Diffusion tensor imaging indices to predict cognitive changes following adult radiotherapy

BACKGROUND Diffusion tensor imaging (DTI) can detect changes to white matter tracts following assaults including high dose radiation. This study aimed to systematically evaluate DTI indices to predict cognitive changes following adult radiotherapy. MATERIALS AND METHODS We searched PubMed and Scopus electronic databases to identify eligible studies according to PRISMA guidelines. Studies were extracted for information on demographics, DTI changes and associations to cognitive outcomes. RESULTS Six studies were selected for inclusion with 110 patients (median study size: 20). 5/6 studies found significant cognitive decline and analysed relationships to DTI changes. Decreased fractional anisotropy (FA) was consistently associated with cognitive decline. Associations clustered at specific regions of cingulum and corpus callosum. Only one study conducted multivariable analysis. CONCLUSION Fractional anisotropy is a clinically meaningful biomarker for radiotherapy-related cognitive decline. Studies accruing larger patient cohorts are needed to guide therapeutic changes that can abate the decline.