Coding for a radionucleotide cisternogram with subsequent head and facial imaging
You would report the lumbar contrast administration code, 62284 with the appropriate CT codes (in your example, 70470 and 70488). Whether or not the insurance will reimburse would depend on their policy. If fluoroscopic guidance is used for the injection, you can also assign CPT code 77003.
Normally you would not assign an administration code for the contrast, but intrathecal contrast is one of the two exceptions (intra-articular being the other).