In this work, we aimed to develop and evaluate multi-band outer volume suppression pulses for increased acceleration rates in simultaneous multi-slice accelerated cardiac MRI. MB-OVS pulses were constructed from a multi-band combination of two slab-selective saturation pulses and tested for various pulse shapes using Bloch simulation and phantom experiment. The MB-OVS pulses were interleaved between imaging pulses to ensure homogeneous suppression throughout the cardiac cycle/imaging window in vivo. Simultaneous multi-slice (SMS) CINE and first-pass myocardial perfusion scans with and without the proposed MB-OVS pulses were compared in terms of residual artifacts at high acceleration rates. Among the tested pulses, both Bloch simulation and phantom experiments showed that amplitude-optimized sinc pulses provided the best trade-off in suppression efficiency, the required B+ 1 , SAR, and slab profile. CINE imaging with 5-fold SMS-OVS acceleration significantly outperformed imaging without MB-OVS, maintaining leakage-free image quality, even when adding 2-fold in-plane acceleration. SMS-OVS also enabled perfusion imaging in 9 slices with 1.7 × 1.7 mm2 resolution, achieving a 16-fold spatial-only acceleration while ensuring accurate contrast dynamics without leakage artifacts. Interleaved MB-OVS modules enabled thorough leakage artifact suppression in cardiac SMS-accelerated CINE and perfusion imaging, particularly at high acceleration rates. The proposed approach may be promising for unlocking further acceleration potential of SMS in cardiac imaging. ... Read more

Purpose
To evaluate single- and dual-band pulse modules for suppressing extra-cardiac signal in cardiac MRI, and test their applicability for time-efficient imaging with reduced FOV in myocardial 𝑇2 mapping at 3 T.

Methods
Outer Volume Suppression (OVS) was implemented using two regional saturation slabs, along the phase-encoding direction. Different Amplitude-Modulated (AM) and Amplitude-Frequency-Modulated (AM-FM) pulses were explored. AM sinc and AM-FM Hyperbolic Secant (HS) pulses, as single- (S:1b and HS:1b) and dual-band (S:2b and HS:2b) versions, were chosen for full evaluation. Pulses were individually optimized for minimal residual signal and optimal suppression-band profiles. Pulse performance was assessed through simulations and phantom experiments, and evaluated in seven healthy subjects using residual signal and quantitative myocardial 𝑇2 mapping with rFOV.

Results
In simulations, optimized HS pulses demonstrated superior suppression-band profile homogeneity and 𝐵0 robustness, while both pulse classes showed comparable 𝐵+1 sensitivity. Phantom data revealed better signal suppression with HS pulses (S:1b: 19.22% ± 3.23%, S:2b: 16.85% ± 6.80%, HS:1b: 4.66% ± 1.04%, HS:2b: 2.85% ± 1.01%). The residual difference across slabs was slightly reduced using simultaneous dual-band compared with sequential single-band approaches (S:1b: 3.81% vs. S:2b: 0.92%; HS:1b: 4.56% vs. HS:2b: 0.66%). In vivo, despite significantly lower residual with HS pulses (p = 0.0015) and visually observed artifacts with sinc pulses, no significant difference in 𝑇2 was observed across all configurations (p = 0.087) in myocardial 𝑇2 mapping.

Conclusion
AM-FM pulses achieved robust suppression of extra-cardiac signals, with dual-band implementations minimizing suppression-band differences. This can enable artifact-free rFOV imaging, for improved image quality in myocardial 𝑇2
mapping. ... Read more

Cardiovascular magnetic resonance (CMR) protocols can be lengthy and complex, which has driven the research community to develop new technologies to make these protocols more efficient and patient-friendly. Two different approaches to improving CMR have been proposed, specifically “all-in-one” CMR, where several contrasts and/or motion states are acquired simultaneously, and “real-time” CMR, in which the examination is accelerated to avoid the need for breathholding and/or cardiac gating. The goal of this two-part manuscript is to describe these two different types of emerging rapid CMR. To this end, the vision of each is described, along with techniques which have been devised and tested along the pathway of clinical implementation. The pros and cons of the different methods are presented, and the remaining open needs of each are detailed. Part 1 will tackle the “all-in-one” approaches, and Part 2 the “real-time” approaches along with an overall summary of these emerging methods. ... Read more