Application Of Quantitative Analysis Of DCE-PWI And ASL In Pathological Grading And Classification Of Meningiomas

Objective:On the basis of conventional MRI plain scan and contrast-enhanced sc anning,the value and advantages of dynamic contrast enhanced MRI（DCE-MRI）and arterial spin labeling（ASL）in the diagnosis of meningioma were discussed.I t can provide reference for pathological grade and subtype classification of menin gioma,and then provide objective basis for accurate diagnosis and scientific treat ment of meningioma.Methods:44 cases of meningioma confirmed by pathology（including benign and malignant meningioma）were collected according to the criteria of inclusion and exclusion.All patients underwent routine MRI scan,2D-ASL,DCE-MRI scan,and then routine enhanced scan before operation.The quantitative parameters of DCE-MRI were obtained by using Siemens Syngo workstation and Tissue-4D software.The quantitative parameters of DCE-MRI were obtained as follows:volume transfer constant,extracellular space volume fraction,blood reflux constant.Using the mosatic split to one sevies program of Siemens Syngo workstation,to generate pseudo color images of relative cerebral blood flow and obtain ASL quantitative parameters:relative cerebral blood flow（rCBF）.The characteristics of the parameters of high and low grade meningiomas and different subtypes of meningiomas were compared,and the correlation between the two perfusion parameters（Ktrans and Ve）and the pathological grade of the tumors was analyzed quantitatively.The diagnostic efficacy was evaluated.All data were statistically analyzed with SPSS22.0 software,and the pathological grade and classification were based on the 2016 version of the WHO classification standard.Results:Two groups were divided into WHO class I meningioma and WHO class II meningioma,38 cases of WHO class I meningioma（benign）,and 6 cases of WHO II meningioma（malignant）.The pathological subtypes were mainly meningeal epithelial type（9 cases）and fibrous type（12 cases）.There were 15 cases of transitional type.All the patients could clearly show the lesions in ASL and DCE.1.Pathological grading and typing of meningiomas ASL parameters characteristics:The rCBF pseudo color images generated by the ASL sequence showed that the perfusion of both benign and malignant meningiomas increased.In comparison among groups,the mean rCBF of benign and malignant meningioma was 622.616±152.5147 and486.250±51.1875 respectively,and there was no statistical difference（t=1.761,P=0.086）.The mean values of rCBF in the near tumor region were 329.050±30.1048and175.892±64.8895 respectively,and the difference was statistically significant（t=1.628,P=0.062）.In group comparison,the rCBF value of benign and malignant meningioma was greater than that of the same level near the tumor peritumoral area（rCBF）,and the difference was statistically significant（P<0.05）.2.Characteristics of DCE parameters in pathological grading and typing of meningioma:Comparison between groups:benign meningiomas Ktrans,Ve and Kep values were（0.105±0.060）min^-1,0.361±0.116,（0.287±0.128）min^-1 and the values of Ktrans,Ve and Kepin malignant meningioma were（0.274±0.078）min^-1,0.652±0.165,（0.422±0.089）min^-1,respectively.There was a significant difference between the Ktrans and Ve values of benign and malignant meningiomas（P<0.05）,and there was no significant difference between the values of Kep（P=0.054>0.05）.There was a statistically significant difference in Ktrans and Kep between different subtypes（meningeal epithelial type,fibrous type,transitional type）of WHO grade I meningioma,and Ve value was not statistically significant.Spearman correlation analysis showed that there was a significant correlation between Ktrans,Ve,rCBF and meningioma（rs=0.475,0.435,-0.328,P<0.05）.The two kinds of perfusion parameters（Ktrans and Ve）were relative（P<0.01）.ROC curve analysis showed that when Ktrans=0.187/min-1,its diagnostic sensitivity and specificity were 100%and 92.1%,respectively.When Ve=0.701,its sensitivity and specificity were 75%and 100%respectively.The time signal intensity curve showed that after the contrast agent head,the elevation of all meningioma regions was significantly higher than that of the normal white matter area of the corresponding part of the contralateral area.Conclusions:Traditional MRI can only show the signal characteristics and surrounding tissues of meningioma.It is difficult to provide valuable information for the differential diagnosis of benign and malignant tumors.PWI technique is a supplementary technique for the diagnosis of meningioma and has been a hot research topic of MRI multimodal imaging in recent years.ASL is simple to operate,no intravenous gadolinium injection is needed,and can be quantitatively evaluated at tissue level for cerebral blood perfusion.The difference of rCBF parameters between benign and malignant meningiomas was statistically significant,which was helpful to the diagnosis of meningiomas.It is worth popularizing the application value of.DCE-MRI is of high value in the application of tumor.DCE can observe the blood vessel distribution and blood perfusion information of tumor tissue.Its perfusion parameters can classify meningiomas and provide accurate information for pathological typing.It is helpful to differentiate the pathological grade and subtype of meningioma and to provide valuable information for preoperative treatment.