Hi Marcella,

For diffusion images, you should use the "DICOM Import" view, not the "File 
Open" or drag n drop. The open dialog will simply trigger the ITK-mechanism for 
loading files, which will not result in appropriate extraction of the b-matrix 
information. Sorry about this confusion.

You mentioned, that you have 4D fsl-files, probably <your-filename>.nii

You could also rename the file to <your-filename>.fsl and create an 
accompanying <your-filename>.fsl.bvecs and a <your-filename>.fsl.bvals file to 
load the dataset.

Please let me know, if you succeeded.

Best
Klaus
 
________________________________________
Von: Marcella Laganà [[email protected]]
Gesendet: Donnerstag, 17. November 2011 15:09
An: Fritzsche, Klaus H.
Betreff: R: about MITK Diffusion

Thank you. The screenshot I've sent you has been done with the first method,
so loading the dicom. I've tried again with another patients of a different
protocol (12 directions and 1 b0, 2 averages), but ITK tensor reconstruction
doesn't become active. I have 1 object in the Data Manager panel and
changing the "Time" point I see the different directions.
First, I wanted to average the 2 runs with Preprocessing--> Reduce Size -->
average redundant gradients, but also that command is not available.
Thanks again
Marcella
-----Messaggio originale-----
Da: Fritzsche, Klaus H. [mailto:[email protected]]
Inviato: martedì 15 novembre 2011 23.17
A: Marcella Laganà
Cc: [email protected]
Oggetto: AW: about MITK Diffusion

Hi Marcella,

you have three different options to load diffusion weighted datasets.

1) dicom import of Siemens files

If you choose one of the following two options, you have to change the
file-endings. If you don't do that, MITK will not be able to differentiate
them form plain 4D-images. After loading, you will recognize the different
icon used for diffusion images, compared to plain 4D images:

2) use the nrrd-format, like Slicer does

first rename
*.nhdr => *.hdwi
*.nrrd => *.dwi

3) use the nifti-format, like FSL does

first rename
*.nii => *.fsl
*.nii.gz => *.fslgz

For option 2), the nrrd-header should include DWMRI_b-value,
DWMRI_gradient_xxxx, measurement frame, modality:=DWMRI, as in the following
example:

NRRD0004
type: short
dimension: 4
space: left-posterior-superior
sizes: 7 32 66 20
space directions: none (1,0,0) (0,1,0) (0,0,1)
kinds: vector domain domain domain
endian: little
encoding: raw
space origin: (0,0,0)
data file: data.raw
DWMRI_b-value:=1000.000000
DWMRI_gradient_0000:=0.000000 0.000000 0.000000
DWMRI_gradient_0001:=0.710300 0.000708 -0.703899
DWMRI_gradient_0002:=-0.710300 0.000708 -0.703899
DWMRI_gradient_0003:=0.002857 -0.708531 -0.705674
DWMRI_gradient_0004:=0.002856 -0.708174 0.706032
DWMRI_gradient_0005:=0.708873 -0.705331 -0.002833
DWMRI_gradient_0006:=-0.708873 -0.705331 -0.002833
measurement frame:=(1.000000,0.000000,0.000000) (0.000000,1.000000,0.000000)
(0.000000,0.000000,1.000000)
modality:=DWMRI



For option 3), the *.fsl (or *.fslgz) file must be accompanied with a bvals
and a bvecs file for the b-matrix information:

diffusionimage.fsl
diffusionimage.fsl.bvals
diffusionimage.fsl.bvecs

with the bvals-file containing
0 1000 1000 1000 1000 1000 1000

and the bvecs-file containing
0 0.7103 -0.7103 0.002857 0.002856 0.708873 -0.708873
0 0.000708 0.000708 -0.708531 -0.708174 -0.705331 -0.705331
0 -0.703899 -0.703899 -0.705674 0.706032 -0.002833 -0.002833

using the same example as in 2). Hope, this helps!

Regards
Klaus


________________________________________
Von: Marcella Laganà [[email protected]]
Gesendet: Dienstag, 15. November 2011 22:17
An: Fritzsche, Klaus H.
Betreff: R: about MITK Diffusion

Thank you for your fast answer.
This software seems very comprehensive, I've read the documentation but I'm
not able to start using it.
I've tried again loading dicom, or different 3D volumes, or 1 4D volume (fsl
output). I've also tried creating a 4D volume which is composed by only 1 b0
and 12 directions, so that I've selected the option of 12 directions.
I've clicked on Tensors and then on the dataset, but the ITK tensor
reconstruction didn't become active (attached the screenshot).
Is it the same to load separate 3D files or 4D or dicom?
Don't I have to insert the B-matrix?
Thanks and regards
Maria Marcella Laganà


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