The usefulness of the parathyroid ^99mTc-sestabmibi SPECT in diagnosis of parathyroid adenoma; 241 patients with parathyroid adenoma suspected in neck CT or US.

Objectives Parathyroid ^99mTc-sestabmibi SPECT is widely used for the diagnosis of primary parathyroid adenoma. We investigate the diagnostic power of ^99mTc-sestabmibi SPECT in the patients with incidental parathyroid adenoma detected by CT or US.

Methods Total 241 patients were detected to the possible parathyroid adenoma by neck CT or US without parathyroid SPECT information were enrolled. In 42 patients, parathyroid ^99mTc-sestabmibi SPECT were additionally performed and 199 patients did not. Comparative study on the diagnostic effectiveness of the parathyroid ^99mTc-sestabmibi SPECT was done by comparing the two groups.

Results Among the 199 patients without performing the parathyroid ^99mTc-sestabmibi SPECT, only 33 patients were pathologically confirmed as parathyroid adenoma. Other 166 patients were diagnosed not adenoma and had transient hyperparathyroidism or normal PTH level. The positive predict value (PPV) of CT and US in this group was just 33/199 and false positive cases were 166. Among the 42 patients who underwent parathyroid ^99mTc-sestabmibi SPECT, 11 patients had positive scan result to rule out parathyroid adenoma. From among those 11 patients, 10 patients were pathologically confirmed as parathyroid adenoma and 1 patient was diagnosed as normal parathyroid by biopsy. The other 31 patients with negative result that no evidence of parathyroid adenoma were diagnosed not adenoma and had transient hyperparathyroidism or normal PTH level. By additionally performing ^99mTc-sestabmibi SPECT, we can accurately diagnose 41 patients among 42, and false positive of CT or US was reduced

Conclusions Neck CT and US are useful imaging modality for detecting parathyroid adenoma. However, those had limitation in the differentiation parathyroid adenoma from lymph node or other lesions. From our results, parathyroid ^99mTc-sestabmibi SPECT could give more accurate diagnosis information for diagnosing parathyroid adenoma.