title: Scan time minimization in hepatic diffusion-weighted imaging: evaluation of the simultaneous multislice acceleration technique with different acceleration factors and gradient preparation schemes.
abstract: OBJECTIVE
  To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences.
  
  
  METHODS
  Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5 = excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test. Bland-Altman plots were calculated for ADC comparison. p values <0.05 were considered significant.
  
  
  RESULTS
  Sms2-DWI offered scan time minimization of 67 % without significant difference in image quality (sum score: sms2-DWI MP/BP: 97 ± 8/92 ± 9; c-DWI MP/BP: 99 ± 8/97 ± 8). Sms3-DWI offered slight additional scan time minimization with significantly inferior image quality (sum score: sms3-DWI MP/BP: 75 ± 14/69 ± 14; p < 0.001). MP preparation provided slightly higher image quality in sms-DWI without statistical significance. ADC in sms-DWI were significantly lower (sms2-DWI MP 1.01 × 10(-3) mm(2)/s; c-DWI MP 1.20 × 10(-3) mm(2)/s; p < 0.001).
  
  
  CONCLUSIONS
  Sms2-DWI provides considerable scan time minimization without significant shortcomings in image quality. Sms3-DWI provides significantly inferior image quality without further scan time minimization. Potentially lower ADC in sms-DWI should be considered in clinical routine.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Taron
authors.affiliation: Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Petros
authors.initials: P
authors.lastname: Martirosian
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Nina F
authors.initials: NF
authors.lastname: Schwenzer
authors.affiliation: Department of Biomedical Magnetic Resonance, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Erb
authors.affiliation: Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kuestner
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Weiß
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Othman
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Mike
authors.initials: M
authors.lastname: Notohamiprodjo
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany. christina.schraml@med.uni-tuebingen.de.
authors.forename: Christina
authors.initials: C
authors.lastname: Schraml
mesh_terms: D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D015203:Reproducibility of Results; D013997:Time Factors
keywords: Bipolar; Diffusion-weighted imaging; Liver; Monopolar; Scan time minimization; Simultaneous multislice