Recent medical techniques use positron emission tomography or PET scans to obtain images of the brain. While the patient is still alive, images of the brain are scanned to help physicians to further research Alzheimer's disease.
The Radioactive dyes, or "tracers" are injected into the blood which permeates the brain and images are obtained. These special scans provide physicians with images of areas of the brain affected by the toxic protein beta-amyloid, which is associated with Alzheimer's disease.
The Alzheimer's Association together with the Society of Nuclear Medicine and Molecular Imaging (SNMMI) assembled a team of experts to determine the usefulness of the new technology. This Amyloid Imaging Taskforce (AIT) found amyloid imaging may be useful in diagnosing individuals with cognitive impairment.
In two new studies, researchers uses two different dyes for the PET scans and compared the results against an existing dye often used. Researchers from Philadelphia's Penn Memory Center evaluated a dye tracer called fluorine 18 (flutemetamol) with the help of seven volunteers who were suspected of having Alzheimer's. The resulting PET scans were accurate and the data matched with the post biopsies performed on the patients.
Banner Alzheimer's Institute in Phoenix evaluated another dye called florbetapir F 18 for their PET scan, conducting a larger study with 68 individuals with probable Alzheimer's, 60 with a serious form of memory loss that at times is the onset of Alzheimer's called "mild cognitive impairment", and a control group of 82 healthy individuals. The PET test reflected the various levels of beta- amyloid that differentiated among the groups.
The two new dyes may offer alternative ways to monitor mild cognitive impairment and Alzheimer's disease progression. Physicians may find the newer dyes easier to use, as they prove to be more stable than the current dye being used called Pittsburg Compound B. To test new drugs to see whether they are effective in preventing progression of Alzheimer's, more accurate and earlier diagnosis is useful.
"With the potential emergence of disease-specific interventions for Alzheimer's disease," biomarkers that provide molecular specificity will likely become of greater importance in the differential diagnosis of cognitive impairment in older adults." said Dr. David A. Wolk, one of the authors of the Penn Memory Center report.
