| Part I: Efficacy of 3D-ASL in preoperative grading of brain gliomas Purpose:To evaluate the efficacy of three-dimensional arterial spin labeling(3D-ASL)in preoperative grading of brain gliomas using pathologic material as a standard.Methods:Fifty-one patients with brain gliomas received plain MRI,contrast enhanced(CE)-MRI and 3D-ASL scanning before surgery(female:24,male:28,the average age was 48.41 ± 14.18 years old),in which low grade glioma(grade I and II)was 23 cases and high grade glioma(grade III and IV)was 28 cases.In 3D-ASL perfusion images,the maximum tumor blood flow(TBF)of tumor parenchyma was measured;relative TBF-M(rTBF-M,using tumor mirror image as control)and rTBF-WM(using contralateral normal whiter mater as control)were calculated.To compare the discrepancy between 3D-ASL and CE-MRI results,the cases were categorized into “ASL dominant”,“CE dominant”and " and "no enhancement without high perfusion type".Afterwards,the relationship between 3D-ASL or CE-MRI imaging findings and pathological results was analyzed.Independent samples t test,Mann-Whitney and U test and one-way analysis of variance(ANOVA)were performed to test the differences of TBF,rTBF-M and rTBF-WM values among brain gliomas with different grades.Spearman rank correlation analysis was performed to assess the correlation between TBF,rTBF-M,rTBF-WM and glioma grades respectively.P <0.05 was considered statistically significant.Receiver operating characteristic(ROC)curve was used to determine the optimal discrimination threshold as well as the sensitivity and specificity of 3D-ASL in the differentiation of gliomas from different grades.Results:In high-grade gliomas(HGG)group,TBF,rTBF-M and rTBF-WM values were higher than those in low-grade gliomas(LGG)group(P < 0.05).Multiple comparison showed the TBF and rTBF-WM values were different between grade I and IV gliomas,as well as between II and III gliomas(both P < 0.05).The rTBF-M value difference was observed solely between grade I and IV gliomas in multiple comparisons(P < 0.05).The values of all 3D-ASL derived parameters were positively correlated with gliomas grading(all P <0.001).TBF showed highest specificity(72.7%)and rTBF-WM showed highest sensitivity(96.4%)when discriminating LGG and HGG using ROC curve.There were 29 CE dominant cases referred to an area of hyperintensity on ASL with equal or smaller distribution to that of the area of enhancement on CE-MRI,in which 23 cases were HGG,6 cases were LGG;9 ASL dominant cases referred to hyperintensity on ASL that is present outside the CE area.,with 4 HGG cases;13 cases with no enhancement and hyperperfusion,in which 1 case was HGG.Conclusion: 3D-ASL can more accurately reflect the glioma perfusion information,and can achieve accurate quantitative measurement(CBF),is of significance to preoperative grading of brain gliomas.More attention needs to be given to ASL dominant patients,which referred to hyperintensity on ASL that is present outside the CE area,or those with hyperintensity on ASL but no enhancement on CE-MRI.Part II: Preoperative grading of gliomas by intravoxel incoherent motion diffusion-weighted MR imagingPurpose: To research the introvoxel incoherent motion diffusion-weighted MR imaging in the non-invasive evaluation of microvascular circulation of glioma,and evaluate its clinical application in preoperative diagnosis and grading of gliomas.Methods:A total of 49 cases with brain gliomas were collected(female: 24,male: 25,age range 48.76 ± 13.00 years old),including 24 low-grade gliomas(LGGs)and 25 high-grade gliomas(HGGs).All cases received conventional magnetic resonance imaging(MRI)scanning and intravoxel incoherent motion(IVIM)scanning.In IVIM pseudocolor images,the ROI was seted in the part with the smallest standard ADC of the tumor parenchyma,and the standard ADC,D,D*,f values were measured.For standardization,the standard ADC,D,D *,f values of the brain mirror regions(M)and contralateral normal whiter mater(WM)were caculated by means of the symmetry axis.The relative ratio of the parameters in the tumor parenchyma were calculated(relative ratio = value in tumor parenchyma /(values in M or in WM)),recording as r Standard ADC-M,rD-M,rD*-M,rf-M,and r Standard ADC-WM,rD-WM,rD*-WM,rf-WM,respectively.Independent samples t test or Mann-Whitney test were performed to test differencesof Standard ADC,D,D*,f,and corresponding r Standard ADC,rD,rD*,rfvalues between LGG and HGG.Analysis of variance(ANOVA)and Kruskal-Wallis test were performed to test thedifferences of Standard ADC,D,D*,f,and corresponding r Standard ADC,rD,rD*,rfvalues in I-IV grade gliomas.Spearman Rank correlation analysis was performed to assess the association of Standard ADC,D,D*,f,and corresponding r Standard ADC,rD,rD*,rf with glioma grades.P <0.05 was considered statistically significant.Receiver operating characteristic(ROC)curve was used to determine the optimal discrimination threshold and its sensitivity and specificity in gliomas with different grades.Results:(1)The Standard ADC,D values in LGG group was higher than HGG group(P <0.05).While the D* value in LGG group was lower than HGG(P <0.05).There was no significant difference in f value between HGG group and LGG group(P > 0.05).The relative ratios of r Standard ADC-WM,rD-WM,rD*-WM were in accordance with the absolute Standard ADC,D,D* values.The relative ratios of r Standard ADC-M,rDM,rD*-M,r f-M were in accordance with the absolute Standard ADC,D,D*and f values.(2)Further comparison between groups revealed that,The values of Standard ADC,D in grade I and II was respectively higher than grade III and IV(P <0.05),and the D* value in grade I and II was respectively higher than grade III and IV(P <0.05).The values of r Standard ADC-M,rD-M in grade I and II respectively higher than grade III and IV(P <0.05),and the rD*-M value in grade IV was respectively higher than grade I and II(P <0.05).The values of r Standard ADC-WM,rD-WM in grade I was respectively higher than grade II,III and IV(P <0.05).The values of r Standard ADC-WM,rD-WM in grade II was respectively higher than grade III and IV(P <0.05),and the rD*-WM value in grade I and II was respectively lower than.grade III and IV(P <0.05).(3)To further evaluate diagnostic efficacy of significantly indicators between LGG and HGG,ROC curve were performed.Results showed that D* value had the highest diagnostic efficacy(AUC: 0.957),and Standard ADC-WM(AUC: 0.883)and D(AUC: 0.891)had relatively higher diagnostic efficacy.ROC curve indicated that D valueshowed highest diagnostic efficacy(AUC: 0.950)and Standard ADC(AUC: 0.878)and D*(AUC: 0.944)had relatively higher diagnostic efficacy in discriminating LGG and HGG.Conclusion:IVIM imaging can visually and sensitively reflect the blood flow status of the capillary bed and provide both perfusionand diffuse information of the lesions.Multiple IVIM parameters,including ADC value,D value,D* value,can be used as non-invasive predictors of preoperative glioma grading.Part III: The Clinical application research of DCE-MRI quantitative parameters in microvessel permeability and preoperative grading of gliomaPurpose:To investigate the clinical values of quantitative parameters(Ktrans,Kep,Ve)of DCE-MRI in glioma microvessel permeability and pathological grading,taking pathological results as golden standard.Methods:A total of 30 cases of glioma patients were collected and confirmed by pathology,including 12 low-grade gliomas(grade II)and 18 high-grade gliomas(grade III +grade IV).Among them,15 males and 15 females had an average age of 48.73 ± 9.21 years.All cases received conventional magnetic resonance imaging(MRI)scanning and dynamic contrast-enhanced magnetic resonance imaging(DCE)scanning,using a 3.0T MR scanner(Discovery 750 w,GE,USA).In DCE parameter images,the ROI was seted in the part with the most obvious enhancement of the tumor parenchyma,and the Ktrans,Ve,Kep values were obtained.The Ktrans,Ve,Kep values were described by x ±s,independent samples t test or Mann-Whitney test were performed to test differencesof these values between LGG and HGG.Analysis of variance(ANOVA)and Kruskal-Wallis test were performed to test the group differences of Ktrans,Ve,Kep values in II-IV grade gliomas.Spearman Rank correlation analysis was performed to assess the association of Ktrans,Ve,Kep values with glioma grades.P <0.05 was considered statistically significant.Receiver operating characteristic(ROC)curve was used to determine the optimal discrimination threshold and its sensitivity and specificity in gliomas with different grades.Results:(1)The Ktrans and Ve values of LGG were lower than HGG(P <0.05).There was no significant difference in Kep value between LGG and HGG(P> 0.05).The Ktrans and Ve values of grade II gliomas were significantly lower than grade III and grade ? gliomas(P <0.05).There was no significant difference in Ktrans and Ve values between grade ? and grade ? gliomas(P>0.05).(2)The Ktrans and Ve valueswere positively correlated with gliomas grading(r=0.724,P<0.02,r=0.622,P<0.01,respectively).(3)To further evaluate diagnostic efficacy of significantly indicators between LGG and HGG,ROC curve were performed.Results showed that Ktrans value had the highest diagnostic efficacy(AUC: 0.972),and Ve value had relatively higher diagnostic efficacy,with the sensitivity and specificity were 94.4% and 83.3%,respectively.ROC curve in discriminating grade II gliomas and grade III gliomas indicated that Ktrans value showed highest diagnostic efficacy(AUC: 0.752)and Ve value had relatively higher sensitivity(85.7%).Conclusion: The quantitative parameters(Ktrans and Ve values)of DCE-MRI can be used to evaluate the preoperative grading in glioma.Part IV: Comparison of the application values of 3D-ASL,IVIM and DCE-MRI in preoperative grading of gliomas.Purpose:To compare the application values of single 3D-ASL,IVIM orDCE-MRI,and the combination of two or three methods in the preoperative grading of gliomas.Methods: A total of 30 cases of glioma patients were collected and confirmed by pathology,including 12 low-grade gliomas(grade II)and 18 high-grade gliomas(grade III +grade IV).Among them,15 males and 15 females had an average age of 48.73 ± 9.21 years.All cases received conventional magnetic resonance imaging(MRI)scanning,3D-ASL scanning,intravoxel incoherent motion(IVIM)scanning,and dynamic contrast-enhanced magnetic resonance imaging(DCE)scanning.The t test was performed to test differencesof values in three methods between LGG and HGG.Receiver operating characteristic(ROC)curve was used to test differencesbetween single and the combination of diagnostic methods.P <0.05 was considered statistically significant.Results:The diagnostic efficacy of DCE-MRI was the highest(Ktrans AUC: 0.972),followed by IVIM(AUC: 0.907)and 3D-ASL(AUC: 0.574),when using a single test.When using a single method,DCE-MRI had the highest diagnostic efficacy(Ktrans AUC: 0.972),followed by IVIM(D*AUC: 0.907)and 3D-ASL(TBF AUC: 0.574).When combining two methods,the combination of D* in IVIM and Ktrans in DCE-MRI improved diagnostic ability(AUC: 0.991).The combination of three methods obviously improved the diagnostic ability,in which the combination of D* in IVIM,TBF in 3D-ASL,and Ktrans in DCE-MRI owned the highest diagnostic ability(AUC = 1).Conclusion: When using IVIM,3D-ASL orDCE-MRI alone,Ktrans in DCE-MRI had the highestdiagnostic ability.The combination of the two or three methods can significantly improve the accuracy of preoperative grading of gliomas. |
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