Revealing sub-voxel motions of brain tissue using phase-based amplified MRI (aMRI)
| Autor: | Kristen W. Yeom, Mahdi Salmani Rahimi, Maged Goubran, Wendy W. Ni, Mehmet Kurt, Greg Zaharchuk, Samantha J. Holdsworth, Michael E. Moseley, Itamar Terem |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Image quality business.industry Phase (waves) Partial volume Motion detection computer.software_genre Imaging phantom Displacement (vector) 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Voxel Radiology Nuclear Medicine and imaging Computer vision Free-form deformation Artificial intelligence business computer 030217 neurology & neurosurgery |
| Zdroj: | Magnetic Resonance in Medicine. 80:2549-2559 |
| ISSN: | 0740-3194 |
| DOI: | 10.1002/mrm.27236 |
| Popis: | Purpose Amplified magnetic resonance imaging (aMRI) was recently introduced as a new brain motion detection and visualization method. The original aMRI approach used a video-processing algorithm, Eulerian video magnification (EVM), to amplify cardio-ballistic motion in retrospectively cardiac-gated MRI data. Here, we strive to improve aMRI by incorporating a phase-based motion amplification algorithm. Methods Phase-based aMRI was developed and tested for correct implementation and ability to amplify sub-voxel motions using digital phantom simulations. The image quality of phase-based aMRI was compared with EVM-based aMRI in healthy volunteers at 3T, and its amplified motion characteristics were compared with phase-contrast MRI. Data were also acquired on a patient with Chiari I malformation, and qualitative displacement maps were produced using free form deformation (FFD) of the aMRI output. Results Phantom simulations showed that phase-based aMRI has a linear dependence of amplified displacement on true displacement. Amplification was independent of temporal frequency, varying phantom intensity, Rician noise, and partial volume effect. Phase-based aMRI supported larger amplification factors than EVM-based aMRI and was less sensitive to noise and artifacts. Abnormal biomechanics were seen on FFD maps of the Chiari I malformation patient. Conclusion Phase-based aMRI might be used in the future for quantitative analysis of minute changes in brain motion and may reveal subtle physiological variations of the brain as a result of pathology using processing of the fundamental harmonic or by selectively varying temporal harmonics. Preliminary data shows the potential of phase-based aMRI to qualitatively assess abnormal biomechanics in Chiari I malformation. |
| Databáze: | OpenAIRE |
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