PURPOSE: To provide an improved correction for gradient nonlinearity (GN) effects in diffusion-weighted imaging (DWI). These effects produce spatially varying apparent diffusion coefficient (ADC), a result that will be significant in large field-of-view imaging, and may be confounded by distortion and concomitant fields related to the DWI acquisition. MATERIALS AND METHODS: The effect of more accurate gradient field maps on GN correction (GNC) of ADC was evaluated. A simulation compared GN effects in commonly imaged anatomy. A temperature-controlled phantom was imaged at positions 0 cm and 11 cm from isocenter and in two whole-body MRI systems at 1.5T with different patient bore diameters (55 cm and 60 cm). Varying correction methods were applied to determine the errors from spatial variance and interscanner reproducibility. RESULTS: As compared to conventional fifth-order spherical harmonics, a seventh-order GNC improved ADC accuracy by 1%. The combination of GNC with a dual-spin-echo pulse sequence and a retrospective concomitant field correction reduced ADC error due to spatial variance from 9.5% to 1.8% (55 cm bore) and from 4.2% to 1.8% (60 cm bore). The error in ADC attributed to interscanner reproducibility was reduced from 5.8% to 0.15% (at isocenter) and from 10% to 0.63% (11 cm from isocenter). CONCLUSION: GNC in DWI improved spatial accuracy and interscanner reproducibility of ADC.
PURPOSE: To provide an improved correction for gradient nonlinearity (GN) effects in diffusion-weighted imaging (DWI). These effects produce spatially varying apparent diffusion coefficient (ADC), a result that will be significant in large field-of-view imaging, and may be confounded by distortion and concomitant fields related to the DWI acquisition. MATERIALS AND METHODS: The effect of more accurate gradient field maps on GN correction (GNC) of ADC was evaluated. A simulation compared GN effects in commonly imaged anatomy. A temperature-controlled phantom was imaged at positions 0 cm and 11 cm from isocenter and in two whole-body MRI systems at 1.5T with different patient bore diameters (55 cm and 60 cm). Varying correction methods were applied to determine the errors from spatial variance and interscanner reproducibility. RESULTS: As compared to conventional fifth-order spherical harmonics, a seventh-order GNC improved ADC accuracy by 1%. The combination of GNC with a dual-spin-echo pulse sequence and a retrospective concomitant field correction reduced ADC error due to spatial variance from 9.5% to 1.8% (55 cm bore) and from 4.2% to 1.8% (60 cm bore). The error in ADC attributed to interscanner reproducibility was reduced from 5.8% to 0.15% (at isocenter) and from 10% to 0.63% (11 cm from isocenter). CONCLUSION: GNC in DWI improved spatial accuracy and interscanner reproducibility of ADC.
Authors: Óscar Peña-Nogales; Yuxin Zhang; Xiaoke Wang; Rodrigo de Luis-Garcia; Santiago Aja-Fernández; James H Holmes; Diego Hernando Journal: Magn Reson Med Date: 2018-11-05 Impact factor: 4.668
Authors: Baxter P Rogers; Justin Blaber; Allen T Newton; Colin B Hansen; E Brian Welch; Adam W Anderson; Jeffrey J Luci; Carlo Pierpaoli; Bennett A Landman Journal: Proc SPIE Int Soc Opt Eng Date: 2018-03
Authors: Baxter P Rogers; Justin Blaber; E Brian Welch; Zhaohua Ding; Adam W Anderson; Bennett A Landman Journal: Proc SPIE Int Soc Opt Eng Date: 2017-03-09
Authors: Myung-Ho In; Ek Tsoon Tan; Joshua D Trzasko; Yunhong Shu; Daehun Kang; Uten Yarach; Shengzhen Tao; Erin M Gray; John Huston; Matt A Bernstein Journal: J Magn Reson Imaging Date: 2019-05-20 Impact factor: 4.813
Authors: Ek T Tan; Robert Y Shih; Jhimli Mitra; Tim Sprenger; Yihe Hua; Chitresh Bhushan; Matt A Bernstein; Jennifer A McNab; J Kevin DeMarco; Vincent B Ho; Thomas K F Foo Journal: Magn Reson Med Date: 2020-02-03 Impact factor: 4.668
Authors: Robert J Young; Ek T Tan; Kyung K Peck; Mehrnaz Jenabi; Sasan Karimi; Nicole Brennan; Jennifer Rubel; John Lyo; Weiji Shi; Zhigang Zhang; Marcel Prastawa; Xiaofeng Liu; Jonathan I Sperl; Robin Fatovic; Luca Marinelli; Andrei I Holodny Journal: Magn Reson Imaging Date: 2016-10-11 Impact factor: 2.546
Authors: David C Newitt; Ek T Tan; Lisa J Wilmes; Thomas L Chenevert; John Kornak; Luca Marinelli; Nola Hylton Journal: J Magn Reson Imaging Date: 2015-03-11 Impact factor: 4.813