ADNI | Question

Select the area you would like to search.
ADNI SITE
DATA DICTIONARY This search queries the ADNI data dictionary. Enter terms or codes used in the dictionary for a definition, or enter search terms to locate data within the archive.
ACTIVE INVESTIGATIONS Search for current projects using the investigator's name, institution, or keywords.
EXPERTS KNOWLEDGE BASE Enter keywords to search a list of questions and answers received and processed by the ADNI team.
ADNI PDFS Search any ADNI publication pdf by author, keyword, or PMID. Use an asterisk only to view all pdfs.

Question

Question Posted 02/26/14:
(Sorry for second issue, the form doesn't like messages past a certain length) We also have a scan that may be a scanner change, again with a series that has an unusual series description (the _ND suffix):
ADNI_013_S_4268_MT1__GradWarp__N3m_S206389_I399886.xml "MPRAGE GRAPPA 2_ND"
We think we need to exclude a scanner change from our longitudinal analysis since it relies on image consistency. Is there a particular meaning to the "_ND" series descriptor?

Response posted 02/27/14 by Bret Borowski:

Thank you for your question to the ADNI MRI Core.

The images that you are referring to are indeed from the ADNI protocol. They are from a new Siemens PET/MR Biograph_mMR scanner. The images that contain the "ND". Which stands for No Distortion correction. This system envokes the product inline 3D gradwarp correction, thus provides both 3D gradient correction and non correct sequences. However, ADNI will still provide pre-processed images for this type of system scanner.

Yes, this a significant scanner change, thus it would be advisable exclude these scans from longitudinal analysis.

ADNI MRI Core

Go back to list of topics >