Differential Diagnosis of Intracranial Lymphoma from Tumor-like Demyelinating Lesions by Using 1H-MRS / 中国医学影像学杂志

ABSTRACT

Purpose To investigate 1H-MRS in differentiating intracranial lymphoma from tumor-like demyelinating lesions. Materials and Methods Thirty-three cases of intracranial lymphoma confirmed by pathology and 18 cases of tumor-like demyelinating lesions confirmed by pathology or clinic were recruited in this study. Imaging data including single-voxel (TE=144 ms) 1H-MRS was retrospective analyzed. The Cho/Cr and Cho/NAA area ratios were calculated. The lipid and lactate peak was visually categorized into 5 grades based on the ratio of Lip-Lac peak to the height of the Cr peak. 1H-MRS findings of the intracranial lymphoma and the tumor-like demyelinating lesions were compared. The differentiation of the two diseases diagnosed by 1H-MRS and conventional MR were evaluated by use of receiver operating characteristic curves. Results There were significant difference of Cho/Cr, Cho/NAA ratio and Lip-Lac peak level between the intracranial lymphoma and tumor-like demyelinating lesions (P2.56, Cho/NAA ratio was>1.71, and Lip-Lac peak grade was>3. Cho/Cr, Cho/NAA ratio and Lip-Lac peak grade were found higher in atypical intracranial lymphomas when compared with those of tumor-like demyelinating lesions. The area under the receiver operating characteristic curve of conventional MR was increased from 0.827 to 0.870 when Cho/NAA ratio was added for analysis in the 28 uncertain cases. Conclusion 1H-MRS has great clinical significance for differentiating intracranial lymphoma from tumor-like demyelinating lesions. The values of Cho/Cr ratio>2.56, Cho/NAA ratio>1.71 and Lip-Lac grade >3 suggest intracranial lymphoma rather than TDLs. When the conventional MR imaging features can not do the differentiation, Cho/NAA ratio is a useful complement.