title: Density weighted turbo spin echo imaging.
abstract: OBJECTIVE
  To optimize the spatial response function (SRF) while maintaining optimal signal to noise ratio (SNR) in T2 weighted turbo spin echo (TSE) imaging by prospective density weighting.
  
  
  METHODS
  Density weighting optimizes the SRF by sampling the k-space with variable density without the need of retrospective filtering, which would typically result in nonoptimal SNR. For TSE, the T2 decay needs to be considered when calculating an optimized sampling pattern. Simulations were carried out and T2 weighted in vivo TSE measurements were performed on a 3 Tesla MRI system. To evaluate the SNR, reversed centric density weighted and retrospectively filtered Cartesian acquisitions with identical measurement parameters and SRFs were compared with TE(eff) = 90 ms and a density weighted k-space sampling optimized to yield a Kaiser function for SRF side lobe suppression for white matter.
  
  
  RESULTS
  Density weighting of a reversed centric reordering scheme resulted in an SNR increase of (43 ± 13)% compared with the Cartesian acquisition with retrospective filtering while maintaining comparable contrast behavior.
  
  
  CONCLUSIONS
  Density weighting is applicable to TSE imaging and results in significantly increased SNR. The gain can be used to shorten the measurement time, which suggests applying density weighting in both time and SNR constrained MRI.
authors: Institute of Radiology, University Clinic, University of Würzburg, Würzburg, Germany. zeller@roentgen.uni-wuerzburg.de
authors: Mario
authors: M
authors: Zeller
authors: Marcel
authors: M
authors: Gutberlet
authors: Daniel
authors: D
authors: Stäb
authors: Christian Oliver
authors: CO
authors: Ritter
authors: Meinrad
authors: M
authors: Beer
authors: Dietbert
authors: D
authors: Hahn
authors: Herbert
authors: H
authors: Köstler
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D003198:Computer Simulation; D017352:Echo-Planar Imaging / Q000379:methods*; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio