Seniors will not be able to receive Medicare coverage for imaging scans to help diagnose Alzheimer’s disease, the Centers for Medicare & Medicaid Services recently announced.

Positron emission tomography (PET) scans can detect beta-amyloid in the brain, which is a sign of Alzheimer’s. Although a PET scan alone is not sufficient grounds for an Alzheimer’s diagnosis, it is used as part of the diagnostic process by doctors. However, there is “insufficient evidence” that PET scans are “reasonable and necessary” for diagnosing and treating Alzheimer’s, according to the Sept. 27 CMS ruling.

Medicare dollars can go toward Alzheimer’s-related PET scans in the context of certain types of clinical trials, CMS stated.

The CMS decision has sparked criticism from some quarters. Opponents say it contradicts an Alzheimer’s action plan released earlier this year by the Department of Health and Human Services itself, noted the Assisted Living Federation of America.