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Question Posted 10/23/13:
The csv file for Complete 3Yr 1.5T image set has images repeated at the same visit. Are these separate acquisitions, or different processing ? How are the markings, MPR/ MPR-R / Scaled vs Scaled_2/ assigned?
Response posted 10/24/13 by Bret Borowski:
Thanks for your Question to the ADNI MRI Core.

There are indeed repeated acquisitions within the ADNI 1.5T protocol. Specially the MPRAGE or IRSPGR should have been repeated for every study, this was done intentionally. However, if there is another series repeated, this was most likely done as a result of motion on the initial scan.

The names of MPR and MPR-R is a result of the naming convention when pre-processing these scans. This was done as we have seen over 170 variations of the series description of MPRAGE and MPRAGE Repeat. Scaled vs. Scaled_2 is also a result of that processing pipeline. Any exams that were scaled a second time (and replaced) have scaled_2 in their names.

Hopefully this answers your questions.

Response posted 10/24/13 by Al Bachman:
What does an MT1 in place of MPR mean ?
Response posted 10/25/13 by Al Bachman:
1. Does "Scaling" refer to spatial normalization (I assume based on the Phantom scans) or some type of intensity scaling?

2. There are 2 "imageRating" entries in the .xml files. Does one or both refer to the final image quality? If so, what is the scale used?
Response posted 10/29/13 by Bret Borowski:
Thanks for your question the ADNI MRI core. For scaling, there was an adjustment of voxel sizes based on phantom measurements acquired near-in-time to the subject image.

For image rating, yes those are done as a final image quality, there should be one rating per T1 series acquired. The scale is 1-4. 1 being excellent/very good, 2 is good, 3 is fair/poor, 4 being unusable.
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