少见型脑膜瘤的CT诊断

目的探讨颅内少见型脑膜瘤的CT表现,并提高其诊断准确性。方法15例经手术病理证实的少见型脑膜瘤,包括Nauta型囊性脑膜瘤8例,恶性脑膜瘤4例,多发性脑膜瘤2例以及完全钙化性脑膜瘤1例,术前均经CT平扫,14例又经对比增强扫描。对所有患者的CT表现结合文献复习进行了回顾性分析。结果多数脑膜瘤位于幕上。Nauta型囊性脑膜瘤CT平扫呈囊实性肿块,增强扫描示肿瘤实质部分明显强化,部分囊壁有强化。恶性脑膜瘤CT平扫呈不规则形混杂密度肿块,或囊性肿块伴结节,肿瘤边缘不规则,增强后实质部分明显强化,瘤周水肿广泛。多发性脑膜瘤CT平扫示多发结节灶,增强扫描示肿瘤轻度强化。完全钙化性脑膜瘤CT平扫呈钙化团块,邻近颅骨骨质增生硬化,瘤周无水肿。本组CT术前正确诊断10例,误诊5例。结论颅内少见型脑膜瘤术前CT易误诊。综合分析各型的CT特征,有助于作出正确诊断和鉴别诊断。     

几种少见类型脑膜瘤的CT分析

目的 探讨颅内几种少见类型脑膜瘤的CT表现特征。资料与方法 18例颅内几种少见类型脑膜瘤术前均行CT检查并经手术后病理证实,其中CT平扫4例,增强扫描4例,平扫加增强扫描10例。结果 18例中,囊性脑膜瘤11例,恶性脑膜瘤5例,多发脑膜瘤1例。肿瘤位于幕上17例,幕下1例。术前CT诊断正确10例,误诊8例。结论 颅内几种少见类型脑膜瘤术前CT扫描易被误诊,综合分析各自的CT特征,有助于诊断与鉴别诊断。     

CT诊断鼻腔鼻窦脑膜瘤的作用

目的：评价CT扫描在诊断鼻腔鼻窦脑膜瘤中的作用。方法：对4例经手术证实的脑膜瘤的CT特征进行回顾性分析。结果：本组病斧正累及范围均较广泛，CT平扫时呈等，低混杂密度灶，瘤周均有环形骨质硬化，其中3例瘤内有不规则的条片状钙化影和低密度的坯 煞费苦心区；病灶均累及鼻中隔和鼻窦，鼻中隔明显偏曲或破坏消失。筛窦和蝶窦受累4例，上颌窦2例，窦腔膨胀性扩大，并被混杂密度影填塞，窦壁骨质受压变薄，但未见明显骨质溶解破坏。结论：CT扫描可正确诊断鼻腔鼻窦脑膜瘤。     

眶内脑膜瘤的CT诊断

目的探讨眶内脑膜瘤的CT表现,提高其CT诊断水平。方法回顾性分析1997-10—2006-10在我院经手术及病理检查确诊的眶内脑膜瘤(原发或继发)17例CT表现和临床资料。结果视神经鞘脑膜瘤11例,眶骨膜脑膜瘤4例,蝶骨嵴脑膜瘤2例。增强扫描,病变大多数呈均匀性强化。"车轨征"、"套袖征"及眶骨增生性改变是眶内脑膜瘤较为特征性的征象。结论CT检查对眶内脑膜瘤的诊断具有重要价值。     

桥小脑角区肿瘤及肿瘤样病变的CT诊断

目的：探讨CT对桥小脑角区肿瘤及肿瘤样病变的诊断价值。方法：回顾性分析经手术病理证实的桥脑小脑角区肿瘤及肿瘤样病变的CT特征。其中听神经瘤9例、胆脂瘤4例、脑膜瘤3例、耳源性脑脓肿5例、三叉神经瘤1例。结果：各种肿瘤的CT特征，随其种类而不同，如听神经瘤均位于内听道开口处，呈等或低密度团块，轻度均匀或环状强化。胆脂瘤呈球形或扁平形，球形位于硬膜外，密度不均，壁有钙化。扁平形位于蛛网膜下腔， 边缘清楚，均匀低密度。脑膜瘤均具有典型脑膜瘤特征，明显强化。耳源性脑脓肿周边有明显水肿、囊壁清晰，囊内呈均匀低密度。三叉神经瘤跨中后颅窝伴岩锥尖骨质破坏。结论：桥脑小脑角区肿瘤各具特点，CT能提供明确诊断。     

颅内海绵状血管瘤的CT和MRI诊断

目的 探讨CT和MRI对颅内海绵状血管瘤的表现和诊断价值。资料与方法 经手术病理证实的颅内海绵状血管瘤22例,其中脑内型海绵状血管瘤21例,脑外型海绵状血管瘤1例。10例行CT检查,16例行MRI检查,13例行MRA检查。结果 脑内型海绵状血管瘤可位于脑内任何部位,单发病灶多见,周围无或轻度水肿,无明显占位效应。CT平扫为稍高密度影,钙化占72．7％,增强扫描大都无强化;MR T1WI表现为桑葚状混杂高信号．周围有云絮状低信号环,增强后病灶大都无强化;MRA检查未见异常血管。脑外型病灶位于中颅窝、鞍旁,MRI呈类似哑铃形较均匀的稍长T1、长T2信号,增强扫描见明显均匀强化．MRA检查未见异常血管。结论 脑内型海绵状血管瘤的MRI表现较有特异性,结合CT和MRA可明确诊断;脑外型者易误诊,对CT和MRI表现类似的中颅窝脑膜瘤,应考虑到本病的可能。     

眶颅沟通性病变的CT和MRI研究

目的 研究、探讨眶颅沟通性病变的沟通路径、CT和MRI表现及其影像学特征。方法 51例患者,男28例,女23例,年龄2－68岁,平均41岁,为手术病理和随访结果证实。51例均行 CT扫描,45例行MR扫描,CT和MR增强扫描各44例。结果 通过眶上裂或视神经管沟通的颅眶沟通笥病变31例,占60.8％。其中9例通过视神经管沟通,包括4例视神经和视交叉胶质瘤、3例视神经鞘脑膜瘤,以及2例视网膜母细胞瘤侵犯视神经和视交叉;通过眶上裂沟通者,包括5例脑膜瘤、4例神经源性肿瘤、2例Tolosa-Hunt综合征、3例炎性假瘤、1例眼眶和海绵窦皮样囊肿,以及7例鼻咽癌同时侵犯海绵窦和眼眶,通过眶骨穿支血管间隙沟通的病变或骨质破坏缺损区沟通的眶颅沟通性病变20例,占39.2％,包括5例眶骨扁平性脑膜瘤、10例眶壁转移瘤、1例眶壁软骨肉瘤侵犯筛窦、额窦和额叶、3例泪腺囊腺癌侵犯颅内和1例额底脑膜瘤侵犯眼眶。结论 CT和MRI,尤其是使用脂肪抑制技术和增强扫描的T1WI能明确显示眶颅沟通性病变的沟通路径和病变特征,为制订治疗方案和手术入路提供重要和直接的依据。     

Detection of cranial meningiomas: comparison of 68Ga-DOTATOC PET/CT and contrast-enhanced MRI

Purpose

PET imaging with somatostatin receptor ligands, such as ⁶⁸Ga-DOTATOC, is a well-established method for detection and target volume definition of meningiomas prior to radiotherapy. Since DOTATOC PET delivers a higher contrast between meningiomas and surrounding tissues than MRI, we conducted a retrospective analysis to compare the diagnostic accuracy of contrast-enhanced MRI (CE-MRI) with ⁶⁸Ga-DOTATOC PET/CT in patients with cranial meningiomas prior to radiotherapy.

Methods

Over a period of 6?years, 134 patients (20–82?years of age, 107 women and 27 men) underwent cranial CE-MRI and ⁶⁸Ga-DOTATOC PET/CT. To compare the two methods, the lesions considered typical of meningiomas visually were counted and analysed with respect to their location and SUVmax.

Results

In the 134 patients investigated by both modalities, 190 meningiomas were detected by ⁶⁸Ga-DOTATOC PET/CT and 171 by CE-MRI. With knowledge of the PET/CT data, the MRI scans were reinvestigated, which led to the detection of 4 of the 19 incidental meningiomas, resulting in an overall detection rate of 92?% of the meningioma lesions that were found by PET/CT.

Conclusion

Ga-DOTATOC PET/CT demonstrated an improved sensitivity in meningioma detection when compared to CE-MRI. Tumours adjacent to the falx cerebri, located at the skull base or obscured by imaging artefacts or calcification are particularly difficult to detect by MRI. Therefore ⁶⁸Ga-DOTATOC PET/CT may provide additional information in patients with uncertain or equivocal results on MRI or could help to confirm a diagnosis of meningioma based on MRI or could help to confirm MRI-based diagnosis of meningiomas in cases of biopsy limitations. It is possible that not only radiotherapy and surgical planning, but also follow-up strategies would benefit from this imaging modality.     

Primary jugular foramen meningioma: imaging appearance and differentiating features

OBJECTIVE: Primary jugular foramen meningiomas behave differently from meningiomas arising elsewhere. The differences have important clinical, imaging, and surgical implications. We reviewed the imaging appearances of primary jugular foramen meningiomas and evaluated them for features that might assist in differentiating them from other common jugular foramen lesions. MATERIALS AND METHODS: A retrospective review identified five cases of primary jugular foramen meningioma. We defined it as primary when it was centered in the jugular foramen and secondary when it was centered in the posterior fossa with secondary extension into the jugular foramen. Secondary jugular foramen meningiomas were excluded from this study. Eight cases of jugular foramen paraganglioma and 10 cases of jugular foramen schwannoma were reviewed for comparison. RESULTS: Primary meningioma was characterized by centrifugal infiltration surrounding the skull base (5/5), a permeative-sclerotic appearance to the bone margins of the jugular foramen (5/5), and prominent dural tails (5/5). Flow voids were absent in all cases. Paraganglioma showed localized skull base infiltration, with predominant superolateral spread into the middle ear cavity (8/8). Flow voids and permeative destruction of the bone margins of the jugular foramen were typical. Schwannoma caused expansion of the jugular foramen with scalloped well-corticate bone margins, without skull base infiltration. CONCLUSION: Primary jugular foramen meningioma is characterized by extensive skull base infiltration. A centrifugal pattern of spread, a permeative-sclerotic appearance of the bone margins of the jugular foramen, the presence of dural tails, and an absence of flow voids are particularly important features that assist in differentiating primary jugular foramen meningioma other more common jugular foramen lesions.     

Imaging and clinical characteristics of temporal bone meningioma

BACKGROUND AND PURPOSE: Imaging characteristics of temporal bone meningioma have not been previously reported in the literature. CT and MR imaging findings in 13 cases of temporal bone meningioma are reviewed to define specific imaging features. METHODS: A retrospective review of our institutional case archive revealed 13 cases of histologically confirmed temporal bone meningioma. CT and MR imaging studies were reviewed to characterize mass location, vector of spread, bone changes, enhancement characteristics, and intracranial patterns of involvement. Clinical presenting signs and symptoms were correlated with imaging findings. RESULTS: Thirteen temporal bone meningiomas were reviewed in 8 women and 5 men, aged 18-65 years. Meningiomas were stratified into 3 groups on the basis of location and tumor vector of spread. There were 6 tegmen tympani, 5 jugular foramen (JF), and 2 internal auditory canal (IAC) meningiomas. Tegmen tympani and JF meningiomas were characterized by spread to the middle ear cavity. IAC meningiomas, by contrast, spread to the cochlea and vestibule. Hearing loss was the most common clinical presenting feature in all cases of temporal bone meningioma (10/13). The presence of tumor adjacent to the ossicles strongly correlated with conductive hearing loss (7/9). CONCLUSION: Meningioma involving the temporal bone is rare. Three subgroups of meningioma exist in this location: tegmen tympani, JF, and IAC meningioma. Tegmen tympani and JF meningiomas spread to the middle ear cavity. IAC meningiomas spread to intralabyrinthine structures. Conductive hearing loss is commonly seen in these patients and can be surgically correctable.     

The value of magnetic resonance imaging in the diagnosis of intracranial meningiomas

Thirty-two patients suspected by Computed Tomography (CT) of having a meningioma were additionally imaged by Magnetic Resonance. Of these, seven patients had an eventual diagnosis other than meningioma. This represents a positive value of 76% for the diagnosis of meningioma by CT. Magnetic resonance imaging (MRI) improved positive predictive value to 86%. A diagnosis other than meningioma was made by MRI with greatest confidence when tumour signal intensity was either much greater or much less than that of grey matter. Comparison of Inversion Recovery (IR) and spin echo (SE) sequences showed IR to be superior for demonstration of supratentorial meningiomas. SE images were superior to IR in demonstrating calcification. MRI was of value in showing anatomical relationships, due to its multiplanar capacity and in demonstrating vessel patency. CT was generally superior in defining meningiomas and in demonstrating calcification.     

脑膜瘤

根据WHO的中枢神经系统肿瘤分类，脑膜瘤分为四类：①脑膜瘤。②脑膜间质非脑膜上皮肿瘤。③原发性黑素细胞病变。④组织来源不明的血管母细胞瘤。脑膜瘤是一组分为15个亚型和3个恶性级别的杂类肿瘤，在脑膜肿瘤中最为多见。本文复习它们的影像学，介绍侵袭性脑膜瘤的概念和影像学表现。已经肯定，大多数骨质增生是由肿瘤直接浸润所致，对此情况应考虑侵袭性脑膜瘤的诊断。单个脑膜瘤可能为硬脑膜上范围相对较大的肿瘤野中生长突出而能见到。基于这个概念，复发性脑膜瘤可分为两类：真性或局部性复发；假性或区域性的复发。非典型性和间变性脑膜瘤的影像学诊断是一个尚未解决的问题。本文对它们的CT和MRI的恶性征象及其可靠性进行探讨，本文叙述了囊性脑膜瘤和无症状性脑膜瘤的影像学，并对MRI所见脑膜尾征的意义进行探讨。     

Magnetic resonance imaging of xanthomatous meningioma

Summary A case of meningioma with extensive xanthomatous metaplasia occurring in the left frontal convexity of a 37-year-old woman is reported. The tumour was demonstrated as a hypodense mass with minimal enhancement on CT. Our findings suggest that magnetic resonance imaging may provide a clue to the diagnosis of meningiomas with extensive xanthomatous metaplasia when CT is less specific.     

富于淋巴浆细胞型脑膜瘤的MRI与病理分析

目的 探讨脑膜瘤亚型富于淋巴浆细胞型的MRI表现特征.方法 回顾性分析7例经手术病理证实的富于淋巴浆细胞型脑膜瘤的影像资料及病理资料,结合相关文献进行对比分析.结果 7例富于淋巴浆细胞型脑膜瘤均为单发病灶,6例病灶沿脑膜匍匐性生长,5例未形成具体瘤结节,2例为不规则分叶状;7例病灶均界限不清,瘤周水肿明显,邻近脑组织不同程度受累.MR平扫T1WI 7例均呈等、略低信号,T2WI 5例呈等、略高信号,2例呈等、略低信号;增强扫描见7例病灶均有显著强化效应,6例脑膜广泛不均匀增厚.病理示细胞丰富,成分多样,见大量淋巴细胞、浆细胞浸润,可见多少不等的梭形瘤细胞及典型脑膜上皮细胞区域.结论 富于淋巴浆细胞型脑膜瘤影像表现不同于常见脑膜瘤,具有一定的影像表现特征,有助于该肿瘤的诊断和鉴别.     

颅底脊索瘤的CT和MRI影像诊断与鉴别诊断

目的探讨颅底脊索瘤CT与MR影像学诊断与鉴别诊断。方法回顾性分析13例经病理证实的颅底脊索瘤的CT与MR影像学资料。结果13例脊索瘤中,发生在斜坡5例,鞍区4例,颅中凹2例,鼻咽部1例,蝶窦1例。肿瘤的形态以不规则形最多8例,圆形3例,椭圆形2例。病灶边界清楚9例,边缘模糊4例。MR表现为T1WI呈低、等、高混杂信号,T2WI则以高、低混杂信号为主。增强后病灶呈轻到中度强化,强化信号不均匀。CT见病灶呈不均匀等或稍高密度肿块,7例可见不同程度的骨质破坏。结论颅底脊索瘤的CT和MR表现有一定的特征性,结合临床大多可以确诊,但需与脑膜瘤、垂体瘤、鼻咽癌、软骨类肿瘤等鉴别。     

脑膜瘤影像诊断误诊分析

目的:探讨颅内影像表现不典型的脑膜瘤MRI与CT表现,分析其误诊原因,以提高脑膜瘤诊断的准确性.方法:回顾性分析经手术病理证实的术前第一诊断误诊的35例脑膜瘤相关病例,所有病例均行MRI平扫和增强扫描,21例同时行CT扫描,MRI与CT表现与手术病理相对照.结果:脑膜瘤误诊为其他肿瘤27例;其他病例误诊为脑膜瘤8例.结论:因组织学结构复杂及一些特殊部位构成了对脑膜瘤误诊的不可避免性;而注重典型MRI特征结合CT征象、仔细阅片及结合病史等,是提高诊断符合率的关键.     

特殊部位的脑膜瘤CT、MRI影像表现

目的　探讨特殊部位脑膜瘤的影像特征。方法　回顾性分析 11例手术和病理证实的特殊部位 (侧脑室、鞍隔、额窦 )脑膜瘤的MRI、CT表现。其中MRI检查 8例 ,CT检查 3例。结果　 11例均为单发。位于侧脑室 4例 ,鞍隔 4例 ,额窦 3例。T1WI加权像上脑膜瘤信号主要为等信号和略低信号。T2 WI加权像上脑膜瘤信号主要为等信号、略高信号、略低信号。MR增强为均匀强化或不均匀强化。CT平扫 :表现为均匀等密度和稍高密度 ,均未做强化。病理分型 :纤维母细胞型 4例 ,血管母细胞型 3例 ,合体细胞型 1例 ,砂粒体型 3例。 11例脑膜瘤中有 9例误诊。结论　提高特殊部位脑膜瘤影像学诊断正确率 ,对临床确定正确手术入路、提高肿瘤手术治愈率有重要意义     

Clinical value of 24-hour delayed imaging in somatostatin receptor scintigraphy for meningioma.

Somatostatin receptor scintigraphy (SRS) using 111In-octreotide has proven useful in patients suspected of having meningiomas. Delayed imaging is regularly performed up to 24 h postinjection. However, this procedure is time consuming and expensive. Therefore, we investigated whether 24-h imaging may be omitted in these patients. METHODS: After clinical examination and standard MRI, 71 patients were suspected of having 92 meningioma lesions. Before surgery, all patients underwent SRS after intravenous injection of 200 MBq (5.4 mCi) 111In-octreotide. Planar whole-body images were obtained at 10 min and 1, 4 and 24 h, and SPECT was performed at 4 and 24 h. Results of SRS in all lesions were evaluated with respect to histology and time of image acquisition. RESULTS: SRS yielded 58 true-positive, 20 true-negative and 14 false-negative results, with the false-negatives all less than 5 mL (2.3+/-2.1 mL) in volume. In 52 of 58 true-positive lesions (89.7%), diagnosis could be established by 4-h imaging without further information by 24-h imaging. In 10 of the 52 lesions, SPECT was necessary to confirm planar findings. Imaging at 24 h was necessary in only 6 of 58 true-positive lesions (10.3%): 3 patients who had intracranial relapse of meningioma (volume < 5 mL) and 3 who had spinal meningioma. Thus, a diagnosis of intracranial meningioma could be established in 52 of 55 lesions (95%) using a 4-h imaging protocol. CONCLUSION: With a 4-h acquisition protocol that includes SPECT imaging, SRS yields sufficient information in patients suspected of having intracranial meningiomas. Delayed imaging at 24 h is recommended only for patients who have small meningiomas (volume < 5 mL), spinal localizations or negative SRS at 4 h.     

A vascular sarcoid mass mimicking a convexity meningioma

We report a 48-year-old woman with a left posterior temporal extra-axial mass that had the imaging characteristics of a meningioma on preoperative CT, MRI and angiography. However, a biopsy diagnosis of sarcoidosis was made. This case illustrates that dural-based sarcoid masses can be very vascular and radiographically indistinguishable from meningiomas. Characteristic imaging features of extra- and intra-axial sarcoid lesions are discussed. Received: 4 March 1999/Accepted: 11 June 1999     

Tumoren der Schädelbasis

Modern imaging techniques have great importance in the diagnosis and therapy of skull-base pathologies. Many of these lesions, especially in relation to their specific location, can be evaluated using CT and MR imaging. Tumors commonly found in the anterior skull base include carcinoma, rhabdomyosarcoma, esthesioneuroblastoma and meningioma. In the central cranial fossa, nasopharyngeal carcinoma, metastases, meningioma, pituitary adenoma and neurinoma have to be considered. The most common neoplasms of the posterior skull base, including the CP angle, are neurinoma, meningioma, nasopharyngeal carcinoma, chordoma and paraganglioma. One major task of imaging is the evaluation of the exact tumor extent as well as its relationship to the neighboring neurovascular structures. The purpose of this review is to recapitulate the most important anatomical landmarks of the skull base. The typical imaging findings of the most common tumors involving the skull base are also presented.