Radionuclide scanning in parathyroid diseases

BACKGROUND: New radionuclide agents and scanning procedures have markedly improved preoperative parathyroid gland localization. The aim of this review was to evaluate the results of parathyroid scanning and to clarify its current place in the clinical management of parathyroid diseases. METHODS: The literature describing the different radioisotopes and available scanning techniques was analysed and their clinical outcome in various parathyroid diseases was evaluated. RESULTS: Using 99mTc-radiolabelled sestamibi or other 9mTc-labelled cationic complexes, parathyroid scintigraphy detects 87 per cent of solitary adenomas (n=894), 55 per cent of abnormal glands in patients with multiglandular disease (n=303) and 75 per cent of persistent or recurrent lesions in patients with previous neck surgery (n=240). If necessary, three-dimensional imaging techniques can clarify the spatial localization of an ectopic uptake focus. The positive predictive value of the available scanning procedures is over 95 per cent, but false-positive uptake may be encountered. CONCLUSION: Radionuclide parathyroid gland scanning with 99mTc-labelled cationic complexes is the initial non-invasive method of choice for preoperative parathyroid gland localization in patients at special risk and/or with previous neck exploration. While scanning has also been proposed to facilitate parathyroidectomy, there is no objective evidence to support its routine use before a first-time surgical procedure.     

Technetium 99m tetrofosmin parathyroid imaging. Results with double-phase study and SPECT in primary and secondary hyperparathyroidism

RATIONALE AND OBJECTIVES: The aim of our study was to evaluate the sensitivity, specificity, and positive predictive value (PPV) of technetium 99m (99mTc) tetrofosmin double-phase scintigraphy and single-photon emission computer tomography (SPECT) in preoperative localization of parathyroid adenoma in case of primary and secondary hyperparathyroidism (HPT). METHODS: Sixty-eight consecutive patients biochemically or sonographically suspected of parathyroid adenoma were included in our study. Apart from biochemical analysis of serum calcium, phosphate, and intact parathyroid hormone, double-phase scintigraphy was performed in each patient 5 and 45 minutes after injection of 370 MBq 99mTc tetrofosmin, followed by SPECT imaging. In consciousness of the scintigraphic results, ultrasound of the neck was performed as well to exclude false-positive results due to thyroid adenomas. RESULTS: Depending on the results of the biochemical analysis in combination with the results of the scintigraphic and ultrasound examination, the patients were classified retrospectively into three groups: group A with primary HPT (n = 35), group B with secondary HPT (n = 13), and group C without any biochemical suspicion of primary or secondary HPT (n = 20). In group A, double-phase study localized 25 of 36 (69.2%) parathyroid adenomas (one double adenoma) as against 34 of 36 (94.4%) with SPECT. Nine adenomas could be visualized only by SPECT. The reason for nonvisualization on planar scans was suspected to be an ectopic location in 2 cases (retrotracheal dislocation, retrovascular dislocation), a maximal diameter less than 15 mm (9-13 mm) in 6 cases, and oxyphilic-cell-poor cellularity in 1 case. Four false-positive retention (3 thyroid adenomas and 1 papillary thyroid carcinoma) were observed. SPECT showed a sensitivity of 94.4%, a specificity of 85%, and a PPV of 91.9% in biochemically suspected primary HPT. In group B, planar scintigraphy demonstrated 12 hyperplastic glands in 5 of 13 patients, and SPECT demonstrated 20 hyperplastic parathyroid glands in 8 out of 13 patients, which corresponds to a sensitivity of 38% and 61.5%, respectively. CONCLUSIONS: Technetium 99m tetrofosmin seems to be a promising alternative tracer with similar capabilities to 99mTc sestamibi in localization of parathyroid adenoma. SPECT showed clear advantages in terms of sensitivity over planar scintigraphy and should be used at least in cases with poor or no uptake in double-phase study. In endemic goiter areas, ultrasound of the neck should be performed to exclude false positive retention in thyroid adenomas. Technetium 99m tetrofosmin, like 99mTc sestamibi, is not ideal for localization of hyperplastic glands in secondary hyperparathyroidism because of low sensitivity.     

Value of ultrasonography, CT and MR imaging in the diagnosis of primary hyperparathyroidism

PURPOSE: To evaluate the significance of preoperative localization of abnormal parathyroid glands to the surgical outcome in patients with primary hyperparathyroidism. MATERIAL AND METHODS: Thirty-nine patients with primary hyperparathyroidism were studied preoperatively with US (39 patients), CT (30 patients) and MR imaging (18 patients). The overall diagnostic accuracy for US was 87%, CT 66% and MR 94%. In patients with a single parathyroid adenoma US was the most cost-effective localization technique with a detection rate of 96%. CT had a lower detection rate (78%) but was of particular value for fairly large ectopic adenomas in the root of the neck. MR imaging was a good confirmatory test (93%). In patients with multiple gland disease (primary hyperplasia and multiple adenomas), no single localization study alone was sufficient. Combination of all 3 studies, however, alerted the physician to the presence of disease in more than one gland in 87% of these patients. CONCLUSION: US, CT and MR imaging followed by surgery performed by an experienced surgeon provided good clinical results in 39 patients with primary hyperparathyroidism. Preoperative localization was especially useful in patients with primary parathyroid hyperplasia or multiple adenomas and in patients with ectopic parathyroid adenomas in the root of the neck. We recommend identification of all abnormal parathyroid glands prior to surgery.     

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.     

Sestamibi scanning is inadequate for directing unilateral neck exploration for first-time parathyroidectomy

OBJECTIVE: To determine whether technetium Tc 99m sestamibi scanning is accurate enough to allow surgeons to perform unilateral neck exploration for first-time parathyroidectomy in patients with primary hyperparathyroidism. DESIGN: Retrospective review. SETTING: University tertiary care center. PATIENTS: Forty patients with primary hyperparathyroidism who underwent sestamibi scanning before first-time parathyroidectomy, of whom 28 had single adenomas, 9 had multiple adenomas, and 3 had hyperplasia. INTERVENTIONS: All 40 patients underwent bilateral neck exploration with identification of 4 parathyroid glands. MAIN OUTCOME MEASURES: We compared the results of preoperative sestamibi scanning with operative and histologic findings. We then used these data to calculate the projected success rates of parathyroidectomy if unilateral neck explorations had been performed based on the results of sestamibi scanning, instead of bilateral explorations. RESULTS: Sestamibi scanning was correct in 20 (71%) of 28 patients with single adenomas, 4 (44%) of 9 patients with multiple adenomas, and 0 (0%) of 3 patients with hyperplasia. If unilateral neck explorations had been performed on the basis of localization by sestamibi scanning, parathyroidectomy would have failed in 4 (10%) of 40 patients. CONCLUSIONS: Sestamibi scanning, although helpful, is inadequate for directing unilateral neck exploration for first-time parathyroidectomy. Surgeons who perform unilateral neck exploration based on the results of sestamibi scanning will record a higher failure rate and incur higher costs than those who perform bilateral neck exploration for first-time parathyroidectomy.     

Expression and function of a scavenger lipoprotein pathway in porcine luteal cells

PURPOSE: To evaluate the usefulness and cost-effectiveness of routine preoperative technetium-99m sestamibi-iodine-123 subtraction scanning in patients with parathyroid gland disease. MATERIALS AND METHODS: Tc-99m sestamibi-I-123 subtraction scanning was performed in 65 patients with primary hyperparathyroidism who were referred for evaluation before first surgery. RESULTS: Focal tracer uptake was detected in the mediastinum in two patients who then underwent primary sternotomy; a parathyroid adenoma, anterior to the ascending aorta, was resected in each case. In a third patient, imaging showed tracer uptake above the thyroid gland; this patient underwent resection of an undescended parathyroid adenoma located in the sheath of the right carotid artery. Initial surgery was curative in all patients. Preoperative subtraction scans depicted 56 of 59 (95%) solitary adenomas. Four patients had hyperplasia; two had double adenoma. Imaging findings indicated multiple parathyroid involvement in five of these patients and facilitated location of 12 of 15 (80%) enlarged glands. Four adenomas and two hyperplastic glands that weighed less than 100 mg were detected. The positive predictive value for any suspected location was 96%. Average surgery time was reduced from 120 to 90 minutes. CONCLUSION: Preoperative subtraction scanning is useful in planning parathyroid surgery and appears to be cost-effective.     

Technetium-99m-tetrofosmin for parathyroid scintigraphy: comparison to thallium-technetium scanning

The efficacy of 99mTc-tetrofosmin for the detection of parathyroid lesions was investigated prospectively in patients with hyperparathyroidism referred for surgical treatment. METHODS: Twenty-seven patients with primary and 18 with tertiary hyperparathyroidism were studied. Twelve patients had undergone one or more previous neck explorations. Static imaging with 201Tl was performed first, immediately followed by a 30-min 99mTc-tetrofosmin dynamic study. Delayed views of up to 3 hr postinjection were also obtained. Technetium-99m-pertechnetate was used for thyroid delineation. The tetrofosmin/99mTc-pertechnetate subtraction scan (TF/TC), the single-tracer washout technique and the thallium/technetium subtraction (TL/TC) were compared. Quantification of relative uptakes of tracers in the thyroid and abnormal parathyroids was accomplished by measuring activity within regions of interest. Kinetics of tetrofosmin in the thyroid and abnormal parathyroids were studied by evaluating the plots of the parathyroid to thyroid ratios against time as well as by calculation of the half-clearance times from the slow component of the time-activity curves. RESULTS: The overall sensitivity, specificity and accuracy of TF/TC and TL/TC were 76%, 92% and 83% and 52%, 85% and 65%, respectively. The respective sensitivities were 87% and 70% for adenomas and 72% and 46% for hyperplasia. The parathyroid-to-thyroid activity ratios of tetrofosmin were significantly higher than those of thallium (p < 0.001). The tetrofosmin single-tracer washout study was less accurate than the subtraction technique (overall sensitivity and specificity, 70% and 69%, respectively). The washout properties of tetrofosmin in abnormal parathyroids were not substantially different from those in the thyroid, with a few exceptions (p = 0.4). No correlation of half-clearance times with parathyroid size, degree of early uptake, parathyroid hormone levels or histology could be established. Comparing adenomas to hyperplasia in respect to tetrofosmin retention, a statistically significant difference was observed (p = 0.005). CONCLUSION: Technetium-99m-tetrofosmin is suitable for parathyroid imaging. The kinetic properties of this agent in parathyroid and thyroid tissues do not warrant differential washout protocols. The diagnostic impact of the observed difference in tetrofosmin kinetics between parathyroid adenomas and hyperplasia requires further investigation.     

The role of thyroid resection during reoperation for persistent or recurrent hyperparathyroidism

BACKGROUND: The role of "blind" thyroid lobectomy in the surgical management of patients with persistent or recurrent primary hyperparathyroidism is not known. We reviewed our experience with reoperation for hyperparathyroidism to determine the utility of blind thyroid resection in this setting. METHODS: From 1982 to 1995, 269 patients underwent reoperation for hyperparathyroidism at our institution. All patients had biochemical confirmation of hyperparathyroidism and underwent noninvasive and if necessary invasive localization studies. Patients who underwent thyroid lobectomy in an attempt to extirpate the hyperfunctioning parathyroid gland form the basis of this report. RESULTS: Thirty-two of 269 patients (12%) underwent thyroid lobectomy to remove a parathyroid gland. Intrathyroidal parathyroids were confirmed in 19 of 32 patients (59%). In 18 of 19 patients (94%), preoperative or intraoperative ultrasonography correctly identified an intrathyroidal lesion suspicious or a parathyroid. Only 1 of 6 patients (17%) undergoing a blind thyroidectomy had an intrathyroidal gland identified. Ultrasonography had a sensitivity of 95% and a negative predictive value of 99.5% in detecting an intrathyroidal parathyroid gland. CONCLUSIONS: The prevalence of an intrathyroidal parathyroid gland in our series is low (19 of 269, 7%). Ultrasonography can be used reliably to select patients for thyroid resection, reducing the need to perform a blind thyroid lobectomy and avoiding the potential morbidity of thyroid resection in this clinical setting.     

Hyperthyroidism and carcinoma of the thyroid gland

The incidence of thyroid carcinoma in hyperthyroidism varies considerably from as low as 0.3% to as high as 16.6% with a higher rate in toxic nodular goiters. Occult thyroid carcinoma (< 1.5 cm or microscopic foci) is the rule and only a few tumors are suspected preoperatively with ultrasonography or fine needle aspiration or 131 I scan. In 408 patients who underwent surgery for hyperthyroidism in our Surgery Department from January 1967 through December 1994 the incidence of thyroid carcinoma was 5.6% (23 cases). In detail, a neoplasm occurred in 5 cases of Graves' disease (specific incidence: 3.8%), in 13 cases of toxic nodular goiter (12.5%) and in 5 cases of hyperfunctioning adenomas (2.8%). 19 cancers were papillary (12 in toxic nodular goiter, 3 in Graves' disease, 4 in hyperfunctioning adenomas), three were follicular (1 in Graves' disease, 1 in toxic nodular goiter, 1 in hyperfunctioning adenomas) and 1 medullary in Graves' disease. A papillary carcinoma was diagnosed preoperatively on fine needle aspiration with ultrasonography in only two patients with Graves' disease and confirmed by postoperative histological examination on permanent section. We do not believe in the frozen-section examination intraoperatively because it's not diagnostical for follicular lesions and evaluates rarely capsular invasion. Twenty patients received total thyroidectomy and four of them also lymphoadenectomy. Three patients received emithyroidectomy: in two cases for occult papillary carcinoma and in the last case for local cancer invasion (T4N0M0). Twenty patients are alive and with no evidence of cancer recurrence. Mean follow-up is 59.6 months. Our retrospective study shows a progressive increase of the incidence of coexisting thyroid malignancy and hyperthyroidism especially in toxic nodular goiter, probably related to extended surgical indications. Our findings do confirm that, even in the presence of hyperthyroidism, all thyroid nodules require careful diagnostics for exclusion of malignancy.     

Ultrasonography of the thyroid and parathyroid glands

High-resolution thyroid and parathyroid ultrasonography can play an integral part in the diagnosis and management of patients with clinically undifferentiated cervical masses, thyroid carcinomas or adenomas, and primary parathyroid hyperplasia or neoplasia. Because the study is inexpensive, noninvasive, and easily performed, ultrasonography can be performed as a screening test early in the evaluation of a patient, and ultrasound findings can corroborate the results of other diagnostic procedures, leading to a more accurate diagnosis.     

Usefulness and limitations of 99mTc-MIBI scintigraphy for detection of parathyroid lesions

To evaluate the usefulness of MIBI scintigraphy (MIBI) for parathyroid lesions, the detectability of lesions by MIBI was compared with that by Tl-Tc subtraction imaging, ultrasonography, CT and MRI in 56 histologically proved lesions. In neck lesions, ultrasonography (92%) and MIBI (85%) showed better detectability than those by the other three modalities. With MIBI, detectability was decreased for smaller parathyroid lesions that coexisted with thyroid disease. Among the five modalities, MIBI showed the highest detectability (88%) for ectopic or metastatic lesions. The smallest parathyroid lesions detected by MIBI were a parathyroid adenoma weighing 220mg and a parathyroid hyperplasia weighing 200mg. MIBI was thought to be more valuable for ectopic or metastatic parathyroid lesions.     

Encephalitis in mice inoculated intranasally with an influenza virus strain originated from a water bird

A retrospective chart review of 43 patients who underwent technetium 99m (Tc-99m) sestamibi scans from June 1995 to January 1997 was performed. Only those who underwent subsequent parathyroid exploration with excision were included in the study. Twenty subjects (13 women and seven men) were included in the study. Ages ranged from 21 to 84 years (mean, 58 years). All patients had laboratory values and clinical findings consistent with primary hyperparathyroidism. Two patients had preoperative magnetic resonance imaging (MRI) scans (one patient with recurrent disease), and one had a preoperative computed tomography (CT) scan. The remaining patients had the sestamibi scan as the only preoperative localization study. There were 18 pathologic diagnoses of parathyroid adenoma and two of parathyroid hyperplasia. Sestamibi failed to correctly identify the location of the parathyroid lesion in two cases. In 18 cases the preoperative sestamibi scan correctly localized the lesion, a predictive value of 90%. We conclude that the Tc-99m sestamibi scan is an accurate preoperative tool that can be used as a single modality to localize parathyroid adenomas.     

Localization of abnormal parathyroid glands of the mediastinum with MR imaging

PURPOSE: To determine the sensitivity of magnetic resonance (MR) imaging for preoperative localization of abnormal parathyroid glands in the mediastinum and to compare the sensitivity of MR imaging with those of scintigraphy and ultrasonography (US). MATERIALS AND METHODS: The prospective sensitivity of MR imaging was compared with those of thallium-technetium scintigraphy and US in 25 patients in whom the abnormal gland was located in the mediastinum at surgery. RESULTS: MR imaging had a much higher sensitivity (22 of 25 cases [88%]) than did scintigraphy (11 of 19 cases [58%]) or US (three of 24 cases [12%]). The most common locations for the mediastinal gland were intrathymic (eight of 25 cases) and paraesophageal (six of 25 cases) sites. CONCLUSION: MR imaging should be considered the modality of choice for preoperative localization in this group of patients.     

Scientific information of health personnel: an approach to the sources, access, costs and research

OBJECTIVE: To study the appropriateness of minimally invasive surgical treatment of primary hyperparathyroidism. DESIGN: Prospective. SETTING: University Hospital Utrecht, the Netherlands. METHOD: In patients with primary hyperparathyroidism, parathyroid adenomas were located preoperatively by means of Doppler assisted ultrasonography and spiral computer tomography. If the results were positive, minimally invasive surgery was performed. RESULTS: Minimally invasive surgery was carried out in 13 out of 15 successive patients with good results (the serum calcium and parathyroid hormone levels returned to normal). Two patients were subjected to conventional neck exploration, also with good results (preoperatively several adenomas were suspected in one, while no adenoma was seen in the other). CONCLUSION: It can be calculated that minimally invasive surgery will probably suffice in 60-70% of the patients with primary hyperparathyroidism, so that conventional neck exploration can be avoided.     

The effect of inorganic pyrophosphate on the transport of oleanolic acid monoglycosides into vacuoles isolated from Calendula officinalis leaves

OBJECTIVE: The objective of our study was to determine the value of using color and power Doppler sonography to reveal extrathyroidal feeding arteries in the detection of abnormal parathyroid glands. SUBJECTS AND METHODS: Forty-four patients with primary hyperparathyroidism were imaged prospectively with high-resolution gray-scale, color flow, and power Doppler sonography. The presence of extrathyroidal arteries supplying the adenomas was noted. All patients underwent subsequent neck exploration. The locations of the abnormal glands were recorded. RESULTS: At surgery, 51 abnormal parathyroid glands were removed in the 44 patients. Sonography correctly revealed an adenoma in 40 of the 44 patients. Likewise, sonography revealed 42 of the 51 adenomas. Nine false-negative and two false-positive interpretations of the sonograms were made. Thus, overall sensitivity was 83%, specificity was 98%, and accuracy was 94%. Three of the false-negative interpretations were ectopic glands within the superior mediastinum. Excluding these three glands from analysis, the sensitivity for detection of adenomas within the neck was 88%, specificity was 98%, and accuracy was 95%. An extrathyroidal artery leading to a parathyroid adenoma was seen in 35 of the 42 adenomas revealed by sonography. The presence of an extrathyroidal artery leading to an adenoma was found to aid in the detection of an otherwise inconspicuous parathyroid gland in five patients, which improved sensitivity from 73% to 83%. CONCLUSION: Prominent vessels supplying parathyroid adenomas are frequently revealed by color flow and power Doppler sonography. These vessels can serve as "road maps" to abnormal parathyroid glands.     

Radionuclide imaging in primary hyperparathyroidism using 99mTc sestamibi--four case reports

Radionuclide imaging using the 99mTc sestamibi either singly or as a subtraction technique with pertechnetate is a recent and reliable method in localising parathyroid adenomas prior to surgery. This is of use in pre-operative planning, as well as in failed first neck exploration. Four local patients with primary hyperparathyroidism whose parathyroid adenomas were localised by this scintigraphy are presented. The value and limitations of this imaging modality are discussed.     

Usefulness of preoperative location studies in the initial surgical intervention in primary hyperparathyroidism

BACKGROUND: The aim of the study was to assess whether preoperative localization is helpful in improving the outcome of initial surgery of primary hyperparathyroidism (PHPT). PATIENTS AND METHODS: Retrospective review of 100 patients treated surgically for PHPT. In 30 cases (group I) 3 or 4 localization studies were performed from the following: ultrasonography (US), computed tomography (CT), thallium-technetium substraction scintigraphy (TTS), and technetium 99m-sestamibi scanning (MIBI). Thirty one patients (group II) were operated without previous localization. Sensitivity and false localization rate of image studies were calculated, and cure and surgical complication rates were compared in both groups. RESULTS: Both groups were similar in mean age (56.2 vs 52.2 years), serum calcium (12.3 vs 12.1 mg/dl), intact PTH levels (304 vs 254 pg/ml), pathology (26 adenomas, 3 hyperplasias and 1 carcinoma vs 27 adenomas, 3 hyperplasias and 1 carcinoma) and additional clinical and biochemical data. The highest sensitivity technique was for MIBI (62.5%). The highest false localization rate was for CT (27.6%). No significative differences were found between groups I and II for the cure rate (90% vs 87.1%) or surgical complications (3.3% vs 3.2%). CONCLUSIONS: In our series of patients with primary hyperparathyroidism preoperative localization studies display low sensitivity and estimable false localization rate. These techniques increment cost and don't improve success rate of initial surgery in PHPT. Therefore, we believe its performance controversial.     

Preoperative localization diagnosis of parathyroid adenomas in 72 cases of primary hyperparathyroidism by selective catheterization of neck veins and parathyroid hormone determination

In 72 cases of primary hyperparathyroidism, selective venous catheterization was performed preoperatively to localize parathyroid adenomas. Diagnosis of primary hyperparathyroidism was proved by operation in all but 5 cases, in which no adenomas could be found intraoperatively. By venous catheterization of the neck and upper region of the thorax, an average of 10 blood samples per patient were taken. Parathyroid hormone was estimated by radioimmunoassay with high sensitivity against the intact PTH-molecule and carboxy-terminal fragments. Only in 24 out of 72 cases was localization of parathyroid adenomas prognosticated correctly with respect to side and height, while in a total of 38 cases localization on the right or left side only could be determined preoperatively. These unsatisfactory results can be improved only by a much more extensive catheterization technic which would be justified only in patients already operated on before without success. The final evaluation of non-invasive methods, e.g. ultrasonics and computerized tomography, is still under discussion.     

Cost utility of routine imaging with Tc-99m-sestamibi in primary hyperparathyroidism before initial surgery

Tc-99m-sestamibi has been shown to localize parathyroid adenomas effectively, but controversy continues as to the use of this scan before initial surgery for primary hyperparathyroidism. We analyzed the cost utility of obtaining this study before initial surgery for primary hyperparathyroidism. Twenty-two consecutive patients with primary hyperparathyroidism underwent dual-phase Tc-99m-sestamibi scan before initial bilateral neck exploration. Surgical findings were correlated with the results of sestamibi scan. There were 15 women and 7 men, with a mean age of 50.5 years (range, 22-76). Preoperative mean total calcium was 11.74 mg/dL (range, 10-15), ionized calcium was 6.19 mg/dL (range, 5.2-7.7), and intact parathyroid hormone was 153.5 pg/mL (range, 83.1-551). Postoperative mean ionized calcium was 4.56 mg/dL (range, 4.1-5.57). Twenty sestamibi scans had a positive localization, and 2 scans had no localization. At surgery, 18 solitary adenomas, 3 diffuse hyperplasias, and 1 patient with four normal parathyroid glands were found. Sixteen sestamibi scans were true positive (solitary adenoma), 4 scans were false positive (2 diffuse hyperplasia, 1 wrong side, and 1 lymph node), 1 negative scan was true negative (diffuse hyperplasia), and 1 negative scan was false negative (adenoma). One patient (four normal glands) at the second operation had a supernumerary fifth gland adenoma excised from the mediastinum. Preoperative Tc-99m-sestamibi scan did not offer any advantage when a complete bilateral neck exploration is performed. Sixteen of (84%) adenomas were correctly localized, but 18 of 19 adenomas were in the neck and were easily found. The 1 ectopic adenoma was not found by scanning or with initial surgery. The 4 of 22 (18%) false-positive localizations and the 2 of 22 (9%) negative scans contributed nothing to the surgery. Of the 22 localizing sestamibi scans, surgery was not altered to affect the outcome. At a cost of $550 per sestamibi scan and with the error inherent in the scan, it is not cost effective to obtain Tc-99m-sestamibi scan before initial surgery for primary hyperparathyroidism.     

Effectiveness of preoperative diagnosis in scintigraphically cold thyroid nodule

PURPOSE: To compare the diagnostic efficacy of different imaging procedures carried out in patients with scintigraphically cold thyroid nodules. METHODS: The preoperative imaging procedures carried out in all patients operated on for cold thyroid lesions at the Department of Surgery of the University of Cologne were recorded in prospective manner for 1 year. Special attention was paid to the difference between in-patient and out-patient management. Diagnostic accuracy was assessed by comparison with the intraoperative findings and histology. RESULTS: The combination of ultrasonography and fine needle aspiration cytology proved effective. Computed tomography should be reserved for the preoperative assessment of large thyroid tumors. Repeat examinations seldom gave additional information. CONCLUSION: Standardized preoperative investigations may be performed on an out-patient basis, provided attention is paid to quality assurance.