The use of positron emission tomography (PET) imaging may help identify findings in brain tissue associated with Alzheimer’s disease (AD), according to two articles published Online First today by Archives of Neurology, one of the JAMA/Archives journals. As scientists seek to understand more about AD and other forms of dementia, they are exploring the use of PET, according to background information in the article.
PET scans involves the use of radioactive tracers to highlight areas of the brain affected by these conditions. Various teams of researchers are studying the effectiveness of different types of tracers for identifying brain findings associated with these conditions.
In one study, David A. Wolk, M.D., from the Penn Memory Center in Philadelphia, and colleagues evaluated use of a tracer called fluorine 18-labeled flutemetamol for imaging the brain. The study involved conducting PET scans on seven patients who were given a dose of this substance. All had previously undergone a biopsy for normal pressure hydrocephalus, a progressive condition that includes dementia and can be difficult to distinguish from AD. Researchers found correspondence between readings of the PET scans and evidence of amyloid lesions—the plaque associated with AD—provided by microscopic evaluation of the biopsied tissue.
In another study, Adam S. Fleisher, M.D., from Banner Alzheimer’s Institute in Phoenix, and colleagues, evaluated PET imaging using the tracer florbetapir F 18. The study population included 68 individuals with probable AD, 60 individuals with mild cognitive impairment, and 82 healthy individuals who served as controls. PET scanning was used to monitor activity of the agent being studied. These researchers found differences in the brain uptake of florbetapir F 18, between the three groups, and in the detection of amyloid plaque; the differences may be large enough to help distinguish between the conditions, and between impaired versus unimpaired brains.
The authors of both articles suggest that their results may demonstrate ways in which PET imaging can be used with selected tracers to help identify findings associated with AD. “With the potential emergence of disease-specific interventions for AD,” state Wolk et al, “biomarkers that provide molecular specificity will likely become of greater importance in the differential diagnosis of cognitive impairment in older adults.” Indeed, Fleisher et al write, “Amyloid imaging offers great promise to facilitate the evaluation of patients in a clinical setting.”
Material adapted from JAMA.
Arch Neurol. Published online July 11, 2011. doi:10.1001/archneurol.2011.153; doi:10.1001/archneurol.2011.150.