神经细胞瘤的MRI表现及鉴别诊断

MRI Findings and Differential Diagnosis of Neurocytomas

目的探讨神经细胞瘤患者临床及MRI特征,旨在进一步提高其术前诊断的准确性。方法回顾性分析我院2009年1月至2014年1月收治的29例经手术及病理证实的神经细胞瘤患者的临床资料和MRI信号特点,所有病例术前均行MRI常规及增强扫描,其中3例中枢神经细胞瘤(CNC)和1例脑室外神经细胞瘤(EVN)行DWI检查,2例CNC行MRS检查。结果 29例神经细胞瘤中,CNC 21例,病灶均位于侧脑室内,其中19例位于Monro孔区,2例位置偏后附于透明隔;肿瘤呈浅分叶状团块,信号不均匀,T1WI多呈等或稍低信号,T2WI多呈等或稍高信号,FLAIR像呈高信号,3例DWI呈高信号,21例边缘或内部出现信号与脑脊液相近的囊变,13例肿瘤内部或边缘可见流空血管影,10例肿瘤边缘可见"绳索征"。EVN 8例,病灶位于大脑半球3例,小脑4例,脊髓1例;7例为囊实性,1例为实性,T1WI多呈等信号,T2WI呈高信号,1例有出血,1例有流空血管影;29例神经细胞瘤FLAIR像上实质部分均呈高信号,增强扫描均有不均匀强化。结论中枢神经细胞瘤有一定的影像学特点,结合患者发病年龄、病变位置可提高本病的确诊率,对于EVN,囊实性且实质部分FLAIR像及DWI上呈高信号应想到此病的可能,但其影像学特点仍需总结,确诊仍需病理检查。

Objective To investigate MRI features of neurocytomas in order to improve its preoperative diagnostic accu- racy. Methods A total of 29 patients with pathologically-proved neurocytoma, who were admitted to authors＇ hospital during the period from 2009 to 2014, were included in this study. The clinical data and the MRI features were retrospective analyzed. Preoperative plain and contrast-enhanced MRI scans were performed in all patients; additional DWI was em- ployed in 3 cases with central neurocytoma （CNC） and in one case with extraventricular neurocytoma （EVN）, and MRS was also carried out in two cases with CNC. Results Of the 29 patients, CNC was found in 21 with the lesion being loca- ted in the lateral ventricle. Among the 21 cases, the lesion was situated at the Monro foramen region in 19 and at the sep- turn pellucidum in 2. The tumor presented as lobulated solid mass, which was characterized by inhomogeneous iso-intensity or slightly hypo-intensity signal on T1WI, iso-intensity or slightly hyper-intensity signal on T2WI and hyper-intensity on FLAIR; in 3 cases the lesion showed hyper-intensity signal on DWI. In 21 cases, cystic degeneration was observed at the lesion＇ s edge or within the lesion which showed the signal similar to that of cerebrospinal fluid; flow-void vascular shadow was seen in 13 cases; ＂rope＂ sign at tumor＇s border was demonstrated in 10 cases. EVN was seen in 8 cases, and the le- sion was located at the cerebral hemisphere （ n =3 ）, the cerebellar hemisphere （ n =4） or the spinal cord （ n = 1 ）. The lesion had cystic component in 7 cases and was solid in one case. The tumor mainly presented as iso-intensity signal on T1WI and hyper-intensity signal on TzWI; hemorrhage was detected in one case and flow-void vascular shadow was ob- served in one case. In all the 29 cases, the solid part of the tumor was manifested as hyper-intensity signal on FLAIR, and inhomogeneous enhancement was seen on contrast-enhanced scans. Conclusion The central neurocytoma has certain ima- ging characteristics, which is helpful in making diagnosis when the patient＇ s age and lesion＇ s location are also taken into consideration. A cystic-solid tumor showing hyper-intensity signal on FLAIR and DWI is highly suggestive of extraventricu- lar neurocytoma, although the confirmation of the diagnosis depends on pathological examination.