First of all, congratulations on conquering the months of chemotherapy and that you have that obstacle behind you.
I'm not a doctor and I am really no expert in imagiology. So I can only talk about my experience...
In the first CT that I had when diagnosed (1/17) a cyst was also found in my liver. 4mm in segment IV. They weren't really sure what it was, so I made an appointment with a imagiologist who I trust and he made an ultrasound of the liver.
It was not easy to find the damn thing, but when he did, he was POSITIVE it was only a cyst. And now 6 months later I've repeated the CT before my surgery and there it was again, 4 mm in the same place. So I don't worry
Maybe an ultrasound would be a valid option for your Husband?
All the best and keep strong,