title: Improved measurement of brain deformation during mild head acceleration using a novel tagged MRI sequence.
abstract: In vivo measurements of human brain deformation during mild acceleration are needed to help validate computational models of traumatic brain injury and to understand the factors that govern the mechanical response of the brain. Tagged magnetic resonance imaging is a powerful, noninvasive technique to track tissue motion in vivo which has been used to quantify brain deformation in live human subjects. However, these prior studies required from 72 to 144 head rotations to generate deformation data for a single image slice, precluding its use to investigate the entire brain in a single subject. Here, a novel method is introduced that significantly reduces temporal variability in the acquisition and improves the accuracy of displacement estimates. Optimization of the acquisition parameters in a gelatin phantom and three human subjects leads to a reduction in the number of rotations from 72 to 144 to as few as 8 for a single image slice. The ability to estimate accurate, well-resolved, fields of displacement and strain in far fewer repetitions will enable comprehensive studies of acceleration-induced deformation throughout the human brain in vivo.
authors.affiliation: Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, Bethesda, MD, USA. Electronic address: andrew.knutsen@nih.gov.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Knutsen
authors.affiliation: Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, Bethesda, MD, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Magrath
authors.affiliation: Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, Bethesda, MD, USA.
authors.forename: Julie E
authors.initials: JE
authors.lastname: McEntee
authors.affiliation: Department of Electrical and Computing Engineering, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Fangxu
authors.initials: F
authors.lastname: Xing
authors.affiliation: Department of Electrical and Computing Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Prince
authors.affiliation: Department of Mechanical Engineering and Materials Science, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University, St. Louis, MO, USA.
authors.forename: Philip V
authors.initials: PV
authors.lastname: Bayly
authors.affiliation: Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, Bethesda, MD, USA; Radiology and Imaging Sciences, Department of Diagnostic Radiology, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Butman
authors.affiliation: Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, Bethesda, MD, USA.
authors.forename: Dzung L
authors.initials: DL
authors.lastname: Pham
mesh_terms: D000054:Acceleration; D000328:Adult; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology; D003198:Computer Simulation; D005260:Female; D006257:Head / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012399:Rotation
keywords: Acceleration; Deformation; Magnetic resonance imaging (MRI); Strain; Traumatic brain injury (TBI)