by kimjones » Thu Aug 30, 2012 3:47 pm
For those who are interested in learning more about alzheimer, read this article:
Researchers hope to discover an easy and accurate way to detect Alzheimer's before these devastating symptoms begin. Experts believe that biomarkers (short for "biological markers") offer one of the most promising paths. Biomarkers are reliable predictors and indicators of a disease process. They include proteins in blood or spinal fluid, genetic variations (mutations) or brain changes detectable by imaging. Sign up for our weekly e-news and stay up-to-date on the latest advances in Alzheimer's diagnosis, treatments, care and research.
Neuroimaging is among the most promising areas of research focused on early detection. Today, a standard workup for Alzheimer's disease often includes structural imaging with magnetic resonance imaging (MRI) or computed tomography (CT). These tests are currently used chiefly to rule out other conditions that may cause symptoms similar to Alzheimer's but require different treatment. Structural imaging can reveal tumors, evidence of small or large strokes, damage from severe head trauma or a buildup of fluid in the brain.
Preliminary research suggests that emerging imaging technologies and new applications of current technology may be able to detect hallmark changes associated with Alzheimer's disease in the brains of living individuals. If further research confirms the potential value of brain imaging, its use may one day be expanded to play a more direct role in diagnosing Alzheimer's and in earlier detection of the disease.
Imaging technologies used in Alzheimer's research
Structural imaging provides information about the shape, position or volume of brain tissue. Structural techniques include magnetic resonance imaging (MRI) and computed tomography (CT).
Functional imaging reveals how well cells in various brain regions are working by showing how actively the cells use sugar or oxygen. Functional techniques include positron emission tomography (PET) and functional MRI (fMRI).
Molecular imaging uses highly targeted radiotracers to detect cellular or chemical changes linked to specific diseases. Molecular imaging technologies include PET, fMRI and single photon emission computed tomography (SPECT).
Structural imaging studies have shown that the brains of people with Alzheimer's shrink significantly as the disease progresses. Research has also shown that shrinkage in specific brain regions such as the hippocampus may be an early sign of Alzheimer's. However, scientists have not yet agreed upon standardized values for brain volume that would establish the significance of a specific amount of shrinkage for any individual person at a single point in time.
Functional imaging research with positron emission tomography (PET) and other methods suggests that those with Alzheimer's typically have reduced brain cell activity in certain regions. For example, studies with fluorodeoxyglucose (FDG)-PET indicate that Alzheimer's disease is often associated with reduced use of glucose (sugar) in brain areas important in memory, learning and problem solving. However, as with the shrinkage detected by structural imaging, there is not yet enough information to translate these general patterns of reduced activity into diagnostic information about individuals.
Molecular imaging technologies are among the most active areas of research aimed at finding new approaches to diagnose Alzheimer's in its earliest stages. Molecular strategies may detect biological clues indicating Alzheimer's is under way before the disease changes the brain's structure or function, or takes an irreversible toll on memory, thinking and reasoning. Molecular imaging also may offer a new strategy to monitor disease progression and assess the effectiveness of next-generation, disease-modifying treatments. Molecular imaging compounds currently used in Alzheimer research include:
Pittsburgh compound B (PIB) was the first radiotracer capable of highlighting deposits of beta-amyloid—one pathological hallmark of Alzheimer's disease—in living individuals during a PET scan. The Alzheimer's Association helped fund early PIB development. The Association in 2006 also awarded a $2.1 million grant to the Alzheimer's Disease Neuroimaging Initiative (ADNI) to expand this long-term, nationwide study to include PIB-PET imaging.
18F flutemetamol (flute), another radiotracer that highlights beta-amyloid in a PET scan, is structurally identical to PIB except for one fluorine atom in place of a carbon atom. That small chemical change enables flutemetamol to remain stable significantly longer than does PIB, potentially increasing its usefulness outside research settings. In phase II study results reported in the Annals of Neurology, flutemetamol performed similarly to PIB. Additional testing is under way.
Florbetapir F 18 (18F-AV-45) is also a radiotracer that highlights brain beta-amyloid during a PET scan. At the 2010 Alzheimer's Association International Conference on Alzheimer's Disease (AAICAD), florbetapir's developer first reported data, later published in the JAMA, showing nearly perfect correlation between brain amyloid levels detected by florbetapir PET scans in study volunteers and levels found in autopsies of the same individuals a few months later. The developer has sought Food and Drug Administration (FDA) approval to market florbetapir under the brand name Amyvid. The FDA has said it will withhold approval until the developer establishes a professional training program to ensure accuracy and consistency in reading and interpreting Amyvid scans.
Florbetaben (BAY 94-9172) is another radiotracer designed to detect beta-amyloid during a PET scan. Phase II study results and other florbetaben data were reported at the 2010 Alzheimer's Association International Conference on Alzheimer's Disease (AAICAD). Phase II data were also later published in Lancet Neurology. Further studies are now under way.
I really enjoyed this article, I hope you like it as well. The more we know about this desease, the more we can fight against it and help the ones we love.