How am I supposed to know that this is +EV?

[suited_ace]

I've been going over all my HHs with SNGPT, and there's always a couple of spots that I missed. In a few of them, I actually thought about it but never had the guts to shove it, but there are a bunch of them that just don't seem logical to me.

I have at least 1 spot like this per tourney, so I've been wondering what can I do to take the right decision when I have a hand like the one below.

Party Poker No-Limit Hold'em Tourney, Big Blind is t150 (4 handed) converter

Button (t1160)
Hero (t1070)
BB (t2240)
UTG (t5530)

Preflop: Hero is SB with 8[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/heart.gif[/img].
<font color="#666666">3 folds</font>.

ICM says this is a push, and it's not even close.

I've been able to figure out most +EV spots on my own, but I still struggle with spots like these. What's your thought process on this spot?