颅底软骨瘤的CT与MRI表现

目的：探讨CT与MRI对颅底软骨瘤的影像诊断价值。方法：12例中，9例行MR平扫及增强扫描，7例行CT平扫，其中3例做增强扫描，4例同时行CT及MR检查，结果：12例软骨瘤均位于颅底中线旁硬膜外，鞍旁肿瘤呈类圆形；同时累及前中颅凹或中后颅凹的肿瘤呈“哑铃”形或不规则形，肿瘤边缘清楚，5例有颅底骨质破坏，其余病例肿块周围骨质呈侵蚀性改变，CT上肿瘤呈等，高混杂密度6例，呈均匀稍高密度1例，钙化表现为斑块状，小球状及弧线样高密度，MRI上T1WI均为低信号，7例肿块T2WI为高，低混杂信号，其余2例T2WI为均匀高信号，6例肿瘤外侧与脑实质之间T2WI上可见弧线样低信号线，冠状位MRI上可见海绵窦有不同程度受累，CT与MR增强扫描肿瘤为不均匀强化，结论：颅底软骨瘤多位于中线旁的硬膜外，特别是鞍旁，前颅凹或后颅凹肿块相连，根据其部位及CT、MRI表现可以做出诊断。

Chondroma of skull base:CT and MR imaging

Objective:To evaluate the value of CT and MR in diagnosing skull base chondroma.Ma terials and Meth-ods:We retrospectively analysed the CT and MRI of 12patients.MR were performed in9patients with administration of Gd-DTPA.Seven patients underwent CT scan,and three of them were enhanced.Results:All skull base chondromas showed as epidural paramedian masses.The parasellar chondromas were round,while the tumors involving both middle and posterior or anterior fossae were dumbbell or irregular in shape.All tumors have clear margins.The skull base surrounding the tumor was destructed(n=5).The others had erosion of the skull bases.The tumors displayed as mixed iso-and hyper-dense in85%(6?7)or homogeneous isodense in15%.The calcification appeared as patchy,globular and curviliness in shape.The masses were hy-pointensity on T 1 ,78%(7?9)of masses were mixed hypo-and hyperintensity on T 2 ,and the rest were homogeneous hyperin-tense on T 2 .The lateral aspects of masses clearly separated from brains by hypointense lines on T 2 WI (n=6).There were vary-ing degree of the cavernous sinuse involvement in all cases on MR coronal sections.The masses were enhanced heteroge-neously on CT and MRI.Conclusion:Most of the tumors are located in epidural paramedian region,especially the parasellae area.The chondromas in anterior or posterior skull bases are usually connected with tumors in central skull bases,and the sizes of the masses are bigger.The correct imging diagnosis is possible based on the tumor locations and CT or MRI findings.