目的 分析中枢神经系统白血病 的影像表现及CT、MRI的诊断效能。方法 选取2016年7月至2017年7月我院收治的40 例中枢神经系统白血病(CNSL)患者为研 究对象，均行CT、MRI平扫与增强扫描检 查，分析其影响学表现，观察病变部位信 号特点，对比不同类型白血病患者中枢神 经系统浸润部位，以脑脊液检查(CSF)结 果为金标准，分析CT与MRI诊断CNSL的灵 敏度、特异度、准确度。结果 本组病例 中，①白血病浸润软脑膜3例，CT可见脑 沟、脑池消失，内见条状低密度灶，MRI 表现为T1WI低信号，T2WI/FLAIR呈高信 号，脑回肿胀，DWI稍高信号，增强后明 显强化，②脑实质浸润6例，均为多发肿 块，MRI呈T1WI低信号、T2WI/FLAIR高信 号、DWI高信号，无明显占位效应，增强 后强化，其中3例合并出血，③硬脑膜受 累19例，累及额部板障，CT见软组织密度 灶，MRI见软组织信号灶，增强后明显强 化，余下12例为上述类型的混合型，包 括软脑膜浸润、脑实质浸润、硬脑膜受累 等同时存在，病灶见混杂短/等T1WI信号 及短/长T2WI信号；不同类型白血病患者 各浸润部位对比差异无统计学意义(P＞ 0.05)；MRI诊断CNSL的特异度83.33%、 准确度87.50%高于CT 16.67%、67.50%(P ＜0.05)，而灵敏度(76.47% vs 88.24%) 对比差异无统计学意义(P＞0.05)。结论 中枢神经系统白血病CT与MRI检查时影像 学表现有一定特征性，尤其是MRI增强检 查有助于提高诊断效能，值得在临床推广 应用。

Objective To analyze the imaging manifestations of central nervous system leukemia and the diagnostic efficiency of CT and MRI. Methods A total of 40 cases of patients with central nervous system leukemia (CNSL) treated in our hospital from July 2016 to July 2017 were selected for the study and treated with CT and MRI plain scan and contrast enhanced scan. The imaging manifestations were analyzed, and the lesions sites and the signal characteristics were mainly observed, and the CNS infiltration sites were compared between different types of leukemia patients. And the sensitivity, specificity and accuracy of CNSL by CT and MRI diagnosis were analyzed by taking the examination results of cerebrospinal fluid (CSF) as the gold standard. Results In this group of patients. ①there were 3 cases of leptomeningeal leukemic infiltration, and the disappearance of sulcus and brain cistern and the stripy low density lesions were seen in the CT, and the low signal in T1WI, high signal in T2WI/FLAIR, gyrus swelling, slightly high and then significantly enhanced signal in the DWI were shown in the MRI. ②there were 6 cases of brain parenchyma infiltration with multiple tumors, and the low signal in T1WI, high signal in T2WI/FLAIR and high signal in DWI, with no obvious occupying effect, enhanced enhancement and 3 cases complicated with hemorrhage were shown by MRI. ③ there were19 cases of dural involvement involving the forehead barrier, and the soft tissue density lesions were seen in the CT, and the soft tissue signal lesions significantly enhanced after enhancement were seen in the MRI. The remaining 12 cases were mixed type of above types, including soft meninges infiltration, parenchymal infiltration, dural involvement, and the short/equal T1WI signal and short/long T2WI signal were seen in the mixed lesions. There was no significant difference in the infiltration sites between different types of leukemia (P>0.05). The specificity and accuracy of CNSL by MRI diagnosis were higher than those by CT diagnosis (83.33% vs.16.67% and 87.50% vs.67.50% ) (P<0.05), but the sensitivity was not statistically significant by the two methods (76.47% vs 88.24%) (P>0.05). Conclusion The imaging manifestations of CT and MRI in central nervous system leukemia have a certain characteristics, especially MRI enhanced examination can help improve diagnostic efficiency and is worthy of clinical promotion and application.