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- Title
Simultaneous Motion and Distortion Correction Using Dual-Echo Diffusion-Weighted MRI.
- Authors
Afacan, Onur; Hoge, W. Scott; Wallace, Tess E.; Gholipour, Ali; Kurugol, Sila; Warfield, Simon K.
- Abstract
<bold>Background and Purpose: </bold>Geometric distortions resulting from large pose changes reduce the accuracy of motion measurements and interfere with the ability to generate artifact-free information. Our goal is to develop an algorithm and pulse sequence to enable motion-compensated, geometric distortion compensated diffusion-weighted MRI, and to evaluate its efficacy in correcting for the field inhomogeneity and position changes, induced by large and frequent head motions.<bold>Methods: </bold>Dual echo planar imaging (EPI) with a blip-reversed phase encoding distortion correction technique was evaluated in five volunteers in two separate experiments and compared with static field map distortion correction. In the first experiment, dual-echo EPI images were acquired in two head positions designed to induce a large field inhomogeneity change. A field map and a distortion-free structural image were acquired at each position to assess the ability of dual-echo EPI to generate reliable field maps and enable geometric distortion correction in both positions. In the second experiment, volunteers were asked to move to multiple random positions during a diffusion scan. Images were reconstructed using the dual-echo correction and a slice-to-volume registration (SVR) registration algorithm. The accuracy of SVR motion estimates was compared to externally measured ground truth motion parameters.<bold>Results: </bold>Our results show that dual-echo EPI can produce slice-level field maps with comparable quality to field maps generated by the reference gold standard method. We also show that slice-level distortion correction improves the accuracy of SVR algorithms as slices acquired at different orientations have different levels of distortion, which can create errors in the registration process.<bold>Conclusions: </bold>Dual-echo acquisitions with blip-reversed phase encoding can be used to generate slice-level distortion-free images, which is critical for motion-robust slice to volume registration. The distortion corrected images not only result in better motion estimates, but they also enable a more accurate final diffusion image reconstruction.
- Subjects
DIFFUSION magnetic resonance imaging; MOTION; ECHO-planar imaging; PHASE coding; IMAGE reconstruction; RECORDING &; registration; DIFFUSION
- Publication
Journal of Neuroimaging, 2020, Vol 30, Issue 3, p276
- ISSN
1051-2284
- Publication type
journal article
- DOI
10.1111/jon.12708