Quantification Of Metabolite Of The Pons Using Proton Magnetic Resonace Spectroscopy

Objective:To determine metabolic concentration in the pons of healthy Chinese adult subjects and mildly traumatic brain injuried patients using proton magnetic resonance spectroscopy (1HMRS),build a set of normal standard metabolic concentration in the pons of healthy Chinese adult subjects,and determine whether the pons were injuried in mildly traumatic brain injuried patients.Materials and methods:Eighty healthy Chinese subjects ranging from 21 to 60 years(average 43.5years) were divided into four groups,21-30years,31-40years,41-50years,51-60years, containing 20 subjects per decade.Eighty mildly traumatic brain injuried patients,with injury scale Glassgow(GCS)13-15,were examined with Light speed VCT,GE Signa Hi-Speed 1.5 T MRI and quantitative 1HMRS within 2 weeks after injury with echo time(TE) = 144 ms and repetition time(TR) = 1500 ms.Eighty healthy Chinese volunteers ranging from 21 to 60 years were examined as control.LCModel software was performed for quantitative metabolic concentration of N-acetylaspartate(NAA) + N-acetylaspartylglutamate(NAAG),creatine(Cr) and choline(Cho).Functool software was performed for relative quantitative metabolic concentration ratios of NAA/Cr,NAA/Cho and Cho/Cr.Results:1.The total mean metabolic concentration of NAA+NAAG,Cr and Cho in subjects ranging from 21 to 60 years were 11.31±0.40mmol/kg,5.54±0.11mmol/kg and 2.50±0.15 mmol/kg,respectively.The metabolic concentration of NAA+NAAG increased with age.The highest metabolic concentration of NAA+NAAG was seen in the 41-50 year group.There were significant change with respect to the others groups(P=0.011).There were no significant changes with respect to metabolic concentration of Cr(P=0.237).The metabolic concentration of NAA+NAAG increased with age.The highest metabolic concentration of Cho was seen in the 51-60 year group.There were significant changes with respect to the other groups(P=0.004). The total mean metabolic ratios of N-acetylasparate/creatine(NAA/Cr),NAA/choline(Cho) and Cho/Cr in subjects ranging from 21to 60 years were 2.13±0.07,1.22±0.11 and 1.81±0.09, respectively.The highest metabolic ratios were seen in the 41-50 year group.The metabolic concentration of NAA+NAAG,Cr and Cho in men was slightly higher than that in women in which group.However,there was no significant change with respect to gender(P=0.066,0.445 and 0.322).2.The mean metabolic concentration of NAA+NAAG of patients with mildly brain injury was 10.90±0.10 mmol/kg,which showed diminished level compared with that of control group. There was significant difference between the two groups(P＜0.01).The mean metabolic concentration of Cr of patients with mildly brain injury was 5.56±0.09 mmol/kg,which increased compared with control group.However,there was no significant difference between the two groups(P＞0.05).The mean metabolic concentration of Cho of patients with mildly brain injury was 2.66±0.06 mmol/kg showed significant higher Cho levels compared with control group.Besides,there was significant difference with the two groups(P＜0.01).The mean metabolic concentration ratios of NAA/Cr and NAA/Cho of patients with mildly brain injury were 2.00±0.06 and 1.04±0.04,which showed lower levels compared with control group. Besides,there was significant difference between the mildly brain injury group and control group (P＜0.01).The mean metabolic concentration of Cho/Cr in mildly brain injury group was 1.91±0.04,which showed higher levels compared with control group.Besides,there was significant difference between two groups(P＜0.01).Conclusion:1.The metabolic concentration of NAA+NAAG and Cho increases with age.The concentration of NAA+NAAG in 41-50years and the concentration of Cho in 51-60years were the highest among all groups.There were significant change with respect to concentration of NAA+NAAG and Cho.There was no significant change with respect to metabolic concentration of Cr.The metabolic concentration of NAA+NAAG,Cr and Cho in men was slightly higher than in women.The metabolic ratios of NAA/Cr,NAA/Cho,Cho/Cr in the pons did not correlate with age or gender of healthy subjects.2.Patients with mildly brain injury showed diminished NAA+NAAG,NAA/Cr and NAA/Cho levels compared with control group.There was no significant difference with respect to Cr between mildly brain injury group and control group.Mildly brain injury group displayed increased Cho and Cho/Cr level compared with control group.The changes of 1HMRS in pons indicated pons local tissue injury after brain injury.