Nuclear medicine experts have issued the first guidelines for using brain scans to help identify Alzheimer’s disease in living patients — recommendations designed to standardize diagnoses and improve care and treatment.
The guidelines, jointly developed by the Society of Nuclear Medicine and Molecular Imaging and the Alzheimer's Association, provide direction on the use of high-quality images of the brain plaques characteristic of Alzheimer's disease produced by positron emission tomography (PET) scans.
The recommendations, published online in Alzheimer's & Dementia: The Journal of the Alzheimer's Association and the Journal of Nuclear Medicine, aim to help clarify what can be learned — and not — from PET images and answer questions about which patients should be tested for suspected Alzheimer's disease.
"Our primary goal is to provide healthcare practitioners with the information and options available to provide patients with the best possible diagnosis and care in a cost effective manner," said Maria Carrillo, Alzheimer's Association vice president of Medical and Scientific Relations.
The guidelines authors noted that elevated beta amyloid plaques are a defining feature of Alzheimer's, but many seniors with normal brain function and other conditions also have elevated levels.
As a result, the recommendations indicate PET imaging must be considered along with other clinical information, and then performed only by trained staff. Potential candidates for PET imaging include:
- People who complain of unexplained memory problems or confusion and who demonstrate impairments using standard tests of cognition and memory.
- Individuals who meet several other criteria for Alzheimer's.
- Patients with progressive and/or early-onset dementia (before age 65).
The guidelines say amyloid PET imaging should not be used in the following cases:
- For seniors who already meet standard criteria for Alzheimer's for whom a positive PET would provide little added value.
- In patients without symptoms who have mental-health complaints, but no clinical confirmation of impairment.
- As a method for determining the severity of dementia.
- When requested solely based on a family history of dementia or presence of other risk factors for Alzheimer's.
- As a substitute for genetic testing for mutations believed to cause Alzheimer's.
- For non-medical reasons, such as insurance, legal or employment decisions.
"As amyloid imaging becomes more prevalent in clinical settings, medical professionals must understand how to appropriately utilize the test," said Frederic H. Fahey, SNMMI president. "Neurology and dementia experts should order the test only when appropriately indicated, and nuclear medicine and molecular imaging professionals must ensure they have been adequately trained to interpret the results of the scan. Working together, we hope that the information garnered from amyloid PET imaging will aid in diagnosis and play a pivotal role in the development of new treatments for Alzheimer's."
PET uses radioactive drugs to produce three-dimensional images of the brain or other body parts. In amyloid PET imaging, drugs injected into a vein bind with amyloid proteins, allowing radiologists to see areas of the brain where plaques have clumped together.
Amyloid imaging is not covered by insurance and PET testing can cost between $1,000 and $3,000, or more.
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