78452-26,93018 and 93016

Hi, we have been billing the codes (78452-26, 93016 and 93018) for Lexiscan done in the hospital. Both 93016 and 93018 were paid by Medicare but not the 78452-26. According to Medicare denial is: B20, Payment adjusted because procedure/service was partially or fully furnished by another provider. Please help me on how to get this procedure paid. Should i add Modifier-77 ? Or is it really not payable? Thank you.