Abnormal Parathyroid Glands In Patients Research Articles

Parathyroid localization with high-resolution ultrasound and technetium Tc 99m sestamibi.

High-resolution ultrasound and technetium Tc 99m sestamibi scanning can be used for preoperative localization of abnormal parathyroid glands in patients with hyperparathyroidism. Ultrasound and sestamibi scanning were performed in patients undergoing neck exploration for hyperparathyroidism. If the 2 scans agreed in identifying a single adenoma, and surgery confirmed the location of a single adenoma and an ipsilateral normal gland, a unilateral exploration was performed. University tertiary care center. Sixty-one consecutive patients undergoing surgery for hyperparathyroidism from September 1, 1994, through September 30, 1997. High-resolution ultrasound was performed in 59 patients and sestamibi scanning in 58 patients; all patients underwent neck exploration by a single surgeon. The results of preoperative ultrasound and sestamibi scanning were compared with operative and histological findings. All patients were cured of hypercalcemia. Specificity of ultrasound and sestamibi scanning was 98% and 99%, respectively; however, their sensitivity was only 57% and 54%, respectively. Both imaging modalities had lower sensitivities in the setting of multigland disease. If both imaging studies were considered as a single test, sensitivity for imaging in patients with primary hyperparathyroidism reached 78%. Our localization protocol allowed a unilateral approach in 43% of patients (23 of 53). These results confirm the value of preoperative localization in patients with hyperparathyroidism. A unilateral approach can be used with a high degree of success in cases when ultrasound and sestamibi scanning agree in the identification of a single adenoma confirmed by surgical exploration with the identification of a normal ipsilateral gland.

The efficacy of technetium-99m-MIBI scan and intraoperative methylene blue staining for the localization of abnormal parathyroid glands.

The efficacy of the technetium-99m-2-methoxyisobutylisonitrile (Tc-MIBI) scan and intraoperative methylene blue staining was analyzed in a consecutive series of 15 patients with primary hyperparathyroidism who underwent neck surgical exploration. A total of 17 abnormal parathyroid glands were removed, 7 of which were confirmed histologically as adenomas and 10 as hyperplasias. The Tc-MIBI scan and the thallium-201-technetium-99m subtraction (Tl/Tc) scan preoperatively localized 11 (69%) of 16, and 6 (40%) of 15 abnormal parathyroid glands, respectively. The Tc-MIBI scan correctly localized two ectopic abnormal parathyroid glands which were not localized by the Tl/Tc scan or ultrasonography (US). However, it also demonstrated false-positive accumulations caused by thyroid diseases in two patients. There were 4 abnormal parathyroid glands not detected by the preoperative imaging techniques, whereas all 17 abnormal parathyroid glands were stained with methylene blue, the infusion of which caused no adverse effects or toxicity. In conclusion, Tc-MIBI scanning and intraoperative methylene blue staining are effective techniques for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism.

LOCALIZATION OF ABNORMAL PARATHYROID GLANDS WITH JUGULAR SAMPLING FOR PARATHYROID HORMONE, AND SUBTRACTION SCANNING WITH SESTAMIBI OR TETROFOSMINE

Accurate pre-operative localization of abnormal parathyroid glands is an essential prerequisite for elective surgical approaches such as the unilateral approach for treatment of primary hyperparathyroidism. In 175 patients undergoing a bilateral neck exploration for primary hyperparathyroidism, localization of abnormal parathyroid glands was performed with jugular venous sampling for parathyroid hormone (PTH, n = 75), subtraction scan with iodine 123 and technetium-99m-sestamibi (MIBI, n = 50), or tetrofosmine (TTF, n = 50). The results of these localization studies were compared with operative findings. The sensitivity of PTH, MIBI, and TTF was 41, 63, and 71%, respectively. The specificity was 90, 98, and 98% and the positive predictive value was 85%, 82%, and 87%, respectively. The smallest abnormal parathyroid that was correctly detected weighed 110 mg with PTH, 118 mg with MIBI, and 70 mg with TTF. Subtraction scan (MIBI and TTF) detected mediastinal glands in five cases out of six. In patients with multiglandular disease, the results of all three studies were severely impaired. Subtraction scanning with MIBI or TTF, but not jugular sampling for PTH, appeared to be useful for localization of abnormal parathyroid glands in patients with primary hyperparathyroidism. Nevertheless, an elective unilateral approach guided by the localization studies would not have allowed the excision of all abnormal parathyroid glands in patients with multiglandular disease.

Localization of Parathyroid Glands in Hemodialysis Patients Using Tc-99m Sestamibi Imaging

Tc-99m sestamibi parathyroid imaging was performed in 28 patients with chronic renal failure to localize abnormal parathyroid glands in patients receiving hemodialysis, and compared the localization with ultrasonography and magnetic resonance (MR) imaging. Methods: We imaged 28 patients with secondary hyperparathyroidism using Tc-99m sestamibi (about 600 MBq) at 10 min and 2–3 h following radiotracer injection. In addition, mediastinal images were recorded at approximately 1 h following injection to identify ectopic parathyroid glands. All patients also were evaluated with ultrasonography and MR imaging. Results: Tc-99m sestamibi scans demonstrated focal uptake in 60 glands of the 28 patients, and was categorized as slight uptake in 71.7% (43/60), and intense uptake in 28.3% (17/60). Seventeen of the 28 patients underwent parathyroidectomy. A total of 64 glands were resected. Sestamibi imaging was more sensitive for localizing abnormal parathyroid glands than ultrasonography or MR imaging. Histologic evaluation of 27 resected parathyroid glands revealed that the number of oxyphil or chief cells was not proportional to sestamibi uptake. Conclusion: Our data indicate that Tc-99m sestamibi imaging should be used initially to localize abnormal parathyroid glands in hemodialysis patients with secondary hyperparathyroidism, prior to MR imaging or ultrasonography. Sestamibi uptake in parathyroid glands may not correlate with the degree of hypercellularity of oxyphil cells.

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.

All the heavens, truthfully represented, it can enclose with its verses

Background. Technetium 99m sestamibi was recently introduced for the preoperative localization of abnormal parathyroid glands in patients with primary hyperparathyroidism with promising results. However, the sensitivity of sestamibi and thallium to detect abnormal parathyroid glands is partly dependent on the gland size. In this study we compared the sensitivity of sestamibi subtraction scintigraphy with thallium subtraction scintigraphy in patients with predominantly mild increase in serum calcium level.Methods. Thirty-nine patients with primary hyperparathyroidism were included. The mean (± SD) serum level of calcium was 2.75 ± 0.17 mmol/L. In 28 (72%) of the patients the serum level of calcium was less than 2.85 mmol/L. These patients were classified as having mild abnormalities in serum calcium. All patients were investigated before operation with both sestamibi and thallium subtraction scintigraphy.Results. In two patients autonomous thyroid adenomas precluded subtraction scintigraphy. Sestamibi subtraction scintigraphy correctly localized 31 (86%) of 36 parathyroid adenomas compared with only 17 (47%) of 36 by thallium subtraction scintigraphy (p < 0.001). There was one false- positive result in the sestamibi group because of a thyroid adenoma, and two of the scans were negative. Both the sestamibi and the thallium subtraction scintigraphy localized one single enlarged gland in all three patients with multiple gland involvement. In no case was multiglandular disease predicted.Conclusions. Sestamibi subtraction scintigraphy is superior to thallium subtraction scintigraphy and has a high sensitivity to localize a solitary parathyroid adenoma in patients with mild increase in serum calcium level. The sensitivity decreases in patients with multiglandular parathyroid disease and concomitant thyroid nodular abnormalities.

Sestamibi versus thallium subtraction scintigraphy in parathyroid localization: A prospective comparative study in patients with predominantly mild primary hyperparathyroidism

Background. Technetium 99m sestamibi was recently introduced for the preoperative localization of abnormal parathyroid glands in patients with primary hyperparathyroidism with promising results. However, the sensitivity of sestamibi and thallium to detect abnormal parathyroid glands is partly dependent on the gland size. In this study we compared the sensitivity of sestamibi subtraction scintigraphy with thallium subtraction scintigraphy in patients with predominantly mild increase in serum calcium level. Methods. Thirty-nine patients with primary hyperparathyroidism were included. The mean (± SD) serum level of calcium was 2.75 ± 0.17 mmol/L. In 28 (72%) of the patients the serum level of calcium was less than 2.85 mmol/L. These patients were classified as having mild abnormalities in serum calcium. All patients were investigated before operation with both sestamibi and thallium subtraction scintigraphy. Results. In two patients autonomous thyroid adenomas precluded subtraction scintigraphy. Sestamibi subtraction scintigraphy correctly localized 31 (86%) of 36 parathyroid adenomas compared with only 17 (47%) of 36 by thallium subtraction scintigraphy (p < 0.001). There was one false- positive result in the sestamibi group because of a thyroid adenoma, and two of the scans were negative. Both the sestamibi and the thallium subtraction scintigraphy localized one single enlarged gland in all three patients with multiple gland involvement. In no case was multiglandular disease predicted. Conclusions. Sestamibi subtraction scintigraphy is superior to thallium subtraction scintigraphy and has a high sensitivity to localize a solitary parathyroid adenoma in patients with mild increase in serum calcium level. The sensitivity decreases in patients with multiglandular parathyroid disease and concomitant thyroid nodular abnormalities.

Recent advances in parathyroid imaging

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

Preoperative MR imaging in hyperparathyroidism: results and factors affecting parathyroid detection.

To determine the sensitivity of MR imaging for the detection of abnormal parathyroid glands in patients with biochemical evidence of hyperparathyroidism and to identify the factors affecting detection. Between 1985, 82 patients with biochemical proof of hyperparathyroidism were referred for MR imaging of the parathyroid glands prior to surgery. Axial T1- (600/20 [TR/TE]) and T2-weighted (2500/40, 80) spin-echo images were obtained using an anterior neck surface coil. The interpretation of the MR image was compared with the findings at surgery and also correlated with gland histology, volume, and weight. Cases in which a false-positive or false-negative diagnosis was made were reviewed to determine the factors affecting detection. MR imaging detected 71 of 92 (77%) surgically proven abnormal glands (sensitivity, 77%; 95% confidence interval (CI), 68-86%) and misdiagnosed five (1.6%) of 314 normal glands as abnormal. There was no difference in the detection of enlarged glands in patients presenting for the first time (n = 71) (sensitivity, 77%; 95% CI, 66-86%) compared with patients with recurrent hyperparathyroidism (n = 12) (sensitivity, 77%; 95% CI, 46-95%). There was no significant difference in the detection of adenomas (sensitivity, 77%; 95% CI, 65-86%) compared with hyperplasia (sensitivity, 71%; 95% CI, 42-92%). Of five patients with ectopic parathyroid glands (1.6%), four had had previous surgery. All five glands were successfully located (three mediastinal, two in the neck). Factors contributing to a false-negative MR imaging diagnosis included small gland size and thyroid disease. Four of five false-positive diagnoses were due to enlarged lymph nodes being mistaken for parathyroid glands. MR imaging is an accurate technique for investigation of hyperparathyroidism. Pitfalls include low sensitivity for the identification of small glands, misinterpretation of enlarged lymph nodes as parathyroid adenomas, and misinterpretation because of thyroid disease. MR imaging is particularly useful in the investigation of patients who remain hypercalcemic following initial surgery.

Preoperative imaging of abnormal parathyroid glands in patients with hyperparathyroid disease using combination Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scans.

To evaluate the efficacy of combined Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scanning for imaging abnormal parathyroid glands in hyperparathyroid disease in a prospective study. Established methods to localize abnormal parathyroid glands lack accuracy for routine use. Tc-99m-sestamibi used in conjunction with iodine-123 has excellent potential for preoperative imaging in patients with hyperparathyroid disease. An alternative method for parathyroid imaging was studied using Tc-99m-pertechnetate and Tc-99m-sestamibi. Thirty patients with hyperparathyroid disease had Tc-99m-pertechnetate and Tc-99m-sestamibi subtraction radionuclide scanning to visualize abnormal parathyroid glands before surgery. The patients had surgery and pathologic confirmation of all parathyroid glands. In 23 patients with primary hyperparathyroidism, 12 of 13 solitary adenomas were visualized. Six of nine patients with diffuse hyperplasia had bilateral uptake consistent with diffuse hyperplasia. Three of nine patients had negative scans. One patient previously operated on for diffuse hyperplasia had only one gland scanned. Seven patients with renal failure-associated hyperparathyroid disease were scanned: five had bilateral uptake of Tc-99m-sestamibi consistent with hyperplasia, and two who had been previously operated on had localization of remaining abnormal parathyroid glands. Tc-99m-pertechnetate combined with Tc-99m-sestamibi subtraction radionuclide scanning is less cumbersome to implement than iodine-123 combined with Tc-99m-sestamibi scanning. It has a high sensitivity for imaging solitary parathyroid adenomas or persistent solitary hyperplastic glands. However it does not have the resolution necessary to delineate all parathyroid glands in diffuse hyperplasia.

Prospective comparison of technetium-99m-sestamibi/iodine-123 radionuclide scan versus high-resolution ultrasonography for the preoperative localization of abnormal parathyroid glands in patients with previously unoperated primary hyperparathyroidism

Surgery for primary hyperparathyroidism is successful in 95% of patients, but ectopic glands and anatomic variations in location are causes of surgical failure. The radionuclide imaging agent, technetium (Tc)-99m-sestamibi, in conjunction with subtraction iodine-123 scanning, is a new method of preoperative localization of abnormal parathyroid glands. In a study approved by the Institutional Review Board, 22 patients with primary hyperparathyroidism underwent preoperative evaluation with high-resolution ultrasonography and Tc-99m-sestamibi/I-123 radionuclide scanning for attempted localization of abnormal parathyroid glands. Results of Tc-99m-sestamibi scanning and ultrasound were correlated with surgical and pathologic findings. Of 22 patients, 16 had a solitary parathyroid adenoma, 1 had a double adenoma, and 5 had diffuse parathyroid hyperplasia. The Tc-99m-sestamibi/I-123 radionuclide scan preoperatively identified a solitary adenoma in 14 of 16 patients (sensitivity: 88%). However, when the data were analyzed retrospectively along with surgical and pathologic findings, the Tc-99m-sestamibi scan correctly localized all parathyroid adenomas for a sensitivity of 100%. The one patient with a double adenoma had a localization image consistent with two enlarged glands. All patients with diffuse parathyroid hyperplasia had Tc-99m-sestamibi imaging consistent with diffuse hyperplasia, although delineation of individual enlarged glands was not possible. High-resolution ultrasound identified 11 of 16 parathyroid adenomas (sensitivity: 69%). The patient with a double adenoma had a negative ultrasound. Ultrasound was less accurate in five patients with diffuse hyperplasia: one scan was completely negative, two scans revealed only one enlarged gland, and two scans revealed two enlarged glands. The Tc-99m-sestamibi/I-123 subtraction radionuclide scan is more sensitive than high-resolution ultrasonography for the preoperative localization of abnormal parathyroid glands. Tc-99m-sestamibi/I-123 radionuclide scanning may be more useful than ultrasonography to the surgeon in the preoperative localization of abnormal parathyroid glands.

Detection of abnormal parathyroid glands in postoperative patients with recurrent hyperparathyroidism: sensitivity of MR imaging.

The efficacy of MR imaging in identifying abnormal parathyroid glands in patients with recurrent hyperparathyroidism after surgery was investigated. Findings on preoperative T1- and T2-weighted MR images in 44 patients with recurrent hyperparathyroidism were prospectively evaluated and compared with surgical/pathologic results in all patients. A blinded retrospective analysis of the MR findings comparing T1- or T2-weighted images alone and in combination for detection of abnormal parathyroid glands also was performed. Seventy-four percent of surgically proved abnormal parathyroid glands were detected prospectively and 65% were detected retrospectively on MR images. The combination of T1- and T2-weighted images increased the sensitivity for detection. The sensitivity for detection of abnormal glands was 72% in the neck and 86% in the mediastinum. The sensitivities for detecting parathyroid adenomas (80%) and hyperplastic glands (69%) were not significantly different. There was no threshold volume for detection of lesions with MR imaging. Both intrathyroid parathyroid adenomas were missed on MR images. Abnormal glands could not be differentiated from lymph nodes on MR images in three cases. MR imaging is a useful technique for detecting abnormal parathyroid glands preoperatively in patients with recurrent hyperparathyroidism after surgery. The combination of T1- and T2-weighted images increases the sensitivity for detection.