The Alzheimer's Disease Neuroimaging Initiative (ADNI): MRI Methods
1Mayo Clinic and Foundation, Rochester, Minnesota, USA.
2National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom.
3Laboratory of Neuro Imaging, Department of Neurology, University of California at Los Angeles School of Medicine, Los Angeles, California, USA.
4Neuroimage Analysis Laboratory, Department of Psychology, Arizona State University, Tempe, Arizona, USA.
5Department of Public Health Sciences, University of California Davis School of Medicine, Davis, California, USA.
6Department of Neuroscience, University of California at San Diego, La Jolla, California, USA.
7Centre for Medical Image Computing, University College London, United Kingdom.
8Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA.
9University of California at San Francisco, and Center for Imaging of Neurodegenerative Diseases (CIND), Department of Veterans Affairs Medical Center, San Francisco, California, USA.
10Department of Neurology and Alzheimer's Disease Center, University of California at Davis School of Medicine, Davis, California, USA.
11Siemens Medical Solutions, Erlangen, Germany.
12General Electric Healthcare, Waukesha, WI, USA.
13Philips Medical Systems, Best, The Netherlands.
14The Phantom Laboratory, Greenwich, New York, USA.
15Departments of Psychiatry and Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA.
16Division of Cognitive Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
17Genetics Program & Alzheimer's Disease Center, Boston University School of Medicine, Boston, Massachusetts, USA.
18Lucas Magnetic Resonance Imaging Center, Department of Radiology, Stanford University, Stanford, California, USA.
19Department of Radiology, University of Virginia School of Medicine, Charlottesville, Virginia, USA.
Dementia, one of the most feared associates of increasing longevity, represents a pressing public health problem and major research priority. Alzheimer's disease (AD) is the most common form of dementia, affecting many millions around the world. There is currently no cure for AD, but large numbers of novel compounds are currently under development that have the potential to modify the course of the disease and slow its progression. There is a pressing need for imaging biomarkers to improve understanding of the disease and to assess the efficacy of these proposed treatments. Structural magnetic resonance imaging (MRI) has already been shown to be sensitive to presymptomatic disease (1
) and has the potential to provide such a biomarker. For use in large-scale multicenter studies, however, standardized methods that produce stable results across scanners and over time are needed.
The Alzheimer's Disease Neuroimaging Initiative (ADNI) study is a longitudinal multisite observational study of elderly individuals with normal cognition, mild cognitive impairment (MCI), or AD (11
). It is jointly funded by the National Institutes of Health (NIH) and industry via the Foundation for the NIH. The study will assess how well information (alone or in combination) obtained from MRI, (18F)-fludeoyglucose positron emission tomography (FDG PET), urine, serum, and cerebrospinal fluid (CSF) biomarkers, as well as clinical and neuropsychometric assessments, can measure disease progression in the three groups of elderly subjects mentioned above. At the 55 participating sites in North America, imaging, clinical, and biologic samples will be collected at multiple time points in 200 elderly cognitively normal, 400 MCI, and 200 AD subjects. All subjects will be scanned with 1.5 T MRI at each time point, and half of these will also be scanned with FDG PET. Subjects not assigned to the PET arm of the study will be eligible for 3 T MRI scanning. The goal is to acquire both 1.5 T and 3 T MRI studies at multiple time points in 25% of the subjects who do not undergo PET scanning [R2C1]. CSF collection at both baseline and 12 months is targeted for 50% of the subjects. Sampling varies by clinical group. Healthy elderly controls will be sampled at 0, 6, 12, 24, and 36 months. Subjects with MCI will be sampled at 0, 6, 12, 18, 24, and 36 months. AD subjects will be sampled at 0, 6, 12, and 24 months.
Major goals of the ADNI study are: to link all of these data at each time point and make this repository available to the general scientific community; to develop technical standards for imaging in longitudinal studies; to determine the optimum methods for acquiring and analyzing images; to validate imaging and biomarker data by correlating these with concurrent psychometric and clinical assessments; and to improve methods for clinical trials in MCI and AD. The ADNI study overall is divided into cores, with each core managing ADNI-related activities within its sphere of expertise: clinical, informatics, biostatistics, biomarkers, and imaging. The purpose of this report is to describe the MRI methods and decision-making process underlying the selection of the MRI protocol employed in the ADNI study.