the normal thyroid than is Tc-99m sestamibi, and both of these tracers may give better results than the old pertechnetate TI-201 subtraction technique.     

Association of parathyroid adenoma and autonomous nodule of the thyroid. Diagnostic efficacy of 201thallium-99mtechnetium scintigraphy

The thallium-technetium subtraction technique, proposed originally by Ferlin and co-workers, is now widely used to localize parathyroid adenoma. We report here the case of a hypercalcemic woman, referred to our ward with the biologically assessed diagnosis of primary hyperparathyroidism. Thallium-technetium subtraction scintigraphy not only successfully localized the parathyroid adenoma but also revealed the existence of an autonomous nodule of the thyroid, which was not suspected. It has previously been shown that this method can localize parathyroid adenoma in cases of cold thyroid nodule. This report shows that this is also true in the case of hot thyroid nodule. No observations of concomitant parathyroid adenoma and autonomous nodule of the thyroid have been reported (at least during the two past decades). Is this association casual or has it never been noticed? Further examinations can be performed with thallium when a hot thyroid nodule is found in a hypercalcemic patient.     

Diagnostic dilemmas in parathyroid scintigraphy.

PURPOSE: Tc-99m MIBI scintigraphy can be useful for preoperative localization of parathyroid adenomas, despite its limited sensitivity. To refine interpretation, the authors conducted prospective reviews of the scintigraphic studies of patients with concomitant thyroid nodular disease and revised the false-negative and false-positive results. MATERIALS AND METHODS: Seventy-seven patients with primary hyperparathyroidism, associated with a solitary parathyroid adenoma, underwent dual-phase MIBI scintigraphy with subsequent injection of Tc-99m pertechnetate before surgery. The false-negative and false-positive scintigraphic findings were identified and revised. RESULTS: After surgery, revision of 19 false-negative scans of the total 77 studies led to the demonstration of an adenoma in seven patients. In five of the seven studies, the adenoma had been overlooked as a result of rapid tracer washout. Two additional small focal lesions would have also been identified if subtraction had been used for differences in contour of the MIBI and pertechnetate images. Four studies were interpreted falsely as abnormal, leading to a positive predictive value of 91%; three were associated with thyroid nodular disease. CONCLUSIONS: Differential washout of MIBI from thyroid and parathyroid tissue is not universal. When MIBI is washed out rapidly from parathyroid adenomas, subtraction of a thyroid image should be performed and differences in contour delineated to localize the adenoma accurately. Some, but not all, thyroid lesions account for the false-positive findings.     

Mediastinal parathyroid localization: Possible pitfall in technetium-thallium subtraction scintigraphy

Two cases of mediastinal localization of parathyroid adenoma are presented, in which technetium-thallium subtraction scintigraphy yielded a positive result. Both patients had already undergone a negative surgical neck exploration. We suggest that, in case of negative subtraction scintigraphy and negative surgical exploration in proven primary hyperparathyroidism, subtraction scintigraphy should be repeated with emphasis on the superior mediastinum, and in all cases, the use of a non-zoom, large field of few procedure is recommended for technetium-thallium subtraction scintigraphy.     

Enhanced scintigraphic protocol required for optimal preoperative localization before targeted minimally invasive parathyroidectomy

At our tertiary care institution, a targeted minimally invasive parathyroidectomy (MIP) is the preferred surgical procedure for primary hyperparathyroidism. Similar to unilateral neck exploration (UNE), preoperative scintigraphic localization of the adenoma in relation to the midline is required. However, in contrast to the abbreviated standard incision for UNE, 2 distinct incision sites, 1 medial and 1 lateral, are available on each side with MIP. The incision site is ultimately chosen based on scintigraphic determination of the adenoma's vascular origin to facilitate ligation and removal. Unfortunately, the scintigraphic location of a parathyroid adenoma does not necessarily reflect the site of its vascular origin. We reviewed our database to identify factors that accurately predict the site of vascular origin of parathyroid adenomas. A retrospective chart review was performed on 125 patients who underwent Tc-99m sestamibi scintigraphy and parathyroidectomy. Scintigraphic localization, surgical findings, and histopathology were recorded. Preoperative image interpretations that were discordant with operative findings were independently reviewed. Scintigraphy identified the presence of an adenoma in 105 of 118 patients (89%) with primary hyperparathyroidism. In 17 of the 105 cases (16%), the scintigraphic interpretation did not accurately reflect the site of superior or inferior vascular origin seen at surgery. In many discordant cases, anterior images were insufficient for determining the vascular origin. The posterior displacement of an adenoma in relation to the thyroid on early lateral images was often critical in determining the superior or inferior vascular origin. Scintigraphic determination of the superior or inferior vascular origin of a parathyroid adenoma directs incision placement for MIP. Imaging protocols should include early lateral images when localizing parathyroid adenomas before minimally invasive parathyroidectomy.     

Preoperative parathyroid gland localization with technetium-99m sestamibi in secondary hyperparathyroidism

Technetium-99m sestamibi scintigraphy has become a valuable tool in locating parathyroid glands in patients with primary hyperparathyroidism. The aim of this study was to evaluate its usefulness in secondary hyperparathyroidism. Twenty patients were injected intravenously with 740 MBq of ^99mTc-sestamibi and images were obtained at 15 min and 2 h post injection. All patients underwent parathyroid ultrasonography (US) as well as bilateral surgical neck exploration and 64 parathyroid glands were removed. US revealed at least one enlarged gland in 15/20 patients (75%), while ^99mTc-sestamibi scintigraphy showed focal areas of increased uptake in at least one gland in 17/20 patients (85%). When imaging results for all glands were evaluated according to surgical results, sensitivity was 54% for parathyroid scintigraphy and 41% for US, and specificity was 89% for both imaging techniques. There was a discrepancy between the two imaging modalities in 28 glands (35%). The mean surgical weight of US-positive glands (1492±1436 mg) was significantly higher than that of US-negative glands (775±703 mg) (P<0.05). However, there were no significant differences in weight between sestamibi-positive and sestamibi-negative glands. When only sestamibi-positive glands were considered, a positive correlation between uptake and weight was found (r=0.4, P<0.05). In conclusion, parathyroid US and ^99mTc-sestamibi scintigraphy are complementary imaging techniques in the preoperative localization of abnormal parathyroid glands in patients with secondary hyperparathyroidism. The limited sensitivity of the techniques means that patients will still require bilateral neck exploration; therefore routine preoperative parathyroid scanning in renal patients is not justified. Received 1 June and in revised form 6 August 1997     

Pre-operative Localization of Parathyroid Adenomas: A Comparison of Power and Colour Doppler Ultrasonography with Nuclear Medicine Scintigraphy

AIM: To compare power and colour Doppler ultrasonography (US) with nuclear medicine scintigraphy (NM) in the preoperative localization of parathyroid adenomas in patients with primary hyperparathyroidism (PHPT). MATERIALS AND METHODS: Thirty-one patients with biochemical evidence of PHPT underwent pre-operative US and NM for parathyroid adenoma localization. Both studies were interpreted independently without prior knowledge of the other study's findings. All patients had surgical removal of the parathyroid adenoma utilizing standard neck exploration or minimally invasive unilateral surgical techniques with rapid serum assay of circulating parathyroid hormone levels. RESULTS: All patients had single parathyroid adenomas at surgery. Prospective sensitivities for US, NM and both studies combined were 65%, 68%, and 74%, respectively, with a positive predictive value of 100% each. The adenoma was localized by only one imaging modality in 16% of cases. CONCLUSIONS: US and NM provide complementary roles in the pre-operative localization of parathyroid adenomas in patients with PHPT.     

Association of parathyroid adenoma and autonomous nodule of the thyroid. Diagnostic efficacy of 201thallium-99mtechnetium scintigraphy

The thallium-technetium subtraction technique, proposed originally by Ferlin and co-workers, is now widely used to localize parathyroid adenoma. We report here the case of a hypercalcemic woman, referred to our ward with the biologically assessed diagnosis of primary hyperparathyroidism. Thallium-technetium subtraction scintigraphy not only successfully localized the parathyroid adenoma but also revealed the existence of an autonomous nodule of the thyroid, which was not suspected. It has previously been shown that this method can localize parathyroid adenoma in cases of cold thyroid nodule. This report shows that this is also true in the case of hot thyroid nodule. No observations of concomitant parathyroid adenoma and autonomous nodule of the thyroid have been reported (at least during the two past decades). Is this association casual or has it never been noticed? Further examinations can be performed with thallium when a hot thyroid nodule is found in a hypercalcemic patient.     

Preoperative 99mTc-sestamibi scintigraphy in patients with primary hyperparathyroidism and concomitant nodular goiter: comparison of SPECT-CT, SPECT, and planar imaging

BACKGROUND: Investigations using a hybrid single photon emission computed tomography/computed tomography (SPECT-CT) scanning technique have been carried out in limited studies and have shown mixed results. However, the assessment of this technique for the detection of parathyroid adenoma in patients with a nodular goiter was performed in only one study with a small sample size. The aim of this prospective study was to assess the role of Tc-sestamibi parathyroid SPECT-CT scans for localization of parathyroid adenomas with a concomitant nodular goiter using Tc-methoxyisobutyl isonitrile (MIBI) scintigraphy and to compare it with SPECT and planar imaging. METHODS: This study was conducted on 48 patients with primary hyperparathyroidism and nodular goiter, who were candidates for parathyroid surgery and had been referred for parathyroid scintigraphy. The patients underwent an early set of planar Tc-MIBI scanning procedures first, followed by SPECT and CT scannings, and finally a delayed set of planar Tc-MIBI scannings. Sensitivity, specificity, negative and positive predictive values, and accuracy were determined on a per-parathyroid-gland basis for each scanning method, as defined by histology and follow-up. RESULTS: The surgery was successful in 48 out of 50 patients with primary hyperparathyroidism concomitant with thyroid nodularity, and data were completed for 80 sites in 48 patients. The accuracy of SPECT-CT in correctly identifying a parathyroid adenoma was 85.00, versus 75.00% for SPECT (P=0.01, significant). The sensitivity and specificity for SPECT-CT were 77.55 and 96.77%, respectively, versus 67.34 and 87.09%, respectively, for SPECT (P=0.12 and 0.12, not significant). There were nine sites that showed better localization on SPECT-CT scans relative to SPECT images, of which five sites were located in the ectopic regions. CONCLUSION: The results of our study indicate that SPECT-CT is more accurate than sestamibi planar imaging and SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism concomitant with thyroid nodularity. Also, we would recommend the use of SPECT-CT for a workup of all patients with ectopic glands who are scheduled for minimally invasive parathyroid surgery.     

The usefulness of single photon emission computerized tomography with pinhole collimator (P-SPECT) in preoperative localization of hyperfunctioning parathyroid glands in patients with secondary hyperparathyroidism

PURPOSE: In this study the usefulness of parathyroid scintigraphy was evaluated in a group of patients affected by secondary hyperparathyroidism, combining the conventional double-tracer subtraction planar scintigraphy with pinhole-SPECT (P-SPECT) acquisition and comparing the scintigraphic data with those obtained by ultrasonography. MATERIALS AND METHODS: Twenty-four patients with secondary hyperparathyroidism were enrolled, 19 with chronic renal failure on haemodialysis and 5 with renal transplant. All patients underwent parathyroidectomy because of their unresponsiveness to medical therapy and/or severe osteodystrophy. Histology ascertained a single adenoma each in 3 patients and 61 hyperplastic glands in the remaining 21 cases. Before surgery, all patients were submitted to high resolution ultrasonography and afterwards to double-tracer subtraction planar parathyroid scintigraphy ((99m)Tc-pertechnetate/(99m)Tc-tetrofosmin) followed by neck P-SPECT acquisition. RESULTS: P-SPECT was true positive in all 24 patients, while both planar and ultrasonography were false negative in one case. Globally, P-SPECT identified 60/64 hyperfunctioning parathyroid glands, planar 47/64 and ultrasonography 45/64. P-SPECT sensitivity (93.7%) was significantly higher than both planar (73.4%; p<0.001) and ultrasonography (70.3%; p< 0.0005). The difference was also significant (p<0.05) when P-SPECT sensitivity was compared with that obtained combining planar scintigraphy and ultrasonography (84.4%). Moreover, P-SPECT defined the exact number of hyperplastic glands in 85.7% of positive patients, while planar in 60% and ultrasonography in 45%. Only 4 hyperplastic glands were false negative at P-SPECT showing a maximum diameter of 10 mm and a weight ranging from 480 to 500 mg. These glands were also false negative at both planar scintigraphy and ultrasonography which missed further 13 and 15 hyperfunctioning glands, respectively, all detected by P-SPECT. Globally, the latter procedure gave the correct preoperative localization of hyperfunctioning parathyroid glands in 87.5%, planar in 62.5% and ultrasonography in 50%. None of the three procedures had false positive RESULTS: CONCLUSIONS: The data of the present study seem to indicate that P-SPECT is a reliable diagnostic method in preoperative localization of hyperfunctioning parathyroid glands in patients with secondary hyperparathyroidism. This procedure identified a significantly higher number of hyperplastic glands than both double-tracer subtraction planar parathyroid scintigraphy and ultrasonography in our cases, thus proving a more useful guide for the surgeon. Given its low false negative rate, a wider use of P-SPECT is suggested in the preoperative management of patients with secondary hyperparathyroidism undergoing either a first operation of parathyroidectomy or a second operation for recurrence.     

2009 EANM parathyroid guidelines

The present guidelines were issued by the Parathyroid Task Group of the European Association of Nuclear Medicine. The main focus was imaging of primary hyperparathyroidism. Dual-tracer and single-tracer parathyroid scintigraphy protocols were discussed as well as the various modalities of image acquisition. Primary hyperparathyroidism is an endocrine disorder with high prevalence, typically caused by a solitary parathyroid adenoma, less frequently (about 15%) by multiple parathyroid gland disease (MGD) and rarely (1%) by parathyroid carcinoma. Patients with MGD may have a double adenoma or hyperplasia of three or all four parathyroid glands. Conventional surgery has consisted in routine bilateral neck exploration. The current trend is toward minimally invasive surgery. In this new era, the success of targeted parathyroid surgery depends not only on an experienced surgeon, but also on a sensitive and accurate imaging technique. Recognizing MGD is the major challenge for pre-operative imaging, in order to not direct a patient towards inappropriate minimal surgery. Scintigraphy should also report on thyroid nodules that may cause confusion with a parathyroid adenoma or require concurrent surgical resection. The two main reasons for failed surgery are ectopic glands and undetected MGD. Imaging is mandatory before re-operation, and scintigraphy results should be confirmed with a second imaging technique (usually US for a neck focus, CT or MRI for a mediastinal focus). Hybrid SPECT/CT instruments should be most helpful in this setting. SPECT/CT has a major role for obtaining anatomical details on ectopic foci. However, its use as a routine procedure before target surgery is still investigational. Preliminary data suggest that SPECT/CT has lower sensitivity in the neck area compared to pinhole imaging. Additional radiation to the patient should also be considered. The guidelines also discuss aspects related to radio-guided surgery of hyperparathyroidism and imaging of chronic kidney disease patients with secondary hyperparathyroidism.     

Accuracy of Four-dimensional CT for the Localization of Abnormal Parathyroid Glands in Patients with Primary Hyperparathyroidism

Purpose: To investigate multiphase multidetector four-dimensional computed tomography (CT) as a technique to correctly localize abnormal parathyroid glands in patients with primary hyperparathyroidism. Materials and Methods: Informed consent was waived by the institutional review body for this retrospective, chart review study. Radiology reports from four-dimensional CT and surgical notes were reviewed in 143 patients with primary hyperparathyroidism (35 men, 108 women; median ages, 58 and 60 years, respectively) who underwent parathyroid surgery between August 2004 and January 2007 and in whom four-dimensional CT predicted a single lesion. Accuracy of four-dimensional CT was stratified by patient and was determined separately for localization to the correct side and quadrant (upper and lower for each side), with surgical findings serving as standard of reference. Results: In 143 patients, 148 abnormal parathyroid glands were found at surgery; 137 (93%) of these were weighed, with mean and median weights of 757 and 417 mg, respectively. Four-dimensional CT lateralized the abnormal glands with 93.7% accuracy (134 of 143). For localization according to quadrant, the accuracy was 86.6% (116 of 134). Conclusion: Four-dimensional CT has sufficiently high accuracy in presurgical localization to allow confident performance of unilateral parathyroidectomy in patients with sporadic primary hyperparathyroidism. The superior accuracy compared with that of ultrasonography and technetium 99m sestamibi scanning may be sufficient to allow four-dimensional CT to be used as the sole presurgical localization method. ? RSNA, 2012.     

Localization of ectopic parathyroid glands using technetium-99m sestamibi imaging: Comparison with magnetic resonance and computed tomographic imaging

The aim of the study was to compare the accuracy of technetium-99m sestamibi imaging for localization of ectopic parathyroid glands in patients with hyperparathyroidism with that of magnetic resonance (MR) and computed tomographic (CT) imaging. Eleven patients with primary (n=3) or secondary (n=8) hyperparathyroidism were studied with^99mTc sestamibi parathyroid imaging CT and MR imaging. Images of the neck were acquired at 10 min and 2–3 after tracer injection. The three patients with primary hyperparathyroidism and five patients with secondary hyperparathyroidism underwent parathyroidectomy. The ectopic glands were confirmed by histopathological examination of the resected specimens. In respect of 20 parathyroid glands in the eight patients explored surgically, the sensitivity and specificity of sestamibi imaging were 70% (14/20) and 88%, respectively, those of CT, 40% (8/20) and 88%, and those of MR imaging, 60% (12/20) and 88%. Of these patients, three had parathyroid adenomas while five had hyperplasia (17 glands). Sestamibi imaging localized eight ectopic parathyroid glands, which were surgically confirmed (six were located in the thymus and two in the mediastinum). In one patient explored surgically, the ectopic gland was located outside the field of the MR coil. Although the remaining three cases of secondary hyperparathyroidism were not confirmed surgically, these patients demonstrated sestamibi uptake in five parathyroid glands, including three ectopic glands. MR images demonstrated abnormal parathyroid glands in the same regions as sestamibi imaging. Our data indicate that^99mTc-sestamibi imaging should be used initially to localize the ectopic parathyroid glands in patients with hyperparathyroidism for anatomical guidance prior to MR or CT imaging.     

原发性甲状旁腺机能亢进的外科治疗

总结了30例原发性甲状旁腺机能亢进患者的手术治疗经验。颈丛或全身麻醉下低领位切口，术中快速病理结果证实28例为甲状旁腺腺瘤，均单发性，其中2例异位于甲状腺内，1例异位于前上纵隔，单纯切除；增生1例，但仅1个旁腺受累，全切除；腺癌1例，侵及食管、气管，肿瘤及受累部分食管气管切除并气管切开。无手术并发症。25例随访8个月至19年，包括增生1例，症状改善无复发。腺癌患者带气管套管生存已4年。提示手术治疗原发性甲状旁腺机能亢进疗效确实，应首先；明确为腺瘤者可行单侧探查，即使腺癌也不要轻易放弃。     

Parameters in the prediction of the sensitivity of parathyroid scanning

OBJECTIVE: Although parathyroid scintigraphy with technetium-99m sestamibi has been shown to be a sensitive and specific test for the detection and localization of parathyroid adenomas in patients with primary hyperparathyroidism, false-negative studies occur. Our goal was to determine whether the presurgical parathyroid hormone level could be used to predict whether a scan would be positive or negative. MATERIALS AND METHODS: A retrospective review of parathyroid scans was performed. Analysis included patients with surgical confirmation of a parathyroid adenoma and a documented parathyroid hormone (PTH) level obtained within 6 months of the scan. Patients with secondary hyperparathyroidism were excluded. A true-positive study was defined by the surgical finding of an adenoma on the side indicated by the scan. A scan was false-negative if it did not detect the adenoma found at surgery. A scan was false-positive if an adenoma was identified in the wrong side of the neck or if an adenoma was called but not found. RESULTS: Of 166 scans, 83 met the criteria for inclusion. There were 56 true-positives, 21 false-negatives, and 6 false-positives. The mean PTH in patients with true-positive scans was 367 pg/mL (range, 46-3231 pg/mL) and with false-positive and false-negative scans was 148 pg/mL (range, 46-390 pg/mL). The difference was statistically significant. CONCLUSION: There is a correlation between the sensitivity of parathyroid scintigraphy and presurgical PTH. The overlap, however, of parathyroid hormone levels in positive and negative scans does not allow one to confidently preselect candidates for preoperative scanning.     

Assessment of thallium-pertechnetate subtraction scintigraphy in hyperparathyroidism

Reliable techniques for detecting and localising abnormal parathyroid tissue have been a persistent problem. We have evaluated thallium-pertechnetate subtraction scintigraphy in a prospective study of 40 patients with clinical and biochemical evidence of hyperparathyroidism prior to parathyroid surgery. Four patients were excluded as they were shown to have goitre, making subtraction scanning non-diagnostic. 89% of parathyroid adenomas (totalling 27 glands in 26 patients) and 41% of hyperplastic glands (17 glands in 6 patients) were accurately localised prior to surgery. These included three retrosternal glands, four patients with renal failure and tertiary hyperparathyroidism and five patients who had previously undergone neck exploration. The apparent discrepancy between detecting hyperplastic and adenomatous glands was associated with the smaller size of the former. For both types of gland, scintigraphy successfully located parathyroids 0.6 g or more in weight. These results suggest that this simple and non-invasive method is a useful technique for locating parathyroid tissue before parathyroid surgery.