From signal-based to comprehensive magnetic resonance imaging

Color-map recommendation for MR relaxometry maps

PURPOSE

To harmonize the use of color for MR relaxometry maps and therefore recommend the use of specific color-maps for representingT 1 $$ {\mathrm{T}}_1 $$ ,T 2 $$ {\mathrm{T}}_2 $$ , andT 2 * $$ {\mathrm{T}}_2^{\ast } $$ maps and their inverses.

METHODS

Perceptually linearized color-maps were chosen to have similar color settings as those proposed by Griswold et al. in 2018. A Delphi process, polling the opinion of a panel of 81 experts, was used to generate consensus on the suitability of these maps.

RESULTS

Consensus was reached on the suitability of the logarithm-processed Lipari color-map forT 1 $$ {\mathrm{T}}_1 $$ and the logarithm-processed Navia color-map forT 2 $$ {\mathrm{T}}_2 $$ andT 2 * $$ {\mathrm{T}}_2^{\ast } $$ . There was consensus on color bars being mandatory and on the use of a specific value indicating "invalidity." There was no consensus on whether the ranges should be fixed per anatomy.

CONCLUSION

The authors recommend the use of the logarithm-processed Lipari color-map for displaying quantitativeT 1 $$ {\mathrm{T}}_1 $$ maps andR 1 $$ {\mathrm{R}}_1 $$ maps; likewise, the authors recommend the logarithm-processed Navia color-map for displayingT 2 $$ {\mathrm{T}}_2 $$ ,T 2 * $$ {\mathrm{T}}_2^{\ast } $$ ,R 2 $$ {\mathrm{R}}_2 $$ , andR 2 * $$ {\mathrm{R}}_2^{\ast } $$ maps. This work originated with the Quantitative MR Study Group of the International Society of Magnetic Resonance in Medicine (ISMRM); it has the approval of the Publication Committee and of the Board of the ISMRM.

Efficient performance analysis and optimization of transient-state sequences for multiparametric magnetic resonance imaging

In transient-state multiparametric MRI sequences such as Magnetic Resonance Spin TomogrAphy in Time-domain (MR-STAT), MR fingerprinting, or hybrid-state imaging, the flip angle pattern of the RF excitation varies over the sequence. This gives considerable freedom to choose an optimal pattern of flip angles. For pragmatic reasons, most optimization methodologies choose for a single-voxel approach (i.e., without taking the spatial encoding scheme into account). Particularly in MR-STAT, the context of spatial encoding is important. In the current study, we present a methodology, called BLock Analysis of a K-space-domain Jacobian (BLAKJac), which is sufficiently fast to optimize a sequence in the context of a predetermined phase-encoding pattern. Based on MR-STAT acquisitions and reconstructions, we show that sequences optimized using BLAKJac are more reliable in terms of actually achieved precision than conventional single-voxel-optimized sequences. In addition, BLAKJac provides analytical tools that give insights into the performance of the sequence in a very limited computation time. Our experiments are based on MR-STAT, but the theory is equally valid for other transient-state multiparametric methods.

Applications of metal-phenolic networks in nanomedicine: a review

The exploration of nanomaterials is beneficial for the development of nanomedicine and human medical treatment. Metal-phenolic networks (MPNs) have been introduced as a nanoplatform for versatile functional hybrid nanomaterials and have attracted extensive attention due to their simple preparation, excellent properties and promising medical application prospects. This review presents an overview of recent synthesis methods for MPNs, their unique biomedical properties and the research progress in their application in disease detection and treatment. First, the synthesis methods of MPNs are summarised, and then the advantages and applicability of each assembly method are emphasised. The various functions exhibited by MPNs in biomedical applications are then introduced. Finally, the latest research progress in MPN-based nanoplatforms in the biomedical field is discussed, and their future research and application are investigated.