title: Effects of MRI scan acceleration on brain volume measurement consistency.
abstract: OBJECTIVE
  To evaluate the effects of recent advances in magnetic resonance imaging (MRI) radiofrequency (RF) coil and parallel imaging technology on brain volume measurement consistency.
  
  
  METHODS
  In all, 103 whole-brain MRI volumes were acquired at a clinical 3T MRI, equipped with a 12- and 32-channel head coil, using the T1-weighted protocol as employed in the Alzheimer's Disease Neuroimaging Initiative study with parallel imaging accelerations ranging from 1 to 5. An experienced reader performed qualitative ratings of the images. For quantitative analysis, differences in composite width (CW, a measure of image similarity) and boundary shift integral (BSI, a measure of whole-brain atrophy) were calculated.
  
  
  RESULTS
  Intra- and intersession comparisons of CW and BSI measures from scans with equal acceleration demonstrated excellent scan-rescan accuracy, even at the highest acceleration applied. Pairs-of-scans acquired with different accelerations exhibited poor scan-rescan consistency only when differences in the acceleration factor were maximized. A change in the coil hardware between compared scans was found to bias the BSI measure.
  
  
  CONCLUSIONS
  The most important findings are that the accelerated acquisitions appear to be compatible with the assessment of high-quality quantitative information and that for highest scan-rescan accuracy in serial scans the acquisition protocol should be kept as consistent as possible over time.
authors.affiliation: Siemens Schweiz AG, Healthcare Sector IM&WS, Renens, Switzerland. gunnar.krueger@siemens.com
authors.forename: Gunnar
authors.initials: G
authors.lastname: Krueger
authors.forename: Cristina
authors.initials: C
authors.lastname: Granziera
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Gunter
authors.forename: Arne
authors.initials: A
authors.lastname: Littmann
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Mortamet
authors.forename: Stephan
authors.initials: S
authors.lastname: Kannengiesser
authors.forename: Alma Gregory
authors.initials: AG
authors.lastname: Sorensen
authors.forename: Chadwick P
authors.initials: CP
authors.lastname: Ward
authors.forename: Denise A
authors.initials: DA
authors.lastname: Reyes
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Britson
authors.forename: Hubertus
authors.initials: H
authors.lastname: Fischer
authors.forename: Matt A
authors.initials: MA
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D009929:Organ Size / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity