An efficient fat suppression technique for stimulated-echo based CMR

Abstract

Background 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. Methods The developed method is based on saturating the fat magnetization prior to applying the STEAM modulation; therefore, only the water-content of the tissues is modulated by the sequence, resulting in fat-suppressed images without the need to run the fat suppression module during image acquisition (Figure 1). The potential significance of the proposed method has been tested in two STEAM-based cardiac MRI applications: complementary spatial-modulation of magnetization (CSPAMM) tagging, and black-blood cine imaging. In vivo experiments were conducted to evaluate the developed technique and compare it to the commonly implemented chemical-shift selective (CHESS)