Learning objectives
1.
An IVIM model is able to obtain unique biomaterial information.
2.
There is a correlation between the IVIM parameter and the shear stiffness of the liver.
Background
Intravoxel incoherent motion (IVIM) imaging is a concept used to quantitatively assess all microscopic translational motions from diffusion-weighted magnetic resonance signals.
There are several IVIM models that can estimate the physical properties of biological tissues [1-4].
A typical IVIM model is as follows (also see Figure 4).
a.
Mono-exponential model
where the subscript of 0 for b0 and S0 indicates b-value and diffusion-weighted (DW) signal at 0 mm2/s,
respectively.
In addition,
b and S are the desired b-value and DW signal at the same b-value....
Findings and procedure details
MR imaging
In this study,
MR imaging was performed on seven patients with liver diseases,
after obtaining written informed consent (Table 1).
The patients underwent scanning with a 1.5-T MR system (Signa Explorer,
GE Healthcare,
Chicago,
IL) using conventional MRE and DW imaging sequences.
The imaging parameters and setting values for the conventional MRE and DW images are shown in Table 2.
An external driver device (60 Hz) was used to induce shear waves in the liver tissue,
and axial imaging of the abdomen with...
Conclusion
The results show that the tissue elasticity changes in the liver tissue affect the amount of non-Gaussian diffusion in the IVIM model.
Additionally,
the amount of non-Gaussian diffusion empirically obtained from the IVIM model is affected by several factors.
In conclusion,
the IVIM model can obtain different biomaterial information,
such as diffusion components,
multiple separable proton pools,
and empirically handles the shear stiffness.
References
1.
Le Bihan D,
Breton E,
Lallemand D,
Grenier P,
Cabanis E,
Laval-Jeantet M (1986) MR imaging of intravoxel incoherent motions: application to diffusion and perfusion
in neurologic disorders.
Radiology.
161:401-7
2.
Clark CA,
Le Bihan D (2000) Water diffusion compartmentation and anisotropy at high
b values in the human brain.
Magn Reson Med.
44:852-9
3.
Sehy JV,
Ackerman JJ,
Neil JJ (2002) Evidence that both fast and slow water ADC
components arise from intracellular space.
Magn Reson Med.
48:765-70.
4.
Bennett KM,
Schmainda KM,...