Demonstration of nonlinearity bias in the measurement of the apparent diffusion coefficient in multicenter trials. Issue 3 (2nd May 2015)

• Record Type: Journal Article
• Authors: Malyarenko, Dariya I.; Newitt, David; J. Wilmes, Lisa; Tudorica, Alina; Helmer, Karl G.; Arlinghaus, Lori R.; Jacobs, Michael A.; Jajamovich, Guido; Taouli, Bachir; Yankeelov, Thomas E.; Huang, Wei; Chenevert, Thomas L.
• Is Part Of: Magnetic resonance in medicine. Volume 75:Issue 3(2016:Mar.)
• Page Start: 1312
• Page End: 1323
• Publication Date: 2015-05-02
• Subjects: quantitative diffusion MRI -- multicenter trials -- gradient nonlinearity -- ADC mapping; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25754
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: Characterize system‐specific bias across common magnetic resonance imaging (MRI) platforms for quantitative diffusion measurements in multicenter trials. Methods: Diffusion weighted imaging (DWI) was performed on an ice‐water phantom along the superior–inferior (SI) and right–left (RL) orientations spanning ±150 mm. The same scanning protocol was implemented on 14 MRI systems at seven imaging centers. The bias was estimated as a deviation of measured from known apparent diffusion coefficient (ADC) along individual DWI directions. The relative contributions of gradient nonlinearity, shim errors, imaging gradients, and eddy currents were assessed independently. The observed bias errors were compared with numerical models. Results: The measured systematic ADC errors scaled quadratically with offset from isocenter, and ranged between −55% (SI) and 25% (RL). Nonlinearity bias was dependent on system design and diffusion gradient direction. Consistent with numerical models, minor ADC errors (±5%) due to shim, imaging and eddy currents were mitigated by double echo DWI and image coregistration of individual gradient directions. Conclusion: The analysis confirms gradient nonlinearity as a major source of spatial DW bias and variability in off‐center ADC measurements across MRI platforms, with minor contributions from shim, imaging gradients and eddy currents. The developed protocol enables empiric description of systematic bias in multicenter quantitative DWI studies. Magn Reson Med 75:1312–1323, 2016. © 2015 Wiley Periodicals, Inc.