原发性中枢神经系统淋巴瘤MRI表现及误诊原因分析

MRI FEATURES OF PRIMARY LYMPHOMA IN CENTRAL NERVOUS SYSTEM AND ITS CAUSE OF MISDIAGNOSIS

目的探讨原发性中枢神经系统淋巴瘤的MRI主要表现,总结其误诊原因。方法回顾性分析21例原发性中枢神经系统淋巴瘤病例MRI表现及误诊原因。结果MRI平扫显示,病灶T1WI多呈稍低信号,T2WI呈等或稍高信号,FLAIR呈稍高或高信号,DWI多为稍高或高信号。MRI增强扫描显示病灶多显著均匀强化,形态为多发节结状、团块状,边缘多有"棘状"突起及分叶,极少数呈环形强化。21例病人中,MRI诊断正确者15例;误诊6例,其中脑胶质瘤3例、转移瘤1例、脑炎1例、脑膜瘤1例,误诊主要原因是其MRI表现不典型。结论MRI诊断原发性中枢神经系统淋巴瘤具有较高的准确性,但对于非典型病例的诊断还有一定的困难。

Objective To study the main MRI features of primary central nervous system lymphoma （PCNSL） and analyse its misdiagnosis. Methods A retrospective analysis was done in 21 cases of PCNSL in terms of its MRI features and causes of misdiagnosis. Results On plain scan： most of them presented slightly low signal on T1-weighted imaging （T1WI） and slightly high signal on T2 weighted imaging （T2WI）, slightly hyper or hyperintense on fluid attented inversion recovery （FLAIR）, and hyperintense on diffusion weighted imaging （DWI）. On enhanced scan： most lesions presented obvious and homogeneous enhancement, multiple nodes or bolus in form, and most have thorn form margin and sublobe and seldom presented ring-form enhancement. Among the 21 cases, 15 were correctly confirmed on MRI, but six failed. Of the misdiagnosed, three were diagnosed as neurospongioma, one as brain metastatic tumor, one as encephalitis, and one as meningothelioma. An atypical appearance on MRI was the main cause of misdiagnosis. Conclusion Higher accuracy of PCNSL diagnosis can be achieved by MRI, but for atypical cases some difficulties still exist.