颅内表皮样囊肿的MRI诊断

目的 分析颅内表皮样囊肿的MR影像特征。资料与方法经手术病理证实的颅内表皮祥囊肿30例，男13例，女17例，除9例仅作MR平扫外，其余均作MR平扫 增强扫描。12例选用FLAIR序列。结果 典型表现者27例，占90％，T1WI上表现为低信号，有时不均匀；非典型表现者3例，占10％，T1WI上肿瘤实质内为高信号。21例增强扫描中，16例无强化，1例分隔状强化，4例边缘强化。T2WI上大多表现为均匀高信号，少数信号不均匀。结论 典型常见的表皮样囊肿T1WI为低信号，信号欠均匀；非典型的表皮样囊肿T1WI呈高信号，信号形成原因是高浓度蛋白质所致，并非脂类物质。

MRI Diagnosis of Intracranial Epidermoid Cyst

Objective To analyze MRI features of intracranial epidermoid cysts.Materials and Methods Thirty patients (13 males and 17 females) with pathologically-proved intracranial epidermoid cysts were enrolled in this study. Both plain and enhanced MRI were performed in 21 cases, and only plain MRI were performed in the remaining 9 cases.Results Typical manifestation was seen in 27 cases (90%), presenting as low signal on T 1WI. Atypical manifestation was seen in 3 cases (10%), being characterized by high signal on T 1WI. On enhanced scans (n=21), the lesions showed no enhancement (n=16), rim enhancement (n=4) or septal enhancement (n=1). On T 2WI, most lesions showed homogeneous high signal, and a few lesions displayed inhomogeneous signal.Conclusion On T 1WI, typical epidermoid cysts are manifested as low, inhomogeneous signal, while atypical epidermoid cysts are marked by high signal, which is due to the high concentration of the protein not due to the lipoids.