颅内生殖细胞瘤的CT和MRI表现

目的探讨颅内生殖细胞瘤的CT和MRI表现。方法经手术病理及放疗证实的颅内生殖细胞瘤19例,回顾性分析其治疗前CT和MRI图像。结果19例肿瘤中,12例位于松果体区,3例位于基底节区及丘脑,4例位于鞍区。松果体区肿瘤MRI呈长T1、等或长T2信号,边缘光滑,出血少见,CT呈均匀等密度或稍高密度,松果体钙化常被肿瘤包埋,增强呈均匀显著强化。鞍区肿瘤垂体柄增粗,垂体后叶正常短T1信号消失,肿瘤T1WI呈等信号,T2WI上信号可以表现为等或高信号,CT上肿瘤实体部分呈高密度,增强扫描有明显强化。基底节及丘脑肿瘤,呈弥漫性生长,瘤体较大,信号及密度不均匀,边缘欠清晰,出血多见,增强呈斑片或花环样强化。结论颅内生殖细胞瘤,根据发生性别、年龄和MR及CT影像表现具有一定特点,在多数情况下可做出术前诊断。

CT and MRI Findings of Intracranial Germinoma

Objective To explore CT and MRI appearances of intracranial germinoma.Methods 19 patients with intracranial germinoma confirmed histologically and radiotherapy were selected as the object of this study.CT and MR findings of germinoma were analysed retrospectively.Results Of 19 cases,the tumors were located at pineal region in 12,the basal ganglia and thalamus in 3 and the sellar in 4.Germinoma of pineal region showed low signal intensity on T1WI,iso or hyper-signal intensity on T2WI,isointensity or slightly hyperintensity on CT with definite margin,the pineal calculus were embedded frequently by tumors.After administration of contrast material,the tumors showed marked and uniformity enhancement.Thickness of pituitary stalk and absence of the hyperintensity of the posterior pituitary on T1WI were found in sellar germinoma.Tumors showed iso-signal intensity on T1WI,but variable signal intensity was exhibited on T2WI.Calcification was absent in all cases,but the solid components of tumors were hyperdense on plain CT,and they were obvious enhancement on contrast-enhanced CT scan.Germinoma located at basal ganglia and thalamus showed diffuse growth,larger volum of tumors,inhomogeneous signal intensity and density with indefinite margin,hemorrhage seen in most of case.After administration of contrast material,the tumors showed patch or chaplet-like enhancement.Conclusion It is possible to make the preoperative diagnosis for intracranial germinoma according to sex,age and CT,MR imaging characteristics.