A year and a half ago, I was diagnosed with dilated cardiomiopathy after an echocardiogram. It showed my EF to be 25%. My cardiologist followed up with a MUGA scan which showed the EF to be 49%. Recently, I had a stress echo test. On it, my pre-exercise EF was 30% and my post-excercise EF was 35%. Again, my cardiologist followed up with a MUGA, which said my EF was 59%. Why such a difference and which is more likely to be correct?