A 35-year-old woman with newly diagnosed ...
MR angiography of the renal arteries
So both causes would result in increased aldo and MR is the only way to differentiate the two?
@USMLE123 I think both are causes of renal artery stenosis and that could be seen via MR angiography. It is asking what could help DIAGNOSE this patient -- and her most likely cause of the findings is fibromuscular dysplasia. So, yes, MR angiography would look different for the 2 different etiologies and thus could can be used to differentiate the two from one another. However, epidemiologically, we are looking to diagnose her with the suspected most probable cause.
I think measuring Aldosterone is an incorrect answer because you already know its increased due to low K. Knowing she has high Aldosterone wouldnt provide you evidence for a final diagnosis.