Thickening in the bowel wall as seen on a CT or MRI can be a sign of both active inflammation or chronic past inflammation. So the short answer is sometimes. Judging from your sig, if your son was only diagnosed this past summer, it's unlikely he's had irreversible damage to his bowel. That's more commonly seen in someone who has poorly controlled inflammation over years and years.
dx'ed UC pancolitis 5/12
past meds: asacol hd, VSL#3, apriso, rowasa, xifaxan, 6mp, cortifoam, pentasa, cimzia, canasa, butyrate, flagyl, cipro, prednisone, remicade, methotrexate, cholestyramine, cortenema
current meds: none!
step one: colectomy, end ileo 1/16/13
step two: j-pouch construction, loop ileo 5/1/13
step three: takedown 7/31/13