PCM is the basis of DTS. and "DTS" does not need "PCM" after it; there is no other sort. PCM is also the format in which the data gets through to the processor for CD and DVD-Audio. Dolby digital AC-3 (5.1) does not use PCM, but something else, SACD something else again. DTS, DD, and SACD all use one or other way of compressing the data, like compressed computer files, in order to get more on a disc. Cd doesn't, it just takes raw PCM, but the quality of sound is limited by the sampling frequency and size.
For my money, DTS is the best DVD-Video sound format. But DVD-Audio beats it hands down. DVD-Audio (aka "DVD-A") uses the much greater capacity of a DVD disc, takes a whole side just for audio, and shoe-horns the PCM data in with Meridian Lossless Packing (MLP), which itself has no audible effect.
I've been thinking DTS was the best thing, until last week, when I got a DVD-Audio player. The sound is completely incredible. In my opinion, DVD-Audio is the most significant development in home sound reproduction since the introduction of stereophony, about 45 years ago.