Improved in vivo measurement of myocardial transverse relaxation with 3 Tesla magnetic resonance imaging

Abstract

Purpose: To develop practical methods at 3 Tesla (T) for measuring myocardial transverse relaxation in normal human myocardium. Materials and Methods: Ten healthy volunteers were investigated with four multi-echo, turbo spin-echo (TSE) methods. Each method traded acquired phase encoding lines per image for echo-image sample points obtained along the T2 decay curve. Four multi-echo turbo field-echo (TFE) methods were also tested. The TFE methods highlighted differences between achievable receiver bandwidth and echo time constraints versus the number of sample points obtained along the T*2 decay curve. Results: Measured transverse relaxation values were consistent in reported means across all scan methods. T2 for the ventricular septum was measured as 58.8 ± 7.7 ms (N = 10). T*2 for the ventricular septum was 31.6 ± 5.8 ms (N = 10). The variation of mean T2 or T*2 within an region of interest improved significantly with increases in acquired echoes. Therefore, four or more echoes may provide for clear distinctions between regions of altered tissue composition within a subject. Conclusion: These results suggest that the 4-echo methods are best suited for measuring variations in transverse relaxation values in the mid-ventricular septum. © 2009 Wiley-Liss, Inc.