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. 2021 Oct 25;301(2):250–262. doi: 10.1148/radiol.2021204288

Figure 7:

Free-breathing (FB) two-dimensional (2D) sequential chemical shift–encoded (CSE) MRI with centric encoding and variable flip angle (VFA) strategy is a promising technique that can mitigate respiratory motion while achieving high signal-to-noise ratio (SNR). Example proton density fat fraction (PDFF) maps using breath holding (BH) and free breathing are shown. (A) Three-dimensional (3D) multi-echo spoiled gradient-echo CSE MRI provides good SNR performance, but reliable breath holding is necessary to avoid motion-related artifacts that can occur even during breath holding (arrows). (B) Free-breathing two-dimensional CSE MRI freezes respiratory motion by using a very short temporal window, at the expense of lower SNR due to the use of low flip angles needed to avoid T1-related bias. (C) In contrast, a recently proposed variable flip angle sequential approach shows promise to avoid breathing artifacts and T1 bias while achieving high SNR performance (101).

Free-breathing (FB) two-dimensional (2D) sequential chemical shift–encoded (CSE) MRI with centric encoding and variable flip angle (VFA) strategy is a promising technique that can mitigate respiratory motion while achieving high signal-to-noise ratio (SNR). Example proton density fat fraction (PDFF) maps using breath holding (BH) and free breathing are shown. (A) Three-dimensional (3D) multi-echo spoiled gradient-echo CSE MRI provides good SNR performance, but reliable breath holding is necessary to avoid motion-related artifacts that can occur even during breath holding (arrows). (B) Free-breathing two-dimensional CSE MRI freezes respiratory motion by using a very short temporal window, at the expense of lower SNR due to the use of low flip angles needed to avoid T1-related bias. (C) In contrast, a recently proposed variable flip angle sequential approach shows promise to avoid breathing artifacts and T1 bias while achieving high SNR performance (101).