ADNI image visit questions

[anlij...@gmail.com]

Dear Tadpole users, 

Considering the Freesrfer version in TADPOLE_D1_D2.csv is FS4.3 and FS5.1, I am trying to process ADNI T1 images with Freesurfer 6.0. 

I have 2 quesions:  

1. I have downloaded ADNI images and found for some subejcts, it would have MPRAGE and MPRAGE Repeat images on one visit, should I directly use MPRAGE Repeat instead of MPRAGE if the visit has  MPRAGE Repeat？

2. I aslo found that there are some visist having MPRAGE GRAPPA2, could you help point out what is this meanning? 

Thanks for your help! 

[illor...@gmail.com]

Hi,

1) Quoting the ADNI procedures, the instructions to obtain the "Repeat" scan are to "Repeat the identical MPRAGE (...) with no changes to the scan prescription. ". [source]

I have seen these image pairs of "scan, re-scan" being used as a check for automatic tools (e.g., segmentation volumes, atrophy quantification), where no changes should be expected (no volume change, no atrophy).

As for the procedure, in my notes for the TADPOLE challenge, I found that

"In all cases, rows between ADNIMERGE and these
spreadsheets were matched using the subject ID and
visit code. Duplicate rows were removed, with the most
recent preferred."

2) GRAPPA is a Parallel Imaging Technique, which can be used to decrease MRI acquisition time or increase the spatial resolution" [source]

Kind regards,

Isaac Llorente
NIC-VICOROB research intern

[Lijun An]

Hi Isaac Llorente, 

Thanks for your explanation, it helps a lot. 

Best Regards,

An Lijun

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[Neil Oxtoby]

If you have specific questions on ADNI data, go here: https://groups.google.com/g/adni-data

Cheers,

Neil