Study On MRI Combined With PET-CT Improving The Diagnostic Accuracy Of Glioma

PurposeThe concept of multimodal image fusion is of great significance for the diagnosis and differentiation of glioma.Firstly,a systematic review was done to assess the merits and demerits of MRI and PET-CT of different tracers.Moreover,the function of multimodal imaging scan in differentiating tumefactive demyelinating lesions?TDLs?and gliomas were studied.MethodPubMed and Cochrane Library were used to retrieve the literature.The literature publication date is before December 2015.According to the criteria,the target literature was selected to extract the information valid for the meta-analysis and then to synthesize the advantages and disadvantages of glioma diagnosis of MRI and PET-CT scan of different tracers.Subsequently,31 cases were collected retrospectively.A total of 17 patients with glioma and 14 patients with demyelinating lesions were enrolled.All patients underwent conventional MRI examination at the stage of disease diagnosis,including MRI and enhanced MRI.PET-CT scans were performed with ¹⁸F-FDG and ¹¹C-MET as tracers after MRI.The following issues were figured out,?1?the importance of each MRI imaging feature for differentiating diffusing gliomas and TDLs;?2?the value of PET-CT using the two different tracers in diagnosing TDLs;?3?the value of CT for diagnosis of glioma.The results were analyzed statistically using R 3.3.2.ResultsA total of 14 target documents were included.Each study involved in the systematic review contains conventional MRI examinations.At the same time,four of these literatures involve ¹⁸F-FDG PET-CT;5 articles involve ¹¹C-MET PET-CT;5 articles involve ¹⁸F-FET PET-CT;3 articles involve ¹⁸F-FLT PET-CT.Conventional MRI has a much stronger ability in showing anatomical structures than PET-CT.However,the ability of MRI detecting the tumor boundary and tumor invasion is inferior to PET-CT scan.¹⁸F-FDG PET-CT can better distinguish "living tissue" and necrotic tissue to show the necrosis inside glioma tissue.¹¹C-MET PET-CT is a more accurate imaging scan in forming the border of glioma when compared with conventional MRI,providing more accurate information for surgery.Both of ¹⁸F-FDG PET-CT and ¹¹C-MET PET-CT have the value of estimating glioma grade.Compared with ¹⁸F-FLT PET-CT,¹⁸F-FET PET-CT showed tumor boundaries closer to the biological boundary of glioma,and has a greater significance for the diagnosis of high-grade gliomas.Subsequently,when only considering MRI features of gliomas and TDLs,the degree of mass effect and edema around the lesions show statistically significant in forming a correct initial diagnosis.The value of ¹⁸F-FDG PET-CT and ¹¹C-MET PET-CT in differentiating glioma from TDLs also has statistically significant.Combined with the information obtained from both conventional MRI and PET-CT,a more exact diagnosis may be formed for the following management program.ConclusionMRI examination can more clearly show the anatomical structure,and PET-CT scan using different kinds of tracers based on the metabolism of glioma have more advantages in judging the degree of malignancy and the tumor boundary.However,the tumor-related information provided by PET-CT with different tracers is not the same.The idea that conventional MRI imaging features in diagnosing gliomas and differentiating glioma and TDLs has been widely recognized already.Statistically,the identification based on such characteristics is indeed sufficiently scientific and reliable.But there are some cases of TDLs in which MRI features are not typical.At this kind of occasion,¹⁸F-FDG PET-CT and ¹¹C-MET PET-CT can provide additional information.Additionally,the first diagnostic step-CT can provide special significance for the differentiation of glioma and TDLs.Combined with different information provided by the means of imaging,learning from each other,the accuracy of the initial diagnosis of glioma can be improved to a large extent.With concept of multimodality imaging diagnosis,the goal of early diagnosis of glioma and early treatment can be achieved,and a better prognosis can be gotten.