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Notes:
FBIRN recommends careful scanner measurements prior to attempting
to combine data across sites or MRI scanners. These can be used as
Quality Assurance (QA) methods to include a site’s data in a study.
These QA scans are routinely performed and used to verify and
measure the scanner stability during a typical fMRI scanning
sequence. The scans are performed on a 17cm spherical phantom
filled with an agar gel. The scans consist of 200 separate image
volumes captured over roughly a 10 minute interval. The drift,
fluctuations, signal to noise ratios, and other measures indicate
the scanner’s background noise relative to its stability.
The FBIRN Phantom QA Procedure Document includes information on
instructions, the recipe, and analysis methods for building and
using an agar phantom, and acquiring and using a spatial phantom
Instructions:
If you unpack the attached archive (which is tarred and gzipped),
you should get a folder with two files. One is a binary mask which
must be copied to the same directory where the acquired DICOM files
are located. The other file is a shell script. It contains a fair
number of comments, including parameters we used to acquire our
data.
This QA requires a recent version of AFNI be installed. We tested
it on GE's DICOM format; in addition to GE, AFNI can import
Siemens' data. Other vendors may not be supported. Once the data is
converted to AFNI's BRIK/HEAD format, the analysis is simple.
Technical contact:
Vinai Roopchansingh
Biophysics
8701 Watertown Plank Rd.
Milwaukee, WI 53226 U.S.A.
Phone: 414-456-4039
Fax: 414-456-6512
e-mail: vroopcha@mcw.edu
Contributing authors:
Vinai Roopchansingh
Andy Nencka
Biophysics
8701 Watertown Plank Rd.
Milwaukee, WI 53226 U.S.A.
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