This is a challenging, complex, and subtle case of internal hernia related to RYGB. There are two major tip-offs that signal something is wrong here:

• Right-sided jejunojejunostomy (JJ) - this is almost always abnormal and an important sign of internal hernia, because the JJ is performed in the left abdomen for RYGB. The prior study showing left-sided location confirms this
• Swirling and angulation of mesenteric vasculature - this is particularly easy to notice on the coronal reformats when following vessels into the right upper quadrant, and a very different configuration from the old study
• Following the terminal/distal ileum retrograde, it rapidly ascends and crosses midline to the left, which is abnormal and different from the prior study 

Finally, don't be fooled by the lack of significant wall-thickening, edema, or obstruction. There are still plenty of findings indicating an internal hernia, and often these patients will have intermittent abdominal pain or be imaged very early in their presentation (as was in this case).

Operative note (edited excerpt): "We identified the Roux limb as it traversed over the top of the transverse colon and we followed this to the jejunojejunostomy. There were several loops of bowel herniating under the Roux limb mesentery. As we traced one of them, we found it was attached to the terminal ileum, which was close to the left upper quadrant. We reduced the bowel by pulling the terminal ileum down toward the right lower quadrant, and we were able to reduce all of the bowel out of this opening. In doing so, there was an obvious twist to the Roux limb...we converted to open...we then saw again an obvious defect under the Roux limb mesentery that allowed nearly all of the small bowel to herniate from the patients right side to the left....we closed the mesenteric defect with several figure of eight silk sutures, and restored the bowel to its correct intraabdominal location..."