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目的:探讨磁共振波谱(MRS)对鉴别桥小脑角神经鞘瘤与脑膜瘤的价值。方法:对8例神经鞘瘤和8例脑膜瘤病例进行MRI平扫和增强扫描,并采用点分辨波谱序列(PRESS,TR/TE=2000/136ms)进行单体素波谱分析。从事磁共振诊断专业的医师根据肿瘤的MRI及MRS表现特征进行鉴别诊断。结果:尽管多数神经鞘瘤(5/8)和脑膜瘤(6/8)具有典型的MRI表现特征并仅经MRI即可得到正确鉴别,但部分病例(5/16)为不典型表现者,如脑膜瘤呈长T1长T2信号并伴有囊变,以及神经鞘瘤呈等信号、均匀强化且不伴有囊变或内听道扩大者,鉴别诊断困难。MRS显示脑膜瘤的胆碱/肌酸比值(Cho/Cr)(2.74±1.47)略高于神经鞘瘤(2.70±1.21),但差异无统计学意义。丙氨酸(Ala)在脑膜瘤中的出现率(4/8)显著高于神经鞘瘤(0/8)(P<0.05),谷氨酸盐/谷氨酰胺(Glx)在脑膜瘤中的出现率(5/8)也高于神经鞘瘤(2/8);而肌醇(Ins)在神经鞘瘤中的出现率(4/8)高于脑膜瘤(2/8)。结合MRS表现,在MRI上尚难鉴别的病例可被明确诊断,并与最终病理结果相符。结论:MRI有助于多数桥小脑角神经鞘瘤与脑膜瘤的鉴别诊断,但对不典型病例有一定局限性;MRS对不典型病例的鉴别具有重要的参考价值。
Objective: To investigate the value of magnetic resonance spectroscopy (MRS) in differential diagnosis of cerebellopontine schwannoma and meningioma. Methods: 8 cases of schwannoma and 8 cases of meningiomas were scanned by MRI and enhanced MRI, and single element spectrum was analyzed by point-resolved spectrum (PRESS, TR / TE = 2000 / 136ms). The doctors engaged in magnetic resonance diagnosis are differentiated according to the MRI and MRS features of the tumor. RESULTS: Although most schwannoma (5/8) and meningioma (6/8) had typical features of MRI and were correctly identified only by MRI, in some cases (5/16) were atypical, Such as meningioma were long T1 long T2 signal accompanied by cystic changes, and schwannoma showed equal signal, uniform enhancement and without cystic change or enlargement of the internal auditory canal, differential diagnosis difficult. MRS showed that the ratio of choline to creatinine in meningioma was (2.74 ± 1.47) slightly higher than that in schwannoma (2.70 ± 1.21), but the difference was not statistically significant. The incidence of alanine (Ala) in meningioma (4/8) was significantly higher than schwanoma (0/8) (P <0.05), glutamate / glutamine (5/8) was higher than schwannoma (2/8). The incidence of Ins in schwannomas (4/8) was higher than that in meningiomas (2/8). Combined with MRS, cases that are difficult to identify on MRI can be clearly diagnosed and are consistent with the final pathology. Conclusion: MRI is helpful for the differential diagnosis of cerebellopontine schwannoma and meningioma, but it has some limitations for atypical cases. MRS has important reference value for the identification of atypical cases.