Quantitative sodium imaging and gliomas: a feasibility study

Abstract

Purpose: Recent advances in sodium brain MRI have allowed for increased signal-to-noise ratio, faster imaging and the ability of differentiating intracellular from extracellular sodium concentration, opening a new window of opportunity for clinical application. In gliomas there are significant alterations in sodium metabolism, including increase in total sodium concentration and extracellular volume fraction. The purpose of this study is to assess the feasibility of using sodium MRI quantitative measurements to evaluate gliomas. Methods: Eight patients with treatment naïve gliomas were scanned at 3 Tesla with a homemade 1H/23Na head coil, generating maps of pseudo-intracellular sodium concentration (C1), pseudo-extracellular volume fraction (α2), apparent intracellular sodium concentration (aISC) and apparent total sodium concentration (aTSC). Measurements were made within the contralateral normal appearing putamen, contralateral normal appearing white matter (NAWM) and in solid tumor regions (area of T2-FLAIR abnormality, excluding highly likely areas of edema, cysts, or necrosis). Paired samples t-test were performed comparing NAWM and putamen and between NAWM and solid tumor. Results: Normal appearing putamen demonstrated significantly higher values for aTSC, aISC, C1 (p<0.001), and α2 (p=0.002) when compared to NAWM. Mean average of all solid tumors, when compared to NAWM, demonstrated significantly higher values of aTSC and α2 (p<0.001), and significantly lower values of aISC (p=0.02), There was no significant difference between the values of C1 (p=0.19). Conclusion: Quantitative sodium measurements can be done in glioma patients and also has provided further evidence that total sodium and extracellular volume fraction are increased in gliomas.

Potential of Sodium MRI as a Biomarker for Neurodegeneration and Neuroinflammation in Multiple Sclerosis

“…In primary brain tumors like low- and high-grade glioma, exaggerated proliferation rates lead to cellular membrane depolarization preceding cell division. Here, 23 NaMRI may additionally be useful as a predictive biomarker for the discrimination of therapy responsive tissue (45, 77, 91–95).…”

X‐nuclei imaging: Current state, technical challenges, and future directions

“…The intracellular concentration and the cell volume fraction can be calculated using tissue compartment models by incorporating a FLORET pulse train or an IR module. This approach was applied to evaluate healthy brain tissue, gliomas, and to determine the relation between cell density and aging (Fig. ).…”

Advancements in Neuroimaging to Unravel Biological and Molecular Features of Brain Tumors

“…A higher SNR not only results in a spatial-resolution improvement, but also allows for a better sensitivity for the detection of metabolite peaks in MRS, and it enables for imaging based on nuclei other than hydrogen (X-nuclei) [ 135 , 137 ], including sodium-23 ( 23 Na) [ 142 ], chlorine-35 ( 35 Cl) [ 143 ], potassium-39 ( 39 K) [ 144 ], and oxygen-17 ( 17 O) [ 145 ]. While the imaging of some X-nuclei (e.g., 23 Na) has also been proven feasible at 3 T [ 146 ] (but still greatly benefits from ultra-high-field), other X-nuclei have been only imaged at 7 T. X-nuclei MRI has the potential to provide unprecedented information regarding tissue electrolyte homeostasis, which is yet to be explored. The 23 Na signal, for instance, probes tissue viability, and was found increased in tumors due to membrane depolarization in the cell division initiating phase (intracellular- 23 Na) and to extracellular space expansion (extracellular- 23 Na) [ 137 ].…”