Makers of F-18 florbetapir (Amyvid) are bankrolling a lawsuit against the Centers for Medicare & Medicaid Services (CMS), which hampered coverage of amyloid imaging earlier this year as a means for ruling out Alzheimer’s disease. The lawsuit was filed in federal court Sept. 5, according to this Wall Street Journal report.

The CMS decision asserted that not enough evidence was available to warrant general coverage of the PET procedure, but without full coverage, WSJ analysts estimate that Lilly stands to gain $100 million in annual revenue. With greater coverage, that number could boom to $500 million. Lilly and other stakeholders claim that without full coverage, the real pathophysiology of cognitive decline will not be elucidated.

Amyvid was approved by the FDA in 2012 and is now one of three PET radiopharmaceuticals approved in the U.S. and Europe to aid in the evaluation of Alzheimer’s.