CT Barrister--I just read the link you posted. It sounds like you had a CT and then an MRI? Did they do the MRI for the very reason that the CT didn't show enough?
My GI at that time told me that the MRI showed more in terms of it enables better visualization of bowel thickness and where the bowel is thickest is where the inflammation is. He actually showed me the films as he described all of this. That MRI did identify major inflammation and a stricture directly at my J Pouch inlet, which was attributed to: (1) backsplash stool, and (2) resultant SIBO. From reading posts on this board over the years I believe this is very common with J Pouch surgery simply because the J Pouch does not have a valve to stop the backsplash, as the colon did. Perhaps some of us are more resistant to this type of thing than others are, I suppose it depends on the surgeon and quality of the J Pouch constructed and also varies depending on the individual sensitivities to SIBO and individual response in scar tissue buildup.
That was back in 2012 and I was able to bring that situation under control dietarily after being put on a short "emergency course" of Entocort in addition to antibiotics to bring the inflammation down.