Toward optimized intravoxel incoherent motion (IVIM) and compartmental T2 mapping in abdominal organs
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Purpose
To quantitatively assess the bias in the intravoxel incoherent motions (IVIM)-derived pseudo-diffusion volume fraction ( f ) caused by the differences in relaxation times between the tissue and fluid compartments, and to develop a 2D fitting approach and an optimal acquisition protocol for the relaxation compensated T2-IVIM imaging in the liver and kidney.
Methods
Numerical simulations were conducted to investigate the TR- and TE-dependent bias in f when using the conventional IVIM model, and to evaluate the applicability of the extended 2D T2-IVIM model for reducing this bias. The in silico findings were then validated using the in vivo IVIM data from healthy volunteers on a clinical 3-Tesla MRI scanner. Finally, a numerical framework for optimizing the T2-IVIM protocol for relaxation-compensated f parameter estimation was proposed and tested using in vivo data.
Results
When using the traditional IVIM model, a trend toward higher f with increasing TE was found in the liver (R = 0.42, P = 0.043), but not in the kidney cortex (R = −0.067, P = 0.76) and medulla (R = 0.039, P = 0.86). The 2D T2-IVIM modeling yielded lower f and reduced the intra-subject variability in the liver. Our results also suggest that a b-TE protocol with six b-values and three different TE values (50, 55, and 100 ms) might be optimal for liver T2-IVIM.
Conclusion
The extended 2D T2-IVIM model combined effectively minimizes the TE-dependent bias in f and allows simultaneous estimation of the IVIM parameter and compartmental T2 values in the liver and kidney.
