Different LVEF values

A while back when I was in the Hospital, I had both a Gated Spec Profusion test and an Echo, The gated Spec measured my LVEF as 25% while the Echo measured it as 35%. which my doctor states on my hospital report as LVEF between 25% to 35% depending on modality. Why is there such a difference between the two?

[jrbon]

First the EF changes almost continuously, although that but itself does not justify that difference.

The Echo has 2 difficulties, first it is measure on an image that is frozen by the operator and second, there is not easy way to recheck it, it is assume that may have a +- 5% of operator error.

The Spec it is supposed to be more precise.

Jesus