Quantification of Proton Magnetic Resonance Spectroscopy in Diffuse Axonal Injury

Objective To conduct proton magnetic resonance spectrum(1H-MRS) research with absolute quantification study of the early-stage diffuse axonal injury(DAI) patients to explore their brain metabolite changes in relevance to the degree of illness and prognosis.Methods Forty-five DAI patients visited the Second Affiliated Hospital of Shantou University and twenty healthy volunteers were studied by 1.5T magnetic resonance imaging machine,routine MRI scan and 1H-MRS examination(single voxel in the occipital gray matter).Forty-five cases of DAI were divided into mild group(GCS 8) and severe group(GCS≤8) according to severity,divided into good outcome group(GOS = 5) and poor outcome group(GOS 2-4) according to the prognosis of the patients.The main metabolites of N-acetyl aspartic acid(NAA),choline(Cho),creatine(Cr) were quantitatively analyzed by LCModel software.Results The level of NAA and NAA/Cr,Cho/Cr were significantly different(F = 1.02,1.21,0.12,P 0.05) among the control group,mild group,and severe group.NAA and NAA / Cr of the three groups were different with statistical significance(P 0.05).There was statistical significance in severe group compared with the control group differences in Cho / Cr(P 0.05).The level of NAA,NAA / Cr and Cho / Cr were different(F = 1.02,1.21,0.08,P 0.05) among the control group,good outcome group,and poor outcome group,but there were no statistical differences betweenCr,Cho(F = 3.48,0.42,P 0.05),NAA and NAA / Cr of the three groups had statistically significant differences(P 0.05).There was statistical significance differences of Cho / Cr between the poor outcome group and the control group(P 0.05),and between the good outcome group and the poor outcome group(P 0.05).The concentration of NAA,NAA/Cr were positively correlated with GCS or GOS,negatively correlated with the time of primary coma and DRS.Cho / Cr was positively correlated with the time of primary coma and DRS,and negatively correlated with GCS or GOS.Conclusion Brain metabolite changes in DAI patients can be used as objective indicators for evaluation of brain tissue injury degree and prognosis judgment.