原发性中枢神经系统淋巴瘤MRI波谱和灌注分析及其病理对照

The H-MRS and PWI analysis of primary central nervous system lymphoma and pathological correlation

目的分析原发性中枢神经系统淋巴瘤（PCNSL）的MRI波谱和灌注特点，提高MRI对该病诊断的准确率。方法选择2010年10月至2014年6月经病理证实的20例PCNSL患者，其中解放军总医院12例，日照市人民医院8例。20例均行MRI平扫及增强扫描，10例行H—MRS波谱分析和PWI灌注扫描，分析其MRI特点，并与病理学对照。结果20例患者中弥漫性大B细胞非霍奇金淋巴瘤19例，T细胞淋巴瘤1例；单发8例，多发12例。共检出40个病灶，其中位于幕上病灶32个，幕下病灶8个。32个位于丘脑、基底节区、胼胝体、中脑及脑桥、小脑半球等深部脑组织，8个位于颞叶、额叶、枕叶及顶叶等脑实质表面。MRI图像18例T1WI呈等或低信号，T2WI多呈等或稍高信号，DWI多呈等或稍高信号，增强扫描18例明显均匀强化，1例不均匀中等强化，1例不均匀环形强化；有2例信号不均匀；10例行H—MRS显示胆碱（Cho）峰明显升高，N-乙酰天门冬氨酸（NAA）峰明显下降，均出现高大的脂质（Lip）峰，有6个病灶出现乳酸（Lac）峰。10例行灌注加权成像，PWI结果显示局部脑血容量、局部脑血流量下降，均为蓝色或蓝黑色灌注，显示为明显低灌注结节。结论T1WI呈等或稍低信号，T2WI呈等或稍高信号，增强扫描明显均匀强化以及H—MRS显示Cho峰明显升高，NAA峰明显下降，均出现高大的Lip峰和Lae峰对诊断PCNSL有明显的提示意义。

Objective To analysis the MRI features of primary central nervous system lymphoma （PCNSL） and improve the accuracy of MRI diagnosis. Methods From October 2010 to June 2014,MRI features of 20 cases of PCNSL confirmed by pathology were retrospectively analyzed, including 12 cases of General Hospital of PLA,8 cases of Rizhao People＇s Hospital.All the cases were accepted MRI plain scanning and enhanced scanning.Ten patients were accepted H-MRS analysis and PWI scan. Results Of the 20 cases,8 were single lesion,12 were multiple lesions.With total of 40 lessions,supra-tentorial lesions were found in 32 lesions,the lesions involved infra-tentorial were found in 8 lessions.32 lesions located in deep- brain tissue, such as the thalamus,basal ganglia,corpus callosum,midbrain,pons and cerebellar hemisphere. Eight lesions located at the surface of the brain,such as the temporal lobe,frontal lobe, occipital lobe and parietal lobe.The PCNSL manifested uniform or low TIWI signal,uniform or slight high T2WI signal,slight high or high signal on FLAIR,and slight high signal on DWI.Eighteen cases manifested uniform signal and 2 cases manifested non-uniform signal.Different degrees of edema and mass effect were found combined with the lesions.In enhancement scanning,significant homogeneous enhancement was shown in 18 cases,moderate heterogeneous enhancement was shown in one case and ring-shaped enhancement was shown in one case.Ten cases H-MRS showed Cho peak significant increased,NAA peak significant decreased, and all showed Lip peak,6 cases showed Lac peak.Ten cases PWI scan showed significant low perfusion lesion,rCBV and rCBF decreased. Conclusion Uniform or low T1WI signal,uniform or slight high T2WI signal and significant homogeneous enhancement,and H-MRS analysis Cho peak significant increased,NAA peak significant decreased,and all showed Lip peak,some showed Lac peak all these certain characteristics was helpful to make correct diagnosis of PCNSL.