The Differential Diagnosis Value Of1H-MRS In Primary Central Nervous System Lymphoma And High Grade Gliomas

Objective: To explore the single voxel different echo time (TE=30/135ms) and multi voxel long echo time (TE=135ms) MRS in primary central nervous system lymphoma (PCNSL) and high grade gliomas (HGG) in the differential diagnosis value.Materials and Methods：A retrospective analysis of19cases of PCNSL (13cases confirmed by pathology,6cases were diagnosed by the diagnostic treatment) and HGG (22cases were confirmed by pathology) patient image data. All patients underwent Siemens Verio3.0T MRI examination, underwent conventional MRI plain and enhancement.19cases of PCNSL underwent single voxel short and long echo time MRS examination, including15cases of multi voxel long echo time MRS examination.22cases of HGG underwent single voxel short and long echo time MRS and multi voxel long echo time MRS examination. Analysis of different echo time single voxel MRS different metabolites in the core of tumor relative ratio, and analysis of different metabolites multi voxel long echo time MRS in the core of tumor and peritumoral in relative ratio. Application of Independent Samples Test and ROC curve analysis of metabolites index of both tumors,19.0SPSS software, P <0.05was statistically significant.Results: Single voxel short echo time MRS Cho/Cr and NAA/Cr had statistical significance in the differential diagnosis of PCNSL and HGG (P <0.05); Cho/NAA and Lac+Lip/Cr had no statistical significance in the differential diagnosis of both tumors (P>0.05). Single voxel long echo time MRS Cho/Cr, NAA/Cr and Cho/NAA were statistically significant in the differential diagnosis of both tumors (P <0.05). Multi voxel long echo MRS the core of tumor Cho/Cr、NAA/Cr and Cho/NAA had no statistical significance in the differential diagnosis of both tumors (P>0.05); peritumoral Cho/Cr, NAA/Cr and Cho/NAA had no statistical significance in the differential diagnosis of both tumors (P>0.05). Youden index of ROC curve was chosen as the best cut-off point for the diagnosis of PCNSL and HGG. Single voxel short echo time MRS the sensitivity and specificity of Cho/Cr, NAA/Cr in the differential diagnosis of both tumors respectively57.9%and95.5%,68.4%and90.9%. Single voxel long echo time MRS the sensitivity and specificity of Cho/Cr、NAA/Cr、Cho/NAA in the differential diagnosis of both tumors respectively42.1%and100%、68.4%and55%、89.5%and59.1%。 Conclusion：Single voxel MRS metabolite is an effective index for differential diagnosis of PCNSL and HGG, multi voxel long echo MRS has limited value in differential diagnosis.