Update to my post: I'm no longer freaking out. This is a very good example of why you need to be in complete control of your own health!
After spending the better part of a day calling the Rheumatologist, the GP, and the imaging department, here is what I learned.......
On the first visit to the Rheumatologist in Aug 17, while reviewing my husband's test results, he stopped at the xray of his lungs and asked us if we saw the shadow on his lower right lobe. We told him that was from the flu/pneumonia he had 4 months earlier. Dr said, "Ok, that answers that" and moved on. Told his nurse to make a note to have another xray taken at a later date to see how it looked then. That note was made but no mention of why the shadow was there in the first place.
Dec 6th the follow up xray was taken. Shadow still there. Here's where it gets interesting. The group that read the first xray wasn't the same as the group that read the second xray so there was no record of the first xray being taken. Flu/Pneumonia was never recorded in his charts which would have been a big help in knowing why they were seeing what they were seeing. As a result of all of this, they put a "stat" order on review and comparison of both xrays on Monday morning. They know about the flu and pneumonia now as well. They are then going to decide if the contrast is necessary.
All I can say is, "WOW!" On a side note. If you are a diabetic and on Metformin DO NOT get a contrast CT without talking to your doctor first because you will have to stop taking your Metformin before and after the CT so you don't risk kidney damage. They didn't tell us that either. Luckily I learned about it before something bad happened.
Curious to see how it all turns out on Monday!
FYI: The American College of Radiology Manual on Contrast Media has since updated its guidelines on metformin: https://www.acr.org/-/media/ACR/Files/Clinical-Resources/Contrast_Media.pdf#page=47
In laymen's terms, there is no longer any need to discontinue metformin before or after IV contrast in most cases.