Standardized Centralized Alzheimer’s
& Related Dementias Neuroimaging
SCAN
About
Images are uploaded by ADRCs to a portal in the Laboratory of Neuroimaging (LONI) at the University of Southern California where they are de-identified, and then processed for quality assurance and harmonization at the PET and MRI laboratories at the University of Michigan and Mayo Clinic. Following this, images are analyzed by the PET laboratory at UC Berkeley, and the MRI laboratories at Mayo Clinic, and UC Davis. Harmonized images are available through queries at NACC (with data stored at LONI), as are numerical summaries. Results will be returned to the ADRCs via the NACC database.
Current SCAN protocols are focused on widely accepted and widely applied biomarkers, generally, but not exclusively related to characterizing research participants in the A/T/N framework. SCAN goals are to assist the ADRCs in the pursuit of collaborative research, but we do not want to stifle innovative new approaches to imaging data. Future directions will be based on the needs and goals of the ADRC program, and may include other MRI techniques or PET tracers as best practices for their acquisition and analysis become available, and depending on the interest of the NIA Alzheimer’s Disease Research Centers.
Prospective image files that meet SCAN acquisition protocols will be included in this project, but existing images and prospective images that don’t meet protocol will still be accepted by NACC.
Mission
For many years, researchers at the NIA-funded Alzheimer’s Disease Research Centers have been collecting different types of PET and MRI images on their research participants. These data, which we call “legacy data” were collected using different acquisition methods. Because of this, image data could not be simply combined across Centers, resulting in lost opportunities for scientific collaboration. Some legacy data is currently stored on the National Alzheimer’s Coordinating Center (NACC) website. However, for the immediate future, SCAN will not focus on this legacy data, but on prospectively acquired data.
The goal of SCAN will be to promote standardization of PET and MR image acquisition so that images can be combined across multiple centers. These prospectively acquired images will be subject to standardized quality control procedures, and then uploaded to NACC where they will be appropriately archived, labeled, and made available to qualified investigators. In addition, the SCAN team will develop numerical summaries of the PET and MR data that will be available on the NACC website and linked to the ADRC participants through their ID. Appropriate images for inclusion in the SCAN workflow are images acquired prospectively on NACC participants, following SCAN protocols regardless of the funding source.
SCAN has a set of required acquisition schemes for PET and MR data. This includes required PET protocols for acquiring amyloid, tau, and FDG PET scans, and required MRI sequences for structural T1 and FLAIR scans. Additional MR sequences are optional. Analyzed data available to investigators will include regional measures of amyloid, tau, and FDG tracer uptake, brain volumes, white matter hyperintensities, cerebral infarction, and, depending on the availability of advanced MR sequences, fractional anisotropy, cerebral blood flow, and functional connectivity.
MRI and PET acquisition protocols
The SCAN MR protocol is the same as ADNI. The current protocol is ADNI 3 and this is what will be used initially in SCAN, but ADNI 4 MR protocol will be preferred when it is finalized. See this set of ADNI MR protocols which have been created for a variety of vendor/model/operating system options.
Current protocols
MRI
MRI technical procedures manualAll longitudinal scans must be performed on the same MRI scanner.
Each MRI scanner must be certified and approved by SCAN. MR scanners that are now certified for ADNI 3 can be certified for SCAN using a phantom scan. MR scanners that have not been certified for ADNI 3 (or SCAN) must be certified using a human volunteer scan. This must be permissible using a local IRB – i.e. SCAN does not plan to create a central IRB nor will SCAN manage local IRB administrative proceedures.
The Standard MRI protocol (using SCAN-specific parameters) is required. Your remaining scan time can be used for your site specific sequences.
There are 2 options for SCAN MR – each site can choose which they prefer.
Option 1: Site only required to do 2 primary SCAN sequences: T1 & FLAIR- The first 10 minutes of exam belongs to NIA/SCAN — this is when the SCAN T1 & FLAIR would be done
- Remainder of exam is unique to site
- SCAN would only collect and analyze T1 and FLAIR
PET
PET technical procedures manualAll longitudinal scans must be performed on the same PET scanner.
Each PET scanner must be certified and approved by SCAN. ADNI approved PET scanners will not need to be re-certified.
The following tracers and imaging protocols are all compatible with SCAN:
Suggested Target Dose ± 10% | Minimum injectable dose | Acquisition start-stop time post-injection (min) | ||||
---|---|---|---|---|---|---|
Tracer | mCi | MBq | mCi | MBq | ||
Amyloid Tracers | ||||||
PIB | 15 | 555 | 8 | 300 | 40–60 or 50–70, 40–70 | |
Florbetapir | 10 | 370 | 6 | 225 | 50–70 | |
Florbetaben | 8 | 295 | 5 | 185 | 90–110 | |
NAV4694 | 8.1 | 300 | 6.5 | 240 | 40–70, 50–70 | |
TAU Tracers | ||||||
Flortaucipir | 10 | 370 | 6 | 225 | 80–100 | |
MK6240 | 5 | 185 | 4 | 150 | 70–90 or 90–110, 70–110 | |
PI2620 | 5 | 185 | 4 | 150 | 30–60, 45–75, 60–90, 45–90 | |
GTP1 | 7 | 260 | 5 | 185 | 60–90 | |
Glucose metabolism tracer | ||||||
FDG | 5 | 185 | 4 | 150 | 30–45, 30–60 |
Data
To be SCAN compliant, all image data (MRI and PET) will be uploaded to LONI accompanied by the required meta-data. Documentation will be posted here when available.
Notes
- SCAN will troubleshoot prospectively with ADRCs to advise on making data SCAN compliant.
- De-face decision pending.
- Only SCAN approved data should be uploaded to LONI, however if non-approved data are uploaded (with or without approved data) it will be quarantined.
- Fate of non-SCAN compliant data uploaded to LONI is currently uncertain — for future decision.
- “Legacy data” already at NACC: decision pending for management/curation/analysis.
Contact data.coordinator@loni.usc.edu for support
Frequently asked questions
Getting Started with PET
- Is my PET data SCAN-compliant (based Human Subjects regulations/IRB)?Images must be acquired under an IRB-approved consent that allows sharing of de-identified data to contribute this data to SCAN. It is the responsibility of each ADRC to ensure their consents allow sharing of de-identified data or to update study consents (and obtain IRB approval) to allow this type of sharing on prospective data.
- Is my PET data SCAN-compliant (based on NACC participation and acquisition parameters)?SCAN images must come from NACC participants. Details on allowed acquisition parameters are available on the SCAN website as well as the PET technical manual.
- Our PET data are acquired with slightly different timing and/or reconstruction parameters than listed in the SCAN PET technical manual – can we still contribute this data to SCAN?No. PET images must be collected using allowed acquisition parameters. It is the responsibility of each ADRC to ensure that their PET acquisition is consistent with the listed parameters.
- How can I upload my PET data to SCAN?SCAN image data and corresponding upload forms should be uploaded to LONI following instructions detailed in the PET technical manual.
- Which participant ID do I use when uploading images?Users must submit both the participant ID (also referred to as PTID, Subject ID, or Local ID) in addition to the participant’s NACCID. If the given PTID and NACCID pair match the record present in the NACC database, the upload process will be allowed to continue. If not, then the user will receive an error message indicating that the PTID and NACCID combination are not valid, and the upload will not be allowed to continue.
- Why are all SCAN images acquired 2021 or later?SCAN is a prospective project that officially launched January 2021. SCAN will not ingest data from before 2021 as retrospective or legacy data were not included in the project aims. There are other, separately funded projects ongoing to harmonize legacy PET data available in NACC, and SCAN will work with these investigators to help make their efforts compatible with SCAN data.
- How do I get a SCAN user account on LONI?
Team
SCAN is a multi-institutional project that was funded as a U24 grant (AG067418) by the National Institute on Aging in May 2020 with the goal of standardizing the acquisition, curation, and analysis of PET and MR images acquired through the NIA Alzheimer’s Disease Research Centers Program. The Principal Investigators are William Jagust (UC Berkeley) and Clifford Jack (Mayo Clinic). Other institutions participating in the leadership of SCAN include UC Davis (Charles DeCarli), Lawrence Berkeley National Laboratory (Suzanne Baker), and the University of Michigan (Bob Koeppe). Cerise Elliott is the NIA program official, and John Hsiao is the NIA scientific officer.