Diffusion‐weighted magnetic resonance spectroscopy boosted by simultaneously acquired water reference signals

Abstract

Using the simultaneously acquired water signal as internal reference allows not only for compensation of phase and frequency fluctuations but also for signal amplitude restoration, and thus improved metabolite ADC estimation. Combination with 2D simultaneous fitting promises access to the diffusion properties even for low signal-to-noise metabolites. The combination of both techniques increases the specificity and sensitivity of estimated metabolite ADC values in the cohort.

Magnetic resonance spectroscopy extended by oscillating diffusion gradients: Cell-specific anomalous diffusion as a probe for tissue microstructure in human brain

“…Resulting ADCs for the major metabolites (based on the full b-value range for PGSE and for the restricted b-value range for OGSE) are presented in C). They are consistently higher for OGSE than PGSE (error bars representing the 95% Full text @ https://www.sciencedirect.com/science/article/pii/S1053811919306639?via%3Dihub linear in these plots, but rather shows some additional signal loss for b>1800s/mm², most likely due to uncompensated motion in spite of the water-signal-based motion-compensation scheme (Döring et al, 2018).…”

“…Single acquisitions were stored without averaging or preprocessing. The acquired inherent water reference was used not only for phase, frequency and eddy-current correction, but also for compensation of motion artifacts (Döring et al, 2018). No triggering was applied.…”

Multiparametric MR Investigation of Proteoglycan Diffusivity, T2 Relaxation, and Concentration in an Ex Vivo Model of Intervertebral Disc Degeneration

“…However, recent hardware developments helped clinical scanners to be retrofitted with an ultrahigh gradient that can reach a maximum strength of 300 mT/m, which is comparable to the preclinical system used in this study . For in vivo motion‐related signal loss, an advanced technique using the inherent water reference for motion compensation has been developed . It is very promising, as the same DW‐MRS approach can be translated in human IVDD.…”

Theoretical description of modern1H in Vivo magnetic resonance spectroscopic pulse sequences

“…In principle, this technique can be extended beyond two frequency dimensions. A second dimension could reflect, for example, another physical parameter like T 1 , T 2 , or diffusion, such as in the NMR technique Diffusion‐Ordered Two‐Dimensional Spectroscopy (DOSY) and a related in vivo application …”

“…A second dimension could reflect, for example, another physical parameter like T 1 , T 2 , or diffusion, such as in the NMR technique Diffusion-Ordered Two-Dimensional Spectroscopy (DOSY) 136 and a related in vivo application. 137 COSY has been combined with sLASER 138,139 and LASER 140 for spatial localization. Furthermore, a LASERlocalized TOtal Correlational SpectrocopY (TOCSY), has been developed.…”