There are several subtle clues indicating a closed-loop obstruction in this case. The proximal small bowel is mildly dilated, but less so that then closed loop segment in the right lower quadrant. The small bowel in the closed loop sticks out as more abnormal than any other segment in the abdomen: more dilated, no oral contrast, and mesenteric edema. The axial images give it away (see annotated image) - the two sites of obstruction are adjacent to each other, indicating a closed loop obstruction. This appearance could be due to internal hernia or (as in this case) adhesive bands.