Imaging Inventory: what’s in the PPMI database

The PPMI repository contains the full set of clinical, imaging and biological data collected as part of this ongoing study. The repository is regularly updated as enrollment and longitudinal follow-up of study subjects continues.  PPMI collects imaging data in several modalities, displayed in the table below:

Total Screening Baseline Year 1 Year 2
DaTSCAN SPECT 969 753 NC 175 41
AV-133 PET 24 NC 24
DTI 389 NC 279 154 28
fMRI 386 NC

Imaging data from PPMI can be accessed from the website by all registered users.  Once users are logged into the Image Data Archive, imaged can be viewed in the IDA Image Viewer, which allows users to adjust orientation, slice, and contract.  Users can also create image data collections, which can be further analyzed.

 To submit an application to access the data, click here.

DaTscan(TM) is a radiopharmaceutical imaging agent that works by binding to dopamine transporters (DaT) in the brain. A specific marker for DaT, DaTscan produces images that provide visual evidence of nigrostriatal degeneration based on a reduced density of dopamine transporters. This information can be used along with other diagnostic tests to help differentiate essential tremor from tremor due to parkinsonian syndromes.

At selected sites with Diffusion Tensor Imaging (DTI) 3T scanner capabilities, subjects undergo MRI DTI at baseline and follow up visits.  Diffusion tensor imaging is conducted to further assess the pathways that connect parts of the brain and the function of cells in those pathways. Goal of PPMI DTI is to determine if DTI can provide a robust marker of PD progression which could serve as a valuable adjunct to clinical assessments and other neuroimaging measures, including radioligand PET and SPECTimaging. Two specific aims:  i) computation of high quality maps of diffusion tensor eigenvalues and eigenvectors which can be used efficiently by other researchers for tests of new hypotheses and other investigations, including tractography; ii) Performance of group analyses of DTI data for tests of specific hypotheses related to the PPMI

Resting state functional magnetic resonance imaging (rsfMRI) examines the brain’s intrinsic functional connectivity by measuring the synchrony of low frequency fluctuations of BOLD (blood oxygen level dependent) MR signal, which is thought to reflect spontaneous metabolic fluctuations of the baseline state of the brain. Studies have demonstrated that the correlation strength of this signal between regions is strongly related to the brain?s underlying structural network architecture . Individual networks identified by rsfMRI have been linked to a variety of high-level brain functions. Importantly, studies have demonstrated that neurodegenerative disease can disrupt brain networks, and that rsfMRI is both sensitive to this disruption and can highlight specific functional connectivity changes in various neurodegenerative disorders.  Based on this background we hypothesize that resting state functional magnetic resonance imaging will be able to demonstrate altered brain networks in Parkinson?s disease (PD), that these alterations will be in networks linked to the neurochemical (i.e., dopamine) and clinical deficits in Parkinson?s disease (e.g., motor, executive, etc.) and that changes in these networks will reflect a patient?s specific symptoms and the use of medications.

Selected sites perform F AV133 imaging, which targets the vesicular monoamince transporter and is used in subject screening for dopaminergic degeneration and to assess progressive dopaminergic degeneration.