“MIBI” is short for sestamibi, a mildly radioactive compound that is used to perform nuclear scans. Sestamibi = technetium-99 = methoxy-isobutyl-isonitrile.
Thallium = TI 201 is another radioactive agent that is used in myocardial perfusions scans.
Either of these agents can be used to perform a nuclear myocardial perfusion rest-stress test, which may also be referred to as single photon emission computed tomography (SPECT). They are equally sensitive in detecting areas of ischemia or scarring. Thallium may be more sensitive for detecting viable myocardium because it is lower energy and redistributes in tissue; it does not remain fixed in myocytes. However, it also has a much longer half-life (73 hours opposed to 6 hours for sestamibi).
These radioactive agents that are used to image the heart are different from the pharmacological agents that are used to stress the heart. Pharmacological agents include adenosine, dobutamine, persantine.
Stress modalities: exercise, pharmacological (*note the terminology is different than in the borrowed image below)
Imaging modalities: EKG, ECHO, nuclear, CT
|Pharmacological (adenosine, dobutamine, persantine)|
You can mix and match any of these to create a stress test that fits your patient’s condition/contraindications best!