Volume 74, Issue 2 pp. 410-419
Full Paper

Flow-compensated intravoxel incoherent motion diffusion imaging

Andreas Wetscherek

Corresponding Author

Andreas Wetscherek

Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

Correspondence to: Andreas Wetscherek, Ph.D., Department Medical Physics in Radiology E020, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany. E-mail: [email protected]Search for more papers by this author
Bram Stieltjes

Bram Stieltjes

Quantitative Imaging-Based Disease Characterization, German Cancer Research Center (DKFZ), Heidelberg, Germany

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Frederik Bernd Laun

Frederik Bernd Laun

Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

Quantitative Imaging-Based Disease Characterization, German Cancer Research Center (DKFZ), Heidelberg, Germany

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First published: 12 August 2014
Citations: 99

Abstract

Purpose

The pseudo-diffusion coefficient D* in intravoxel incoherent motion (IVIM) imaging was found difficult to seize. Flow-compensated diffusion gradients were used to test the validity of the commonly assumed biexponential limit and to determine not only D*, but also characteristic timescale τ and velocity v of the incoherent motion.

Theory and Methods

Bipolar and flow-compensated diffusion gradients were inserted into a flow-compensated single-shot EPI sequence. Images were obtained from a pipe-shaped flow phantom and from healthy volunteers. To calculate the IVIM signal outside the biexponential limit, a formalism based on normalized phase distributions was developed.

Results

The flow-compensated diffusion gradients caused less signal attenuation than the bipolar ones. A signal dependence on the duration of the flow-compensated gradients was found at low b-values in the volunteer datasets. The characteristic IVIM parameters were estimated to be v = 4.60 ± 0.34 mm/s and τ = 144 ± 10 ms for liver and v = 3.91 ± 0.54 mm/s and τ = 224 ± 47 ms for pancreas.

Conclusion

Our results strongly indicate that the biexponential limit does not adequately model the diffusion signal in liver and pancreas. By using both bipolar and flow-compensated diffusion gradients of different duration, the characteristic timescale and velocity of the incoherent motion can be determined. Magn Reson Med 74:410–419, 2015. © 2014 Wiley Periodicals, Inc.

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