| BACKGROUNDBrain lesions have various kinds, and many lesions have the same morphologic feature, so it is difficult to accurate diagnosis and therapy for brian leisions by using the morphologic images solely.With the maturity of technique, brain MRS has combined the information of the concentration of the brian metabolites with the anatomic or morphologic images of brain.It display a window for us by its enormous amount of information of the biochemical changes of bian .So MRS provide a highly valuable diagnostic method for bain lesions. OBJECTIVETo study the diagnostic value for brain lesions by using 2D CSI ~1H-MRS.Through the difference of the concentration and ratio of various metabolites of brain ,we try to classify the various brain tumors with different kind and grade,and differentiate the common intracerebral lesions with the same morphologic feature. METHOD:1 84 cases patients confirmed by histopathologic findings or clinical follow-up,including 45 giiomas(10Ⅱ ,20 Ⅲ,15 Ⅳ), 12 meningiomas,13 metastatic tumors,8 inflammations (involve 2 pyogenic abscesses),6 radiation damages (involve 1 radiation necrosis).2 High resolution images were achieved by 1.5T Avanto MR with combined of head coils.3 The spectral maps of 2D CSI ~1H-MRS which based and displayed on high resolution MRI were achieved to analysis the concentration and ratio of Cho,NAA,Cr in every voxel.4 Wilconxon test was performed to compare the difference of the concentration and ratio of Cho,NAA,Cr in tumoral region,peritumoral region and normal contralateral cerebralparenchyma of 3 group tumors(include glioma,meningioma and metastatic tumor). All the statistical data were displayed as x +s, P value of less than 0.05 indicated astatistically significant difference.5 Wilconxon test was performed to compare the difference of the concentration and ratio of Cho,NAA,Cr in tumoral :region,peritumoral region and normal contralateral cerebral parenchyma of 3 group gliomas(include grade II ,III,IV). All the statistical data weredisplayed as x + s, P value of less than 0.05 indicated a statistically significantdifference.6 Wilconxon test was performed to compare the difference of the concentration and ratio of Cho,NAA,Cr in enhancing region(including the inner of enhancing region ) of 4 group ring-like enhancing intracerebral lesions(including high-gade glioma, metastatic tumor,inflammation and radiation damage). All the statistical data were displayed asx ± s, P value of less than 0.05 indicated a statistically significant difference.RESULT:1 The ratio of NAA/Cho in the tumoral region of glioma,metastatic tumor andmeningioma is 0.51 ±0.29, 0.76±0.25, 0.40±0.27 respectively,and has statistic difference;the concentration of Cho in peritumoral region of 3 group is 0.40±0.16, 0.27±0.09, 0.19±0.07 respectively,and has markedly significant difference. Compare with the nomal contralateral cerebral parenchyma,the whole variable in tumoral region of 3 group tumors have statistic difference. A threshold value of 0.45 for Cho in the peritumoral region provide 86.7%, 78.2%, 83.3%, 73.9% for the sensitive, specificity, PPV, NPV for differentiation of glioma from metastatic tumor and meningioma;When analysed by MRI solely, the sensitive, specificity, PPV, NPV for differentiation of glioma from metastatic tumor and meningioma is 80.1%, 82.3%, 83.7%, 76.7%, respectively;While combined MRI with MRS ,the sensitive, specificity, PPV, NPV for differentiation of glioma from metastatic tumor and meningioma is 90.1%, 87.5%, 93.2%, 84.1%.2 The ratio of Cho/Cr in the tumoral region of the grade II ,III,IV gliomas is 1.62+0.52, 2.76±1.82, 3.03±1.51, respectively,and has statistic difference. The ratio of Cho/Cr inthe peritumoral region of the grade II ,111, IV gliomas is 0.86±0.45, 1.46+0.74, 1.76±0.64, respectively.Compare with the nomal contralateral cerebral parenchyma,the whole variable in tumoral region of 3 group gliomas have statistic difference,the concentration of Cho and NAA in peritumoral region of grade II glioma have statistic difference,the whole variable in the peritumoral region of grade III, IV gliomas have statistic difference. A threshold value of 2 for Cho/Cr in the tumoral region provide 80.9%, 70.1%, 87.9%, 60.1% for the sensitive, specificity, PPV, NPV for differentiation of hige-grade gliomas from low-grade gliomas;A threshold value of 1 for Cho/Cr in the peritumoral edema region provide 83.5%, 74.2%, 88.5%, 73.6% for the sensitive, specificity, PPV, NPV for differentiation of hige-grade gliomas from low-grade gliomas;When analysed by MRI solely, the sensitive, specificity, PPV, NPV for differentiation of hige-grade gliomas from low-grade gliomas is 89.6%, 78.1%, 91.2%, 63.7%, respectively;While combined MRI with MRS the sensitive, specificity, PPV, NPV for differentiation of hige-grade gliomas from low-grade gliomas is 94.3%, 80.1%, 94.2%, 80.2% respectively.3 The ratio of NAA/Cho in the enhancing region of hige-grade glioma in the 4 groupring-like enhancing intracerebral lesions (include high-gade glioma,metastatic tumor,inflammation and radiation damage)has statistic difference compared with other 3 groups,the ratio of NAA/Cho of the 4 groups is 0.43±0.32, 0.69±0.29, 1.26±0.53, 0.63±0.34, respectively.The concentration of Cr of the metastatic tumor(0.10+0.05) has statistic difference compared with high-gade glioma, inflammation and radiation damages with the value of 0.17±0.05, 0.21±0.08, 0.21+0.09, respectively.The concentration of NAA of the inflammation (0.65±0.29)has statistic difference compared with high-gade glioma,metastatic tumor and radiation damages with the value of 0.18±0.09, 0.14±0.07, 0.21+0.10. A threshold value of 0.4 for NAA/Cho in the enhancing region provide 80.2%, 77.4%, 71.5%, 89.4% for the sensitive, specificity, PPV, NPV for differentiation of hige-grade glioma from other 3 groups;A threshold value of 0.06 for Cr in the enhancing region provide 81.3%, 81.9%, 74.1%, 90.1% for the sensitive, specificity, PPV, NPV for differentiation of metastatic tumorfrom other 3 groups.When analysed by MRI solely, the sensitive, specificity, PPV, NPV for differentiation of hige-grade glioma from other 3 groups is 70.1%, 70.6%, 66.4%, 82.4%, respectively. While combined MRI with MRS the sensitive, specificity, PPV, NPV for differentiation of hige-grade glioma from other 3 groups is 90.1%, 81.2%, 81.3%, 94.7%, respectively. When analysed by MRI solely,the sensitive, specificity, PPV, NPV for differentiation of metastatic tumor from other 3 groups is 71.5%, 72.7%, 65.5%, 82.4%, respectively;While combined MRI with MRS, the sensitive, specificity, PPV, NPV for differentiation of metastatic tumor from other 3groups is 89.5%, 83. 8%, 83.7%, 94.1% .respectively. Conclusion1. Through the ratio of NAA/Cho in the tumoral region and the concentration of Cho inthe peritumoral region, we can differentiate glioma, metastatic tumor and meningioma;When differentiate glioma from metastatic tumor and meningioma ,the threshold value of 0.45 for Cho in the peritumoral region have the same diagnostic value as MRI;While combined MRI with MRS, the diagnostic value is higher than the method analysised by MRI or MRS solely.2. Through the ratio of Cho/Cr in the tumoral region or peritumoral region, we can differentiate 3 groups gliomas(II,III,IV). When differentiate high-grade glioma from low-grade glioma, the threshold value of 2 or 1 for Cho/Cr in the tumoral region or peritumoral region have lower diagnostic value compare with MRI;While combined MRI with MRS,the diagnostic value is higher than the method analysised by MRI or MRS solely.3. In the 4 group ring-like enhancing intracerebral lesions(include high-gade glioma,metastatic tumor,inflammation and radiation damage), the threshold value of 0.4 for NAA/Cho in the enhancing region for differentiation of hige-grade glioma from other 3 groups have higher diagnostic value compared with MRI;The method combined MRI with MRS provide higher diagnostic value than the method analysised by MRI or MRS solely.
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