title: Paired self-compensated spin-lock preparation for improved T1ρ quantification.
abstract: Spin-lock (SL) imaging allows quantification of the spin-lattice relaxation time in the rotating frame (T1ρ). B0 and B1 inhomogeneities impact T1ρ quantification because the preparatory block in SL imaging is sensitive to the field heterogeneities. Here, a modified preparatory block (PSC-SL) is proposed that attempts to alleviate SL sensitivity to field inhomogeneities in scenarios where existing approaches fail, i.e. high SL frequencies.
  
  
  
  Computer simulations, phantom and in vivo experiments were used to determine the effect of field inhomogeneities on T1ρ quantification. Existing SL preparations were compared with PSC-SL in different conditions to assess the advantages and disadvantages of each method.
  
  
  
  Phantom experiments and computer modeling demonstrate that PSC-SL provides superior T1ρ quantification at high SL frequencies in situations where the existing SL preparation methods fail. This result has been confirmed in pre-clinical neuro and body imaging at 7T.
  
  
  
  PSC-SL complements existing methods by increasing the accuracy of T1ρ quantification at high spin-lock frequencies when large field inhomogeneities are present. A-priory information about the experimental conditions such, as field distribution and spinlock frequency are useful for selecting an appropriate spin-lock preparation for specific applications.
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Bogdan G
authors.initials: BG
authors.lastname: Mitrea
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Axel J
authors.initials: AJ
authors.lastname: Krafft
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Ruitian
authors.initials: R
authors.lastname: Song
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Ralf B
authors.initials: RB
authors.lastname: Loeffler
authors.affiliation: Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA. Electronic address: claudia.hillenbrand@stjude.org.
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Hillenbrand
mesh_terms: D000465:Algorithms; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Quantitative MRI; Spin-lock; T(1)(ρ)