Highlights from

AAN 2019

American Academy of Neurology annual meeting

Philadelphia, USA 4-10 May 2019

Amyloid PET in cognitively impaired patients

The use of amyloid PET significantly influences clinical management, including the use of medications and counselling, of patients with MCI or dementia [1]. Changes in management were observed in about 60% of cases, more than double what the researchers had expected. This was the main finding of the Imaging Dementia – Evidence for Amyloid Scanning (IDEAS) study, presented by Prof. Gil Rabinovici (University of California San Francisco, USA).

“IDEAS was a nationwide effort to get evidence for the clinical utility of PET amyloid in MCI”, he stated. This was a requested study after the national US Centers for Medicare & Medicaid Services decided in 2013 not to cover PET scanning for routine clinical care due to insufficient evidence. The study’s main aim was to investigate the impact of the PET scan results on patient management. At 595 clinical dementia sites, 11,409 Medicare beneficiaries with MCI (60.5%) or dementia (39.5%) were recruited. “This has been the only time in my career that recruitment was finished early and under budget”, Prof. Rabinovici observed. “I think it reflects a desire by everyone involved to have amyloid PET covered by insurance.”

A total of 18,295 scans were completed. The primary objective was to assess whether there was a ≥30% change in post-PET patient management in AD drug therapy; other relevant drug therapy; and counselling about safety and future planning. The composite endpoint largely exceeded the target of 30%: it changed in 60.2% of patients with MCI and in 63.5% of patients with dementia (P<0.001). The most common change involved AD medications: their use largely increased in patients with positive scans and slightly decreased, though still significantly, in patients with negative scans (P<0.001). The aetiologic diagnosis of AD was changed to non-AD in 25.1% of participants, and from non-AD to AD in 10.5%. There were also post-PET reductions in the use of neuropsychological testing, other brain imaging, and CSF studies. Analyses of the impact of amyloid PET scans on health outcomes are underway.

  1. Rabinovici G, et al. AAN 2019, Plen01.001.

The content and interpretation of these conference highlights are the views and comments of the speakers/authors.