The results of a landmark trial conducted in part at the Memory and Aging Program at Butler Hospital and published this month in the Journal of the American Medical Association (JAMA) show that amyloid PET brain scan imaging significantly improves both the accuracy of diagnosis and the subsequent medical management of patients with mild cognitive impairment and dementia. The findings suggest that the use of amyloid PET imaging as a diagnostic tool for Alzheimer’s disease should be made more accessible to patients with cognitive impairment who are suspected of having Alzheimer’s disease.
The Imaging Dementia – Evidence for Amyloid Scanning (IDEAS) study was launched in 2016 and enrolled more than 16,000 Medicare beneficiaries with mild cognitive impairment or dementia of uncertain cause. The goal: to determine if providing clinicians with the results of positron emission tomography (PET) scans that identify amyloid plaques in the brain would have any effect on diagnosis or management of Alzheimer’s disease.
Alzheimer’s disease is characterized by the accumulation of both amyloid protein plaques and tau protein “tangles” in the brain, the presence of which is required for a definitive diagnosis. Until recently, amyloid plaques could only be detected by postmortem analysis of autopsied brain tissue. With the advent of amyloid PET — which involves injecting patients with “tracer” molecules that stick to amyloid plaques and can be used to visualize their location in the brain — it became possible to detect plaques with a brain scan and therefore more accurately diagnose people living with the disease. The misdiagnosis rate of Alzheimer’s disease in clinical practice (without the aid of amyloid PET scanning) is approximately 30%.
The IDEAS study revealed that providing clinicians with the results of amyloid PET scans changed medical management — including the use of medications and counseling — in nearly two-thirds of cases, more than double what researchers predicted in advance of the study. Use of amyloid PET scanning also altered the diagnosis of the cause of cognitive impairment in more than one in three study participants.
The study was managed by the American College of Radiology and led by scientists at the Alzheimer’s Association, UC San Francisco, Brown University School of Public Health, Virginia Commonwealth University School of Public Health, Washington University School of Medicine in St. Louis, UC Davis School of Medicine, and the Kaiser Permanente Division of Research.
Brown University School of Public Health was the coordinating data center for the trial. Dr. Stephen Salloway, Director of Neurology and the Memory and Aging Program at Butler Hospital and Martin M. Zucker Professor of Psychiatry and Human Behavior and Professor of Neurology at the Warren Alpert Medical School of Brown University, helped to plan the initial protocol. Memory programs at Butler Hospital and Rhode Island Hospital together recruited more than 130 participants, making Brown a leading center in the trial. Dr. Salloway is also the senior author on the pivotal trial that led to FDA approval of flutemetamol, one of the 3 tracers used in the IDEAS study.
Many in the field of Alzheimer’s treatment and research are hopeful that the results of this study will spur greater access to amyloid PET imaging for patients with suspected Alzheimer’s. Although the FDA has approved the use of amyloid tracers, the use of amyloid PET imaging in the diagnosis of suspected Alzheimer’s disease is not currently covered by Medicare or health insurance plans, making it unavailable to most people.
“These are very significant findings that could – and should – impact the way patients with suspected Alzheimer’s disease are diagnosed in the future,” Dr. Salloway said. “This study provides proof that amyloid PET imaging can provide a more accurate and earlier diagnosis of Alzheimer’s, leading to improvements in our ability to manage the symptoms of the disease, and for patients and their families to be better prepared to make the important decisions and arrangements that become necessary as the disease progresses.”
In a press release about the study, the Alzheimer’s Association further explains why reliable and early diagnosis is so important even for a disease that doesn’t yet have a cure, and lays out what comes next in the study of how amyloid PET scans could be used to improve Alzheimer’s diagnosis and treatment:
Though there is no cure for Alzheimer’s disease, early diagnoses enable physicians to prescribe appropriate symptom-management therapies, counsel families on important safety and care-planning issues and direct people to clinical trials for promising new drugs. It also allows people with the disease and their families to plan for the future, including legal and financial issues, and accessing resources and support programs. PET imaging results that reveal no signs of amyloid buildup in the brain rule out Alzheimer’s disease as the cause of memory loss, which can prompt an evaluation for alternative and sometimes reversible causes, such as medication side effects, sleep or mood disorders and other medical conditions.
The work of the IDEAS study does not end here. In a second phase of the study, the team will examine how PET scans affect the ultimate health outcomes of patients, comparing hospitalization rates and Emergency Department visits of those who received scans to those who did not. Those findings are expected to be published in 2020.
A second study called New IDEAS is also planned. It will include more people with both typical and atypical clinical presentations of Alzheimer’s and recruit a study group that better reflects the racial and socioeconomic diversity of the national population.
The Memory and Aging Program is currently seeking people with normal cognitive function as well as those with mild memory impairment to participate in current and future studies such as this one. To learn more and to get involved, visit butler.org/memory.
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