Hai-Yu Wang, Ye-Yu Xiao, Ren-Hua Wu Department of Medical Imaging Quantitative Analysis of Brain Metabolite Concentrations Using MRS in Acute Hypoxia Ischemic Encephalopathy Hai-Yu Wang, Ye-Yu Xiao, Ren-Hua Wu Department of Medical Imaging Shantou University China

Background Our studies

Background NAA／Cr，Cho／Cr,Ino/Cr,etc Should we use ratios in the future? NAA／Cr，Cho／Cr,Ino/Cr,etc

Background Metabolite ratio is a useful method to express measurement results in the field of MR spectroscopy (MRS). However, a major disadvantage of the metabolite ratio is that ratio results are not comparable with absolute metabolite concentrations in vivo. Accurate for MRS method?

Background S = N  e(-TE/T2)  [1-e(-TR/T1)] Wu RH, Silverstone P. Proceedings of 9th ISMRM meeting 2001; p1012, Glasgow, UK Huang W, et al. Am J Psychiatry.1999;156(12):1879-86 Vermathen P, et al. Magn Reson Med. 2000;43(5):665-75

Background

Background Localized brain proton Magnetic Resonance Spectroscopy (MRS) can non-invasively provide biochemical information form distinct regions of the brain by quantitation of brain metabolites, which can be used for disease detection, disease progression monitoring and treatment.

Purpose To explore the dynamic changes of brain metabolite concentrations using absolutely quantitative external standard MRS in acute hypoxia ischemia encephalopathy (HIE) piglet model.

Studies Eight piglets were subjected to HI insult and scanned on a GE 1.5 T scanner with a standard head coil. Prior to the MRI examination, the animals were intramuscularly anesthetized and then banded on a board in a supine position.

Studies The external standard 5 mmol N-acetylaspartate (NAA) 5 mmol -aminobutyric acid (GABA) 2.5 mmol glutamine/2.5 mmol glutamate 4mmol creatine 1 mmol choline chloride 2.5 mmol myo-inositol.

Studies

Studies PRESS sequence TE=30 msec TR=3000 msec 64 scan averages

Studies The quantification of N-acetylaspartate (NAA), creatine (Cr) and lactate (Lac) were accomplished by the LCModel.

Studies One piglet was excluded because it was over anesthetized to dead. Seven piglets’ data were analyzed.

Studies TE135 TR1500 TE50 TR1500

Studies

Studies

Studies The concentration of NAA in the pre- and post-HI was 6.86±0.49mmol/kg and 5.73±0.88mmol/kg respectively; Cr was 4.65±0.73mmol/kg and 4.40±0.80mmol/ kg; Lac was 0.0mmol/kg and 0.43±0.39 mmol/kg.

Studies The concentration of NAA in the post-HI was decreased, and the difference was of statistical significance (t=0.579, P=0.002). The concentration of Cr was decreased, but the difference was not of statistical significance (t=0.579, P=0.584). The concentration of Lac was increased, and the difference was of statistical significance (t=2.933, P =0.026).

Studies

Studies non HIE HIE 2h

Conclusion External standard MRS using LCModel has great value in quantitative analysis of brain metabolites. The concentration of NAA and Cr were decreased, and Lac increased in the animal model of acute HIE. Cerebral metabolites change dynamically in acute HIE.

Acknowledgements National Natural Science Foundation of China (NSFC) Li Ka Shing Foundation

Acknowledgements