Extra-Cardiac Uptake of Technetium-99m-MIBI: Normal and Abnormal Variants

Abstract

Objective: Myocardial perfusion agents such as ²⁰¹TI-chloride and ^99mTc-sestamibi (Cardiolite, DuPont de Nemours, N. Billerica, MA) have been used with success in evaluating myocardial ischemia. Many authors have also found extracardiac uptake in the thorax for various pathological conditions when using both of these agents. This article explores both normal and abnormal variants of extracardiac uptake of ^99mTc-sestamibi.

Methods: More than 400 consecutive patients from our lab were reviewed. We examined both normal and abnormal variants of extracardiac ^99mTc-MIBI uptake in the thorax, and evaluated factors which may influence ^99mTc-sestamibi uptake.

Results: This paper describes cases of previously undiagnosed broncho-alveolar carcinoma and thymoma. Possible explanations for ^99mTc-MIBI uptake in other extracardiac sites are presented, including the sternum, thoracic spine and thyroid.

Conclusion: A series of coronal slices may prove useful in all myocardial perfusion studies. This can be accomplished with only incidental institutional cost. The additional information can aid in early diagnosis of unknown thoracic pathologies which physiologically incorporate this agent.