PRE-OPERATIVE LOCALIZATION AND TISSUE UPTAKE STUDY IN PARATHYROID IMAGING WITH TECHNETIUM-99m-SESTAMIBI

Background: The diagnostic ability of 99mTc-sestamibi was compared with other techniques and the mechanism of parathyroid uptake was investigated. Methods: Double-phase 99mTc-sestamibi scanning was performed in 52 primary and 28 renal hyperparathyroidism patients. Gene expressions of mdr1 and mrp were examined by reverse transcriptase polymerase chain reaction in parathyroid tissue. Results: The sensitivity of 99mTc-sestamibi in primary and renal hyperparathyroidism was 91% and 75%, respectively, higher than for ultrasonography, Tl/Tc subtraction scintigraphy, or computed tomography. Early 99mTc-sestamibi uptake was washed out in delayed images in 7% and 30% of glands in primary and renal hyperparathyroidism, respectively. Expression of mdr1 and mrp mRNA was found in 5 of 23 and 16 of 31 glands, respectively, and their expression correlated with washout in delayed images. Conclusion: 99mTc-sestamibi was the best localization test. mdr1 and mrp were associated with 99mTc-sestamibi washout, but their role in the parathyroid remains unclear.