Preoperative detection of parathyroid adenomas with Tc-99m MIBI and Tc-99m pertechnetate scintigraphy:...

The objective of this study was to compare the dual phase MIBI scinitgraphy with MIBI and Tc-99m pertechnetate (MIBI + Tc-99m) study in defining the parathyroid adenomas, and to evaluate the effect of histologic and biochemical characteristics on the imaging of parathyroid adenomas with Tc-99m methoxyisobutylisonitrile (MIBI) scintigraphy.

Thirty-six patients with parathyroid adenomas were studied prospectively. All patients were evaluated with both MIBI and (MIBI + Tc-99m) study. MIBI uptake of adenomas correlated with oxyphill, chief cell and tumour weight of the surgically excised glands. MIBI uptake was also compared with serum calcium (Ca), phosphorus (P) and intact parathormone (iPTH) levels.

A total of 38 parathyroid adenomas were surgically excised from 36 patients. MIBI + Tc-99m identified 35 of the parathyroid lesions (92%). Whereas, MIBI study detected 30 of the 38 parathyroid adenomas (79% sensitivity) (p=0.0001). There were no false positives. Adenoma weight showed significiant correlation with MIBI uptake (p=0.001). Oxyphyill cell content also showed high correlation with MIBI uptake. Delayed images showed better correlation than the early views (Early MIBI p=0.033; Delayed MIBI; p=0.001).

MIBI + Tc-99m pertechnetate interpretation is more sensitive than only dual MIBI imaging for the detection of parathyroid adenoma. Oxyphill cell content and weight of the lesions proved to be important determinants of 99mTc-MIBI accumulation in parathyroid adenoma. We found no significant correlation between MIBI accumulation, Ca, P and iPTH serum levels (Tab. 2, Fig. 2, Ref. 15). Full Text (Free, PDF) www.bmj.sk.