The Application Of Magnetic Resonance Spectroscopy And Quantization Metohds In Analysising Metabolite Concentration Of Hippocampus Subfiel About Alzheimer Disease

In this study, the metabolite concentration of hippocampus subfield in Alzheimer Disease ?AD? pathology was researched. Different MRS analysis tools get different quantifying result, so a comparison between LCModel which is a commercial analyzing tool and TARQUIN which is a free analyzing tool was made.62 subjects were included in analyzing metabolite concentration of hippocampus subfield in AD, include 21 subjects in normal control,24 subjects considered as MCI and 17 subjects considered as probable AD. The MRI image and MRSI data were acquired for each subject. Firstly, hippocampus and hippocampus subfields were obtained by segmenting MRI image. Then, the registration between the segmentation result and voxels of MRIS was made to get the volumetric amout of each hippocampus subfields and hippocampus in each voxel. Finally, the metabolite concentration in the hippocampus subfield was calculated by proper seclection of voxel according to the volume of the hippocampus subfield in each voxel. Group differences in metabolite concentration were tested with one-way analysis of variance ?ANVOA?. The metabolite concentration ratio including NAA/Cr, mI/Cr, Cho/Cr and NAA/mI was studied between different groups. The MRS of hippocampus detected by our method indicated a asymmetry pattern of metabolite changes. Significant differences of NAA/Cr ?P=0.008? Cho/Cr ?P=0.010? and NAA/mI ?P=0.015? between the CN and MCI subjects were observed in the right hippocampus, while the left hippocampus was relatively spared, except NAA/Cr ?P=0.000?. Significant differences of NAA/Cr, Cho/Cr and NAA/mI between the CN and MCI subjects were observed in the left hippocampus subfields, such as CA1, CAA₃ and CA4_DG, while right subfields were relatively spared.In the comparison between LCModel and TARQUIN,21 healthy adults were involved and the MRS of hippocampus was acquired for each subject. The correlation coefficient and bias of metabolite concentration ratio, includeing NAA/Cr, mI/Cr, Cho/Cr and Glx/Cr, was calculated between LCModel and TARQUIN. Lastly, TARQUIN and LCModel were respectively used to calculate the metabolite concentration ratio, including NAA/Cr, mI/Cr, Cho/Cr and NAA/ml, of hippocampus subfields for CN, MCI andAD, then significance level was obtained between groups. A comparison of significance level between LCModel and TARQUIN was made. The correlation coefficient of mI/Cr, NAA/Cr, Cho/Cr and Glx/Cr was 0.42,0.26,0.84 and 0.67 respectively. The metabolite concentration ratio calculated by TARQUIN is smaller than by LCModel. NAA/Cr and Glx/Cr agreed with an error smaller than 34%. Cho/Cr and mI/Cr agreed with an error smaller than 8%. The model signal obtained by TARQUIN was similar to LCModel. The significance level between groups calculated TARQUIN was different with LCModel, except Cho/Cr which had a approximate significance level between TARQUIN and LCModel.