松果体区肿瘤的影像表现及鉴别诊断

CT and MRI characteristics and differential diagnosis of pineal region tumors

目的 分析松果体区肿瘤的影像特点,以提高诊断及鉴别诊断的准确率.方法 回顾性分析经手术及病理证实的28例松果体区肿瘤的CT和MRI表现,其中8例患者术前行1H-MRS和DWI检查.结果28例松果体区肿瘤分别为生殖细胞瘤11例,畸胎瘤4例,星形细胞瘤3例,室管膜瘤1例,小脑幕缘脑膜瘤3例,松果体细胞瘤2例,松果体母细胞瘤1例,错构瘤1例.表皮样囊肿2例.影像学主要表现为松果体区囊实性肿块,密度/信号多变,部分肿瘤有其特征的形态、密度/信号及强化方式.生殖细胞瘤及松果体细胞肿瘤绝大部分为均匀实性肿块,密度/信号均匀.胶质瘤多为囊实性,且形态多变,密度/信号不均,变化大.成熟性畸胎瘤一般为混杂囊状密度/信号.胶质瘤1H-MRS可见到典型高Cho峰及低NAA峰,脑膜瘤往往测不到NAA峰,松果体母细胞瘤Cho峰较高,无Lip峰,而生殖细胞瘤多出现Lip峰.结论 松果体区肿瘤的形态、密度/信号特征及强化方式有助于松果体区病变的诊断,1H-MRS及DWI对鉴别诊断有帮助,但部分肿瘤鉴别困难.

Objective To analyze the CT and MRI characteristics of the pineal region tumors （PRTs） to improve the accuracy of diagnosis and differential diagnosis.Methods The MRI and CT findings of 28 patients with PRTs proved by operation and pathology were retrospectively analyzed.Eight of them were performed preoperative 1H-MRS and DWI examination and thier data were analyzed too.Results of these 28 patients,11 were diagnosed as having germinoma,4 teratoma,3 astrocytoma,3 meningioma,2 pinealocytoma and 1 epidermoid cyst,1 pineoblastoma,1 hamartoma and 1 dermoidcyst.The main imaging characteristics were cystic tumors in the pineal region,variational density/signal intensity with few tumors having their specified morphology,density/signal intensity and enhancement style.The germinomas and the pineoblastomas were mainly homogeneous solid masses with symmetrical density/signal.The astrocytoma was cystic-solid,mostly,with changing shapes and odds density/signal.The mature teratoma showed blending density/signal.The 1H-MRS showed typical high Cho peak and low NAA peak in the astrocytoma; no NAA peak was found in the meningeoma; high Cho peak and no Lip peak were found in the pineoblastoma; the germinoma was noted having Lip peak.Conclusion Observation on the changes of the morphologic features,density/signal intensity and enhancement style can help in the differential diagnosis of PRTs.DWI and 1H-MRS examinations can improve the accuracy of differential diagnosis to some extent,but some PRTs remain to be non-differentiable.