Purpose-Single-scan multi-slice acquisition schemes play key roles in MRI. Central among these "ultrafast" experiments stands EPI, a technique that although of optimal sampling is challenged by T 2 * artifacts. Recent studies described alternatives based on spatiotemporal encoding (SPEN), which are particularly robust if implemented in a "full-refocusing" mode. The present work extends this modality from the single-slice acquisitions in which it has hitherto been implemented, by introducing a variety of multi-slice schemes scanning 3D volumes.Methods-Multi-slice SPEN employing either inversion or stimulated echo pulses and timed to fulfill the demands of full-refocusing, are demonstrated. The performance of the ensuing methods was examined in "Hybrid" modalities encoding data in k-and direct-space, in low-SAR stimulated-echo approaches, and in direct-space SPEN approaches.Results-When applied in phantoms and in in vivo systems, the ensuing single-shot sequences evidenced similar robustness, sensitivity and resolution qualities as previously discussed 2D single-slice schemes -while enabling a rapid sampling of the third dimension via multi-slicing. Conclusion-The unique benefits deriving from fully-refocused, multi-slice, single-scan SPEN sequences were corroborated by phantom tests, as well as by in vivo scans at 3T and 7T. Low SAR multi-slice SPEN variants compatible with human studies were demonstrated.

The referenceless correction enables robust single-scan imaging under changing conditions-such as patient motion and changes in shimming over time-without the need of ancillary navigators. This opens new options for real-time MRI and interactive scanning.

Developments in metamaterials and related structures such as metasurfaces have opened up new possibilities in designing materials and devices with unique properties. Here we report a new hybrid metasurface structure, comprising a two-dimensional metamaterial surface and a very high permittivity dielectric substrate, that has been designed to enhance the local performance of an ultra-high field MRI scanner. This new flexible and compact resonant structure is the first metasurface which can be integrated with multi-element close-fitting receive coil arrays that are used for all clinical MRI scans. We demonstrate the utility of the metasurface acquiring in-vivo human brain images and proton MR spectra with enhanced local sensitivity on a commercial 7 Tesla system.

A novel method for acquiring and processing quality multislice spectroscopically resolved 2D images in a single shot is introduced and illustrated. By contrast to the majority of single-scan spectroscopic imaging sequences developed so far, the method here discussed is not based on the acquisition of echo planar data in the k/t-space, but rather on the use of recently proposed spatiotemporal encoding methods. These techniques provide a robust alternative to classical techniques, as they can scan two spatial plus one spectral dimension by oscillating a single imaging gradient. This work demonstrates that the use of extended spectral/spatial super-resolution algorithms coupled to new experimental spatiotemporal encoding formulations based on swept inversions rather than on chirped excitations can lead to novel spatiotemporal encoding-based tools for resolving complex multisliced 2D images according to the chemical shifts in subsecond experiments. A number of phantom-based models were explored to clarify the relative merits of this technique and estimate its sensitivity performance. In vivo results of fat and water separation on abdominal imaging of mice at 7 T and on human breast imaging at 3 T are presented.

We have developed an interleaved SPEN approach for the acquisition of high-definition images that promises a wider range of functional and diffusion MRI applications even in challenging environments.