目的　探讨急性淋巴细胞白血病患儿化疗后可逆性脑病的临床和影像学特点。方法　回顾分析2015年9月1 日至2018年9月1日住院时发生脑病的急性淋巴细胞白血病患儿的临床资料。结果　研究期间共收治新发急性淋巴细胞 白血病582例， 9例患儿发生10次可逆性脑病（1例患儿发生2次）， 其中男6例、女3例，脑病发生中位年龄6.55岁（3.9~12.5 岁）。 最常见的神经系统临床表现是抽搐，其次是肌无力和感觉异常。 7例患儿曾接受培门冬治疗； 5例患儿在脑病发生前 有急性高血压病史； 6例患儿在脑病发生时有低钠血症，部分有低纤维蛋白原血症。头颅磁共振成像检查均提示T1和T2 信号异常，累及部位多见于顶枕叶。结论　联合化疗、化疗药物鞘内注射和急性高血压是可逆性脑病发生的高危因素；监 测血压、血钠、纤维蛋白原，以及头颅磁共振成像检查有助于早期发现可逆性脑病。

Objective　Posterior reversible encephalopathy syndrome (PRES) is a neurological complication associated with chemical agents. This study is to investigate clinical characteristics and radiological features of this disease. Methods Demographic and medical data of all acute lymphoblastic leukemia patients who had radiological and clinical manifestations consistented with PRES between September 2015 and September 2018 were retrospectively analyzed. Results　Among 582 patients with acute lymphoblastic leukemia, a total of 9 patients were included and 7 patients received pegaspargase therapy before PRES. Five patients had acute hypertension before PRES. Seizure was the most common clinical manifestation, followed by myasthenia and paresthesia. In brain magnetic resonance imaging, parietal and occipital lobes were found to be involved in six (60%) patients and other involvements including temporal lobes, frontal lobes, cerebellum, brainstem, thalamus and basal ganglia. Hyponatremia was observed in six (60%) patients, while six (60%) patients suffered from hypofibrinogenemia. Conclusions Pegaspargase, intensive chemotherapy, intrathecal therapy and acute hypertension were risk factors for PRES development. hyponatremia and hypofibrinogenemia may indicate the development of PRES.