多形性黄色星形细胞瘤的影像表现

目的：探讨多形性黄色星形细胞瘤（PXA）的影像特征。方法：回顾性分析经手术病理证实的12例PXA的影像表现，其中10例行MR检查，2例同时行CT及MR检查。结果：12例患者共有13枚病灶，颞叶6枚，颞叶为主累及多个脑叶4枚，岛叶2枚，额叶1枚。13枚病灶中囊实性5枚，囊伴结节型6枚，实性结节2枚。增强后实性区及壁结节有明显强化，囊伴结节型病灶囊壁均不强化。13枚病灶中2枚出现邻近软脑膜强化，1枚有钙化。6枚行DWI检查的病灶中，表观弥散系数（ADC）值均高于对侧相应正常区，其中2例WHO Ⅲ级PXA的ADC值及相对表观弥散系数（rADC）值明显低于另外4例WHO Ⅱ级PXA。2枚行1H-MRS检查的病灶中，实性部分Cho峰升高，NAA峰下降，Cho/NAA值为0.84、1.06，1例出现Lac峰。结论：PXA的影像表现有一定特征性，认识这些特征并结合MR多种功能成像技术，有助于正确诊断。

Imaging findings of pleomorphic xanthoastrocytomas

Objective： To investigate the imaging features of pleomorphic xanthoastrocytoma（PXA）.Methods： A retrospective study was based on 12 cases of PXA proved by operation and pathology.Ten cases only underwent MRI scanning,2 cases underwent both CT and MRI scanning.Results： Thirteen lesions were detected in the 12 cases.Six lesions located in the temporal lobe,4 lesions mainly located in the temporal lobe but involving multiple cerebral lobes,2 lesions were in the insular lobe and 1 lesion in the frontal lobe.Thirteen lesions could be divided into 3 types of imaging findings： cystic-solid lesion（n=5）,cystic lesion with nodule（n=6） and solid nodule（n=2）.The solid components and mural nodules enhanced intensely.All the cyst walls had no enhancement in the 5 cystic lesions with nodule.The cerebral piamater closed to the lesion was enhanced in 2 cases.One lesion showed calcification.The apparent diffusion coefficient（ADC） values of solid portions were higher than contralateral tissue.ADC values and relative apparent diffusion coefficient（rADC） values of 2 cases of WHO Ⅲ were obviously lower than 4 cases of WHO Ⅱ.Cho peak ascended and NAA peak declined,with the Cho/NAA values of 0.84 and 1.06 respectively on 1H-MRS of 2 cases.Lac peak was detected in 1 case.Conclusion： There are some imaging characteristics in PXA.Recognizing these characteristics with multi-functional imaging technology of MRI is helpful to improve accuracy of diagnosis.