Lateralizing Ability Of MRS In Temporal Lobe Epilepsy

Magnetic resonance spectroscopy(MRS) analysis has been confirmed as a new method for the diagnosis and assessment of epilepsies in recent years,especially temporal lobe epilepsy (TLE),and it was assessed as a tool for detection of metabolite alterations in vivo patients with TLE. It supports 1H-MRS as a suitable non-invasive method for the study of hippocampal sclerosis deeply into histology level in patients with TLE. Metabolite alterations detected by 1H-MRS correlated with de- gree of segmental neuronal cell loss and amount of astrogliosis. Just because of the lower sensitivity,signal-to-noise ratio and special resolution of 31P-MRS,1H-MRS is used widely in the clinical adoption.The decrease of NAA is thought to reflect mitochondrial dysfunction.The concentration of NAA is typical- ly reduced in the region of the seizure focus in TLE and is thought to be not only the reflection of neuronal loss ,but also neuronal dysfunction and the electrotic reaction of abnormal discharge in the seizure focus.TLE is the most common type of epilepsies in the clinical, which possess 60 percent in the intrac- table epilepsies.As a non-invasive, preoperative tool to the exact and pricise localization of the sezure forcus in TLE , 1H-MRS plays a very important role in the TLE therapy.NAA/(Cho+Cr) ratio is used widely in most literatures as the standard for locali- zation diagnosis of TLE. Patients with TLE often have hippo- campal sclerosis(HS)(70-80%).Epilepsy surgery evolved as a valuable treatment option for controlling seizures in the group of patients who had undertaken the section of seizure forcus.MRS can detect the HS and sub-clinical seizure focus much earlier than does MRI.It identifies abnormalities contralateral to the predominant seizure focus more often than does MRI and can define the weaker lateration as the seizure focus.MRS has much higher inaccordance with seizure forcus than does MRI. It has also been revealed to be a useful tool for the classification of TLE and can provide evidence for the specific localization of TLE. Although intracranial EEG is the golden standard in the diagnosis of TLE, it is invasive and has a number of limitations. Comparing with PET and SPECT, MRS can be free of radiation exposure and medical metabolite injures,which is defined as a kind of less expensive, noninvasive and objective method and cannot be affected by individual vascular differnce and blood glucose level et al. Further advances including the use of a smaller VOI,multi-voxel MRS and measurement of the absolute amount of metabolites in this field promise to improve the clinical utility of MRS in epilepsy.