I had two MIBI stress tests on the treadmill with radio-opaque dye. Both times my cardiologist ordered them, three years apart, because he thought I have ischemia (almost always due to blockages or stenosed arteries). In both cases, there was no measurable plaque. This was when I was in my late 60's. He referred me to an electrophysiologist to stop my fibrillating left atrium. As a workup for that, my EP wanted his own diagnostics to also rule out ischemia (no use in tying up his operatory with a heart that needed other more urgent care). He ordered an MRI, and then an angiogram. As the gentleman withdrew the catheter during the angiogram, he leaned over to my face and said, 'Minor deposits, you're good.' (He also muttered, halfway through, 'Too much ectopy!' My heart was actively fibrillating due to the experience.)

So, I was unfortunately exposed to about 1000 x-rays worth of radiation over those two MIBI tests, only to have a much less dangerous angiogram show I had no dangerous stenosis anywhere in my heart. A Doppler ultrasound of my carotids showed they are clear. As I said, already well into my 60's, male.....but a lifelong runner, some of it competitive. I think that made a difference.