1H-Magnetic Resonance Spectroscopy (MRS) in analysis of cerebral metabolite: MRS image for elderly patient anesthesia

Background: The phenomenon of population aging is progress rapidly and globally, indicating more research is needed to target elderly cohort. It’s well-known that general anesthesia can have a neurocognitive impact on elderly patients, affecting their prognosis. However, the underlying mechanism of how general anesthesia affects brain function has not yet been elucidated. The impact of general anesthesia on brain metabolism may be the key to studying the effects of anesthetic drugs on the brain. At present, research on brain metabolism mainly relies on cerebrospinal fluid and animal models, and Magnetic Resonance Spectroscopy (MRS) can explore changes in metabolic products in specific regions of the brain, providing a new non-invasive in vivo detection method for studying the effects of general anesthesia on brain metabolism. Objective: To evaluate the effect of general anesthesia on brain metabolism before and after aging brain anesthesia, using non-invasive brain MRS method. This experiment is a one arm two sessions longitudinal imaging study aimed at investigating the brain metabolic changes in patients before and after anesthesia induced by general anesthetics. Method: 30 patients with oral and maxillofacial tumors were randomly selected and evaluated with a cognitive function scale before surgery to ensure that they have no neurocognitive dysfunction. Perform preoperative and one day postoperative head MRS scans testing on patients. The detection sequences included MEGA-PRESS optimsed for GABA detection, and short echo-time as well as long echo-time PRESS sequences at left prefrontal area. MRS data were analyzed and compared using LCModel and TARQUIN. Paired t-test was conducted to detecting metabolites’ change before and after the surgery. Result: 30 patients were observed to have changes in the prefrontal cortex. We found a significant decrease of GABA concentration using MEGA-PRESS sequence, and a significant increase of Glutamate/Glutamineconcentration detected by both short TE and long TE PRESS sequences.