There have been some modifications to the types of scans acquired throughout the ADNI study. All scans remain available for download by qualified users and are accessible via the Image Data Archive. Listed below are the types of scans collected from each phase of the study. To view a full list of study data, review the data inventory page.
Each scan obtained in the ADNI study is reviewed by the ADNI MRI QC team at the Mayo Clinic. The QC ensures that the scans meet the specifications outlined in the MRI protocol and identifies any clinically significant findings. A single phantom scan must also be performed each day participants are scanned.
- CLINICALLY SIGNIFICANT FINDINGS
When significant abnormalities are seen on the screening MRI scan, such as a hemispheric infarction, the participant is excluded. Additionally, sites are notified by email in the event that a radiological finding that is not normal for age is identified by the MRI QC team.
- PROTOCOL COMPLIANCE OF SCAN
If it is found that the scan was performed incorrectly, the MRI QC team contacts the technologist directly to provide further instructions and the study coordinator and site PI are also notified of the failed scan. When requested, a repeat scan is scheduled within four weeks of the original scanning date. In the event that the scan occurs outside of the four-week window, the protocol deviation is logged.
Recommended Image Data: Which scan to select?
For researchers who are interested in the imaging process as a whole, imaging files are available at every stage of pre- and post-processing. However, most researchers will prefer to use the scans that have undergone the maximum level of correction. These MPRAGE files are considered the best in the quality ratings and have undergone gradwarping, intensity correction, and have been scaled for gradient drift using the phantom data. These files are identified with “N3″ and “scaled” in the file name.