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The MR Signs About Meningiom
The pushing border sign: 肿瘤附近的脑皮质和脑白质受压向内移 位，局部珠网膜下腔扩大，肿瘤被CSF 信号或流空血管信号包绕，构成脑膜瘤 特有的征象。
• 占颅内手术肿瘤的15%。据认为与22号常染色体的遗传因素 有关，也认为与性染色体有关系。儿童罕见，若发生在儿童， 多为神经纤维瘤病。
Epidemiology

Epidemiology: Meningomas account for 13% to 17% of intracranial tumors. Multiple meningiomas are 1% to 6% of this total.
THE 1993 WHO CLASSIFICATION
Meningioma variants: meningothelial乳头型, fibrous (fibroblastic)纤维母, transitional (mixed)过渡, psammomatous沙粒体, angiomatous血管母, microcystic, secretory, clear cell, chordoid索样, lymphoplasmacyte-rich, and metaplastic subtypes

False positive :脑炎、胶质瘤累及硬脑膜、 转移瘤、手术后等。
胶质瘤术后一月
MRS of Meningiom



NAA N-乙酰天门冬氨酸，神经元标志物。 Cho 所有肿瘤升高，恶性肿瘤标志物。 Cr 存在神经元和胶质细胞，能量代谢产物。 MRS对颅内外肿瘤鉴别有重要意义。脑外肿瘤：脑 膜瘤、转移瘤、神经鞘瘤、脊索瘤、垂体瘤等不含 神经元，不含NAA和Cr。若出现：肿瘤浸润；兴趣 区过大。 脑膜瘤Cho和Cr明显升高（正常脑组织300倍）。
The MRI Diagnosis of Meningiomas 脑膜瘤的MRI诊断
潍坊市人民医院放射科 王永奇
Introduction 简介 Contents General Considerations of Meningiomas MR in diagnosis of Meningiomas(two signs) Management of Meningiomas Surgery Radiation Therapy Gamma Knife for Meningiomas
Meningioma
Meningioma (typical) (90%) Atypical meningioma (6-8%) Anaplastic (malignant) meningioma (2-3%)
Meningioma - Malignant

Description: Malignant meningiomas are aggressive tumors that arise from the meninges in the same manner as benign meningiomas. These tumors grow rapidly, invade brain (as opposed to the pushing border of the benign meningioma) and may metastasize (spread elsewhere in the body, uents with a meningioma the only radiographic study needed is magnetic resonance imaging (MRI). If information is needed about bone detail, computed tomography (CT) is done. Angiography is indicated in those patients in whom embolization may be a consideration or when more information about the arterial supply or venous drainage is needed to plan the operation than can be gained from MRI or magnetic resonance angiography (MRA).
The dural tail sign 脑膜尾征
The dural tail sign is seen on contrast enhanced T1 weighted MRI. This finding is considered specific for meninggiom. The reviewers reproted the presence of a dural tail from 40% to 80%.

General Considerations of Meningiomas
Meningioma is the most common nonglial primary intracranial tumor, consisting of approximately 15% of all operated intracranial tumors. A genetic predisposition mediated by chromosome 22 is recognized as well as a sex hormone influence. Meningiomas are rare in children; when they do occur in children, there is a strong association of neurofibromatosis.

Women are preferentially affected with a ratio of 2:1. 女：男为2：1。


Classification of Benign Meningiomas:
Fibrous meningiomas纤维型 are 7% to 25 % of all meningiomas. These tumors are rubbery质韧 and may contain “psammoma bodies” when viewed under the microscope. 沙砾体型 Transitional meningniomas are 21% to 40% of all meningiomas. The cells are spindle shaped under the microscope. 过渡型 Meningotheliomatous meningiomas, or syncytial 合体meningiomas are the most common and are 53% to 63% of meningiomas, depending upon the series. The cellular nuclei are central and large. “Microcysts” may be present. 上皮（乳头）型

MRI Characters
Typical appearances : T1 weighted images shows hypointense or isointense to grey matter . T2 weighted images show hyperintense or isointense to gray matter. Atypical appearances, which include cystic changes, hemorrhage within the tumor, calcification , unusual locations, atypical signal intensity.
Different Diagnosis 鉴别诊断

大多数脑膜瘤具有典型表现， 依据发生 部位及病灶的信号特点不难诊断，然而 约10%左右具有不典型表现。另一方面， 一些病变具有与脑膜瘤相似的表现—— 假脑膜瘤(mimicking a meningioma)，需 根据不同的部位仔细鉴别。如软骨肉瘤、 听神经瘤、转移瘤、脑脓肿、淋巴瘤等。
Management
Surgery Radiation
of Meningiomas
Therapy Gamma Knife for Meningiomas

Recurrence: Overall recurrence rates range from 13% to 40% and are functions of extent of prior resection, which in turn is a function of location (difficulty of resection).