Localization Of Abnormal Parathyroid Glands Research Articles

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.

Evaluation of CT, Subtraction Scintigraphy and MRI in Primary Hyperparath yroidism

To evaluate CT, 201T1-99mTc subtraction scintigraphy and MRI in the preoperative localization of abnormal parathyroid glands, we examined 11 patients with primary parathyroidism who were referred to us by the Department of Urology. Nine patients presented parathyroid adenomas and the rest hypertrophy of the parathyroid glands. Two patients were complicated with papillary carcinomas of the thyroid grand, with one concealing an abnormal parathyroid gland. All patients underwent CT and subtraction scintigraphy. We could detect an abnormal parathyroid gland in four patients (36.4%) by CT and nine patients (81.8%) by subtraction scintigraphy. The detection rate was markedly higher for subtraction scintigraphy than for CT. Recently, three patients underwent MRI with one of them who was not detected by CT and subtraction scintigraphy being successfully detected by MRI. The combination of high-resolution MRI and subtraction scintigraphy may constitute the most useful method for detecting abnormal parathyroid in the future.

Pre‐Operative localization and interventional treatment of parathyroid tumors: When and how?

A variety of diagnostic tests are currently used for parathyroid localization. In patients who have not had previous surgery, none of these are as sensitive or specific for the localization of abnormal parathyroid glands as an experienced surgeon. In these patients, no pre-operative localization procedures are normally needed. Patients who have had previous thyroid or parathyroid surgery require pre-operative localization. Noninvasive imaging procedures (ultrasound, scintigraphy, computed tomography, magnetic resonance imaging) should be performed until an abnormal gland is identified in the same location on at least 2 examinations. The order in which these studies are performed is not important. In the 50% to 70% of patients in whom noninvasive studies are inconclusive, suspicious lesions may be aspirated or biopsied with imaging guidance. If this cannot be done or is nondiagnostic, angiography and, if necessary, parathyroid venous sampling should be done. Intra-operative ultrasound examination of the neck is helpful during re-operations. In selected patients, parathyroid tumors may be ablated by injection of contrast material through an angiographic catheter into the artery supplying the gland, or by percutaneous injection of alcohol into the gland itself. Angiographic ablation is best used for mediastinal glands supplied by the internal thoracic artery or by a descending branch of the inferior thyroid artery. Percutaneous alcohol injection may injure the recurrent laryngeal nerve permanently and should be limited to the rare patient with a neck lesion who has a prohibitive surgical risk. Neither technique is as effective as surgery.

Preoperative Diagnosis of Localization of Abnormal Parathyroid Glands

Preoperative Diagnosis of Localization of Abnormal Parathyroid Glands

Do we really need another localizing technique for parathyroid glands?

To evaluate magnetic resonance imaging (MRI) in the preoperative localization of abnormal parathyroid glands, we examined 16 patients with primary hyperparathyroidism at initial presentation with MRI and ultrasound of the neck. These studies were analyzed prospectively and compared with the findings at bilateral neck exploration. The surgeon was intentionally blinded to the imaging studies. MRI was accurate in the lateralizing of an abnormal gland in 21 of 32 sides (66 percent). Sensitivity was 65 percent and specificity was 66 percent. Ultrasound was accurate in 19 of 32 sides (59 percent). Sensitivity was 50 percent and specificity was 75 percent. The difference was not statistically significant. We do not believe that MRI is indicated prior to initial exploration in patients with primary hyperparathyroidism.

MRI of the Upper Aerodigestive Tract and Neck

The application of new technology has improved the ability of MR to image the upper aerodigestive tract and neck. Improved resolution along with inherent high tissue contrast and multiplanar capability now allow clear definition of detailed anatomic and pathologic tissue planes. MR currently rivals other imaging modalities in this region. At present, it is often better in demonstrating the depth of tumor infiltration and the presence of nodal metastasis. Initial studies also suggest that MR can effectively image postoperative sites and discriminate chronic fibrosis from recurrent tumor. Localization of abnormal parathyroid glands, particularly for re-exploration, is a promising technique. If the present limitations are recognized, such as identification of soft tissue calcification, MR can play an important role in the evaluation of the face and neck. With additional investigation and continued technologic improvements it is likely that this role will continue to increase.

Localization of abnormal parathyroid gland(s) using thallium-201/iodine-123 subtraction scintigraphy in patients with primary hyperparathyroidism.

Tl-201/I-123 subtraction scintigraphy was performed in 17 patients with clinical symptoms and biochemical measurements suggestive of primary hyperparathyroidism. Nineteen abnormal sites were identified. These results were correlated with PTH measurements and surgical findings. Three sites were considered unrelated to the parathyroid glands, two corresponding to palpable thyroid nodules and one to muscle uptake of unknown origin. One scintigram did not reveal either of two abnormal glands while two others were considered falsely positive in view of surgical failure. Fourteen sites corresponded to abnormal parathyroid gland at surgery; five glands, weighing more than 2000 mg, could be correctly located on the Tl-201 scintigraphy prior to the subtraction procedure; six glands, weighing between 500 and 2000 mg, were easily localized after the subtraction procedure; three glands, weighing between 180 and 200 mg, were correctly localized after further manipulation of the subtraction procedure. In a patient with parathyroid hyperplasia, one gland, weighing 150 mg, was not located and another was not found upon surgery. Overall sensitivity was 87.5%. A positive correlation between PTH levels, tumor weight, and ease of detection on scintigraphy was found. This correlation was particularly useful in excluding large abnormal uptake related to thyroid disorder or artifact. The results suggest that Tl-201/I-123 parathyroid scintigraphy could become an alternative to Tl-201/Tc-99m parathyroid scintigraphy, with possibly improved detection of low weight abnormal parathyroid glands.

Parathyroid Localization

Twenty-nine consecutive patients with suspected primary hyperparathyroidism were examined preoperatively using ultrasound, sonographically guided fine needle aspiration, and aspirate immunostaining for PTH. In 25 patients, localization of enlarged parathyroid glands was successful. In 2 patients, the tumors were located retrosternally and, thus, could not be detected by ultrasound. One patient had a multinodular goiter which impeded localization. In 1 patient with renal osteodystrophy, 2 enlarged parathyroid glands in the neck were not visualized preoperatively. Cytology was not diagnostic, although some cytological features were suggestive of parathyroid cells. Immunostaining of the aspirated smears for PTH, however, correctly diagnosed all preoperatively localized lesions. Ultrasound should be the routine procedure of choice for preoperative localization of abnormal parathyroid glands in primary hyperparathyroidism. Fine needle aspiration and immunocytochemistry can supply confirmation, if necessary.

A new method with high sensitivity and specificity for localization of abnormal parathyroid glands.

A novel method for localization of abnormal parathyroid glands involving color-processing of nuclear scintigrams of the neck after injection of Thallium-201 and Technetium pertechnetate is presented with surgical correlation. Preoperative localization of single parathyroid adenomas was successful in 88% of previously unoperated patients and in 85.7% of those with adenomas not located at previous surgery. Eighty-three per cent of glands with secondary hyperplasia, 66% of glands with primary hyperplasia, and one carcinoma were localized. No abnormal studies were seen in non-hyperparathyroid hypercalcemia, and no false positive studies were seen. Localization appeared related to larger adenomas (300-5000 mg), although one of 60 mg was localized. Color-comparison dual-isotype scintigraphy was useful for localization of parathyroid adenomas and hyperplastic glands and exceeded the reported sensitivity of either ultrasonography or computerized tomography. It deserves wider evaluation in preoperative management of at least hyperparathyroidism of the primary or persistent types.

Localization of abnormal parathyroid glands using thallium-201

Ectopically located parathyroid adenomas may be difficult to find during initial neck exploration. They account for over 70 percent of missed adenomas found at reexploration. Preoperative localization of parathyroid adenomas would reduce unnecessary dissection and possibly reduce the number of negative results of initial neck exploration. Before reoperative parathyroid surgery is performed, some means of localization is mandatory to detect ectopic adenomas in the neck and mediastinum. Computed tomography and ultrasonography cannot effectively evaluate the mediastinum. Angiography and venous parathyroid hormone sampling are invasive, costly, and tedious to perform. We have shown that thallium-201 will accurately localize ectopic parathyroid adenomas. All 10 adenomas found in positions not immediately adjacent to the thyroid gland were detected by thallium-201 scintigraphy. One was a mediastinal adenoma resected with a median sternotomy. Our results suggest that thallium-201 scintigraphy should be the initial localization procedure of choice before all reexplorations. Its use before initial explorations, as well, will enable the surgeon to immediately direct attention to the area of the localized adenoma. If mediastinal uptake is found to be present, then median sternotomy may be performed during initial surgery provided a thorough neck exploration is performed first.

Diagnostic usefulness of201T1-chloride scintigraphy for preoperative localization of parathyroid tumors

201Tl-chloride scintigraphy was performed in 10 patients with hyperparathyroidism to assess the localization of abnormal parathyroid glands. This approach proved to be useful in 8 of 10 patients. In particular, an intramediastinal ectopic gland was clearly demonstrated in one patient. Several disadvantages were noted, however, 201Tl-chloride scintigraphy could be the first choice for preoperative localization of abnormal parathyroid glands. If a negative image is obtained, further examinations such as arteriography or parathyroid hormone assay be selective venous blood sampling should be done.