Comparative study of FAST gradient echo MRI sequences: Phantom study

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Abstract
Purpose: To investigate a balanced steady state free precession sequence (b‐SSFP) under a large range of conditions and to compare its performance with other types of gradient echo sequences for dynamic imaging.Materials and Methods: Balanced turbo field echo (b‐TFE; Philips Medical Systems, Best, The Netherlands) was investigated in vitro at a range of T2/T1 along with T1‐contrast enhanced turbo field echo (T1‐TFE) and turbo field echo (TFE) so that a comparison could be made. Performance was quantified in terms of the initial slope of the signal‐to‐noise ratio (SNR) vs. 1/T1 curve (sensitivity) and the range of 1/T1 before signal saturation (contrast dynamic range [CDR]).Results: The b‐TFE sequence was found to best perform, in terms of an optimal CDR, with a 90° flip angle (FA), saturation preparation, and short inversion time. Using these parameters, the sensitivity was also higher than that of the TFE sequence and T1‐TFE sequence under their respective optimal conditions. For detection of small changes in contrast agent concentration (0.0–0.1 mM), b‐TFE was also found to be the sequence of choice, with optimized parameters as follows, 90° FA, shortest TR/TE, and no magnetization preparation. The smallest matrices gave the highest signal sensitivity for all three sequences.Conclusion: The CDR of b‐TFE was much narrower than that of T1‐TFE but could be widened under optimized conditions. The sensitivity of the b‐TFE technique was the highest of the three sequences under all conditions tested. J. Magn. Reson. Imaging 2004;20:1030–1038.