毛细胞型星形细胞瘤的功能MRI表现  

Functional Magnetic Resonance Imaging of Pilocytic Astrocytoma

作　　者：马芸[1] 李晓光[1] 黄杰[1] 康厚艺[1] 张伟国[1] 

机构地区：[1]第三军医大学野战外科研究所,重庆400042

出　　处：《中国医学影像学杂志》2015年第6期423-427,共5页Chinese Journal of Medical Imaging

基　　金：重庆市自然科学基金重点项目(cstc2012jj B10028);重庆市研究生教育教学改革研究重点项目(Yjg 110227);第三军医大学临床科研基金资助项目(2009XLC29)

摘　　要：目的 探讨毛细胞型星形细胞瘤（PA）的磁共振灌注成像（PWI）、扩散加权成像（DWI）、磁共振波谱成像（MRS）和磁敏感加权成像（SWI）的影像学特点,提高对本病的诊断准确性。资料与方法 回顾性分析11例经手术病理证实的PA的MRI表现,分析其常规MRI及生理代谢成像特点。结果 完全为囊性或实性病变各1例,其余9例为囊实性病变;10例病变表现为混杂长T1长T2信号,FLAIR呈混杂高信号;1例表现为均匀长T1长T2信号,FLAIR呈高信号;增强扫描病变实性部分和囊壁及壁结节均呈明显强化,6例为花状样强化,3例为结节状和花环状强化,1例为明显强化,1例为轻度环形强化;3例SWI表现为片状低信号,2例为点状低信号,2例未见低信号显示,其平均肿瘤内低信号分级为1.57级。PWI表现为高灌注,其最大相对脑血容量为2.64±1.22。肿瘤实性部分胆碱（Cho）明显升高,N-乙酰天门冬氨酸（NAA）明显降低,Cho/NAA比值为5.13±4.72（1.46~15.26）,5例出现乳酸峰增高。DWI示1例实性病例可见明显扩散受限,其余7例囊实性病例均未见明显扩散受限,其平均相对ADC值为1.60±0.58。结论 PA符合低级别胶质瘤的绝大多数影像学表现,但其MRI生理代谢成像有一定的特征性,其灌注明显高于同级别的胶质瘤,正确认识其表现有助于提高诊断和鉴别诊断的准确性。Purpose To investigate the imaging characteristics and accuracy of diagnosing pilocytic astrocytoma （PA） with perfusion weighted imaging （PWI）, diffusion weighted imaging （DWI）, magnetic resonance sprectroscopy, susceptibility weighted imaging （SWI） and diffusion tensor imaging. Material and Methods MRI imaging of 1 l patients with PA was retrospectively analyzed for functional imaging features. Results In 11 patients with PA, there were 9 mixed cystic and solid lesions, 1 case of cystic lesion and 1 case with solid lesion. Ten lesions showed mixed hypointensity on T1Wl, and mixed hyperintensity on T2WI and FLAIR. One case was hypointense on T IWl, and hyperintense on T2WI and FLAIR. Prominent contrast enhancement was seen in the solid portion, capsular wall and mural nodules. On SWl 3 cases showed patchy low signal, 2 cases of dot-like low signal and 2 cases without low signal, with average intratumoral susceptibility signal intensity classification of 1.57. PWI findings were characterized by high perfusion with relative cerebral blood volume averaging 2.64± 1.22. There was elevated choline component in the solid portion with significantly decreased NAA with average Cho/NAA ratio of 5.13±4.72 （1.46-15.26）. Lactate peak was increased in 5 cases. On DWI there was limited diffusion in 1 case. 7 cases did not demonstrate limited diffusion with average relative apparent diffusion coefficient of 1.60±0.58. Conclusion Most MRI features of pilocystic astrocytoma are consistent with low grade glioma. There are characteristic functional imaging findings with higher perfusion than other gliomas. Functional MRI can evaluate tumor metabolism and prognosis.

关 键 词：星形细胞瘤 脑肿瘤 磁共振成像 扩散加权成像 扩散张量成像 磁共振波谱学 灌注成像 诊断 鉴别 

分 类 号：R730.264[医药卫生—肿瘤] R730.42[医药卫生—临床医学]