Myocardial T1 and T2 mapping at 3T: reference values, influencing factors and implications.

Florian Von Knobelsdorff-Brenkenhoff,Thoralf Niendorf,Matthias A Dieringer,Andreas Greiser,Ralf Wassmuth,Jeanette Schulz-Menger,Marcel Prothmann,Carsten Schwenke

doi:10.1186/1532-429x-15-53

Abstract

BackgroundMyocardial T1 and T2 mapping using cardiovascular magnetic resonance (CMR) are promising to improve tissue characterization and early disease detection. This study aimed at analyzing the feasibility of T1 and T2 mapping at 3 T and providing reference values.MethodsSixty healthy volunteers (30 males/females, each 20 from 20–39 years, 40–59 years, 60–80 years) underwent left-ventricular T1 and T2 mapping in 3 short-axis slices at 3 T. For T2 mapping, 3 single-shot steady-state free precession (SSFP) images with different T2 preparation times were acquired. For T1 mapping, modified Look-Locker inversion recovery technique with 11 single shot SSFP images was used before and after injection of gadolinium contrast. T1 and T2 relaxation times were quantified for each slice and each myocardial segment.ResultsMean T2 and T1 (pre-/post-contrast) times were: 44.1 ms/1157.1 ms/427.3 ms (base), 45.1 ms/1158.7 ms/411.2 ms (middle), 46.9 ms/1180.6 ms/399.7 ms (apex). T2 and pre-contrast T1 increased from base to apex, post-contrast T1 decreased. Relevant inter-subject variability was apparent (scatter factor 1.08/1.05/1.11 for T2/pre-contrast T1/post-contrast T1). T2 and post-contrast T1 were influenced by heart rate (p < 0.0001, p = 0.0020), pre-contrast T1 by age (p < 0.0001). Inter- and intra-observer agreement of T2 (r = 0.95; r = 0.95) and T1 (r = 0.91; r = 0.93) were high. T2 maps: 97.7% of all segments were diagnostic and 2.3% were excluded (susceptibility artifact). T1 maps (pre-/post-contrast): 91.6%/93.9% were diagnostic, 8.4%/6.1% were excluded (predominantly susceptibility artifact 7.7%/3.2%).ConclusionsMyocardial T2 and T1 reference values for the specific CMR setting are provided. The diagnostic impact of the high inter-subject variability of T2 and T1 relaxation times requires further investigation.

Highlights

Myocardial T1 and T2 mapping using cardiovascular magnetic resonance (CMR) are promising to improve tissue characterization and early disease detection
This study examined myocardial T1 and T2 mapping techniques at 3 T in a large sample of healthy volunteers
The main findings are: i) T2 and T1 mapping achieve a high grade of diagnostic image quality, susceptibility artifacts entailed the exclusion of a limited number of myocardial segments from the analysis. ii) Observer dependency of T2 and T1 relaxation time quantification was low. iii) Mean values and 95% tolerance interval of myocardial T2 and T1 relaxation times are presented per slice and per segment and can be used as reference values specific for this MR setting. iii) An inter-subject distribution of T2 and T1 values became apparent and may constitute a limitation to define appropriate cut-offs

Summary

Introduction

Myocardial T1 and T2 mapping using cardiovascular magnetic resonance (CMR) are promising to improve tissue characterization and early disease detection. This study aimed at analyzing the feasibility of T1 and T2 mapping at 3 T and providing reference values. Cardiovascular magnetic resonance (CMR) provides techniques for non-invasive myocardial tissue characterization. T1 and T2 mapping of the left ventricular myocardium, i.e. quantification of the myocardial T1 and T2 relaxation times, as well as the T1-derived extracellular volume fraction have been demonstrated to add valuable information [1,2,3,4,5,6].

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