Answer: Per level reporting is appropriate for 72285 (Discography, cervical or thoracic, radiological supervision and interpretation) and 72295 (Discography, lumbar, radiological supervision and interpretation). To answer your question, yes, you may report the radiological supervision and interpretation codes once per level, just as you do injection codes 62290 (Injection procedure for discography, each level; lumbar) and 62291 (... cervical or thoracic).
Support: The March 2010 CPT® Assistant describes discography and offers a coding example for a three-level lumbar discography for payers who allow use of modifier 51 (Multiple procedures):
Different payers may have different preferences for how you report multiple procedures covered by the same code. For example, the payer might request that you report multiple units of the same code rather than appending a modifier.
Procedure: Diagnostic discography involves two separate components, the March 2012 CPT® Assistant explains. One part involves inserting the needle in the disc and injecting contrast. The other part involves checking the dye pattern, interpreting the disc structure, and perhaps interpreting pain response. A single physician might perform (and report) both components. In other cases, one physician may perform and report the injection while another physician performs and reports the supervision and interpretation.
Remember: Contrast injection and localization are included in the discography injection. Do not report 77003 (Fluoroscopic guidance and localization of needle or catheter tip for spine or paraspinouos diagnostic or therapeutic procedures ...) or any other fluoroscopy code with these procedures.