title: Effect of number of acquisitions in diffusion tensor imaging of the pediatric brain: optimizing scan time and diagnostic experience.
abstract: OBJECTIVE
  Diffusion tensor imaging (DTI) is useful for multiple clinical applications, but its routine implementation for children may be difficult due to long scan times. This study evaluates the impact of decreasing the number of DTI acquisitions (NEX) on interpretability of pediatric brain DTI.
  
  
  METHODS
  15 children with MRI-visible neuropathologies were imaged at 3T using our motion-corrected, parallel imaging- accelerated DT-EPI technique with 3 NEX (scan time 8.25 min). Using these acquisitions, NEX = 1 (scan time 2.75 min) and NEX = 2 (scan time 5.5 min) images were simulated. Two neuroradiologists scored diffusion-weighted images (DWI), apparent diffusion coefficient (ADC), fractional anisotropy (FA), and first eigenvector color-encoded (EV) images from each NEX for perceived SNR, lesion conspicuity and clinical confidence. ROI FA/ADC and image SNR values were also compared across NEX.
  
  
  RESULTS
  NEX = 2 perceived SNR, lesion conspicuity, and clinical confidence were not inferior to NEX = 3 images. NEX = 1 images showed comparable lesion conspicuity and clinical confidence as NEX = 3, but inferior perceived SNR. FA and ADC ROI measurements demonstrated no significant difference across NEX. The greatest SNR increase was seen between NEX = 1 and NEX = 2.
  
  
  CONCLUSIONS
  Reducing NEX to shorten imaging time may impact clinical utility in a manner that does not directly correspond with SNR changes.
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA.
authors.forename: Salil
authors.initials: S
authors.lastname: Soman
authors.affiliation: Department of Radiology, Lucas Center, Stanford University, Stanford, CA.
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Holdsworth
authors.affiliation: Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Skare
authors.affiliation: University of Washington, Radiology, Seattle, WA.
authors.forename: Jalal B
authors.initials: JB
authors.lastname: Andre
authors.affiliation: Department of Radiology, Lucas Center, Stanford University, Stanford, CA.
authors.forename: Anh T
authors.initials: AT
authors.lastname: Van
authors.affiliation: Department of Radiology, Lucas Center, Stanford University, Stanford, CA.
authors.forename: Murat
authors.initials: M
authors.lastname: Aksoy
authors.affiliation: Department of Radiology, Lucas Center, Stanford University, Stanford, CA.
authors.forename: Roland
authors.initials: R
authors.lastname: Bammer
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA.
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Barnes
authors.affiliation: Department of Radiology, Stanford University, Stanford, CA.
authors.forename: Kristen W
authors.initials: KW
authors.lastname: Yeom
mesh_terms: D000293:Adolescent; D016477:Artifacts; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002983:Clinical Competence; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D016526:Workload
keywords: DTI; MRI acquisition time; Pediatric brain; SNR