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Magnetic resonance imaging (MRI) offers valuable structural information about organs and tissues in the body, providing high-resolution images that help diagnose a wide range of conditions and dysfunctions. However, data underlying functional activity of the structure is often limited.

Proton magnetic resonance spectroscopy (MRS) is a non-invasive, in vivo technique complementary to MRI that interrogates the tissue for the presence and concentration of various metabolites and provides knowledge of the metabolic chemical environment. Its sensitivity to neurological abnormalities in the presence of apparently normal structural MRI images has aroused interest in its use as a biomarker of brain disorders such as epilepsy.

Scientists from the University of Illinois College of Medicine decided to gain a better insight into the role of MRS in the evaluation of temporal lobe epilepsy, the most common type of epilepsy, often resistant to all forms of seizure medications. Twenty patients with temporal lobe epilepsy and 10 healthy control subjects participated in the study. Although the epileptic participants suffered from chronic temporal lobe epilepsy, previous MRIs were negative regarding significant pathological findings (MRI-negative temporal lobe epilepsy). All participants in the study underwent MRI and MRS of the brain. MRI images were transferred to Analyze software where the hippocampi were manually traced and volumes were measured in order to assess hippocampal atrophy. The team used MRS of the brain to investigate the levels of the metabolites N-acetylaspartate, creatine, and choline in the hippocampi of the study subjects.

Results from this study indicate that both N-acetylaspartate/creatine and N-acetylaspartate/(creatine + choline) ratios were significantly lower in the hippocampi belonging to the hemisphere where the seizure occurred, compared with the hippocampi on the opposite side and with control subjects. These findings suggest that MRS may be an appropriate technique for the detection of early neuronal damage due to significant metabolic changes not yet noticeable on structural MRI. Furthermore, MRS data may help patients avoid invasive studies, such as depth electrode placement, that increase the risk for complications.

Related: Differentiating Temporal Lobe Epilepsy through Functional Neuroimaging

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Tags: Brain Metabolism, Brain Studies, Epilepsy