Ectopic parathyroid

Abstract: Background Ectopic parathyroid glands are a cause for failed parathyroid exploration. Methods Patients with hyperparathyroidism and ectopic parathyroid glands were identified from a parathyroid database. Laboratory data, gland weights, and surgical outcomes were obtained. The locations of the ectopic glands were correlated with results of technetium-99m–sestamibi imaging. Results Of 231 patients operated on for hyperparathyroidism, 37 (16%) had ectopic parathyroid glands. Ectopic inferior glands (N = 23 [62%]) were intrathymic, n = 7 (30%); anterosuperior mediastinal, n = 5 (22%); intrathyroidal, n = 5 (22%); within the thyrothymic ligament, n = 4 (17%); and submandibular, n = 2 (9%). Ectopic superior glands (N = 14 [38%]) were in the tracheoesophageal groove, n = 6 (43%); retroesophageal, n = 3 (22%); posterosuperior mediastinal, n = 2 (14%); intrathyroidal, n = 1 (7%); in the carotid sheath, n = 1 (7%); and paraesophageal, n = 1 (7%). Sestamibi scans were true-positive in 81%, identifying 13 of 16 retrosternal glands, and false-negative in 19%. Conclusions A 16% incidence of ectopic parathyroid glands and a 100% positive predictive value of sestamibi scintigraphy underscore the importance of sestamibi imaging in patients with primary hyperparathyroidism.

Abstract: Summary objective To determine the utility of ultrasonography for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism, and to compare this method with 99mtechnetium sestamibi scintigraphy. design The results of ultrasonography for localization of enlarged parathyroid glands were determined in 120 consecutive patients with primary hyperparathyroidism and compared with findings at surgery (n = 86) and with the results of 99mtechnetium sestamibi scintigraphy (n = 99). patients All patients had biochemically documented primary hyperparathyroidism based on elevated serum calcium and ‘intact’ parathyroid hormone measured by immunoassay. Patients with prior parathyroid surgery or secondary hyperparathyroidism were excluded. measurements High-resolution ultrasonography was performed by a single observer. 99mTechnetium sestamibi scintigraphy was performed using early and delayed (2-h) views, and correlated with simultaneous thyroidal 123I uptake in most patients. results Ultrasonography detected putative enlarged parathyroid glands in 92 of 120 unselected patients (77%). It correctly predicted surgical findings in 64 of 86 patients undergoing surgery (74%), including 61 of 72 patients with solitary eutopic parathyroid adenomas (84%), but only two of eight patients with solitary ectopic adenomas, and only one of six patients with multigland parathyroid disease. Sestamibi scintigraphy was positive in 87 of 99 unselected patients (88%), a higher proportion than ultrasonography (P < 0·05), reflecting superior sensitivity for the detection of ectopic parathyroid adenomas. For 74 patients undergoing parathyroid surgery who underwent both imaging tests there was no statistically significant difference between ultrasonography and sestamibi scintigraphy in ability to correctly predict surgical findings (74%vs. 82%, respectively) or in positive predictive value (93%vs. 90%, respectively). However, sestamibi scintigraphy was clearly more sensitive for ectopic parathyroid adenomas, providing correct localization in 8/8 cases. When one test was negative, testing with the second method was usually positive, improving the likelihood of a positive result to 98% when both tests were employed. conclusions Ultrasonography can be a sensitive and accurate method for preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism, comparable in overall utility to sestamibi scintigraphy. These results suggest that a strategy of initial testing with one or the other method, followed by the alternate imaging test if the first test is negative, would provide correct parathyroid imaging in most patients without prior parathyroid surgery.

Abstract: Background Parathyroidectomy has a success rate of >95 % for cure of primary hyperparathyroidism. In about 6–16 % of cases, one or more hyperfunctioning parathyroid gland(s) are found in an ectopic location. Accurate preoperative imaging can aid in detecting these ectopically located glands and allow a focused surgical approach with an even higher success rate. The objective of this study was to assess the utility of ultrasonography (US) and technetium-99m-sestamibi (MIBI) scans in locating ectopic parathyroid glands in previously unexplored patients who presented with primary hyperparathyroidism.

Abstract: As SPECT/CT technology evolves, its applications and indications need to be evaluated clinically for more efficient and cost-effective use. This retrospective study evaluated the clinical value of simultaneously acquired 99mTc-sestamibi SPECT/CT versus conventional SPECT in diagnosing and locating parathyroid adenomas or hyperplasia in patients with primary hyperparathyroidism. Methods: Immediately and 60 minutes after intravenous administration of 740–925 MBq of 99mTc-sestamibi, static planar images of the neck and chest were obtained. SPECT/CT images were acquired 30 minutes after injection. Two experienced masked readers independently evaluated whether conventional SPECT images provided information beyond what was available from the planar images either by changing the diagnosis or by better locating the glands and whether the SPECT/CT images provided information beyond what was available from the planar plus conventional SPECT images. Forty-eight consecutive patients with a clinical diagnosis of primary hyperparathyroidism were included in the study. The 32 whose scans showed positive results underwent surgical resection and were examined histopathologically. Results: Planar and SPECT imaging, with or without CT fusion, identified 89% of the surgically confirmed diseased parathyroid glands. Use of SPECT/CT changed the diagnosis in only 1 patient (2%) from positive to negative and better located the glands in only 4 patients (8%). SPECT/CT was particularly helpful in locating the 2 ectopic parathyroid adenomas diagnosed in this cohort. Tracer retention in diseased glands did not correlate with histologic characteristics. Also, biochemical markers did not correlate with the scan findings. Conclusion: SPECT/CT has no significant clinical value additional to that of conventional SPECT for parathyroid imaging except in locating ectopic parathyroid glands. Eliminating the CT acquisition will spare patients the additional time, radiation exposure, and expense.