Technetium-99m sestamibi scintigraphy and bone densitometry in primary hyperparathyroidism.

OBJECTIVE

To review our recent experience with technetium-99m sestamibi scintigraphy in identification and localization of parathyroid adenomas and to determine bone mineral loss associated with primary hyperparathyroidism.

METHODS

Thirty-two double-phase technetium-99m sestamibi scans were obtained in 26 patients (22 female and 4 male patients; age range, 14 to 78 years). Serum calcium and intact parathyroid hormone concentrations were measured before scintigraphy. Histopathologic correlation was obtained in all patients who underwent a surgical procedure. Seventeen patients underwent bone densitometry studies of the lumbar spine and hip with use of dual-energy x-ray absorptiometry.

RESULTS

Of the 32 scans, 17 (53%) were suggestive of a parathyroid adenoma ("positive"). In these patients, the mean serum calcium concentration was 2.68 mmol/L and the mean serum parathyroid hormone concentration was 669 pg/mL. Overall, one false-negative scan and one false-positive scan were encountered. The overall sensitivity for surgically proven detection and localization of parathyroid adenoma was 90%. The bone density measurements in patients with positive scans were substantially lower in the lumbar spine (mean T score, 2.9) and in the hip (mean T score, 2.1) in comparison with normal control subjects and significantly lower than in those with a negative scan (spine, P = 0.011; hip, P = 0.015).

CONCLUSION

Double-phase technetium-99m sestamibi scintigraphy is highly sensitive and useful in detection and localization of parathyroid adenomas. Patients with primary hyperparathyroidism lose bone mineral from both cortical and cancellous bone sites.