It really depends on if one physician billed SE or it was broken up.
My physicians perform stress echo's in the hospital, however, they perform all professional components.
I bill:
93351-26
93320-26
93325-26
Echo portion is included with 93351 so you can't bill 93016/93018.
Now, when all professional services of a stress test are not performed by the same physician performing stress echo, use 93350-26 with appropriate codes.
The hospital/facility is going to bill with TC since they are provding the equipment ect.
Now, if this were performed in the physician's office AND he/she owned the Stress echo equipment - and was performed by the same physician, you could bill 93351, no modifier.
Take a look on pg. 510 in your CPT book and you will see where it discusses how to bill. I have the AMA Professional CPT book so if you have a different one, the page may be different.
HTH