OPERATIVE NOTE EXCERPT: 

The proximal small intestine was very well perfused; however, there was a segment of approximately 14 inches above the ileocecal valve, which had poor perfusion. There was no frank dead bowel or frank severely ischemic bowel. However, the perfusion of this portion of the segment was compromised and slower compared to the remaining portion of the bowel. There were also patches of focal ischemia throughout the segment...

(note the patient also underwent embolectomy at the time of small bowel resection)

PATHOLOGY FINAL DIAGNOSIS: 

Small Intestine: Small Bowel Resection 14 cm; Small intestine with mucosal necrosis and extensive submucosal hemorrhage

It is not common to actually see thromboemboli within the arterial lumen as in this case, but it does provide a lot of educational value. The patient had early signs of ischemia/reperfusion injury on the initial CT with mild wall thickening of the distal ileum, but that finding alone has a broader differential which would include infection, inflammation and angioedema. However, given the advanced patient's age, atrial fibrillation, and elevated lactate (for example), ischemia should be considered with very high suspicion and a CTA could be appropriately ordered. The patient developed worsening symptoms and underwent angiographic evaluation the next day, which illustrates the progressive changes of small bowel injury following arterial ischemia and reperfusion, which was confirmed in the pathology specimen.