Amyloid PET imaging improves prognosis for MCI, suspected Alzheimer’s patients

Amyloid PET could be a useful diagnostic tool for patients with mild cognitive impairment (MCI) or suspected Alzheimer’s, according to a study published this summer in JAMA Neurology, yielding changes in diagnosis, treatment decisions and physician confidence regardless if scan results are positive or negative.

The study, part of a three-year trial in the Netherlands dedicated to assessing imaging for Alzheimer’s patients in a non-research setting, was penned by Arno de Wilde, MD, of the Alzheimer Center at VU University Medical Center in Amsterdam, and colleagues. The team offered amyloid PET scans using fluoride-18 florbetaben to 476 patients who visited the center’s memory clinic, as  well as 31 patients with mild cognitive impairment (MCI) who frequented the University Medical Center Utrecht clinic.

Participants, who were largely in their sixties, were evaluated for a pre-amyloid and post-amyloid diagnosis that consisted of both a clinical syndrome and a suspected etiology, according to the study. Clinical syndromes could be dementia, MCI or subjective cognitive decline, while suspected diagnoses ranged from Alzheimer’s to non-neurodegenerative diseases. Clinicians noted their diagnostic confidence throughout the process.

Suspected etiology changed for nearly 25 percent of patients after amyloid PET, more often due to a negative rather than a positive result. Amyloid PET was positive in more patients with dementia, MCI and suspected Alzheimer’s. Diagnostic confidence in clinicians’ etiological diagnoses increased from 80 percent to 89 percent during the study.

In almost a quarter of cases where patients received a positive PET scan, neurologists changed that patient’s treatment plan, usually with adjustments to their medication.

“The takeaway for this study for clinicians should be that amyloid PET can be a useful diagnostic test when trying to determine the underlying cause for dementia or mild cognitive impairment,” Eric McDade, DO, an assistant professor of neurology at Washington University in St. Louis, told Neurology Today. McDade wasn’t connected to the study. “This is particularly the case when the clinical diagnosis is uncertain and at the mild cognitive impairment stage.”

McDade said amyloid PET could aid physicians in reaching a more accurate diagnosis for MCI patients, improve prognosis and guide treatment if needed. But when it comes to subjective cognitive decline (SCD), he and WU colleague Beau M. Ances, MD, PhD, agreed PET should be left alone.

“In SCD, a negative result can provide clarity, but it can also not,” Ances, also unconnected to the project, said in Neurology Today. “It’s just a number of what you look like at that particular time, so that in five or seven years there may be enough of an accumulation that you may be in preclinical Alzheimer’s disease.”

Identifying that Alzheimer’s diagnosis, though, is important, he said.

“Trying to establish Alzheimer’s disease in the earliest phase is a big goal for a memory clinic, along with making a diagnosis as early as possible,” study leader de Wilde said in Neurology Today. “It’s about giving patients as accurate a diagnosis as you can and as early as you can. If the patient has an accurate diagnosis, it allows them to move further and make decisions about work, finances, driving safety and clinical trial participation.”