The Study Of Clinical Applications Of ～1H-MRS In Brain Gliomas

Background and objective: Brain gliomas are the most common in intra-axial tumors, the right preoperative diagnosis and judging this type of tumor's grade are very important for treatment program and assessment of prognosis.Sometimes,it is difficult to diagnose brain gliomas and judge the tumor's grade by routine CT and MRI. Magnetic resonance spectroscopy (MRS) is a only non-invasive technique for measureing chemical materials in vivo now, it could reveal the change of metabolic materials,such as N-acetylaspar-tate(NAA), choline(Cho), creatine(Cr), Myo-Inosito(MI), Lactate(Lac), Lipids(Lip), and evaluate pathological changes on molecule level.As MRS rapid development in technology and widen application in central nervous system, proton magnetic resonance spectroscopy (~1H-MRS) play an important role in preoperative diagnosis of brain gliomas, judging glioma's grade and invasion,it could replenish shortage of routine CT and MRI. The purpose of this research is to explore the feature of ~1H-MRS in brain gliomas and corrlation between ~1H-MRS and pathlogical grading,tumor invasion of gliomas, and evaluate the clinical application value of SV 1H-MRS in brain gliomas.Materials and methods: 47 patients of brain gliomas were included in the study,all of them underwent surgery and were confimed by pathology. According to 2000 WHO classification and grading standard,47 patients of brain gliomas were divided two groups: 29 cases of low-grade group(grade I～grade II) , 17 male, 12 female, age from 7~62 years,mean age 38 years; 18 cases of high-grade group( gradeIII～gradeIV), 12 male, 6 female, age from 19～69 years,mean age 42 years. Among 29 cases of low-grade gliomas ,there existed 8 cases of astrocytomas grade I , 15 cases of astrocytomas grade II , 6 cases of oligodendrogliomas. Among 18 cases of high-grade gliomas, there existed 8 cases of anaplastic astrocytomas, 7 cases of glioblastomas, 2 cases of anaplastic oligodendrogliomas, 1 case of medulloblastoma.47 cases of patients underwent ~1H-MRS before surgery, and all ~1H-MRS were gained on plain MR1 scan. Using single voxel scan and point-resolved spectroscopy (PRESS), ~1H-MRS was performed on GE Singna 1.5T supraconductor MR unit. Using Function Tool reconstruction metabolism spectral line, MRS software automatically accomplished baseline correction,signal average,metabolic materials recognition,metabolic materials semiquantitative analysis and relative quantitative analysis. The statistical analysis was executed by SPSS 11.0 software,statistical methods were t-test and spearman rank correlation analysis, significant level was set asα=0.05.Results:1.The findings of 1H-MRS in brain gliomas included distinctly decreased NAA and increased Cho,MI increased ,invariant and ruleless Cr,the ratio of Cho/Cr increased, the ratio of NAA/Cr , NAA/ Cho decreased, Lac and Lip could emerge. 2.Significant differences between gliomas parenchyma and corresponding tissue in contralateral brain hemispheres were found in the value of Cho (83.50±31.47,53.78±22.31) and the ratios of NAA/Cr (0.92±0.37,1.57±0.36) , Cho/Cr (1.97±0.87,1.0.1±0.22) and NAA/Cho (0.58±0.32,1.64±0.38 ) (P<0.05); No Significant differences were found in the values of NAA (37.96±26.89,81.48±36.19) ,Cr (47.89±29.43,54.17±22.11) ,MI (45.52±19.16,39.40±11.86) (P>0.05). 3.Significant differences between low grade gliomas parenchyma and high grade gliomas parenchyma were found in the value of Cho (69.26±34.69,120.72±89.11) and the ratios of the ratios of NAA/Cr (0.89±0.33,0.57±0.36) , Cho/Cr (1.61±0.51,3.39±1.36) ,NAA/Cho (0.64±0.32,0.32±0.18) and MI/Cr (1.41±0.79,0.87±0.41) (P<0.05); No Significant differences were found in the values of NAA (39.91±26.50,28.00±17.91) ,Cr (48.26±27.74,40.61±27.28) ,MI (43.95±19.33,51.50±34.28) (P>0.05). 4.Significant differences between peritumoral edema of gliomas and gliomas parenchyma, corresponding tissue in contralateral brain hemispheres found in the value of Cho(77.35±34.15,92.35±51.43,50.16±24.68)and the ratios of NAA/Cr(0.99±0.27,0.78±0.35,1.38±0.31) , Cho/Cr (1.53±0.49,2.58±0.41,0.89±0.20) and NAA/ Cho (0.88±0.18,0.54±0.23,1.52±0.56) (P<0.05) . 5.There was significant correlation between the ratios of Cho/Cr, NAA/Cr and NAA/ Cho and the pathological grading of gliomas, there was significant positive correlation in the ratio of Cho/Cr (rs = 0.694, P<0.05) , and negative correlation in the ratios of NAA/Cr (rs =—0.562, P<0.01 ) and NAA/ Cho (rs =—0.576; P<0.01) . The ratio of Cho/Cr reflected pathologic grade of gliomas relatively steadily. 6.Lac emerges on both of the low grade gliomas and high grade gliomas , there was no correlation between the appearance of Lac and the pathological grading of gliomas. 7.Lip emerges on the high grade gliomas, the appearance of Lip could be help to differentiated high grade gliomas and low grade gliomas.Conclusion: 1. ~1H-MRS is the important and useful method for diagnosing gliomas.2. The combination of ~1H-MRS and routine MRI could improve preoperative diagnostic accuracy of gliomas.3. ~1H-MRS has made it possible to exactly evaluate the grade of gliomas and reflect the biochemistry metabolism information. 4. ~1H-MRS has made it possible to eistimate peritumoral edema and reflect the invasion of gliomas.