血管和缺血性病变

发生于海绵窦或颈内动脉膜上部分的Berry动脉瘤可以侵入鞍内。纡曲的颈内动脉可以在中线相遇（颈动脉吻），前交通动脉、后交通动脉和基底动脉瘤均可突入鞍上池。大的或钙化的动脉瘤在CT平扫上表现为密度增高区或弧线状钙化。无血栓部分的动脉瘤在增强CT上致密均匀强化。小的，无钙化的或血栓形成的动脉瘤在CT上可漏诊。累及蝶鞍和鞍上池的动脉瘤在MRI上容易发现。T1加权像上显示境界清楚的无信号病变（信号流空）。血液流动可产生明显的伪影，在相位编码方向产生多种阴影，动脉瘤内血栓在T1加权像上表现为多层面高信号，完全地或部分地填充瘤腔。

（郭　亮　惠国桢）

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