Thank you for your reply. I have read the same kinds of things about skip lesions and prednisone treatment potentially producing a false negative reading. I was diagnosed after complaining of pain and stiffness for a little over 2 weeks which my PCP ignored as possible statin side effect ( new medication for me)and told me to try to continue statin. I finally threw in the towel because of excruciating pain and told him I would not continue statin and asked if I had PMR...a friend suggested that's what I had. PCP ran blood work and although my inflammation markers were low, he diagnosed PMR. So, I started prednisone at 20 MG for 1 week. Then he lowered it to 15MG for 20 days....then he wanted me to go to 10 MG, but I balked because of all I had read about slower taper and I went to 12.5 MG for another 19 days. Then I saw rheumatologist...she wants the GCA test because of headaches, but at this point I don't think ultrasound or biopsy are going to be reliable...so what do I do? Get another opinion? My inclination is to try ultrasound because it cannot hurt. I wish I could remember when the headaches started...if it was only after the prednisone, is it possible that these are prednisone headaches?