On the Field Strength Dependence of Bi- and Triexponential Intravoxel Incoherent Motion (IVIM) Parameters in the Liver

Riexinger A, Martin J, Rauh S, Wetscherek A, Pistel M, Kuder TA, Nagel AM, Uder M, Hensel B, Müller L, Laun FB (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Book Volume: 50

Pages Range: 1883-1892

Journal Issue: 6

DOI: 10.1002/jmri.26730

Abstract

Background: Studies on intravoxel incoherent motion (IVIM) imaging are carried out with different acquisition protocols. Purpose: To investigate the dependence of IVIM parameters on the B0 field strength when using a bi- or triexponential model. Study Type: Prospective. Study Population: 20 healthy volunteers (age: 19–28 years). Field Strength/Sequence: Volunteers were examined at two field strengths (1.5 and 3T). Diffusion-weighted images of the abdomen were acquired at 24 b-values ranging from 0.2 to 500 s/mm². Assessment: ROIs were manually drawn in the liver. Data were fitted with a bi- and a triexponential IVIM model. The resulting parameters were compared between both field strengths. Statistical Tests: One-way analysis of variance (ANOVA) and Kruskal–Wallis test were used to test the obtained IVIM parameters for a significant field strength dependency. Results: At b-values below 6 s/mm², the triexponential model provided better agreement with the data than the biexponential model. The average tissue diffusivity was D = 1.22/1.00 μm²/msec at 1.5/3T. The average pseudodiffusion coefficients for the biexponential model were D^* = 308/260 μm²/msec at 1.5/3T; and for the triexponential model D^* = 81.3/65.9 μm²/msec, D^* 2 = 2453/2333 μm²/msec at 1.5/3T. The average perfusion fractions for the biexponential model were f = 0.286/0.303 at 1.5/3T; and for the triexponential model f1 = 0.161/0.174 and f2 = 0.152/0.159 at 1.5/3T. A significant B0 dependence was only found for the biexponential pseudodiffusion coefficient (ANOVA/KW P = 0.037/0.0453) and tissue diffusivity (ANOVA/KW: P < 0.001). Data Conclusion: Our experimental results suggest that triexponential pseudodiffusion coefficients and perfusion fractions obtained at different field strengths could be compared across different studies using different B0. However, it is recommended to take the field strength into account when comparing tissue diffusivities or using the biexponential IVIM model. Considering published values for oxygenation-dependent transversal relaxation times of blood, it is unlikely that the two blood compartments of the triexponential model represent venous and arterial blood. Level of Evidence: 1. Technical Efficacy Stage: 2. J. Magn. Reson. Imaging 2019;50:1883–1892.

Authors with CRIS profile

Involved external institutions

Deutsches Krebsforschungszentrum (DKFZ) Germany (DE) Royal Marsden Hospital / The Royal Marsden NHS Foundation Trust United Kingdom (GB)

How to cite

APA:

Riexinger, A., Martin, J., Rauh, S., Wetscherek, A., Pistel, M., Kuder, T.A.,... Laun, F.B. (2019). On the Field Strength Dependence of Bi- and Triexponential Intravoxel Incoherent Motion (IVIM) Parameters in the Liver. Journal of Magnetic Resonance Imaging, 50(6), 1883-1892. https://dx.doi.org/10.1002/jmri.26730

MLA:

Riexinger, Andreas, et al. "On the Field Strength Dependence of Bi- and Triexponential Intravoxel Incoherent Motion (IVIM) Parameters in the Liver." Journal of Magnetic Resonance Imaging 50.6 (2019): 1883-1892.

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