目的 探讨不典型脑后部可逆 性脑病综合征(PRES)的临床表现及MRI 特点。方法 收集我院5例确诊为不典型 PRES患者的临床资料，分析其临床及MRI 图像特点。结果 5例不典型PRES患者有 男性1例，女性4例，其相关病因为：原 发性高血压(1例)、剖宫产术后高血压(3 例)以及肾功能不全高血压(1例)。发病 时患者的收缩压高值平均为188mmHg， 临床症状主要为头痛。患者恢复时间为 2-14d。头颅MRI：病变主要发生于额叶 (1例)，脑干(3例)，基底节区(1例)，3 例伴其他部位病灶，其中仅1例伴右侧 顶枕叶病灶。T1WI病变区呈等或略低信 号；FLAIR及T2WI病变区呈高信号；大部 分(4例)DWI病变区呈等或低信号，ADC呈 高信号，小部分(1例)DWI病变区呈高信 号，ADC呈等信号。患者于治疗后2-4周 复查MRI，病变区均有不同程度的缩小或 消失。结论 不典型PRES临床表现亦不典 型，但是结合MRI表现还是有其特征性， 影像诊断医生应当提高对其认识，尤其 是对有相关基础疾病的患者，临床症状 与MRI表现明显不符，需要考虑本病的可能。

Objective To investigate the clinical manifestations and features of MRI of the atypical posterior reversible encephalopathy syndromes (PRES). Methods The clinical data of 5 patients with atypical PRES in our hospital were collected, analyzed the clinical manifestations and the features of MRI images. Results There are 1 male and 4 female in the 5 atypical PRES patients. Related factors included essential hypertension (1 cases), cesarean section postoperative hypertension (3 cases) and renal insufficiency hypertension (1 cases). Mean peak systolic blood pressure at presentation was 188 mmHg. The main clinical symptoms were headache. Patients recovered in 2-14d. Head MRI: Lesions occurred mainly in the frontal lobe (1 cases), brain stem (3 cases) and basal ganglia (1 cases).3 cases of them with other lesions and only 1 cases with right parietal occipital lobe lesion.T1WI lesions showed equal or slightly low signal. FLAIR and T2WI lesions showed high signal. Most (4 cases) DWI lesions showed equal or low signal and ADC showed high signal. Small (1 cases) DWI lesion showed high signal and ADC showed equal signal. The lesions had different degrees of reduction or disappearance when patients review MRI after 2-4 weeks of treatment. Conclusion The clinical manifestations of atypical PRES are not typical, but still have characteristics with MRI examination. Imaging diagnosis of doctors should improve the knowledge, especially for the underlying disease. Clinical symptoms and MRI findings were inconsistent, need to consider the possibility of this disease.