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 the 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 T 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 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: The normal-appearing putamen demonstrated significantly higher values for aTSC, aISC, C1 (p < 0.001), and α2 (p = 0.002) when compared to those of NAWM. The mean average of all solid tumors, when compared to that of NAWM, demonstrated significantly higher values of aTSC and α2 (p < 0.001), and significantly lower values of aISC (p = 0.02) for each patient. 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.