Today's state-of-the-art in diagnosing Alzheimer's is the F18 PET Scan. See how it changed one man's life. Learn how 87% of patients who received an F18 scan made at least one change in their treatment plan.
Until recently, the hardest part in diagnosing Alzheimer's was the difficulty in "seeing" what was going on in the brain. F18 PET scans changed all that, allowing doctors to "see" how much Alzheimer's plaque, if any, appeared in the brain.
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When the first F18 tests hit the market, they cost a few thousand dollars and were available from only one source. Since then, there has been a rush of activity on the part of pharmaceutical companies to bring better and less expensive F18 tests to market.
The first F18 test to detect brain amyloid deposits (also known as Alzheimer's plaques) was approved by the FDA in 2012. It was called Florbetapir F18 (renamed AMYViD™).
F18 tests approved by the FDA include:
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A Closer Look at Florbetapir F18Seeing the amount of Alzheimer's plaque provides doctors with useful information on treatment and further testing for patients with cognitive impairment, according to the study published online by the journal Alzheimer Disease & Associated Disorders. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.
Positron emission tomography (PET) scans "light up" the florbetapir F18 biomarker to show amyloid plaques in the brain — a characteristic feature of Alzheimer's disease (AD).
"Amyloid imaging results altered physicians' diagnostic thinking, intended testing and management of patients undergoing evaluation for cognitive decline," according to the study by Dr. Mark Mintun of Avid Pharmaceuticals, Philadelphia, and colleagues.
Is It Alzheimer's? Florbetapir Provides EvidenceThe researchers designed a "real-world" study to determine how florbetapir would affect clinical management of patients with cognitive impairment. While a florbetapir PET scan showing amyloid plaques doesn't prove that AD is present, it provides a previously unavailable piece of evidence to support the diagnosis.
The study included 229 patients seen by neurologists or other specialists for evaluation of cognitive decline or impairment of uncertain etiology. Before the florbetapir PET scan, doctors provided a provisional diagnosis, an estimate of their diagnostic confidence, and their plans for further testing and treatment. The goal was to assess the value of florbetapir PET in making the final diagnosis and in providing doctors with useful information for clinical decision making.
The florbetapir PET scans showed amyloid deposits in 113 out of 229 patients. The information provided led doctors to change their diagnosis in 55 percent of cases.
When the provisional diagnosis was AD, imaging results led to a change in diagnosis in 37 percent of cases. When the pre-scan diagnosis was either “indeterminate” or another cause of dementia, the diagnosis changed in over 60 percent of cases. In either direction, the scans increased the physicians' ratings of diagnostic confidence by about 20 percent.
Impact on Treatment and Testing DecisionsFlorbetapir PET also provided useful information for treatment decision-making: in 87 percent of patients, the results contributed to at least one change in the treatment plan. The main impact was in deciding whether or not to use medications that are helpful in AD. The scan results also affected decisions on further testing—in many cases, physicians dropped plans to perform additional brain imaging studies or neuropsychological tests.
Alzheimer disease is the most common cause of dementia, but the diagnosis can be challenging to make. The only definitive way to diagnose AD is by autopsy examination of the brain after death. Up to 20 percent of patients diagnosed with AD turn out not to have had AD on autopsy, while up to 40 percent of patients diagnosed with other causes of dementia have evidence of AD at autopsy.
Florbetapir PET is the first FDA-approved imaging that can estimate amyloid deposits in the brain of a living patient. Previous studies have shown that the scans are accurate in identifying patients later shown to have AD at autopsy.
The new results show that florbetapir PET scans can have a significant effect in "real world" clinical evaluation of patients with cognitive impairment. By strengthening the case for or against a diagnosis of AD, this test can have a significant impact on patient management—particularly related to the use of AD medications and the need for further testing. Additional studies will be needed to confirm whether "clinical care that includes amyloid imaging will translate into better outcomes" for patients with cognitive impairment and possible AD.
About Alzheimer Disease & Associated Disorders
Alzheimer Disease & Associated Disorders is a leading international forum for reports of new research findings and new approaches to diagnosis and treatment. Contributions fall within all relevant scientific fields and clinical specialties, including neurobiology, neurochemistry, molecular biology, neurology, neuropathology, neuropsychology, psychiatry, gerontology, and geriatrics.
About Lippincott Williams & Wilkins
Lippincott Williams & Wilkins (LWW) is a leading international publisher of trusted content delivered in innovative ways to practitioners, professionals and students to learn new skills, stay current on their practice, and make important decisions to improve patient care and clinical outcomes. LWW is part of Wolters Kluwer Health, a leading global provider of information, business intelligence and point-of-care solutions for the healthcare industry. Wolters Kluwer Health is part of Wolters Kluwer, a market-leading global information services company with 2011 annual revenues of €3.4 billion ($4.7 billion).