title: Evaluation of dual-source parallel RF excitation for diffusion-weighted whole-body MR imaging with background body signal suppression at 3.0 T.
abstract: OBJECTIVE
  To evaluate the use of dual-source parallel RF excitation (TX) for diffusion-weighted whole-body MRI with background body signal suppression (DWIBS) at 3.0 T.
  
  
  METHODS
  Forty consecutive patients were examined on a clinical 3.0-T MRI system using a diffusion-weighted (DW) spin-echo echo-planar imaging sequence with a combination of short TI inversion recovery and slice-selective gradient reversal fat suppression. DWIBS of the neck (n=5), thorax (n=8), abdomen (n=6) and pelvis (n=21) was performed both with TX (2:56 min) and with standard single-source RF excitation (4:37 min). The quality of DW images and reconstructed inverted maximum intensity projections was visually judged by two readers (blinded to acquisition technique). Signal homogeneity and fat suppression were scored as "improved", "equal", "worse" or "ambiguous". Moreover, the apparent diffusion coefficient (ADC) values were measured in muscles, urinary bladder, lymph nodes and lesions.
  
  
  RESULTS
  By the use of TX, signal homogeneity was "improved" in 25/40 and "equal" in 15/40 cases. Fat suppression was "improved" in 17/40 and "equal" in 23/40 cases. These improvements were statistically significant (p<0.001, Wilcoxon signed-rank test). In five patients, fluid-related dielectric shading was present, which improved remarkably. The ADC values did not significantly differ for the two RF excitation methods (p=0.630 over all data, pairwise Student's t-test).
  
  
  CONCLUSIONS
  Dual-source parallel RF excitation improved image quality of DWIBS at 3.0 T with respect to signal homogeneity and fat suppression, reduced scan time by approximately one-third, and did not influence the measured ADC values.
authors.affiliation: Department of Radiology, University of Bonn, Germany. petra.muertz@ukb.uni-bonn.de
authors.forename: Petra
authors.initials: P
authors.lastname: Mürtz
authors.forename: Marius
authors.initials: M
authors.lastname: Kaschner
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
authors.forename: Guido M
authors.initials: GM
authors.lastname: Kukuk
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Büdenbender
authors.forename: Dirk
authors.initials: D
authors.lastname: Skowasch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.forename: Winfried A
authors.initials: WA
authors.lastname: Willinek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult