Using Sodium MRI to Understand Cerebral Giomas - A Pilot Study

31 January 2020

Cerebral glioma is the most common type of primary brain tumour and is associated with poor prognosis. A key factor in enabling an effective treatment strategy is an understanding of the molecular genetic profile of the glioma, including detail relating to the isocitrate dehydrogenase enzyme (IDH)

expression

in the brain. However, this ordinarily involves invasive tissue sampling. Consequently, steps towards a method to obtain this information non-invasively are of great interest.

 

It is known that positron emission tomography (PET) using O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) improves the diagnosis of cerebral gliomas compared with conventional magnetic resonance imaging (MRI) and that tumour metabolism can be assessed using sodium MRI. In this pilot study, the relationship between [18F]FET-PET and sodium MRI is explored in patients with cerebral gliomas in relation to the mutational status of the enzyme isocitrate dehydrogenase (IDH).

 

Based on a cohort of 10 patients with untreated cerebral gliomas and one

pre-treated

patient, the results of this pilot study support the hypothesis that the use of sodium imaging presents information with which to predict IDH mutational status. Moreover, sodium MRI appears to be more strongly related to IDH mutational status than [18F]FETPET parameters. However, as previous reports have shown the performance of [18F]FET-PET to be excellent, further evaluation of a combination of the two methods to assess gliomas is promising.

 

Although sodium imaging suffers from low signal to noise ratio and low resolution at standard clinical field strengths, it is anticipated that as the availability of 7T MRI scanners increases, a combination of these methods will become feasible, opening up new horizons for the non-invasive assessment of the molecular profile of gliomas.

Original publication:

Comparison of [18F]Fluoroethyltyrosine PET and Sodium MRI in Cerebral Gliomas: a Pilot Study