open-discussion
open-discussion > RE: concatenated DTI scans
Nov 2, 2016 01:11 PM | Martin Styner
RE: concatenated DTI scans
Hi Chris
Yes, you should be able to concatenate, we do it all the time in our studies
Did you try to feed DTIPrep directly the nii.gz image? If so, I don't think that this would work, you would have to first convert the image to NRRD (with DWIConvert).
Also Re b0, Currently DTIPrep does not allow to specify the minimal b-value for a b0 to be detected. Only those gradients with very small gradient entry (10-7) are currently detected as b0.
Something we need to improve.
Btw, for combining multiple DWI's you can also use CombineDWIs https://github.com/NIRALUser/CombineDWIs
Martin
Originally posted by Christopher Petty:
Yes, you should be able to concatenate, we do it all the time in our studies
Did you try to feed DTIPrep directly the nii.gz image? If so, I don't think that this would work, you would have to first convert the image to NRRD (with DWIConvert).
Also Re b0, Currently DTIPrep does not allow to specify the minimal b-value for a b0 to be detected. Only those gradients with very small gradient entry (10-7) are currently detected as b0.
Something we need to improve.
Btw, for combining multiple DWI's you can also use CombineDWIs https://github.com/NIRALUser/CombineDWIs
Martin
Originally posted by Christopher Petty:
What should be happening in the scenario where
i've concatenated 6 scans together?
They were scanned back to back during the same scanning session, with the same 15 direction + 2 b0 protocol. I concatenated them all together into a long 4D nii.gz ( including the bvalues and bvectors ).
I was expecting DTIPrep to average all the B0 and treat the all the gradient directions individually, but what actually happened is that they were averaged into a single 17 direction scan, then processed. Also, my b0s were never averaged.
They were scanned back to back during the same scanning session, with the same 15 direction + 2 b0 protocol. I concatenated them all together into a long 4D nii.gz ( including the bvalues and bvectors ).
I was expecting DTIPrep to average all the B0 and treat the all the gradient directions individually, but what actually happened is that they were averaged into a single 17 direction scan, then processed. Also, my b0s were never averaged.
Threaded View
| Title | Author | Date |
|---|---|---|
| Christopher Petty | Nov 1, 2016 | |
| Martin Styner | Nov 2, 2016 | |
| Christopher Petty | Nov 10, 2016 | |
| Martin Styner | Nov 11, 2016 | |
| Christopher Petty | Nov 2, 2016 | |
| Christopher Petty | Nov 1, 2016 | |