So her insurance company of course refused it. They asked to see my notes (we faxed them), and the reason why I wanted it (we told them). They still refused to cover it, but told me I could appeal by calling one of their "physician reviewers". So I called him a minute ago.
He asked me why I wanted the MRA. I told him because the patient had a stroke.
His response: "Oh, why didn't you just tell us that in the first place? We'll cover that".