Relaxometry and quantification in sodium MRI of cerebral gliomas: A FET‐PET and MRI small‐scale study

NMR in Biomedicine, vol. 33, pp. e4361

Abstract

Sodium MRI is a promising method for assessing the metabolic properties of brain tumours. In a recent study, a strong relationship between semi‐quantitative abnormalities in sodium MRI and the mutational status of the isocitrate dehydrogenase enzyme (IDH) with untreated cerebral gliomas was observed. Here, sodium relaxometry in brain tumour tissue was investigated in relation to molecular markers in order to reveal quantitative sodium tissue parameters and the differences between healthy tissue and brain tumour. The previous semi‐quantitative approach is extended by use of suitable relaxometry methods accompanied by numerical simulation to achieve detailed quantitative analysis of intra‐ and extracellular sodium concentration using an enhanced SISTINA sequence at 4 T. Using optimised techniques, biexponential sodium relaxation times in tumour (T*2f, T*2s) and in healthy contralateral brain tissue (T*2f,CL, T*2s,CL) were estimated in 10 patients, along with intracellular sodium molar fractions (χ, χCL), volume fractions (η, ηCL) and concentrations (ρin, ρin,CL). The total sodium tissue concentrations (ρT, ρT,CL) were also estimated. The ratios T*2f/T*2f,CL (P = .05), η/ηCL (P = .02) and χ/χCL (P = .02) were significantly lower in IDH mutated than in IDH wildtype gliomas (n = 4 and n = 5 patients, respectively). The Wilcoxon rank‐sum test was used to compare sodium MRI parameters in patients with and without IDH mutation. Thus, quantitative analysis of relaxation rates, intra‐ and extracellular sodium concentrations, intracellular molar and volume fractions based on enhanced SISTINA confirmed a relationship between abnormalities in sodium parameters and the IDH mutational status in cerebral gliomas, hence catering for the potential to provide further insights into the status of the disease.

Authors 5

1. Wieland Alexander Worthoff corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany

   Wieland A. Worthoff and Aliaksandra Shymanskaya both contributed equally to this study

2. Aliaksandra Shymanskaya

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Neuroscience and Medicine ‐ 11 Forschungszentrum Jülich Jülich Germany

   Wieland A. Worthoff and Aliaksandra Shymanskaya both contributed equally to this study

3. Johannes Lindemeyer

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany

4. Karl‐Josef Langen Aachen Department of Nuclear Medicine

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Department of Nuclear Medicine RWTH Aachen University, JARA Aachen Germany

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany

5. Nadim Jon Shah Aachen Department of Neurology

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Department of Neurology RWTH Aachen University, JARA Aachen Germany

   Institute of Neuroscience and Medicine ‐ 11 Forschungszentrum Jülich Jülich Germany

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany

   Institute of Neuroscience and Medicine ‐ 4 Forschungszentrum Jülich Jülich Germany