Early results from Alzheimer’s neuroimaging studies could speed research

Alzheimer's disease researchers may be able to reduce the time and expense associated with clinical trials, according to early results from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a public-private research partnership organized by the National Institutes of Health.

Preliminary results from the ADNI, a $60 million five-year study that began recruiting in early 2006, show how it might yield improved methods and uniform standards for imaging and biomarker analysis, according to studies presented this month at the International Conference on the Prevention of Dementia held in Washington, DC.

Dr. Christine Fennema-Notestine and colleagues at the University of California, San Diego found that analyses of MR and PET images could detect early changes in cerebral cortex thickness in brains of people with mild cognitive impairment over a six-month period. Further study would be needed to see if the changes, with other brain measures, could predict conversion from mild cognitive impairment to Alzheimer's, the researchers said.

A study reported Dr. Kewei Chen and colleagues at the Banner Alzheimer's Institute in Phoenix compared changes over time in PET scans of glucose metabolism in people with normal cognition, mild cognitive impairment, and Alzheimer's. The study found that scans correlated with symptoms of each condition and that images from different clinical sites were comparable or consistent. This study suggests the validity of PET for use in future clinical trials.

A Mayo Clinic study from Dr. Clifford R. Jack's team found that a standard anatomic model of a brain can be used successfully to monitor performance of MR scanners at many different clinical sites. This will ensure accuracy of the MR images produced from ADNI volunteers using 80 MR scanners from scores of sites over five years.

University of Pennsylvania scientists compared analyses of cerebrospinal fluid samples among seven laboratories. The study evaluated differences within and among the labs' performance. This study will ensure that methods for measuring biomarkers are accurate and comparable across laboratories.

Recruiting of 800 participants from 58 sites in the U.S. and Canada finished in May. Subjects comprise 200 with Alzheimer's disease, 400 with mild cognitive impairment, and 200 controls. Subjects will undergo a 1.5T structural MRI every six months for two to three years. Half of the subjects will also have FDG-PET scans, and 25% will undergo a 3T MR scan at each time point.

ADNI also offers a publicly accessible database that contains thousands of brain MR and PET scans, clinical data, and biomarker data. To date, more than 200 researchers have signed up for database access.

For more from the Diagnostic Imaging archives:

PIB-PET study establishes link between mild cognitive impairment and Alzheimer's disease

Novel PET agent breaks through in Alzheimer's diagnosis

Danish study finds novel solution to problems in high-field MRI of brain

Dementia drugs give impetus to early and accurate diagnosis