Andreas Wetscherek1, Bram Stieltjes2, Wolfhard Semmler1, Frederik Bernd Laun1
1Dept. of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Quantitative imaging based disease characterization, German Cancer Research Center, Heidelberg, Germany
To investigate the origin of the IVIM models diagnostic capabilities we measured the signal attenuation in the pancreas for bipolar and flow compensated diffusion gradients. The diffusion weighting time T was varied while TE was kept fixed. Using a simple model relying on microscopic parameters of blood flow in microvasculature, we were able to reproduce the observed T-dependence in the flow compensated DWI data and the strong signal decay at small b-values for the bipolar DWI data. We found the characteristic time τ > 100 ms implying that only a fraction of the blood exhibits directional changes during T.
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