Dear DTIPrep experts,

I am running DTIPrep on multi-shell diffusion data.

I am having very strange values in the diffusion bcheck step for every gradient:

DWMRI_gradient_0001 mismatch!
DWI: [ -0x1.84ca3b8c8efc9p-5 0x1.0b17b1aa502d8p-1 0x1.b422f64036d8ep-1 ]
protocol: [ -0x1.f1688d1f2f156p-5 0x1.97a41e01e39a7p-2 0x1.d4a6eb2ee00d5p-1 ]
Colinearity angle (degrees): 0x1.001bffb706bdcp+3 > 0x1p+0

Do you have some advice on things we should check? Or do you think it is safe to ignore these warnings based on the answer to a previous topic titled "DTIPrep on multi-shell data + DWMRI gradient mismatch error".

I am sending you the QCReport file attached.

Thanks in advance for your help!

The gradient mismatch is quite sensitive. In general, the bcheck step helps in identifying whether the wrong protocol was used during the acquisition (e.g. the wrong b-table), but it's perfectly fine for individual gradients to mismatch with the protocol.

Martin