Lu S-S, Kim S J, Kim H S, Choi C G, Lim Y-M, Kim E J, Kim D Y, Cho S H
From the Department of Radiology and Research Institute of Radiology (S.-S.L. S.J.K., H.S.K., C.G.C., D.Y.K., S.H.C.).
AJNR Am J Neuroradiol. 2014 Feb;35(2):270-7. doi: 10.3174/ajnr.A3677. Epub 2013 Aug 8.
It may be challenging to differentiate primary CNS lymphomas, especially primary CNS lymphomas with atypical MR features, from tumefactive demyelinating lesions by the use of conventional MR. This study aimed to investigate the usefulness of (1)H-MR spectroscopy for making this discrimination.
Forty-four patients with primary CNS lymphomas and 21 with tumefactive demyelinating lesions were enrolled. Single-voxel (TE = 144 ms) (1)H-MR spectroscopy scans with the use of the point-resolved spectroscopy sequence were retrospectively analyzed. The Cho/Cr and Cho/NAA area ratios were calculated. The lipid and/or lactate peak was visually categorized into 5 grades on the basis of comparison with the height of the Cr peak. The (1)H-MR spectroscopy findings were compared in all of the primary CNS lymphomas and the tumefactive demyelinating lesions and in the subgroup of atypical primary CNS lymphomas and tumefactive demyelinating lesions. The thresholds and added value of (1)H-MR spectroscopy to conventional MR were calculated by use of receiver operating characteristic curves.
Discrepancies between all of the primary CNS lymphomas and tumefactive demyelinating lesions were found in the Cho/Cr ratio (P = .000), Cho/NAA ratio (P = .000), and the lipid and/or lactate peak grade (P = .000). Lymphoma rather than tumefactive demyelinating lesions was suggested when the Cho/Cr ratio was >2.58, the Cho/NAA ratio was >1.73, and a high lipid and/or lactate peak grade (grade >3) was seen. Higher Cho/Cr ratios, Cho/NAA ratios, and lipid and/or lactate peak grades were found in atypical primary CNS lymphomas when compared with those of tumefactive demyelinating lesions. The area under the receiver operating characteristic curve of conventional MR was improved from 0.827 to 0.870 when Cho/NAA ratio was added in the uncertain cases.
(1)H-MR spectroscopy may be useful for differentiating primary CNS lymphomas from tumefactive demyelinating lesions. Cho/NAA ratio could provide added value to conventional MR imaging.
使用传统磁共振成像（MR）来鉴别原发性中枢神经系统淋巴瘤，尤其是具有非典型MR特征的原发性中枢神经系统淋巴瘤与瘤样脱髓鞘病变可能具有挑战性。本研究旨在探讨氢质子磁共振波谱成像（¹H-MR光谱）在进行这种鉴别诊断中的作用。
纳入44例原发性中枢神经系统淋巴瘤患者和21例瘤样脱髓鞘病变患者。回顾性分析使用点分辨光谱序列进行的单体素（回波时间[TE]=144毫秒）¹H-MR光谱扫描。计算胆碱/肌酸（Cho/Cr）和胆碱/ N-乙酰天门冬氨酸（Cho/NAA）面积比。根据与肌酸（Cr）峰高度的比较，将脂质和/或乳酸峰在视觉上分为5个等级。比较所有原发性中枢神经系统淋巴瘤和瘤样脱髓鞘病变以及非典型原发性中枢神经系统淋巴瘤和瘤样脱髓鞘病变亚组的¹H-MR光谱结果。使用受试者工作特征曲线计算¹H-MR光谱相对于传统MR的阈值和附加值。
在Cho/Cr比值（P = .000）、Cho/NAA比值（P = .000）以及脂质和/或乳酸峰等级（P = .000）方面，所有原发性中枢神经系统淋巴瘤与瘤样脱髓鞘病变之间均存在差异。当Cho/Cr比值>2.58、Cho/NAA比值>1.73且出现高脂质和/或乳酸峰等级（等级>3）时，提示为淋巴瘤而非瘤样脱髓鞘病变。与瘤样脱髓鞘病变相比，非典型原发性中枢神经系统淋巴瘤的Cho/Cr比值、Cho/NAA比值以及脂质和/或乳酸峰等级更高。在不确定的病例中加入Cho/NAA比值后，传统MR的受试者工作特征曲线下面积从0.827提高到0.870。
¹H-MR光谱可能有助于鉴别原发性中枢神经系统淋巴瘤与瘤样脱髓鞘病变。Cho/NAA比值可为传统MR成像提供附加值。
