I have a cardiology coding question regarding Transesophageal Echocardiography (TEE). Often we see that some of our cardiologists do a pre and post surgical TEE. How can I bill for both visits?

Sometimes the same physician performs both pre and post surgical TEE and*sometimes two different physicians perform this exam.

Can some on explain me in brief for my following queries:

1)If both pre and post TEE's can be billed?
2)Are they both payable?
3)If same physician does what are the codes and modifier i should use?
4)If different physician does what are the codes and modifier i should use?
5)What is the coding guidelines for this procedure?