Magnetic Resonance Spectroscopy in Epilepsy
摘要
Magnetic resonance spectroscopy (MRS) can detect in vivo cerebral metabolites non-invasively. Principles underlying MRS are basically the same as those of magnetic resonance imaging(MRI). The results of MRS measurement are always presented in terms of semi-quantitative ratios or quantitative intensities of metabolites, Technique differences, parameter inconsistency and regional variations will influence the spectral profiles and significantly change the results. Therefore, it is very important to keep the sequences and parameters used for spectral acquisition consistent in order to make the measurements reproducible and longitudinal studies. comparable. The effects of different acquisition techniques and parameters must be considered when interpretation or comparison of MRS data is made. In vivo MRS is increasingly used for clinical study in seizure patients, especially in those with temporal lobe epilepsy. Phosphorus MRS can detect the levels of high-energy phosphates in the brain, but has the disadvantages of low signal-to-noise ratio, poor spatial resolution and unavailability on clinical MR systems. Proton MRS can be performed together with MRI during the same examination session, providing biochemical data in addition to structural information. Reduced intensity of N-acetylaspartate on proton spectra is consistently identified in the mesial temporal lobe or hippocampus of patients with temporal lobe epilepsy, reflecting underlying neuronal loss or dysfunction. Pre-surgical lateralization, post-ictal metabolite changes, prediction of surgical outcome, post-treatment features, and differences between temporal and extra-temporal epilepsy are under intensive investigation using in vivo proton MRS. Despite being regarded as a research imaging modality for patient evaluation, proton MRS has the promising potential to be helpful in seizure management.