title: Assessing the effects of subject motion on T2relaxation under spin tagging (TRUST) cerebral oxygenation measurements using volume navigators.
abstract: OBJECTIVE
  Subject motion may cause errors in estimates of blood T2when using the T2-relaxation under spin tagging (TRUST) technique on noncompliant subjects like neonates. By incorporating 3D volume navigators (vNavs) into the TRUST pulse sequence, independent measurements of motion during scanning permit evaluation of these errors.
  
  
  METHODS
  The effects of integrated vNavs on TRUST-based T2estimates were evaluated using simulations and in vivo subject data. Two subjects were scanned with the TRUST+vNav sequence during prescribed movements. Mean motion scores were derived from vNavs and TRUST images, along with a metric of exponential fit quality. Regression analysis was performed between T2estimates and mean motion scores. Also, motion scores were determined from independent neonatal scans.
  
  
  RESULTS
  vNavs negligibly affected venous blood T2estimates and better detected subject motion than fit quality metrics. Regression analysis showed that T2is biased upward by 4.1 ms per 1 mm of mean motion score. During neonatal scans, mean motion scores of 0.6 to 2.0 mm were detected.
  
  
  CONCLUSIONS
  Motion during TRUST causes an overestimate of T2, which suggests a cautious approach when comparing TRUST-based cerebral oxygenation measurements of noncompliant subjects. Magn Reson Med 78:2283-2289, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Harvard-MIT Health Sciences and Technology, Institute for Medical Engineering & Science, MIT, Cambridge, Massachusetts, USA.
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Stout
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA.|Radiology, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: M Dylan
authors.initials: MD
authors.lastname: Tisdall
authors.affiliation: Department of Electrical Engineering and Computer Science, MIT, Cambridge, Massachusetts, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: McDaniel
authors.affiliation: Department of Radiology, Boston Children's Hospital, Boston, Massachusetts, USA.
authors.forename: Borjan
authors.initials: B
authors.lastname: Gagoski
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Divya S
authors.initials: DS
authors.lastname: Bolar
authors.affiliation: Department of Radiology, Boston Children's Hospital, Boston, Massachusetts, USA.|Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA.
authors.forename: Patricia Ellen
authors.initials: PE
authors.lastname: Grant
authors.affiliation: Harvard-MIT Health Sciences and Technology, Institute for Medical Engineering & Science, MIT, Cambridge, Massachusetts, USA.|Department of Electrical Engineering and Computer Science, MIT, Cambridge, Massachusetts, USA.
authors.forename: Elfar
authors.initials: E
authors.lastname: Adalsteinsson
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D015233:Models, Statistical; D009038:Motion; D010092:Oximetry; D010100:Oxygen / Q000737:chemistry*; D012044:Regression Analysis; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: T2 relaxation; blood oxygen saturation; motion; volume navigators; TRUST