New Myocardial Imaging Agent, Tc 99m MİBİ: Clinical Application, Advantages, and Limitations

The diagnostic value of a new myocardial imaging agent, technetium-99m hexaxis-2-methoxy-2- isobutyl isonitrile (Tc 99m MİBİ), in coronary artery disease (CAD) was investigated in 12 subjects. Advantages and limitations of MİBİ were reviewed. Exercise myocardial perfusion study with Tc 99m MİBİ and selective coronary arteriography were performed in all subjects. Tc 99m MİBİ was found to be negative in all 3 patients with normal coronary arteries. In 8 of 9 patients with angiographically documented CAD, perfusion defects were shown in one or more regions (sensitivity 88%). Liver uptake of Tc 99m MİBİ was considerable, and high background caused by high liver acitivity might interfere with image interpretation both qualitatively and quantitatively. We concluded that Tc 99m MİBİ provides a reliable method of assessment of CAD with a high sersitivity and, probably, a high specificity, but it has some disadvantages: high cost, high liver uptake and the requirement for a separate day resting injection.