Temporal DeltaB0 and relaxation in the rat heart

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

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 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.

CONCLUSION

These results suggest that the 4-echo methods are best suited for measuring variations in transverse relaxation values in the mid-ventricular septum.