QMRITools`
QMRITools`
BayesianIVIMFit3
BayesianIVIMFit3[data,bval,init,mask]
performs bayesian IVIM fit of data. data is the data which should be {slice, Ndiff, x, y}. bval is the bvector whould be length Ndiff. init is the initalization of the bayesian fit which comes from IVIMCalC, (without s0 using 3 compartments). mask is the region in which the bayesian fit is performed. output is {f1, f2, dc, pdc1, pdc2}. The fractions f1 and f2 are defined between 0 and 1, the dc, pdc1 and pdc1 is in mm^2/s.
Details
- The following options can be given:
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ChainSteps {20000, 1000, 10} ChainSteps is an option for BayesianIVIMFit2 and BayesianIVIMFit3. It determines how long the algorithm runs. three values must be given {itterations, burn steps, sample density}. UpdateStep {0.5, 0.5, 0.1, 0.5, 0.5} UpdateStep is an option for BayesianIVIMFit2 and BayesianIVIMFit3. It determines how often the parameters are updated. Is optimized during the first 500 burn steps. FixPseudoDiff False FixPseudoDiff is an option for BayesianIVIMFit2 and BayesianIVIMFit3. If the pDc1 and pD2 were fixed in IVIMCalc this value should be True. CorrectPar True CorrectPar is an option for BayesianIVIMFit2 and BayesianIVIMFit3. If True it removes the values outside the contraints using CorrectParMap. OutputSamples False OutputSamples is an option for BayesianIVIMFit2 and BayesianIVIMFit3. If set True the full marcov chain is given as an additionaln output. FixPseudoDiffSD 0.5 FixPseudoDiffSD is an option for BayesianIVIMFit2 and BayesianIVIMFit3. Gives the standard deviation of pDc1 and pD2 if FixPseudoDiff is True. FitConstrains {{0.000500201, 0.9995}, {0.000500201, 0.9995}, {0.0000453999, 0.00408677}, {0.00150344, 0.100259}, {0.00551656, 1.}} FitConstrains is an option for BayesianIVIMFit2 and BayesianIVIMFit3. Gives the contraints of the parameters. The values are used for displaying the histograms and for the initialization if CorrectPar is True.