In this patient with flank pain, the most likely diagnosis is this is kind of a good case because when you look at the images, the kidneys seem to function symmetrically, but it's kind of obvious there's something in the left renal vein, which you can see on the axial and the coronal venous imaging, and that's obviously a renal vein thrombosis.
It's not total occlusion of the renal vein, which explains in probably the logical explanation why there's no profusion changes in the left kidney.
This is not renal infection, I don't see changes in the parankhma, this is not renal infarction, this is not stone disease, this is renal vein thrombosis.
Now, renal vein thrombosis, usually I see it as related to a tumor, like a renal cell carcinoma, but it does not necessarily need to be due to that, and obviously there's no obvious renal tumor here.
It could be due to a hyperquiacability state, it could be due to infection or inflammation, and those are some of the possibilities you can see it in post-op patients as well.
You can see it in patients with endocarditis, and this ended up being a case of renal vein thrombosis without occlusion due to endocarditis.
