Thallium and Sestamibi Stress Tests

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Special Considerations

Sometimes a thallium or sestamibi test produces heart image that looks like a defect, but it's a pseudo-defect that gives a false positive test result (i.e., a falsely abnormal test). This is due to interference with the heart image from non-heart tissues such as the diaphragm (diaphragm attenuation), and, in women, the breast tissue ("breast attenuation").

When non-heart tissue attenuation is clearly the cause of an abnormal image, nothing additional needs to be done. If an attenuated image instead is thought to coincide with a true defect or area of ischemia (reduced blood flow), then your doctor may recommend additional testing such as a stress echocardiogram or a cardiac catheterization.