Reconsideration of the use of 99Tcm-MIBI thyroid imaging for detection of thyroid malignancy in thyroid nodules

Objective: To reconsider the use of 99Tcm-methoxyisobutylisonitrile (MIBI) thyroid imaging for detection of thyroid malignancy in thyroid nodules. Methods: One hundred and one of 106 thyroid nodules patients underwent routine 99TcmO4- scan first, then after injection of 370 MBq 99Tcm-MIBI dual-phase (15 min and 2 h) thyroid imaging was performed in all 106 patients within 1 week. After operation the result of thyroid imaging was compared with pathologic findings. Results: Among 5/13 cases of thyroid malignancy and 23/93 of benign nodules, 99Tcm-MIBI imaging showed positive result. The sensitivity, specificity, positive predictive value and negative predictive value of 99Tcm-MIBI scintigraphy were 38.5%, 75.3%, 17.9% and 89.7%, respectively. No statistics difference was found between benign and malignant thyroid nodules χ2=0.49, P > 0.05). Conclusions: 99Tcm-MIBI thyroid imaging is not specific for thyroid malignancy. Thereby its clinical value is limited. (authors)