MR signal of the solid portion of pilocytic astrocytoma on T2-weighted images: is it useful for differentiation from medulloblastoma?
MR signal of the solid portion of pilocytic astrocytoma on T2-weighted images: is it useful for differentiation from medulloblastoma?
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DOI：
10.1007/s00234-006-0048-5
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发表时间：
2006-04-01
期刊：
影响因子：
2.8
通讯作者：
Endo, K
中科院分区：
文献类型：
--
作者：
Arai, K;Sato, N;Endo, K
背景和目的：虽然小脑毛细胞型星形细胞瘤和髓母细胞瘤的影像学特征已在许多文献中描述，但这两种肿瘤之间的磁共振强度的原始比较是有限的。在本研究中，磁共振成像（MRI）的结果进行了审查，特别是对这些肿瘤的实性部分的信号强度的重点。方法：回顾性分析10例小脑毛细胞型星形细胞瘤和10例髓母细胞瘤的MRI表现。固体组分的信号强度按1至5的等级分级，分数越高表示信号强度越接近水的信号强度。在MR图像上评估增强程度、肿瘤囊肿和周围水肿。当实性部分不均匀（即混合信号强度或增强程度）时，选择优势区域进行评价。结果如下：在T2加权像上，50%的毛细胞型星形细胞瘤的实性部分的信号强度等于脑脊液（CSF）。没有髓母细胞瘤表现出这样的高信号。大多数髓母细胞瘤（80%）与灰质呈等信号。在T1加权像上，毛细胞型星形细胞瘤的信号强度变化很大;然而，所有髓母细胞瘤均与灰质等或低信号。MR增强模式、囊性成分和周围水肿在两种肿瘤类型中均不同，未发现特异性特征。结论：在T2加权像上，实性部分的信号强度与脑脊液的信号强度相等是小脑毛细胞型星形细胞瘤的特征，而在髓母细胞瘤中没有观察到。注意肿瘤实性部分的T2加权成像容易且有助于鉴别小脑毛细胞型星形细胞瘤和髓母细胞瘤。
Background and purpose: Although imaging features of cerebellar pilocytic astrocytoma and medulloblastoma have been described in many texts, original comparisons of magnetic resonance intensity between these two tumours are limited. In the present study the results of magnetic resonance imaging (MRI) were reviewed, focusing especially on the signal intensity of the solid portion of these neoplasms. Methods: MR images of ten cerebellar pilocytic astrocytomas and ten medulloblastomas were reviewed. The signal intensities of the solid components were graded on a scale of 1 to 5, with higher scores indicating a signal intensity closer to that of water. The degree of enhancement, tumour cysts and peripheral oedema were evaluated on MR images. When the solid portion was heterogeneous (i.e. mixed signal intensity or degree of enhancement), the dominant area was selected for evaluation. Results: On T2-weighted images, the signal intensity of the solid portion was equal to that of cerebrospinal fluid (CSF) in 50% of pilocytic astrocytomas. No medulloblastomas showed such hyperintensity. Most medulloblastomas (80%) were isointense to grey matter. On T1-weighted images, the signal intensity varied widely in pilocytic astrocytomas; however, all medulloblastomas were iso- or hypointense to grey matter. The MR enhancement pattern, cystic component and peripheral oedema all varied in both tumour types and no specific features were identified. Conclusion: A signal intensity of the solid portion isointense to CSF on T2-weighted images was characteristic of cerebellar pilocytic astrocytomas; this was not observed in medulloblastomas. Attention to T2-weighted imaging of the solid portions of a tumour is easy and helpful in differentiating between cerebellar pilocytic astrocytoma and medulloblastoma.