New imaging test aids Alzheimer's diagnosis
The image on the left is a PET scan of a normal brain. The image on the right is heavily blackened throughout the cerebral cortex due to the the presence of amyloid plaques. Amyloid is found in the brains of patients with dementia due to Alzheimer’s disease
In research studies, scientists regularly use positron emission tomography (PET) scans to detect signs of Alzheimer's disease. Now, Washington University physicians at Barnes-Jewish Hospital are the first in Missouri to offer a new type of PET scan for patients with memory disorders and other forms of cognitive impairment who are not involved in research studies.
This new imaging test is now available to patients being evaluated for Alzheimer's disease because the U.S. Food and Drug Administration (FDA) recently approved the use of a radioactive diagnostic agent, Amyvid™ (Florbetapir F 18 Injection), for use in a clinical setting.
The agent detects neuritic plaques, a hallmark of Alzheimer's disease, by binding to abnormal deposits of the protein beta-amyloid that develop in the brains of patients with the disorder. This makes the plaques "light up" during a PET scan.
This video is not supported by your browser at this time."We're using the scans in patients whose cognitive function is impaired," says Farrokh Dehdashti, MD, professor of radiology in the Division of Nuclear Medicine at the Mallinckrodt Institute of Radiology. "First, the patient sees a neurologist, or other specialist in cognitive disorders, to confirm that a test like this would be appropriate, and then we conduct the PET scan to learn whether amyloid plaques are present. In that way, the test allows both doctors and patients to have a better idea of whether the patient's cognitive impairment is related to Alzheimer's disease or some other illness."
With FDA approval, nuclear medicine specialists like Dehdashti can now use the diagnostic agent, which has a longer half-life than the compound used in research studies, making it better suited for clinical use. As a single test, PET scans can't confirm Alzheimer's disease, but a negative test that finds no evidence of elevated beta-amyloid can help rule out the disease as the cause for the patient's cognitive impairment.
"What complicates the results of a scan is that although Alzheimer's disease is very common, it's not the only reason that we might detect amyloid," according to Jonathan McConathy, MD, PhD, assistant professor of radiology. "A positive scan could mean that a person has Alzheimer's disease, or it could be related to some other neurologic disorder. It's also possible to find amyloid in the brain of a person who has no symptoms of Alzheimer's disease or other cognitive problems, so a positive test doesn't confirm that someone has the disease."
He says a positive scan indicates only that elevated levels of amyloid are present. But amyloid plaques can accumulate in the brains of people with other types of neurologic problems, such as dementia with Lewy bodies or cerebral amyloid angiopathy. Plaques also can occur in some older adults who are cognitively normal.
"The test should be used in conjunction with other diagnostic evaluations from a neurologist," Dehdashti says. "But when a scan is negative, it's highly unlikely that the cognitive impairment is due to Alzheimer's disease."
"These PET scans have the potential to be really useful as treatments for Alzheimer's are developed," McConathy says. "Once we have treatments to significantly slow down or stop the progression of Alzheimer's disease, then I think this kind of imaging will become very important in deciding who should be treated and, potentially, whether a treatment is working."
- Mount Sinai is first in New York state to perform new Alzheimer's imaging test in clinical setting Jun 20, 2012 | not rated yet | 0
- Alzheimer's plaques in PET brain scans identify future cognitive decline Jul 11, 2012 | not rated yet | 0
- Imaging test detects Alzheimer's disease that is likely to progress Dec 15, 2009 | not rated yet | 0
- Alzheimer's-like brain changes found in cognitively normal elders with amyloid plaques Mar 30, 2011 | not rated yet | 0
- Brain imaging study supports the 'cognitive reserve' hypothesis Nov 10, 2008 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Differences of Classical Mechanics when learned with Calc vs algebra?
1 hour ago what are the differences? Every example I find usually has a derivative or integral or some kind of calculus defined concept that seems to make it...
what is the distance traveled
5 hours ago Hi. I have newly started to study mechanical physics. based on study, I conduct a simple experiment. But unfortunately i am unable apply the laws in...
Image of a Convex Lens Cut in Half Horizontally
9 hours ago Hello everyone, A friend of mine came up with this question in class and I really do not have a good answer. Suppose you have a convex lens...
Ray tracing throught optical system of thick lenses
9 hours ago Can you advise me a free software that allow to draw rays passed throught system of thick lenses (preferable in 3D)?
Faraday's law on circular wire
10 hours ago In my examples on Faraday's law in my book, they use a drawing of a magnet approaching a circular wire. The changing magnetic flux then induces an...
Specific Exergy vs Specific Flow Exergy
12 hours ago I'm having some difficulty understanding exactly what the difference between the definitions of these values are. As I understand it, in terms of...
- More from Physics Forums - Classical Physics
More news stories
Researchers at USC have found that a class of pharmaceuticals can both prevent and treat Alzheimer's Disease in mice.
Alzheimer's disease & dementia May 21, 2013 | 5 / 5 (7) | 0 |
Researchers have pinpointed a catalytic trigger for the onset of Alzheimer's disease – when the fundamental structure of a protein molecule changes to cause a chain reaction that leads to the death of neurons ...
Alzheimer's disease & dementia May 20, 2013 | 5 / 5 (4) | 0 |
A new study looking at sleep-disordered breathing (SDB) and markers for Alzheimer's disease (AD) risk in cerebrospinal fluid (CSF) and neuroimaging adds to the growing body of research linking the two.
Alzheimer's disease & dementia May 19, 2013 | 5 / 5 (3) | 0 |
The devastating effect of Alzheimer's disease on bilingual people has been thrown into focus in Canada, where the sudden loss of a second language can leave sufferers feeling like strangers in their own country.
Alzheimer's disease & dementia May 19, 2013 | not rated yet | 0
(Medical Xpress)—Working with lab mice models of multiple sclerosis (MS), UC Davis scientists have detected a novel molecular target for the design of drugs that could be safer and more effective than current FDA-approved ...
Alzheimer's disease & dementia May 17, 2013 | 5 / 5 (2) | 0 |
(HealthDay)—For HIV-infected individuals with recurrent Clostridium difficile infection, fecal microbiota therapy is feasible, according to a letter published in the May 21 issue of the Annals of Intern ...
7 minutes ago | not rated yet | 0
(HealthDay)—Implementation of systematic monitoring for medication adherence will allow for identification of barriers to adherence and tailoring of interventions, according to a viewpoint piece published ...
57 minutes ago | not rated yet | 0
(AP)—A federal panel of medical experts says that an experimental insomnia drug from Merck & Co Inc. appears safe and effective, despite evidence from company trials that the pill can cause daytime sleepiness and difficulty ...
18 minutes ago | not rated yet | 0
(HealthDay)—The American Cancer Society, which is celebrating on Wednesday a century of fighting a disease once viewed as a death sentence, is making a pledge to put itself out of business.
57 minutes ago | not rated yet | 0
(HealthDay)—Migraines and depression can each cause a great deal of suffering, but new research indicates the combination of the two may be linked to something else entirely—a smaller brain.
2 hours ago | 5 / 5 (1) | 0 |
Until now, little was scientifically known about the human potential to cultivate compassion—the emotional state of caring for people who are suffering in a way that motivates altruistic behavior.
2 hours ago | not rated yet | 1 |