Yes, absolutely you can use a patterned rug. You want to choose a pattern that is transitional or traditional, the key is using the same colors in your fabrics. In a dining room, there is limited textiles, meaning not a lot of fabric, you don't have to worry about too many patterns. You want to try to duplicate what is on the wall to the floor. I hope this helps.

I would choose something a bit more neutral since this fabric is a bit busy.

Nice fabric. It might be safer more neutral.

If you choose a pattern I'd choose something simple like a stripe that won't compete with the curtains. An oriental rug such as this one http://www.abccarpet.com/store/store/pc/Ziegler-105p233.htm would have a pattern that doesn't compete with the curtains.

Beautiful curtain fabric. Patterned rug would definitely work. Pick a colour from the fabric and look for rugs that have a soft geometric pattern. Not too rectangular, no chevron, but something with a bit of a rounded edge or a pattern that relates to the shapes that are in the curtain. Found a couple of examples at homedecorators.com