Jim,
They are one in the same.
Check out link below.

Here is a link that might be useful: Wisteria tree thread

The 'tree' is really a vine that is grown as a semi-self-supporting plant. I wouldn't expect it to continue to grow upward and support itself, like a real tree would. The growth that will come from it will be viney. If I wanted to grow a free-standing wisteria in an open location, I'd put a large timber in the ground and grow the vine on that. Eventually with some prudent trimming you'd get what looks like a wisteria trunk, but is really a timber covered, more or less, in thick wisteria vines, with a shaggy growth of vines coming out of the top. You can do the same thing with Trumpet Creeper.

A neighbor of mine in Massachusetts used to have one of those "trees" in her front yard. It was quite old, and stood on its own. It was kept short by pruning, I guess, and flowered nicely every year. It was quite attractive, and the trunk was a bit wavy looking, but looked like it was all one trunk--probably about six or eight inches wide. It probably was several vines twisted together, though.

I suspect keeping it to size in Pennsylvania might be more of a challenge; things grow in a more restrained fashion in Massachusetts. The soil is poorer, and the climate is a bit more challenging than in PA.