Aetna considers an amyloid PET scan (including florbetapir F18 [Amyvid], florbetaben F18 [Neuraceq] flortaucipir F 18 injection [Tauvid], flutemetamol F18 [Vizamyl]) medically necessary for persons with mild cognitive impairment due to Alzheimer disease who are being considered for aducanumab (Aduhel...