Using Sodium MRI to characterise tumours - a small scale study
Wieland A. Worthoff, Aliaksandra Shymanskaya, Johannes Lindemeyer Karl‐Josef Langen, N. Jon Shah
Sodium plays an essential role in human cell physiology and alterations in its distribution can be indicative of disease. Sodium concentrations in the body can be measured noninvasively in vivo via MRI, enabling the assessment of a range of metabolic disease, including brain tumours.
The isocitrate dehydrogenase enzyme (IDH) catalyses the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and carbon dioxide. Mutations in IDH are associated with brain tumours, and in a recent study involving untreated cerebral glioma patients, a strong relationship between semiquantitative abnormalities in sodium MRI and the mutational status of the isocitrate dehydrogenase enzyme was observed.
In this study, sodium relaxometry in brain tumour tissue was investigated in relation to molecular markers and IDH mutational status in order to reveal quantitative sodium tissue parameters and the differences between healthy tissue and brain tumour. The approach of the study extends a previous semi‐quantitative approach by combining suitable relaxometry methods with numerical simulation to achieve detailed quantitative analysis of intra‐ and extracellular sodium concentration using an enhanced SISTINA sequence at 4 T.
Based on the quantitative analysis of relaxation rates, intra‐ and extracellular sodium concentrations, intracellular molar and volume fractions, the results confirmed a relationship between abnormalities in sodium parameters and the IDH mutational status in cerebral gliomas.
These results demonstrate the potential of sodium MRI using the enhanced SISTINA method to gauge and characterise metabolic information in brain tumours. By using detailed sodium relaxometry in conjunction with other investigative methods, it is anticipated that improvements will be made in the diagnosis and treatment planning for brain tumour patients, eventually leading to personalised medicine.
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