Patient had a CT for "?obstruction" .

This axial image shows a grossly dilated stomach and duodenum. The third part of the duodenum is compressd between the superior mesenteric artery and the aorta (arrow). Beyond this, the small bowel is collapsed.

 

 

 

 

Here's an oblique reconstruction which shows this a bit more elegantly.


 

 

 

 

 

This sagittal image shows the acute angle between the SMA and aorta. The arrowhead shows the point where the duodenum is compressed.


 

 

 

This barium study was done afterwards at the request of the surgeon, and shows the same thing as the CT.

 

 

  

And here's an article on this topic.