Ask Dr. Z

I have a chart where the doctor is stating procedure reason is "to place internal stent". The history says, "Patient returns for diagnostic antegrade pyeloureterogram and stent placement." The dictation says, "The contrast through existing tube. Cath was cut and removed. Fluoroscopy confirms uretral stone. Double J stent placed, new percutaneous catheter was placed, contrast confirmed position, and tube placed to gravity drainage." (I am shortening this a lot.) In the findings, doctor says pyelogram shows decompression and dilation of ureter, 1 cm stone that has migrated, ureter is obstructed at the level of the stone, and calcified uterine fibroid noted in pelvis. I know I can report codes 50393/74480 and 50398-59/75984, but is this enough info to also report codes 50394/74425?  Your book says it has to be diagnostic to be coded, and I feel this is diagnostic, but I'm not sure. Can you explain what I need to look for to be able to code diagnostic grams?