Brain MRI morphometry for structural alterations in patients with glioma - A systematic review

It is already known that patients with glioma develop functional plasticity, including recruiting regions of contralateral hemisphere. However, it is still unclear, if and what kind of structural changes in contralateral hemisphere are present, and there is lack of comprehensive comparison of studies on this issue.

First aim of this review was to summarize methodology and findings of morphometric studies of contralateral hemisphere of patients with glioma before treatment. Second aim was to discuss the possible neurobiological background of changes, methodological difficulties and possibilities, and to identify challenges for future studies.

Neuroimaging studies were searched in four electronic databases. Found studies were compared and discussed regarding their methodology and outcomes, and undergone thorough quality assessment.

In this systematic review, we eventually included 16 studies from 2080 initially found articles. Analyzed groups of patients suffered from different types and grades of gliomas. For brain scan analyses, authors used voxel-based or surface-based morphometry. Results differed across studies, reporting both increase and atrophy of contralateral grey matter. We identified some methodological issues in papers, which were further discussed.

Contralateral hemisphere in glioma patients undergoes complicated structural changes, including grey matter volume increase and atrophy, which both could be signs of compensation. These are dependent on tumor location, grade of glioma, individual attributes of a given patient, and should be interpreted carefully. There is still need for further research, and we present challenges and issues which should be overcome.