DIPY - IVIM TRR fit is unprecise

1

Hi there,

I’m trying to use the dipy library to fit an IVIM image.
I’ve only tried the TRR method for now, as VarPro seems to be (extremely) long (over 1.5hours for a 120x120x20x11 image)

The problem i’m encountering is the fit is not precise at all : when I plot the results I get this : ivim_voxel_plot

which does not seem good to me at all.
I believe the problem might be caused by one of two warnings I get when fitting the data :

/src/src/ivim.py:432: UserWarning: x0 obtained from linear fitting is not feasible as initial guess for leastsq while estimating f and D_star. Using parameters from the linear fit.
  warnings.warn(warningMsg, UserWarning)
/src/src/ivim.py:503: UserWarning: x0 is unfeasible for leastsq fitting. Returning x0 values from the linear fit.
  warnings.warn(warningMsg, UserWarning)
/src/src/ivim.py:336: UserWarning: Bounds are violated for leastsq fitting. Returning parameters from linear fit
  warnings.warn(warningMsg, UserWarning)

I do not however seem to find any way to fix these (this is my first week using the library)

Can any of you help ?

2

giving it an up :smile: !