颅内巨大动脉瘤的MR影像学分析

目的　分析颅内巨大动脉瘤的MR影像学表现。方法　搜集 40例经手术病理证实的颅内巨大动脉瘤。结果　颅内巨大动脉瘤的MR信号表现多样 ,主要与动脉瘤内是否出现血栓 ,血栓的大小和形成时间的长短 ,和动脉瘤引起的继发改变等因素有关。瘤腔信号 :绝大部分巨大动脉瘤表现出典型的流空现象或流动信号。瘤腔水平可见的血管流动伪影 ,注药后明显强化。血栓信号 :大部分动脉瘤中出现了血栓 ,血栓信号差异很大 ,多呈层状或涡状的混杂信号 ,增强扫描无强化。无血管流空伪影。DSA和MRA可显示动脉瘤瘤腔 ,不能显示动脉瘤内是否存在血栓或闭塞 ,低估动脉瘤的大小。绝大部分动脉瘤可在MRA中证实。结论　MR可清楚显示颅内巨大动脉瘤的全貌 ,包括瘤腔和血栓形成情况 ,是DSA检查的必要补充。

The MR Diagnosis of Giant Intracranial Aneurysms

Objective To analysis the imaging appearances of giant intracranial aneurysms(GIA).Methods Forty pathological proven GIA were included in this study.Results The MR appearances were variable depending on the present of thrombosis,the size and age of the thrombosis,and the secondary changes of the GIA.The typical flow void presented in majority patients.The flow artifacts were displayed across the residual lumen in the phase direction of MR image.The residual lumen showed dense contrast enhancement.The thrombosis was found in 26 GIAs with variable signal intensity from homogeneous hypo-or hyperintensity to onion or turbo like heterogeneous signal intensity without contrast enhancement.DSA studies displayed residual lumen of GIAs and fail to display totally thrombosis GIAs.Conclusion MR studies clearly show the residual lumen and thrombosis of GIAs.MR study is an important conjunctive tool of the DSA studies in diagnosis GIA.