Choice of reference measurements affects quantification of long diffusion time behaviour using stimulated echoes

Michiel Kleinnijenhuis, Jeroen Mollink, Wilfred W. Lam, Paul Kinchesh, Alexandre A. Khrapitchev, Sean C. Smart, Saad Jbabdi, Karla L. Miller

Onderzoeksoutput: Bijdrage aan tijdschriftArtikelpeer review

5 Citaten (Scopus)

Samenvatting

Purpose: To demonstrate how reference data affect the quantification of the apparent diffusion coefficient (ADC) in long diffusion time measurements with diffusion-weighted stimulated echo acquisition mode (DW-STEAM) measurements, and to present a modification to avoid contribution from crusher gradients in DW-STEAM. Methods: For DW-STEAM, reference measurements at long diffusion times have significant b0 value, because b = 0 cannot be achieved in practice as a result of the need for signal spoiling. Two strategies for acquiring reference data over a range of diffusion times were considered: constant diffusion weighting (fixed-b0) and constant gradient area (fixed-q0). Fixed-b0 and fixed-q0 were compared using signal calculations for systems with one and two diffusion coefficients, and experimentally using data from postmortem human corpus callosum samples. Results: Calculations of biexponential diffusion decay show that the ADC is underestimated for reference images with b > 0, which can induce an apparent time-dependence for fixed-q0. Restricted systems were also found to be affected. Experimentally, the exaggeration of the diffusion time–dependent effect under fixed-q0 versus fixed-b0 was in a range predicted theoretically, accounting for 62% (longitudinal) and 35% (radial) of the time dependence observed in white matter. Conclusions: Variation in the b-value of reference measurements in DW-STEAM can induce artificial diffusion time dependence in ADC, even in the absence of restriction. Magn Reson Med 79:952–959, 2018.

Originele taal-2Engels
Pagina's (van-tot)952-959
Aantal pagina's8
TijdschriftMagnetic Resonance in Medicine
Volume79
Nummer van het tijdschrift2
DOI's
StatusGepubliceerd - feb. 2018
Extern gepubliceerdJa

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