When an interventional radiology procedure is performed (US guided bx), then a followup scan (such as a CT) is performed to verify, is the CT included or should it be coded separately? (All done during the same encounter).[/QUOTE
It depends on the documentation. As described, I would think the CT was part of the procedure as guidance, not a separate encounter/procedure.
There are codes for CT guidance (77012-13) that should be used for this instead of diagnostic CT procedure codes.
HTH