Correlation of 99mTc sestamibi uptake with size and weight of parathyroid adenoma as well as serum levels of calcium, PTH and vitamin D

Objectives To predict the accuracy of preoperative 99mTc sestamibi SPECT/CT we correlated 99mTc sestamibi uptake with size and weight of proven parathyroid adenoma as well as serum levels of calcium, intact parathyroid hormone (PTH) and vitamin D.

Methods A retrospective analysis was performed in 79 patients (24 men, age 58.4± 14.3) who underwent preoperative parathyroid imagings and parathyroidectomies, and also found to have parathyroid adenomas based on greater than 50% drop of baseline PTH levels at 5 or 10 min after operation. Following injection of 740-1110 MBq (20-30 mCi) of 99mTc sestamibi, preoperative planar images of neck and chest were obtained at 15-30 min and 90-120 min, and SPECT/CT images at 60-90 min. Preoperative serum calcium, intact PTH and vitamin D levels as well as size and weight of proven parathyroid adenomas were correlated with grades of sestamibi uptakes (mild with similar thyroid activity, moderate with greater than thyroid, marked with similar salivary gland).

Results 79 patients had 108 hyperactive parathyroid lesions. SPECT/CT found 86 of 94 adenoma lesions (91.4%), 6 of 11 hyperplasia lesions (54.5%), and 3 of 3 (100%) tumor lesions. Size and weight of parathyroid adenoma, and serum vitamin D (1,25 dihydroxycholecalciferol) level had positive correlations with the grade of 99mTc sestamibi uptakes, while serum calcium, PTH and vitamin D (25 hydroxycholecalciferol) levels had no correlation.

Conclusions Size and weight of parathyroid adenoma, and serum vitamin D (1,25 di hydroxy) level had positive correlations with the grade of 99mTc sestamibi uptakes. SPECT/CT using 99mTc sestamibi is reliable in detecting and localizing parathyroid adenomas