目的 分析非典型性脑膜瘤的影 像学表现特征，以期提高其诊断准确率。 方法 回顾分析17例经手术病理证实的非 典型性脑膜瘤的影像学资料。结果 17例 患者中男性12例，年龄18～76岁，平均 (51.8±14.0)岁。病灶多数较大,呈分叶 状。CT平扫均呈稍高密度，内部密度欠均 匀，瘤内或瘤周见低密度囊变区。9例可 见小斑点、斑块状钙化，增强后病灶多数 呈明显欠均匀强化，6例可见邻近颅骨受 侵。MRI平扫12例T1WI呈等或稍低信号， 5例呈等或稍高信号；T2WI呈稍高或稍低 混杂信号15例，病灶内或瘤周见大小不等 囊变灶12例；DWI呈稍高/低信号15例； 增强后呈明显不均匀强化14例；瘤内见流 空血管影15例。7例伴轻度瘤周水肿，5例 为中度，另外5例为重度。13例可见脑膜 尾征，其中7例表现为粗短脑膜尾征。结 论 非典型性脑膜瘤大多在CT与MRI上具有 一定的表现特征，结合患者的临床发病特 点，可提高该肿瘤的诊断准确率。

Objective To evaluate the imaging characteristics of atypical meningioma and to improve the diagnostic accuracy. Methods 17 cases with atypical meningioma confirmed by pathology were studied retrospectively. All cases underwent MRI and 10 cases underwent CT examinations. Results There were 12 men and 5 women，ranged from 18 to 76 years old in age with average of (51.8±14.0) years. Most of the lesions were large with lobular form, and showed inhomogeneous density before and after contrast administration with cystic low density in tumor or tumor edge. In 9 cases, small spots and plaque calcification were observed. 6 cases were seen adjacent to the cranial bone invasion. The lesions demonstrated isointensity/slightly hypointensity(12cases), isointensity/slightly hyperintensity(5 cases) on T1WI, and slightly hyperintensity/isointensity mixed signal(15 cases)on T2WI. The lesions showed multiple cystic necrosis in tumor or tumor edge(12 cases). 15 cases of DWI are slightly higher/low signal. After Gd-DTPA injection, obvious inhomogeneous enhancement were showed in 14 cases. The lesions showed multiple flow void blood vessels in 15 cases. Slight peri-tumorous edema was found in 7 cases, moderate edema in 5 cases and marked edema in 5 patients. There were 13 cases of meningeal tail signs, including 7 cases of coarse short meningioneal tail signs. Conclusion The most of atypical meningiomas are of characteristics on CT and MRI, according to the patient's clinical history, which can help us to improve the diagnosis of the tumor．