title: Simultaneous dual contrast weighting using double echo rapid acquisition with relaxation enhancement (RARE) imaging.
abstract: OBJECTIVE
  This work proposes a dual contrast rapid acquisition with relaxation enhancement (RARE) variant (2in1-RARE), which provides simultaneous proton density (PD) and T2 * contrast in a single acquisition.
  
  
  METHODS
  The underlying concept of 2in1-RARE is the strict separation of spin echoes and stimulated echoes. This approach offers independent weighting of spin echoes and stimulated echoes. 2in1-RARE was evaluated in phantoms including signal-to-noise ratio (SNR) and point spread function assessment. 2in1-RARE was benchmarked versus coherent RARE and a split-echo RARE variant. The applicability of 2in1-RARE for brain imaging was demonstrated in a small cohort of healthy subjects (n = 10) and, exemplary, a multiple sclerosis patient at 3 Tesla as a precursor to a broader clinical study.
  
  
  RESULTS
  2in1-RARE enables the simultaneous acquisition of dual contrast weighted images without any significant image degradation and without sacrificing SNR versus split-echo RARE. This translates into a factor of two speed gain over multi-contrast, sequential split-echo RARE. A 15% broadening of the point spread function was observed in 2in1-RARE. T1 relaxation effects during the mixing time can be neglected for brain tissue.
  
  
  CONCLUSIONS
  2in1-RARE offers simultaneous acquisition of images of anatomical (PD) and functional (T2 *) contrast. It presents an alternative to address scan time constraints frequently encountered during sequential acquisition of T2 * or PD-weighted RARE.
authors.affiliation: Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Fuchs
authors.forename: Fabian
authors.initials: F
authors.lastname: Hezel
authors.forename: Sabrina
authors.initials: S
authors.lastname: Klix
authors.forename: Ralf
authors.initials: R
authors.lastname: Mekle
authors.forename: Jens
authors.initials: J
authors.lastname: Wuerfel
authors.forename: Thoralf
authors.initials: T
authors.lastname: Niendorf
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000473:pathology*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio
keywords: dual contrast; fast imaging; magnetic resonance imaging; spin echo; stimulated echo; susceptibility