[Brain metabolic disorders after chemotherapy in the study by magnetic resonance spectroscopy]

The purpose of our study was to evaluate CNS pathology due to chemotherapy neurotoxicity, using MRI and localized proton MRS in patients with lung cancer treated with cisplatine, Vinca alkaloids and etoposide. A reduction in N-acetylaspartate was expected as a result of chemotherapy neurotoxicity.31 patients aged 42 to 73 years underwent the following procedures before and after chemotherapy: clinical examination; MRI of the brain (Elscint Prestige 2T), MRS (PRESS sequence, TR 1500 ms, TE 80 ms) with volumes of interest (VOI) of 8 ml localized in the semi-oval center and a cerebellar hemisphere. The analysis of each patient's NAA/Cr and Cho/Cr ratios was carried out separately for the semi-oval center and cerebellum measurements.None of the patients demonstrated any clinical manifestations of the CNS neuropathy. MRI of the brain did not reveal any abnormalities caused by chemotherapy. Pre-treatment NAA/Cr and Cho/Cr ratios in the semi-oval center did not differ significantly from these measured after chemotherapy. However, the analysis of the cerebellar spectra showed a significant decrease in the NAA/Cr ratio (p0.05) and a time-related decrease in the Cho/Cr ratio (p0.05) after chemotherapy. An analysis of Pearson's correlations showed a very strong linear relationship between NAA/Cr and Cho/Cr ratios (p0.001), both in the semi-oval center and cerebellum.The decreased NAA/Cr ratio can indicate some neuronal loss caused by chemotherapy. The decrease in the Cho/Cr ratio could be associated with some myelin damage. The MRS results suggest the presence of a sub-clinical selective cerebellar neuropathy caused by chemotherapy. The MRS revealed that reaction to chemotherapy was different at the semi-oval center than that in the cerebellum. The results allow theorizing about an alternative or two-stage brain response to the neurotoxic factor found both in the cerebrum (the semi-oval center) and cerebellum. These initial results indicate that proton MR spectroscopy is a potentially useful modality for detecting an early stage of the CNS pathology caused by neurotoxicity of chemotherapy.