| Part 1 The preliminary study of T1 relaxation time in the rotating frame imaging in glioma gradingOBJECTIVETo investigate the diagnostic value of T1 relaxation time in the rotating frame(T1ρ) imaging in preoperative glioma grading.METHODSClinical diagnosis of suspected brain tumor patients were collected in Our hospital, before the study we had got the informed consent of all the patients or their guardians. Inclusion criteria were as follows:①The patients did not take any treatment before surgery. ② Conventional MRI plain scan, T1ρ imaging and conventional enhanced MRI span were performed before surgery respectively. ③The patients could complete the MRI examination, and the quality of the scanned images could be guaranteed. ④ Surgical resection and pathological diagnosis were performed within one to two weeks after MRI examination. ⑤ All patients were histopathologic diagnosed as different grades of gliomas after surgery.38 patients were included in the study, of which 22 cases of low-grade gliomas (both WHO Ⅱ grade) and 16 cases of high-grade gliomas (7 cases of WHOⅢ grade,9 cases of WHOIV grade).All patients were examined by Philips 3.0T superconductive MRI scanner using a 8-channel phased-array head coil. Conventional MRI plain scan(include T1WI, T2WI,T2-FLAIR sequence), T1p sequence and conventional enhanced MRI span were performed respectively. In the process of post-processing of T1p images, we placed three same size regions of interest(ROI) in the glioma solid area, peritumoral area and contralateral cerebral white area respectively. The average values of 3 ROIs were calculated and standardized as the rTlp values of solid areas and peritumoral areas.The rTlp values of solid areas and peritumoral areas were compared statistically between different histopathologic grades of gliomas. The correlation of two quantitative indicators with WHO histopathologic grades were analysed. Finally, receiver operating characteristic(ROC) curve were performed to evaluate the diagnostic efficiency of two quantitative indicators and to determine the diagnostic thresholds, sensitivities and specificities for glioma grading.RESULTS1. The solid areas of high-grade gliomas group had lower rTlp value (1.604±0.22) compared with low-grade gliomas group (2.133±0.385) (P<0.001);The peritumoral areas of high-grade gliomas group had higher rTlp value (2.022±0.402) compared with low-grade gliomas group (1.602±0.42) (P<0.01).2. The population mean of rTlp values of solid areas were not all equal between WHO Ⅱ,Ⅲ,Ⅳ grade gliomas groups, the difference was statistically significant. The solid areas of WHO Ⅱ grade gliomas group had higher rTlp value (2.133±0.385) compared with WHO Ⅲ, Ⅳ grade gliomas groups (1.701±0.176,1.528±0.23) (P<0.001); The rTlp value of solid areas from WHOⅢ grade gliomas group was slightly higher than WHOⅣ grade gliomas group (P>0.05). The polulation mean of rT1p value of peritumoral areas were not all equal between WHOⅡ,Ⅲ,Ⅳ gliomas groups, the difference was statistically significant. The peritumoral areas of WHO Ⅱ grade gliomas group had lower rTlp value (1.602±0.42) compared with WHOⅢ gliomas group (1.965±0.498) (P>0.05); The rT1p value of peritumoral areas from WHO II gliomas group was significantly lower than WHO Ⅳ gliomas group (P<0.05); The rT1p value of peritumoral areas from WHOⅢ gliomas group was slightly lower than WHOIV gliomas group (P>0.05).3. A strong negative correlation was found between the rT1p values of glioma solid areas and the WHO pathological grades, the spearman correlation coefficient was 0.719 (P<0.001). A moderate positive correlation was found between the rT1p values of glioma peritumoral areas and the WHO pathological grades, the spearman correlation coefficient was 0.492 (P<0.05).4. The area under the receive operating curve (AUC) of rT1p values of solid areas for evaluating the giloma pathologic grade was 0.908±0.046, with high diagnostic efficiency. The AUC of rTlp values of peritumoral areas for evaluating the giloma pathologic grade was 0.778±0.076, with certain diagnostic performance. A maximum value of the Youden index is used as the cutoff value, and the AUC of rT1p values of solid areas was 1.96 with a sensitivity of 100% and specificity of 72.73% respectively; The AUC of rT1p values of peritumoral areas was 1.96 with a sensitivity of 100% and specificity of 72.73% respectively.CONCLUSIONT1p imaging has high application value to evaluate the pathological grading of gliomas. It can reflect the histopathological grade and the degree of invasion accurately and sensitively, and has potential to be a quantization standard to discriminate high and low grade gliomas, even different WHO grades. In conlusion, T1p imaging can provide accurate and efficient references to assist preoperative treatment planning and prognosis judging.Part 2 The comparative study of T1p imaging and perfusion weighted imaging in glioma gradingOBJECTIVETo investigate and compare the diagnostic value of T1p imaging and perfusion weighted imaging(PWI) in preoperative glioma grading.METHODSClinical diagnosis of suspected brain tumor patients were collected in Our hospital, before the study we had got the informed consent of all the patients or their guardians. Inclusion criteria were as follows:①The patients did not take any treatment before surgery. ② Conventional MRI plain scan, T1p imaging, PWI and conventional enhanced MRI span were performed before surgery respectively. ③The patients could complete the MRI examination, and the quality of the scanned images could be guaranteed. ④ Surgical resection and pathological diagnosis were performed within one to two weeks after MRI examination. ⑤All patients were histopathologic diagnosed as different grades of gliomas after surgery.30 patients were included in the study, of which 17 cases of low-grade gliomas (both WHO Ⅱ grade) and 13 cases of high-grade gliomas (6 cases of WHOⅢ grade,7 cases of WHOⅣ grade).All patients were examined by Philips 3.0T superconductive MRI scanner using a 8-channel phased-array head coil. Conventional MRI plain scan(include T1WI, T2WI,T2-FLAIR sequence), T1p sequence, PWI sequence and conventional enhanced MRI span were performed respectively. The post-processing of T1p images was as part1, In the process of post-processing of PWI images, we placed three same size regions of interest(ROI) in the glioma solid area, peritumoral area and contralateral cerebral white area respectively in the CBV images. The average values of 3 ROIs were calculated and standardized as the rCBV values of solid areas and peritumoral areas. The selection of ROI and the calculation of value in the CBF images was corresponded to the CBV images.Each indicators of solid areas and peritumoral areas were compared statistically between different histopathologic grades of gliomas. The correlation of each quantitative indicators with WHO histopathologic grades were analysed. The correlation between each quantitative indicators of solid areas and peritumoral areas were analysed. Finally, receiver operating characteristic(ROC) curve were performed to compare the diagnostic efficiency of each quantitative indicators and to determine the diagnostic thresholds,sensitivities and specificities for glioma grading.RESULTS1. The solid areas of high-grade gliomas group had lower rTlp value (1.627±0.222) compared with low-grade gliomas group (2.172±0.374) (P<0.001); The solid areas of high-grade gliomas group had higher rCBV value (4.503± 1.728) compared with low-grade gliomas group (2.562± 1.240) (P<0.01); The solid areas of high-grade gliomas group had higher rCBF value (3.736±0.922) compared with low-grade gliomas group (2.804±1.153) (P<0.05); The peritumoral areas of high-grade gliomas group had higher rT1p value (2.071±0.397) compared with low-grade gliomas group (1.587±0.445) (P<0.01); The peritumoral areas of high-grade gliomas group had slightly lower rCBV value (0.982±0.526) compared with low-grade gliomas group (0.790±0.372) (P>0.05); The peritumoral areas of high-grade gliomas group had slightly lower rCBF value (0.763±0.397) compared with low-grade gliomas group (0.824±0.413) (P>0.05).2. The population mean of rTlp, rCBV and rCBF values of solid areas were both not all equal between WHO Ⅱ,Ⅲ, IV grade gliomas groups, the difference was statistically significant. The solid areas of WHO Ⅱ grade gliomas group had higher rTlp value (2.172±0.374) compared with WHOⅢ,Ⅳ grade gliomas groups (1.692±0.191,1.571±0.245) (P<0.05); The rTlp value of solid areas from WHOⅢ grade gliomas group was slightly higher than WHO IV grade gliomas group (P>0.05); The rCBV value of solid areas from WHO II grade gliomas group (2.562±1.240) was lower than WHO Ⅲ grade gliomas group (3.569±1.308) (P>0.05); The solid areas of WHOⅣ grade gliomas group had higher rCBV value (5.303±1.711) compared with WHO Ⅱ,Ⅲ grade gliomas groups (P<0.05). The rCBF value of solid areas from WHO Ⅱ grade gliomas group (2.804±1.153) was slightly lower than WHOIII grade gliomas group (3.150±0.485) (P>0.05); The rCBF value of solid areas from WHOⅢ grade gliomas group was lower than WHO Ⅳ grade gliomas group (4.238±0.931) (P>0.05); The rCBF value of solid areas from WHO Ⅱ grade gliomas group was lower than WHOIV grade gliomas group (P<0.05); The polulation mean of rT1p value of peritumoral areas were not all equal between WHO Ⅱ,Ⅲ, Ⅳ gliomas groups, the difference was statistically significant. The peritumoral areas of WHO Ⅱ grade gliomas group had lower rT1p value (1.587±0.445) compared with WHO Ⅲ, Ⅳ gliomas group (2.073±0.448, 2.070±0.384) (P<0.05); The rTlp value of peritumoral areas from WHOⅢ gliomas group was slightly higher than WHOIV gliomas group (P>0.05). The polulation mean of rCBV and rCBF values of peritumoral areas were equal between WHO II, III, IV gliomas groups, the difference had no statistically significant; The pairwise comparisons of the rCBV values of three groups had no statistically significant (0.790±0.372,1.053±0.560,0.921±0.532) (P>0.05); The pairwise comparisons of the rCBF values of three groups had no statistically significant (0.824±0.413, 0.829±0.481,0.706±0.339) (P>0.05).3. A strong negative correlation was found between the rTlp values of glioma solid areas and the WHO pathological grades, the spearman correlation coefficient was 0.737 (P<0.001); A strong positive correlation was found between the rCBV values of glioma solid areas and the WHO pathological grades, the spearman correlation coefficient was 0.623 (P<0.001); A moderate positive correlation was found between the rCBV values of glioma solid areas and the WHO pathological grades, the spearman correlation coefficient was 0.451 (P<0.05); A moderate positive correlation was found between the rTlp values of glioma peritumoral areas and the WHO pathological grades, the spearman correlation coefficient was 0.509 (P<0.05); No correlation was found between the rCBV, rCBF values of glioma peritumoral areas and the WHO pathological grades, the spearman correlation coefficients were 0.134 and 0.148 respectively (P>0.05).4. With WHO histopathologic grades as control viriables, No correlation was found between the rCBV, rCBF values and the rTlp values of glioma solid areas, the pearson correlation coefficients were 0.117 and 0.068 respectively (P>0.05). A moderate positive correlation was found between the rCBV values and the rCBF values of glioma solid areas, the pearson correlation coefficient was 0.517 (P<0.05). A weak negative correlation was found between the rTlp values and the rCBF values of glioma peritumoral areas, the pearson correlation coefficient was 0.375 (P<0.05); A moderate negative correlation was found between the rTlp values and the rCBF values of glioma peritumoral areas, the pearson correlation coefficient was 0.465 (P>0.05); A very strong positive correlation was found between the rCBV values and the rCBF values of glioma peritumoral areas, the pearson correlation coefficient was 0.787 (P<0.05).5. The AUC of rTlp values of solid areas for evaluating the giloma pathologic grade was 0.928±0.045, with high diagnostic efficiency. The AUC of rCBV values of solid areas for evaluating the giloma pathologic grade was 0.835±0.075, with certain diagnostic efficiency. The AUC of rCBF values of solid areas for evaluating the giloma pathologic grade was 0.719±0.096, with certain diagnostic efficiency. The AUC of rTlp values of peritumoral areas for evaluating the giloma pathologic grade was 0.803±0.08, with certain diagnostic performance. The AUC of rCBV values of peritumoral areas for evaluating the giloma pathologic grade was 0.602±0.11, with low diagnostic performance. The AUC of rCBF values of peritumoral areas for evaluating the giloma pathologic grade was 0.570±0.111, with low diagnostic performance. A maximum value of the Youden index is used as the cutoff value, the AUC of rT1p values of solid areas was 1.96 with a sensitivity of 100% and specificity of 76.47% respectively; The AUC of rCBV values of solid areas was 2.55 with a sensitivity of 84.62% and specificity of 76.47% respectively; The AUC of rCBF values of solid areas was 2.72 with a sensitivity of 92.31% and specificity of 58.82% respectively; The AUC of rTlp values of peritumoral areas was 1.7 with a sensitivity of 84.62% and specificity of 70.69% respectively; The AUC of rCBV values of peritumoral areas was 1.36 with a sensitivity of 30.77% and specificity of 100% respectively; The AUC of rCBF values of peritumoral areas was 0.85 with a sensitivity of 76.92% and specificity of 47.06% respectively.CONCLUSIONT1p imaging has higher application value than DSC-PWI to evaluate the pathological grading of gliomas. Both can reflect the histopathological grade from different imaging angles. In conlusion, T1ρ and PWI imaging may complement and combine with each other to provide effective accurate references in glioma grading, which can guide preoperative treatment planning and prognosis judging in the clinical work. |
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