Which surgical procedure has this person had?
Roux-en-Y gastric bypass: this is indicated by division of the stomach, a gastro-jejunostomy, and a further anastomosis between small bowel loops which is a jejunojejunostomy.
What complication has arisen?
Clustered loops of small bowel in lower abdomen with mesenteric fat stranding, bunching of vessels and some bowel wall thickening - internal hernia with ischaemic bowel.
This is a case of an internal mesenteric hernia but not a Petersen's type (see below). There is abnormal clustering of small bowel loops in the lower abdomen, with pinching of the mesenteric vessels and mild fat stranding around the involved loops. Some enhance poorly, raising the possibility of ischaemia. This is in keeping with a mesenteric hernia, which may have been iatrogenic but this is difficult to surmise purely from the images. These are most commonly seen at the site of the jejunojejunostomy. At surgery, a hernia sac was identified and the small bowel loops, whilst being ischaemic were not necrotic and no resection was necessary.