病历摘要：患者，女性，19岁，因眩晕伴呕吐1周入院。体检：眼震，步态不稳，余未见异常。做头颅MRI检查。<img src="/Image1/d0/d027e9024a4374f6ff14c2efdd3f9550.jpg" /><img src="/Image1/c9/c9e97eceeb3b257acfb5c22897f94bb2.jpg" /><img src="/Image1/2c/2c477b825cabb3b2b73b73b735bbebd5.jpg" /><img src="/Image1/e1/e1f62c48a6352cb932f95ff50b70e87f.jpg" /> 3.鉴别诊断有哪些？