Multiparametric Quantitative MRI Evaluation of Changes in Brain Myelin Content after the First Course of Chemotherapy

Abstract

Objective. Quantitative assessment of changes in brain myelin content after the first course of chemotherapyMaterials and Methods. T1 and T2 maps as well as myelin water fraction (MWF) and macromolecular proton fraction (MPF) maps, reflecting myelin content, were acquired in 6 patients (mean age — 13.7 ± 2.4 years) before and after the first course of chemotherapy. The study was carried out using on 3T MRI scanner. Statistical data processing was carried out using the GraphPad Prism.Results. MPF and T2 values showed an increase in the thalamus and white matter of the occipital lobes of the brain, while MWF values showed an increase in the cerebellum and a decline in the white matter of the frontal lobes. Significant changes were not found for T1 values.Discussion. According to MWF the structures of the brain which are primarily affected by treatment with toxic drugs — the white matter of the frontal lobes and the cerebellum, were revealed. MWF values decreasing in the white matter of the frontal lobes may indicate the process of demyelination in this area, while increased MWF values in the cerebellum could be caused either by remyelination processes or by incomplete cleansing of myelin residues accumulation by macrophages at the site of degeneration. Conclusion. The results obtained demonstrated high potential of MWF values serve as early changes biomarker of neurotoxicity after the chemotherapy treatment. Along with this, the MPF index, which is more sensitive to cerebral edema, may be a predictor of demyelination.