Application Value Of Multimode Magnetic Resonance Imaging In Differential Diagnosis Of Tumors In The Fourth Ventricle

ObjectiveMultimodal magnetic resonance imaging(DWI,DKI and MRS)was used to determine the internal composition and cell proliferation status of the tumor in the four-ventricle.The diagnostic efficacy of single parameter and multiparameter in the diagnosis of different levels and types of tumors were analyzed.The aim of this study is to analyze the correlation between the imaging parameters and the Ki-67 positive indexes,and to determine the value of magnetic resonance imaging parameters as the biomarker of proliferation in diagnosis brain tumors of the fourth ventricle.Materials and MethodsA total of 43 patients with four ventricle brain tumors were collected,and all patients had informed consent prior to the examination.According to the world health organization(WHO)2016 central system tumor classification standard,cases include 8 cases WHO ? grade(8 cases of pilocytic astrocytoma),12 cases WHO ? grade(7 cases of ependymoma,1 case of oligoastrocytoma,3 cases of diffuse astrocytoma,1 case of myxoid astrocytoma),8 cases WHO ? grade(8 cases of anaplastic ependymoma),15 cases WHO IV grade(13 cases of medulloblastoma,1 case of central nervous system embryonal tumors NOS,1 case of glioblastoma).Of these,29 were men and 14 were women.The average age was 17.63 ±13.01 years.There were 20 patients in]ow grade tumor group(WHO I grade and II grade)and 23 patients in the high grade group(WHO III grade and ? grade).All the 43 patients underwent routine T1WI,T2WI,DWI,DKI and MRS scanning.The multimodal imaging paremeters including apparent diffusion coefficient(ADC)value,the average diffusion kurtosis(MK)value,radial kurtosis(Kr)value,axial kurtosis(Ka)value,average diffusion coefficient(MD)value,fractional anisotropy(FA)value,and choline/cretine(Cho/Cr)ratio value were compared for the four ventricle brain tumors.Spearson correlation analysis was used to analyze the correlation between multimodal imaging parameters(MK,MD,Kr,Ka,FA,ADC,Cho/Cr)and Ki-67 positive indexes.Pathologic results as the gold standard.Independent sample t test(measurement)or chi-square test(count)was used to compare the difference of multimodal imaging parameters in high grade and low grade group and between different types of tumors.The independent sample t-test and logistic regression analysis and the ROC curve was used in evaluation parameters and multi-parameter joint value,sensitivity and specificity in the identification of the tumors,and the area under the curve(AUC)was calculated.P<0.05 has statistical significance.Results1.The age and gender differences of four ventricle brain tumor between high grade tumor group and low grade group,anaplastic ependymoma and medulloblastoma were statistical analyzed.The results showed that the average age of the high grade group was lower than that of the low grade group,and the difference was statistically significant(P=0.0028).The mean age of anaplastic ependymoma was lower than that of medulloblastoma,and the difference was not statistically significant(P=0.466).There was no statistically significant difference in the gender between each groups(P>0.05).2.The values of MK,Ka,Kr and Cho/Cr in the high grade group were higher than those in the lower grade group,and the difference was statistically significant.The ADC and MD values of the high grade group were lower than those in the low grade group and the difference was statistically significant(P<0.05).The FA value of the high grade group was higher than that of the low grade group,and the difference was statistically significant(P=0.039).The area under the curve of MK,Kr,Ka,MD,FA,ADC and Cho/Cr was 0.937,0.889,0.925,0.810,0.742,0.800 and 0.760 respectively.The area under the curve of multiparameter combined diagnosis was 0.980.The sensitivity and specificity of multiparameter combined diagnosis were 100%and 85.7%.The MK,Kr,Ka and Cho/Cr value of medulloblastoma were higher than those of anaplastic ependymoma(P<0.05).The MD value of medulloblastoma was lower than that of the anaplastic ependymoma,and the difference was statistically significant(P<0.05);The FA value and ADC value of medulloblastoma were slightly lower than that of the anaplastic ependymoma,which was not statistically significant(P>0.05).The area under the curve of MK,Kr,Ka,MD,FA,ADC and Cho/Cr was 0.952,0.893,0.786,0.857,0.774,0.643 and 0.738 respectively.The area under the curve of multiparameter combined diagnosis was 0.964.The sensitivity and specificity of multiparameter combined diagnosis were 100%and 85.7%.3.Ki-67 positive indexes in the high grade group was higher than that of the low grade tumor group,and the highest level of medulloblastoma,followed by the anaplastic ependymoma,ependymoma and astrocytoma in four ventricle region.MK,Kr and Ka values increased with the increase of Ki-67 positive indexes,and there were positively correlated with Ki-67(R value was 0.884,0.777,0.850,respectively,P<0.01).The MD and ADC value decreased with the increase of Ki-67,and there were negatively correlated with Ki-67,and the difference was statistically significant(The r value was-0.881 and-0.812 respectively.P<0.01).The FA value was not statistically significant(r=0.490,P>0.05).Cho/Cr value increased with Ki-67 and positively correlated with Ki-67,and the difference was statistically significant(r=0.879,P<0.01).ConclusionsDWI,DKI and MRS are valuable in diagnosis of tumors in the four ventricle.For single mode parameter in identification of high and low grade tumor in the four ventricle,DKI has the highest diagnostic accuracy,and diagnosis efficiency of MK is the highest.Multimode of DKI combining DWI,MRS can increased specificity of magnetic resonance imaging in diagnosing tumors in the four ventricle.The magnetic resonance parameter MK value can be used as a index for the evaluation of proliferation level in the tumor of the four ventricle,and the MK value is the best independent factor to predict status of Ki-67 positive indexes.