Thanks, John!
Warm regards,
Jeff
Sent from my iPhone
On Nov 25, 2011, at 4:50 PM, John Ashburner <[log in to unmask]> wrote:
> The T-SPOON paper in NeuroImage may give you some ideas about how to
> look at ADC or FA values in WM.
>
> Jee Eun Lee, Moo K. Chung, Mariana Lazar, Molly B. DuBray, Jinsuh Kim,
> Erin D. Bigler, Janet E. Lainhart, Andrew L. Alexander. A study of
> diffusion tensor imaging by tissue-specific, smoothing-compensated
> voxel-based analysis. NeuroImage, Volume 44, Issue 3, 1 February 2009,
> Pages 870-883
>
> Various co-workers of mine use an extension of this approach that
> weights the values with Jacobian scaled WM (or GM), rather than just
> WM. Off the top of my head, I'm not sure where the best place to find
> a description of this would be. It may be in a recent quantitative
> imaging paper by Bogdan Draganski, or maybe in a recent paper on
> cortical thickness mapping by Chloe Hutton.
>
> Best regards,
> -John
>
> On 20 November 2011 18:31, Jeff Browndyke <[log in to unmask]> wrote:
>> Just a quick follow up...
>> Does the same non-modulation ("preserves volumes") of VBM8/DARTEL transforms
>> hold for ADC and FA maps, as well?
>> Thanks,
>> Jeff
>> On Nov 16, 2011, at 9:31 PM, Jeff Browndyke wrote:
>>
>>
>> No, you don't want to apply jacobian modulation to BOLD and ASL data.
>>
>> cheers,
>>
>> -MH
>>
>> On Wed, 2011-11-16 at 14:51 -0500, Jeff Browndyke wrote:
>>
>> Thank you for the input, Roberto.
>>
>> Thought it might be o.k., but wanted to double-check before tying up
>> processing resources for a couple of days.
>>
>> Am I correct about the "preserve volumes" (modulation) option, as it applies
>> to preserving EPI and ASL concentrations after high dimensional warping?
>> The VBM8 deformations routine does not provide any guidance on the matter
>> and is clearly written with the assumption that the images being transformed
>> are structural.
>>
>> Warm regards,
>>
>> Jeff
>>
>>
>> ---- [log in to unmask] wrote:
>>
>> Dear Jeff,
>>
>> I have VBM8 segmented (w/ DARTEL high-dimensional warp and
>>
>> non-linear modulation of grey and white maps) a large group of
>>
>> structural images that also have co-registered ASL and EPI series
>>
>> images and in the same voxel dimensions.
>>
>> Any problems in applying the forward transforms to the ASL and EPI
>>
>> data to bring them into atlas space?
>>
>> Having carried out several studies with ASL, I could not see a
>>
>> systematic difference between using the strategy you describe or
>>
>> normalizing the EPI average to the EPI template when I looked at it. I
>>
>> think both are acceptable. I also think that there is no ASL-specific
>>
>> issue here to consider.
>>
>> Best wishes,
>>
>> Roberto Viviani
>>
>> Department of Psychiatry, University of Ulm
>>
>>
>>
>>
>>
>> -----------------------------------------------------------------------
>> Jeff Browndyke, Ph.D.
>> Clinical & Research Neuropsychologist
>> Durham VA & Duke University Medical Centers
>>
>> [log in to unmask] / [log in to unmask]
>> office: (919) 286-0411 ext. 4656
>> cell: (336) 264-4222
>>
>> -----------------------------------------------------------------------
>> Jeff Browndyke, Ph.D.
>> Clinical & Research Neuropsychologist
>> Durham VA & Duke University Medical Centers
>> [log in to unmask] / [log in to unmask]
>> office: (919) 286-0411 ext. 4656
>> cell: (336) 264-4222
>>
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