An efficient fat suppression technique for stimulated-echo based CMR
© Fahmy et al. 2016
Published: 27 January 2016
Stimulated-echo acquisition mode (STEAM) is one of the key pulse sequences in CMR imaging, as it alleviates rapid magnetization decay with T2 relaxation. Fat suppression is frequently implemented in cardiac imaging to improve visualization and tissue characterization, albeit at the cost of reduced temporal resolution and signal-to-noise ratio (SNR), as well as possible increase of specific absorption rate (SAR). The purpose of this work is to develop an efficient fat suppression method (Spectrally-Presaturated Modulation (SPM)) for STEAM sequences to enable imaging at high temporal-resolution, with high SNR, and no increase in scan time.
The results from the in vivo experiments showed superior performance of the proposed SPM method compared to the CHESS and SSSP techniques (Figure 2). The SPM technique provided the highest temporal resolution and SNR, as well as reduced SAR, among the studied fat suppression techniques. Moreover, the SNR did not drop with time as it did in the SSSP and CHESS techniques. The SPM technique allowed for acquiring 40 cardiac phases compared to 19 and 28 phases for the CHESS and SSSP techniques, respectively. The resulting SAR level was 0.2, 0.37, and 0.15 W/kg for the SPM, CHESS, and SSSP techniques, respectively. It can be seen that the CHESS technique suppressed the myocardial signal along with the fat signal, which could be attributed to magnetic field inhomogeneity around the heart. Although the same shimming settings were used for the SPM technique, it did not show such an artifact.
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