Can ct scan clearly pin point the location of colon perforation and determine the size of the hole, using color contrast drink?

Diverticulitis: Is well demonstrated on ct though the actual hole, or perforation, is uncommonly seen. If contrast leaks out of the colon into a abscess the perforation itself may be sometimes be identified.

Sometimes : If the perforation is large enough, and the oral contrast is in that loop of bowel, then yes. A very small hole may not be seen that way, but the ct will show air that has leaked out of the bowel, which can help the surgeons if an open repair is required.