title: Targeted radiofrequency field mapping using 3D reduced field-of-view-catalyzed double-angle method.
abstract: OBJECTIVE
  The aim of this study was to develop a targeted volumetric radiofrequency field (B(1)(+)) mapping technique to provide region-of-interest B(1)(+) information.
  
  
  METHODS
  Targeted B(1)(+) maps were acquired using three-dimensional (3D) reduced field-of-view (FOV) inner-volume turbo spin echo-catalyzed double-angle method (DAM). Targeted B(1)(+) maps were compared with full-FOV B(1)(+) maps acquired using 3D catalyzed DAM in a phantom and in the brain of a healthy volunteer. In addition, targeted volumetric abdomeninal B(1)(+) mapping was demonstrated in the abdomen of another healthy volunteer.
  
  
  RESULTS
  The targeted reduced-FOV images demonstrated no aliasing artifacts in all experiments. Close match between targeted B(1)(+) map and reference full-FOV B(1)(+) map in the same region was observed, with percentage root-mean-squared error <0.4% in the phantom and <0.8% in the healthy volunteer brain. The abdominal B(1)(+) maps showed small B(1)(+) variation in the kidneys and liver from the healthy volunteer.
  
  
  CONCLUSIONS
  The proposed 3D reduced-FOV catalyzed DAM provides a rapid, simple and accurate method for targeted volumetric B(1)(+) mapping and can be easily implemented for applications related to radiofrequency field mapping in small targeted regions.
authors.affiliation: Siemens Medical Solutions USA, Inc., Minneapolis, MN 55455, USA. dingxin.wang@siemens.com
authors.forename: Dingxin
authors.initials: D
authors.lastname: Wang
authors.forename: Sven
authors.initials: S
authors.lastname: Zuehlsdorff
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
mesh_terms: D016477:Artifacts; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007668:Kidney / Q000473:pathology; D008099:Liver / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011846:Radio Waves; D015203:Reproducibility of Results