Diffusion MRI: Difference between revisions

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Jadrian Miles (talk | contribs)
Jadrian Miles (talk | contribs)
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| 2.0x2.0x2.0
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| {{hidden | ta1 = left | headercss = font-size: 100%; width: 24ex; | contentcss = font-size: 90%; width: 24ex;
| header = Not done
| header = Not processed
| content = Single dataset needs to be processed ASAP for social reasons
| content = Single dataset needs to be processed ASAP for social reasons
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| header = Not downloaded
| header = Not downloaded
| content = Longitudinal data and old proof-of-concept data need to be loaded into <code>$G/data/diffusion</code>
| content = Longitudinal data and old proof-of-concept data need to be loaded into <code>$G/data/diffusion</code>
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| header = Not collected
| header = Not collected
| content = Still waiting for the 7T protocol to finalize
| content = Still waiting for the 7T protocol to finalize

Revision as of 15:55, 19 August 2008

Collaborative Research Projects

Project Location Collaborators Dataset Date Received / Path Scanner Format Resolution (voxels) Voxel Size (mm) Orientation Status
Cognitive Aging St. Louis Rob Paul (UMSL), Tom Conturo (WUSTL) ?? Interfile 83x110x64 x 36 DWIs 2.0x2.0x2.0 ??
Fibers at Risk Colorado Jack Simon unknown / not transferred 1.5T ?? ?? ?? ?? ??
Portland, OR Jack Simon (Portland VA), Bill Rooney (phys. chemist at OHSU AIRC) not transferred 7T GE ?? ?? ?? ??

Software

File Formats

DICOM

DICOM Mosaic

Analyze

NIfTI

Files ending in .nii are in the NIfTI medical image format; it is becoming a standard export format for many different software packages, including FSL. .nii files combine the metadata header and image data into a single file, but NIfTI-1 is a modified form of Analyze 7.5, so it sometimes comes in .hdr/.img pairs. You can test for the format by using the is_nifti_file() function in the I/O wrapper library.

The format was created by the Neuroimaging Informatics Technology Initiative at NIH. It is a superset of Analyze 7.5, re-purposing empty fields in the Analyze format to support more features. Fortunately for us, the NIfTI reference library is available in the public domain, and $G/src/nifti is set up to download the latest version (with make download), build it, and install it in $G/lib/nifti and $G/include/nifti. You might also try snooping around $G/doc/nifti to see what they have to say in their documentation. $G/src/nifti2mriimage/nifti2mriimage.cpp demonstrates reading the header and extracting information from it, as well as reading the image data.

To use the NIfTI I/O wrapper library, simply #include <nifti1_io.h> in your code and add the following to the library list in your makefile: niftiio znz m z.

From the command line or shell scripts, the nifti_tool utility is pretty powerful and can read the header in a structured way.

The online documentation for NIfTI is also pretty sweet:

Interfile

MRIimage

MRIimage is our in-house format for storing MRI data. It is manipulated by the gg/mri_g++-* library and its header is <gg/mri/image.H>.