title: Interleaved T(1) and T(2) relaxation time mapping for cardiac applications.
abstract: OBJECTIVE
  To diagnose acute myocardial infarction (MI) with MRI, T(1)-weighted and T(2)-weighted images are required to detect necrosis and edema. The calculation of both T(1) and T(2) maps can be relevant for quantitative diagnosis. In this work, we present a simultaneous quantification of T(1)-T(2) relaxation times of a short-axis view of the heart in a single scan.
  
  
  METHODS
  An electrocardiograph (ECG)-triggered, navigator-gated, interleaved T(1) and T(2) mapping sequence was implemented for the quantification of the T(1) and T(2) values of phantoms, healthy volunteers, and three patients with acute MI. The proposed acquisition scheme consisted of an interleaved two-dimensional (2D) steady-state free precession (SSFP) sequence with three different modules: an inversion-recovery (IR) sequence with multiple time delays, followed by a delay of one cardiac cycle for magnetization recovery and a T(2)-preparation pulse with multiple echo-times for T(2) quantification.
  
  
  RESULTS
  Measurements of in vivo relaxation times were in good agreement with literature values. The interleaved sequence was able to measure T(1) and T(2) relaxation times of the myocardium.
  
  
  CONCLUSIONS
  The interleaved sequence acquires data for the calculation of T(1) and T(2) maps in only one scan without the need for registration. This technique has the potential to differentiate between acute and chronic MI by estimating the concentration of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in the necrotic tissue and to assess the extent of edema from T(2) maps.
authors.affiliation: King's College London, UK. Ulrike.Blume@kcl.ac.uk
authors.forename: Ulrike
authors.initials: U
authors.lastname: Blume
authors.forename: Timothy
authors.initials: T
authors.lastname: Lockie
authors.forename: Christian
authors.initials: C
authors.lastname: Stehning
authors.forename: Stephen
authors.initials: S
authors.lastname: Sinclair
authors.forename: Sergio
authors.initials: S
authors.lastname: Uribe
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
mesh_terms: D000328:Adult; D003198:Computer Simulation; D003287:Contrast Media; D004487:Edema / Q000175:diagnosis; D004562:Electrocardiography; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009336:Necrosis / Q000175:diagnosis; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA