Difference between echocardiography and heart scan ?

See below: Echocardiogram is an ultrasound exam (no radiation) to evaluate valve function and heart pumping power (ejection fraction). It can also detect thickening of the heart muscle. A heart scan is a nuclear medicine (radiation) test that images flow to the heart muscle and thus detect narrowing or obstruction of the coronary arteries. It can also give an estimate of ejection fraction.