CT is helpful in delineating the cause of bowel dilatation.  Always look for a point of transition from dilated to collapsed bowel = site of obstruction.  In this case there is no transition point to the anus this mechanical obstruction is unlikely.  On that basis this is likely to be a functional disorder of the bowel ie poor or absent peristalsis.  Dilatation can be extreme even leading to venous ischemia of the bowel wall and perforation.