Improved in vivo measurement of myocardial transverse relaxation with 3 Tesla magnetic resonance imaging.
OBJECTIVE
To develop practical methods at 3 Tesla (T) for measuring myocardial transverse relaxation in normal human myocardium.


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 T(2) 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. T(2) 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 T(2) 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.


CONCLUSIONS
These results suggest that the 4-echo methods are best suited for measuring variations in transverse relaxation values in the mid-ventricular septum.
Cobb
Jared Guthrie
JG
Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, USA. jared.g.cobb@vanderbilt.edu
Paschal
Cynthia B
CB
D000328:Adult; D000704:Analysis of Variance; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D019047:Phantoms, Imaging; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors