Hi,
I found this answer in a previous topic (http://adni.loni.usc.edu/support/experts-knowledge-base/question/?QID=187):
"Response posted 02/26/14 by Bret Borowski:
Thank you for your question to the ADNI MRI Core.
After checking with colleagues in the MRI core, they feel that:
One should be able to merge ADNI-1 3T with the UN-ACCELERATED ADNI-2/ADNI-GO for Philips and Siemens 3T images. (GE used a MPRAGE scan in ADNI1 and a IR-FSPGR in ADNI, thus would recommend combining)
We would NOT advocate combining accelerated with unaccerlerated images.
Thank you
ADNI MRI Core"
Did you actually mean that combining data for Siemens and Philips for ADNI1 and ADNI2 was fine, but not for GE because of the IR-FSPGR format in ADNI2?
What is the difference between MPRAGE and IR-FSPGR?
Thank you VERY much
Yes, -- Thank you -- I did mean ADNI2.
MP-RAGE and IR-SPGR are both used for 3D T1 weighted imaging. At the time ADNI-1 started. Philips and Siemens both used MPRAGE, however GE did not offer it. Thus for ADNI-1 we worked with GE to create a non-product MPRAGE research pulse sequence. This however was not feasible for ADNI2 as we wanted to only used product sequences available at all sites.
As far as the differences, they both utilize spoiled fast gradient echoes for data acquisition during inversion recovery, but differ in acq. timing.
Hope this helps.
Bret
