Brain scanning may improve the diagnosis and treatment of Alzheimer's disease, according to a new study.
The researchers assessed the use of PET scanning to identify Alzheimer's-related amyloid plaques in the brain. The study includes more than 11,000 Medicare beneficiaries with minor impairment of thinking or dementia with uncertainty.
Better medical management
This scanning technique changed the diagnosis of the cause of mental disability in more than a third of the study participants.
Brain scan results also changed management – including drug use and counseling – in nearly two-thirds of cases, according to the study published in Journal of the American Medical Association,
"These results represent very reliable, large-scale evidence that amyloid PET imaging can be a powerful tool to improve the accuracy of Alzheimer's diagnosis and lead to better medical management, especially in difficult-to-diagnose cases," said study co-author Maria Carrillo , chief scientific officer of the Alzheimer's Association.
"It is important that amyloid PET images are more widely available to those who need it," she added in an association report.
Funding for the study is by Avid Radiopharmaceuticals Inc., General Electric Healthcare and Life Molecular Imaging.
There is no cure for Alzheimer's disease
"We are impressed by the scale of these results, which clearly show that amyloid PET images can greatly influence the way we diagnose and care for patients with Alzheimer's disease and other forms of cognitive decline," said the lead author, Dr Gil Rabinovichi. He is a professor of neurology at the Center for Memory and Aging at the University of California at San Francisco.
There is no cure for Alzheimer's disease, but early diagnosis means that patients can receive treatment to manage symptoms and target clinical trials for new drugs.
Early diagnostics also means that patients and families can plan their future, including safety, care, legal and financial issues as well as access resources and support programs, researchers said.
In this study, PET scanning showed that about one-third of patients who had previously been diagnosed with Alzheimer's disease had no significant amyloid accumulation, and the Alzheimer's diagnosis was reversed.
Exact diagnoses are critical
But in almost half of the patients who were previously not diagnosed with Alzheimer's disease, PET scanning showed a significant accumulation of amyloid plaque leading to a new diagnosis of Alzheimer's disease.
One third of the study participants who had previously been targeted at Alzheimer's clinical trials did not show evidence of amyloid accumulation based on PET scanning. Based on these results, physicians have managed to ensure that almost all (93%) of the patients included in the Alzheimer's studies are amyloid-positive, which is critical to the success of these studies.
"Accurate diagnosis is crucial to ensuring that patients receive the most appropriate treatments, especially Alzheimer's drugs can worsen cognitive decline in people with other brain diseases," Rabinovicci said.
"But perhaps more fundamentally, people coming to the clinic with memory concerns want answers." The early, definitive diagnosis may allow individuals to be part of planning for the next stage of their lives and make decisions that otherwise they would have to be made by others, "he said.
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