| ObjectiveThe brain metastases and high grade gliomas are common malignancies in the brain.The misdiagnosis often appeared due to partial overlap findings in the conventional MRI.In particular,when the brain metastases lack a history of primary neoplasms,the differential diagnosis between brain metastases and high grade gliomas may be more difficult.Misdiagnosis before surgery or improper choice of clinical treatment can greatly increase the risk of tumor metastasis or recurrence.Therefore,it is of great significance for clinic to use non-invasive means to qualitatively and quantitatively analyze tumor blood vessels and blood supply characteristics to assist in qualitative diagnosis and differential daignosis,which is also a difficult problem in clinical reseach.Dynamic susceptibility contrast-enhanced perfusion-weighted imaging(DSC PWI)can obtain several blood flow parameters to reflect the level of new capillary blood vessels,permeability and maturity of blood vessels,which is widely used in the brain metastases and high grade gliomas.The purpose of this study was to evaluate the value of mean regional cerebral blood volume(rCBVmean)value of the maximal tumor and the peritumoral edema?the standardized rCBV(rCBVstandard)value?themaximal tumorous mean regional cerebral blood flow(rCBFmean)? mean transit time(MTTmean)and time to peak(TTPmean)from DSC PWI,to analyze the value in differential diagnosis of the metastatic brain tumors from high grade gliomas by statistic analysis.MethodsAn analysis of conventional MRI and DSC PWI data of 26 cases of metastatic brain tumor,15 cases of high grade gliomas was performed.According to previous studies,the tumors and the peritumoral edema can be defined as: tumor,near peritumoral edema area(on the contrast enhanced imagings,the area within 1cm from the outer margin of the enhanced tumor),and far peritumoral edema area(on the contrast enhanced imagings,the area outside 1cm from the outer margin of the enhanced tumor).In this study,the region of interest(ROI)was placed on the junction of near peritumor edema area and far peritumor edema area.Post-processing software was performed to generate rCBV pseudo-color map,measuring rCBVmeanvalue of maximal tumor and peritumoral edema,calculating the ratio of the two values(the maximal tumorous rCBVmeanvalue/ peritumor edema rCBVmeanvalue to genereta the standardized rCBV(rCBVstandard)value.Meanwhile,the maximal tumorous rCBFmean value ? MTTmean value and TTPmeanvalue were generated on corresponding perfusion parameters maps to analyze the value in differential diagnosis of the metastatic brain tumor from high grade gliomas statistically.ROC was used to evaluate the diagnostic efficiency of tumorous rCBVmean and rCBVstandard value between the metastatic brain tumor and high grade glioma.The corresponding sensitivity,specificity,Younden index and area under the curve(AUC)were calculated,and a comparison of diagnostic efficacy was performed.ResultsTumorous rCBFmean values of metastatic brain tumor and high grade glioma were(15.16±6.42)ml/100g/s?(31.55±11.95)ml/100g/s respectivelyas revealed no statistical differences(P>0.05).Tumorous MTTmeanvalues of metastatic brain tumor and high grade glioma were(22.25±7.75)s ?(22.73±2.86)s respectively as revealed no statistical differences(P>0.05).Tumorous TTPmean values of metastatic brain tumor and high grade glioma were(22.25±7.75)s?(22.73±2.86)s respectively as revealed no statistical differences(P>0.05).Tumorous rCBVmeanvalues of metastatic brain tumor and high grade glioma were197.68±49.24ml/100 g ? 362.05±58.02ml/100 g respectively as revealed statistical differences(t=-2.397,P<0.05).The rCBVstandardvalues were2.26±1.06 ? 6.60±2.48 respectively,also with statistical differences(P<0.05).There were no statistical differences in the peritumoral edemal rCBVmean values(P>0.05),which were52.29±12.53ml/100 g and 54.17±16.59ml/100 g respectively.With 196.06ml/100 g as the optimal diagnostic threshold for rCBVmean value,the corresponding sensitivity?specificity and AUC were 61.54%?73.33% and0.654 respectively,but with 1.89 as the optimal diagnostic threshold for rCBVstandard value,the corresponding sensitivity?specificity and AUC were88.46%?73.33% and 0.826 respectively.The rCBVstandard value can appear higher diagnostic efficiency in differentiating brain metastasis from high grade glioma with DSC PWI(Z=2.259,P<0.001).Conclusion1.There were higher differential diagnostic efficiency in differentiating brain metastasis from high grade glioma and more clinical significance in the method of rCBVstandard value(the ratio of maximal timorous mean rCBV value and peritumoral edema mean rCBV value,tumorous rCBVmean value /peritumoral edema rCBVmean value)than the method of timorous rCBV value.2.There were no statistical differences in tumorous rCBFmean ?MTTmean ? TTPmean values,which showed less significance for clinic to distinguish brain metastasis from high grade glioma.3.There are less significance in distinguishing brain metastasis from high grade glioma by the peritumoral edemal(the junction of near peritumor edema area and far peritumor edema area)rCBVmean value.However,the peritumoral edemal rCBVmean value can standardize the timorous rCBV value to improve the diagnostic efficiency. |
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