Radiology Question for the Week of January 19, 2026

Question:

On the hospital side, during an MAA mapping study, the doctors are using a device called a TriNav catheter to temporarily occlude the vessel. To be clear, they are not performing an embolization at this point. Historically, we have billed for catheterization and imaging, but with the release of the C9797 code, we are now being instructed to bill C9797 during the MAA mapping, even when no true embolization is performed. The patient returns a few weeks later for the Y90 treatment, which also involves the use of the TriNav catheter. At that time, I billed the procedure with C9797. What is the correct way to bill for the MAA mapping session on the hospital side?

Answer:

For the hospital-side MAA mapping session, C9797 should not be reported if no true embolization or vessel occlusion is performed. While the TriNav catheter may be used to temporarily occlude the vessel during mapping, the key determinant for reporting C9797 is that a vascular embolization or occlusion procedure is actually performed, not just vessel access or temporary positioning of a pressure-generating catheter.

During the mapping session, typical reporting should include:

• Catheterization and diagnostic imaging were performed to map the hepatic vasculature.
• Any fluoroscopic guidance, roadmapping, or intraprocedural imaging needed to perform the mapping.

The C9797 code should be reserved for the subsequent Y-90 treatment session, when embolization or occlusion is actually performed using the TriNav catheter or other devices to deliver therapy. Billing C9797 for the MAA mapping session would be inaccurate, as the procedure does not meet the CPT definition of embolization or occlusion. Code Summary:

• MAA mapping session: report catheterization and imaging only (no C9797).
• Y-90 treatment session: report C9797, as embolization/occlusion is performed.