Based on the video, you either read what you see Mt Gox = Mount Gox
or you say the acronym MTGOX  (Magic The Gathering Online Exchange) = MTGOX or M.T.G.O.X.   (Like we say FBI)

either way 'M T Gox' would be an illogical and inappropriate language usage unless Mt Gox identified themselves as such (which they didn't, see logo).