FNA usually stands for Fine Needle Aspiration.
I believe, and I may be incorrect here, but fine needle aspiration assessments can be more accurately guided to abnormal appearing areas with the aid of a concurrent CT scan.
I checked medline and all I could come up with was the same results as a google search...apparently it has earned some attention with respect to the adrenal glands? The relevance of this to OC...who knows?
Maybe Brian, Gary or another knowledgeable soul can shed some light on this.
Pete, I have no idea whatsoever what an "F'iNg Asseeement" is but, I'm certain that it isn't very polite. When I googled it my keyboard hit me! LoL.

Cheers,
Mike