Answer: fatty liver

This is a little outside my normal case list, but it was one I saw while working. Let’s work through this. It is a nuclear medicine scan (if you don’t realize that we need to talk). It is of the lungs and there is a series of images (if you can see the text it says POST_Washout). So this is the ventilation/washout portion of a V/Q scan (ie the V portion). What do we use for that? Xenon-133 (good distribution and no clumping). How do we perform it? The ventilation exam is imaged posteriorly so you are looking at the patient’s back. Thus, the activity you are seeing below the diaphragm is actually the liver.

So we have Xenon activity in the liver, which is commonly caused by hepatic steatosis (Ie fatty liver). Xenon is fat soluble and is thus taken up proportionally to the degree of fat in the liver.

reference: http://pubs.rsna.org/doi/full/10.1148/radiographics.30.4.304958

btw, that’s the corresponding liver up above