原发性中枢神经系统淋巴瘤的MRI及^1H-MRS特点

MRI and 1 H-MRS Characteristics of Primary Central Nervous System Lymphomas (PCNSL)

目的探讨免疫功能正常人原发性中枢神经系统淋巴瘤(PCNSL)的常规MRI及多体素质子磁共振波谱(1H-MRS)表现。资料与方法对21例经手术病理证实的PCNSL的MRI和1H-MRS表现进行回顾分析。结果21例患者共检出33个病灶,其MRI及1H-MRS表现具有如下特点:(1)病灶T1WI多呈低或等信号,T2WI呈等或稍低信号,单发或多发,境界清晰。(2)轻中度瘤周水肿,并可见“火焰样”特征性水肿。(3)增强后病灶多明显均匀强化;“缺口征”、“尖角征”的出现具有特异性。(4)1H-MRS常表现为胆碱(Cho)峰升高,肌酸(Cr)降低,氮-乙酰天门冬氨酸(NAA)缺失,并出现高耸的脂质(Lip)峰。在实性肿瘤中出现明显升高的Lip峰对诊断PCNSL具有高度特异性。结论传统MRI在PCNSL的诊断中起着重要的作用,结合1H-MRS表现,可以提高MRI对PCNSL的诊断水平。

Objective To discuss MRI and ^1H-MRS findings of PCNSL in immunocompetent patients. Materials and Methods MRI and ^1H-MRS findings in 21 patients with pathologically proved PCNSL were analyzed retrospectively. Results 33 lesions were identified in 21 patients. The MRI and ^1H-MRS findings of PCNSL were as follows： （1）hypo or isointense on T1-weighted images and iso or slightly hypointense on T2-weighted images, solitary or multiple lesions and well-defined; （2）slightly or moderate peritumoral edema, and character by flame-like edema; （3）enhancement was intense and homogeneous, the presence of “incision sign” and “angular sign” were more specific： （4）proton MR spectroscopy showed different spectral peaks including prominent choline-containing compounds, decreased or absence of creatine and N-acetyl aspartate, together with a massively elevated lipid resonances. The presence of highly elevated lipids in a solid tumor was more specificity for the diagnosis of PCNSL. Conclusion Conventional MRI plays an important roles in the diagnosis of PCNSL, MR spectroscopy combined with conventional MRI can improved MRI diagnostic accuracy of PCNSL.