Ultrasound modifier?

Example bilateral knee injections where US guidance for needle placement was used for each injection site. I am aware of the NCCI edit for 76942 allowing only one unit at a single encounter but the disclaimer states a modifier can be used to override edit:

CPT codes 76942, 77002, 77003, 77012, and 77021 describe radiologic guidance for needle placement by different modalities. CMS payment policy allows one unit of service for any of these codes at a single patient encounter regardless of the number of needle placements performed. The unit of service for these codes is the patient encounter, NOT number of lesions, number of aspirations, number of biopsies, number of injections, or number of localizations.

The CMS instruction is that imaging guidance is billed once per encounter and not per lesion. Society guidelines have always defined imaging guidance as reported per lesion or anatomical area involved.

This edit will allow use of NCCI associated modifiers if 76942 is utilized for a separate procedure unrelated on the same date of service.

***Has anyone been successful in using a modifier on the 2nd 76942 billed? I have some test claims out, but unsure which modifier is appropriate*** What are you using? Need help please,Thanks

Ultrasound modifier?