脑内型表皮样囊肿的MRI诊断

MRI Diagnosis of Intracranial Epidermoid Cysts

目的探讨脑内型表皮样囊肿的MRI特点,以加强对该病的认识,提高正确诊断率。资料与方法分析经手术病理证实的8例脑内型表皮样囊肿的MRI表现。全部患者均进行了T1WI、T2WI平扫及增强检查,5例患者行液体衰减反转恢复(FLAIR)序列检查。结果8例表皮样囊肿中,位于颞叶5例,额叶2例,额、颞叶交界区1例。所有病灶均发生在皮质区或皮质下区。病变轮廓不光整者5例,较光整者3例。病变与周围组织结构均分界清晰。在T1WI上病灶呈均匀低信号3例,以低信号为主其内间以斑片状、点状及条状中等信号或略高信号者4例,中心呈低、等混杂信号外围见同心圆形等信号者1例;在T2WI上呈均匀高信号,信号强度与脑脊液信号相似者4例,以高信号为主其内间以斑片状、点状及条状略高信号者3例,以高信号为主其内间以略高信号及略低信号者1例;5例行FLAIR序列检查,病灶均呈略高、等、低混杂信号,病灶周边环以线样或斑片样高信号。除1例病灶周围脑组织有轻度水肿外,均未见灶周水肿征象。病灶占位效应轻,周围组织受压征象不明显。MR增强扫描,2例见斑片状不均匀强化,其余病例均未见明显强化。结论脑内型表皮样囊肿的MRI表现具特征性,MRI表现有助于对该病的诊断。

Objective To explore the MRI features of intracranial epidermoid cysts in order to improve the diagnostic accuracy of this disease. Materials and Methods 8 patients with intraeranial epidermold cysts confirmed surgically pathologically were performed MR scan, including T1WI, T2WI and enhanced MR scan, 5 patients with FLAIR scan. Results Of the 8 epldermoid cysts, 5 lesions were located in temperal lobe, 2 in frontal lobe, 1 in eonjunetional area of temporal lobe and frontal lobe. All lesions were occurred in cortex or sub-cortex. 5 lesions were not in irregular margin, and 3 lesions in relatively irregular and smooth margin. All lesions were well-defined with surrounding tissues. On T1-weighted images, lesions of 3 cases appeared homogeneous signal hypointensity. 4 lesions presented mainly signal hypointensity with patchy, spot and striped hypefintensily or slight hyperintensity signal. 1 lesion presented hypolntensity and isointensity signal in center area, surrounded by isointensity circle. On T2- weighted images, 4 lesions presented homogeneous hyperintensity similar to CSF signal. 3 lesions were mainly hyperintensity with patchy, spot and striped slight hyperintensity signal. 1 lesion presented mainly hyperintensity signal with slight hyperintensity and slightly hypointensity signal inside. In l lesion, hyperintensity and slight hyperintensity signal was found in center area, surround- ed by isointensity circle. All lesions appeared mixed signal intensity including slight hyperintensity, isointensity and/or hypointensity signal, surrounded by linear or patchy hyperintensity signal on FLAIR. in 5 patients. Only one lesion depicted slight edema around the lesion. Mass effect was slight and brain tissue was not markedly compressed. On enhanced images, 2 lesions presented heterogeneous enhancement, and the others were not enhanced. Conclusion MRI findings of intracranial epidermoid cyst are relatively characteristic, and are helpful to the diagnosis.