Reproducibility of three different cardiac T2 -mapping sequences at 1.5T

J Magn Reson Imaging. 2016 Nov;44(5):1168-1178. doi: 10.1002/jmri.25258. Epub 2016 Apr 4.

Abstract

Purpose: To elucidate the impact of technical and intraindividual reproducibility on the overall variability of myocardial T2 relaxation times.

Materials and methods: 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) (T2 prep), and gradient-spin-echo with and without fat saturation (GraSE/GraSEFS ). Repeated measurements were performed for T2 prep and GraSE. Segmented T2 -maps were generated for each slice according to the American Heart Association (AHA) 16-segment model.

Results: The coefficients of variation and intraclass correlation coefficients for intraobserver variability were: 1.3% and 0.89 for T2 prep, 1.5% and 0.93 for GraSE, 3.1% and 0.83 for MESE; and for interobserver variability: 3.3% and 0.66 for T2 prep, 2.0% and 0.83 for GraSE, 3.6% and 0.77 for MESE. No systematic difference of T2 times 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 T2 prep: 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 GraSEFS 57.1 ± 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 T2 prep: 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 T2 times over multiple timepoints than for repeated measurements within the same scan (variance components of the model fit for intraday variance vs. repeated measurements: T2 prep 2.22 vs. 1.36, GraSE 3.76 vs. 2.09, GraSEFS 3.96 vs. 1.58, MESE 1.86; and for interweeks variance vs. repeated measurements: T2 prep 2.21 vs. 0.80, GraSE 3.20 vs. 2.10, GraSEFS 8.82 vs. 1.18, and MESE 4.49).

Conclusion: Technical reproducibility and intra- and interobserver agreement of myocardial T2 relaxation 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 T2 times 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.

Keywords: cardiac T2-mapping; cardiovascular magnetic resonance; reproducibility.

MeSH terms

  • Adult
  • Aged
  • Algorithms*
  • Cardiac Imaging Techniques / methods*
  • Computer Simulation
  • Female
  • Heart Ventricles / anatomy & histology*
  • Heart Ventricles / diagnostic imaging*
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods*
  • Magnetic Resonance Imaging, Cine / methods*
  • Male
  • Middle Aged
  • Models, Biological
  • Models, Statistical
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Signal Processing, Computer-Assisted*
  • Young Adult