title: Reproducibility of three different cardiac T2-mapping sequences at 1.5T.
abstract: To elucidate the impact of technical and intraindividual reproducibility on the overall variability of myocardial T2relaxation times.
  
  
  
  Thirty healthy volunteers were examined three times (day 1 morning/evening, evening after 2-3 weeks) at 1.5T. During each examination three different T2-mapping sequences were acquired twice at three slices in short axis view: multi-echo-spin-echo (MESE), T2-prepared balanced steady-state free precession (SSFP) (T2prep), and gradient-spin-echo with and without fat saturation (GraSE/GraSEFS). Repeated measurements were performed for T2prep and GraSE. Segmented T2-maps were generated for each slice according to the American Heart Association (AHA) 16-segment model.
  
  
  
  The coefficients of variation and intraclass correlation coefficients for intraobserver variability were: 1.3% and 0.89 for T2prep, 1.5% and 0.93 for GraSE, 3.1% and 0.83 for MESE; and for interobserver variability: 3.3% and 0.66 for T2prep, 2.0% and 0.83 for GraSE, 3.6% and 0.77 for MESE. No systematic difference of T2times was observed due to diurnal effects and on long-term analysis using one-way analysis of variance (ANOVA) with Tukey-type multiple comparisons (morning vs. evening scan for T2prep: 52.5 ± 2.4 vs. 51.7 ± 2.7 msec, P = 0.119; for GraSE: 58.6 ± 4.0 vs. 58.5 ± 3.8 msec, P = 0.984; for GraSEFS57.1 ± 3.2 vs. 57.2 ± 3.9 msec, P = 0.998, and for MESE: 53.8 ± 2.7 vs. 53.3 ± 3.3 msec, P = 0.541; scans between weeks for T2prep: 51.7 ± 2.7 vs. 51.4 ± 2.4 msec, P = 0.873; for GraSE: 58.5 ± 3.8 vs. 58.1 ± 3.4 msec, P = 0.736; for GraSEFS: 57.2 ± 3.9 vs. 57.0 ± 4.6 msec, P = 0.964, and for MESE: 53.3 ± 3.3 vs. 53.4 ± 2.4 msec, P = 0.970). ANOVA components, however, demonstrated a greater variance of T2times over multiple timepoints than for repeated measurements within the same scan (variance components of the model fit for intraday variance vs. repeated measurements: T2prep 2.22 vs. 1.36, GraSE 3.76 vs. 2.09, GraSEFS3.96 vs. 1.58, MESE 1.86; and for interweeks variance vs. repeated measurements: T2prep 2.21 vs. 0.80, GraSE 3.20 vs. 2.10, GraSEFS8.82 vs. 1.18, and MESE 4.49).
  
  
  
  Technical reproducibility and intra- and interobserver agreement of myocardial T2relaxation times are excellent and intraindividual variation over time is small. Therefore, we consider subject-related factors to explain most of the interindividual variability of myocardial T2times reported in previous studies. The acknowledgment of this subject-related, biological variability may be important for the future diagnostic value of T2-mapping. J. Magn. Reson. Imaging 2016;44:1168-1178.
authors.affiliation: Department of Radiology, University Hospital of Cologne, Germany. bettina.baessler@uk-koeln.de.
authors.forename: Bettina
authors.initials: B
authors.lastname: Baeßler
authors.affiliation: Institute of Biostatistics, Faculty of Natural Sciences, Leibniz Universität Hannover, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schaarschmidt
authors.affiliation: Philips Research, Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Stehning
authors.affiliation: Philips, Healthcare Germany, Hamburg, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnackenburg
authors.affiliation: Department of Radiology, University Hospital of Cologne, Germany.
authors.forename: Agathe
authors.initials: A
authors.lastname: Giolda
authors.affiliation: Department of Radiology, University Hospital of Cologne, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Maintz
authors.affiliation: Department of Radiology, University Hospital of Cologne, Germany.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Bunck
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D057791:Cardiac Imaging Techniques / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: cardiac T2-mapping; cardiovascular magnetic resonance; reproducibility