Abdominal CT - Asthma

I have the occaisonal lump stick out of my abdominal area - about 2 inches above belly button and to the left. Thought it may be a hernia, so wanted to check before I get pregnant. I went to the Dr. today (a sugeon). Dr examined me - said he was not certain that it was a hernia, but he did notice that there was a slight differance between the right a left side of my abdominal area. He is sending me for a CT with contrast. Problem - I have asthma. I guess with people who have asthma, a reaction could accour with the contrast solution. The radiology office I called for the appt. called the Dr. and asked whether they could do the CT without the contrast. Dr. still stated he wanted the contrast. So now I have to go to the hospital to do this and have to take steriods the day of the ct. Is this worth it? I mean taking the contrast solution with asthma? Is there that big a differance in the results between contrast vs. no contrast?