The Value Of Enhanced MRI And PET/CT In Differential Diagnosis Of Primary Central Nervous System Lymphoma

Purpose: The enhanced MRI and PET/CT in primary central nervous system lymphoma(PCNSL),high-grade gliomas,metastases of different imaging features were analyzed,summarized the characteristic features of the summary of the performance of PCNSL,in order to improve the diagnostic accuracy of PCNSL,used to guide the development of clinical treatment programs.Methods: The subjects were treated by surgery to obtain pathological results,including 9 cases of PCNSL,17 cases of high-grade gliomas and 10 cases of metastases.High-grade glioma in WHO Ⅲ grade 4 cases,WHO Ⅳ grade 13 cases.Metastases originated from the lung.All patients were not treated with radiotherapy,chemotherapy and hormone therapy,head enhancement MRI and PET/CT were performed within 2 weeks before operation.Enhanced MRI examination using contrast agent Gd-DTPA.MRI focuses on the location of different pathological types of tumors,peritumoral edema and the characteristics of strengthening.PET/CT was examined using tracers for18F-FDG and11C-MET.Visual analysis of different types of tumor18F-FDG and11C-MET PET/CT metabolism.Semi-quantitative analysis method was used to analyze the white matter ratio(T/WM)of different types of tumors,and to compare the difference of T/WMFDG and T/WMMET between tumors,ROC curve was used to determine the differential diagnosis threshold of PCNSL with high-grade gliomas and metastases.SPSS17.0 software was used for statistical analysis.Results:1,the enhancement on MRI,PCNSL,respectively,compared with high-grade glioma,metastases,close to the midline and around lateral ventricle and uniformly enhanced lesions was statistically significant difference(P < 0.05),there was no statistically significant difference in the peritumoral edema(P > 0.05).2,PET/CT visual analysis: PCNSL,respectively,compared with metastases,in18F-FDG PET/CT metabolic level difference was statistically significant(P < 0.05),there was no statistically significant difference compared with high-grade glioma(P>0.05).However,in11C-MET PET/CT metabolism,PCNSL with high-grade glioma,metastases are characterized by high metabolism.3,PET/CT semi-quantitative analysis:T/WMFDG in PCNSL were compared with highgrade glioma,metastases,the difference was statistically significant(P < 0.05).According to Youden index,the differential diagnosis threshold of T/WMFDG in PCNSL and high-grade gliomas was 3.40,sensitivity 77.8%,specificity 58.8%,and accuracy 65.4%,positive predictive value 50.0%,negative predictive value 83.3%.In the differential diagnosis of PCNSL and metastases,the threshold of L/WMFDG was3.15,sensitivity 88.9%,specificity 70.0%,and accuracy 78.9%,positive predictive value 72.7%,negative predictive value of 87.5%.There was no significant difference in T/WMMET between PCNSL and high-grade gliomas and metastases(P> 0.05).Conclusions:Enhanced MRI and PET/CT contribute to the diagnosis and differential diagnosis of PCSNL.In the enhancement of MRI,according to the predilection site and the characteristics of the lesions can be initially identified PCNSL.18F-FDG visual analysis is better than11C-MET in differential diagnosis of PCNSL and metastases.T/WMFDG can be evaluated at 3.40,3.15 as PCNSL and high-grade glioma and metastases differential diagnosis threshold.