title: Quick water-selective excitation of fast relaxing tissues with 3D UTE sequences.
abstract: OBJECTIVE
  The aim of this study was to implement a time effective 1-1 double pulse water-selective excitation (WE) into a three-dimensional ultrashort echo time (UTE) sequence (WE-UTE) for visualization of short-T2 tissues with positive contrast and sufficient suppression of surrounding fat.
  
  
  METHODS
  First, an analytical description of magnetization components in the steady state applying WE-UTE was derived and results were compared with numerical simulations based on Bloch's equations. Parameters were optimized for best positive contrast between short-T2 tissues and fat under consideration of variable relaxation properties over a broad range. Maximal signal yield and signal efficiency of on-resonant protons were compared with UTE sequences with and without off-resonance fat saturation (FatSat). WE-UTE was exemplarily applied for in-vivo musculoskeletal imaging on a 3T whole-body MR unit.
  
  
  RESULTS
  Steady state magnetization of WE-UTE could be described analytically and showed excellent accordance with numerical simulations. Even for tissues with T2 = 1 ms WE-UTE resulted in 79% of maximal signal yield of UTE without FatSat and was more efficient regarding signal yield if compared with UTE with FatSat. Using WE-UTE in-vivo tendons and ligaments could be well delineated with positive contrast to surrounding fat.
  
  
  CONCLUSIONS
  WE-UTE provides a quick method for visualizing short-T2 tissues with positive contrast.
authors: Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Germany; Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Germany.
authors: Fabian
authors: F
authors: Springer
authors: Günter
authors: G
authors: Steidle
authors: Petros
authors: P
authors: Martirosian
authors: Ulrich
authors: U
authors: Grosse
authors: Roland
authors: R
authors: Syha
authors: Christoph
authors: C
authors: Schabel
authors: Claus D
authors: CD
authors: Claussen
authors: Fritz
authors: F
authors: Schick
mesh_terms: D017352:Echo-Planar Imaging / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D013710:Tendons / Q000033:anatomy & histology