[Camino-users] Two-tensor Fitting to HCP Data

[John Plass]

Hello Camino experts,
I was wondering if anyone could help me with processing Human Connectome
Project Data with Camino. I've seen 2 previous posts on this topic, but I
couldn't find any details on going this far. So far, I've successfully been
able to (a) fit single tensors and (b) threshold voxels according to the SH
fit, both with spatial variations in b-values being accounted for. Both
look great! However, when I try to fit a two-tensor model, I get the
following feedback repeatedly:

imaging.DW_Scheme normalizeData
WARNING: No b=0 data, cannot normalize

I assume this is due to the fact that the b=0 volumes actually have
b-values around 5. Is there an easy way to get around this?

Any help would be much appreciated!

Thanks,
John Plass

[For reference, here are the commands I've been using:]
-Single tensor fit
wdtfit dwi.Bfloat hcp.scheme -bgmask nodif_brain_mask.nii.gz -outputfile
dt.Bdouble -gradadj grad_dev.nii.gz

-Classification (treshold values eyeballed)
voxelclassify -inputfile dwi.Bfloat -schemefile hcp.scheme -order 4
-gradadj grad_dev.nii.gz -ftest 1.0E-50 1.0E-15 1.0E-01 > dwi_VC.Bint

-Double tensor fit
modelfit -inputfile dwi.Bfloat -model pospos ldt_wtd -schemefile hcp.scheme
-bgmask nodif_brain_mask.nii.gz -gradadj grad_dev.nii.gz >
TwoTensorCSymA.Bdouble
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