Utility of proton MR spectroscopy in the diagnosis of radiologically atypical intracranial meningiomas

Our aim was to evaluate the usefulness of proton MR spectroscopy ((1)H MRS) in the diagnosis of radiologically atypical brain meningiomas. We studied 37 patients with intracranial meningiomas with MRI and (1)H MRS (TE 136 ms). Their spectra were quantitatively assessed and compared with those of 93 other intracranial brain neoplasms: 15 low-grade and 14 anaplastic astrocytomas, 30 glioblastomas and 34 metastases. The most characteristic features of meningiomas were the presence of alanine, high relative concentrations of choline and glutamine/glutamate and low concentrations of creatine-containing compounds, N-acetyl-containing compounds and lipids. These resonances were assembled in algorithms for two-way differentiation between meningioma and the other tumours. The performance of the algorithms was tested in the 130 patients using the leave-one-out method, with 94% success in differentiating between meningioma and other tumour. Of the 37 meningiomas, five (14%) were thought atypical on MRI, and in only one of these, found to be malignant on histology, was a diagnosis other than meningioma suggested by the algorithm. The other four were correctly classified. We suggest that (1)H MRS provides information on intracranial meningiomas which may be useful in diagnosis of radiologically atypical cases.     

Computed tomography in the diagnosis of intracranial meningioma.

The CT findings in 53 meningiomas are reported. Based upon the plain and post-contrast CT pattern and density characteristics, the diagnosis of meningioma was accurately predicted in 28 of 35 convexity, parasagittal, subfrontal, middle fossa and sphenoid wing lesions (80%). In 2 calcified nonenhancing meningioma, the diagnosis was suspected by CT findings. CT was extremely accurate in detecting 16 juxtasellar, intraventricular, tentorial and posterior fossa meningiomas, but the CT pattern was less specific such that differentiation from other neoplastic or vascular lesions was not always possible. There were only 2 false negative cases; these occurred when contrast infusion had not been performed.     

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。     

"脑膜瘤"MRI误诊分析

目的　研究MRI在脑膜瘤诊断实践中的差距。方法　 15 2例经MR扫描初诊为脑膜瘤的病例与手术、病理相对照 ,从中遴选出诊断不符合的 16例进行分析。结果　脑膜瘤误诊为其他肿瘤的共 10例 ,占 6.5 % ;其他肿瘤误诊为脑膜瘤的共 6例 ,占4%。总误诊率为 10 .5 %。结论　因组织学结构复杂、设备性能和扫描技术 ,构成了MRI对脑膜瘤误诊的不可避免性 ;而舍弃年龄、部位的先入思想、注重典型特征、仔细阅片及善用病史等 ,又是提高符合率的关键。     

Computer tomography in the diagnosis of cerebellopontine angle tumours

Summary 53 patients clinically suspected of having a cerebellopontine angle (CPA) lesion were examined by computer tomography (CT) with 160 x 160 matrix EMI scanner. 17 cases (32%) had tumour positive CT, of which 12 were neurinomas and 1 meningioma. 1 CT suggestive of a CPA lesion was false positive and 1 unoperated case is probably a false negative CT. Three of the eleven verified neurinomas (27%) were of the medial type originating in the angle cistern. One neurinoma protruding 1 cm into the cistern showed no contrast enhancement. 2 CT scans (3.8%) were unsatisfactory due to movements and the large size of the head. CT is valuable for the investigation of CPA pathology and the diagnostic efficiency compares favourably to other neuroradiological procedures.     

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.     

Intracranial meningioma with pulmonary metastases: diagnosis by percutaneous fine-needle aspiration biopsy and electron microscopy

The authors report a patient with a history of recurrent intracranial meningiomas in whom two lung nodules developed. A percutaneous fine-needle aspiration biopsy of one nodule demonstrated spindle-form cells; the tumour was specifically diagnosed as metastatic meningioma on the basis of electron microscopic findings.     

囊性脑膜瘤的影像学与病理学诊断（附21例分析）

目的：探讨囊性脑膜瘤的临床表现、影像学和病理学特点。方法：回顾性分析21例临床上少见的囊性脑膜瘤的影像学和病理学表现。结果：21例患者肿瘤全切除14例,次全切除7例。结论：CT、MRI对诊断囊性脑膜瘤很有价值,依据囊性脑膜瘤的病理特征,将其分为真性囊性脑膜瘤和假囊性脑膜瘤。肿瘤因囊肿形成,病情发展迅速,常引起严重的临床症状,极易误诊为其他性质的病变。本文对其临床病理诊治经验进行了探讨。     

Pneumosinus dilatans in anterior skull base meningiomas

Introduction

Skull base meningiomas are often missed on non-contrast CT or MR examinations due to their close proximity to bone and low lesion to brain contrast. The purpose of this study is to illustrate that pneumosinus dilatans can be an indicator of anterior skull base meningiomas.

Methods

A retrospective search of the radiology information system and picture archiving and computing system database was performed. Search terms were “meningioma” in association with “pneumosinus dilatans.” Medical records and imaging studies were reviewed independently by two experienced neuroradiologists and were read in consensus. We recorded the patient age at the time of discovery of the meningioma, main presenting symptom(s), location of the tumor, and imaging characteristics. We also performed a comparative literature search for pneumosinus dilatans and its association with meningiomas.

Results

Ten patients (six women; four men) were identified in whom a meningioma of the anterior skull base was associated with a pneumosinus dilatans. Three patients had multiple meningiomas, so a total of 14 intracranial tumors were identified. Mean age at discovery was 59 years with an age range of ±20 years. All meningiomas were diagnosed by MRI and/or CT.

Conclusion

Pneumosinus dilatans can be a helpful sign to indicate the presence of a meningioma of the anterior skull base.     

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。     

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.     

Haemangiopericytoma diagnosed from a metastasis 11years after surgery for "atypical meningioma"

Meningeal haemangiopericytoma (HPC) is a rare tumour often mistakenly reported as "vascular meningioma". Unlike meningiomas, HPC has a high rate of local recurrence and distant metastases, which may occur several years after initial treatment. We report a patient in whom a HPC was misdiagnosed as benign vascular meningioma and the patient discharged from follow-up. HPC was diagnosed 11 years later from biopsy of a skeletal metastasis. Histological review of the meningeal tumour confirmed the diagnosis of meningeal HPC. Meningeal HPCs resemble meningiomas clinically, radiologically and even light microscopically. As a result, they can be reported as atypical meningioma, as in this case. HPC's are more aggressive than typical meningiomas, with a high rate of recurrence and distant metastasis, often late in the course of the disease. Management of meningeal HPC differs from that of typical meningioma, with a need for post-operative radiotherapy and long-term follow-up.     

Reactive osseous changes in intracranial types of meningioma (author's transl)]

Reactive osseous changes are so characteristic of meningiomas that diagnosis of meningioma is not infrequently possible by merely x-raying the cranium. The x-ray film shows flat or bed-like growing intracranial types (meningioma en plaque) which occupy little space or none at all, where the skeletal changes are most prominent. This type of meningioma escapes contrast medium diagnosis and is positive only in the conventional x-ray of the cranium or - in the state of beginning spread - in the tomogram.     

Lung metastasis of a meningioma

Case report of a 35-year-old male patient. 1976: operation for a falx-meningioma. 1981: meningioma recurrence and further intracranial meningiomas. Histology: 1976 and 1981 endotheliomatous meningioma: no signs of malignancy. Prior to the 2nd operation in 1981 a lung tumor was diagnosed for the first time. Histology of the lung tumor: endotheliomatous meningioma, same histology as in cerebral meningiomas.     

3D-CE-TOF-MRV对上矢状窦旁脑膜瘤术前评估的应用价值

目的探讨三维对比增强时间飞跃法磁共振静脉成像(three dimensional contrast enhance time of flight magnetic resonance venography,3D-CE-TOF-MRV)技术对上矢状窦旁脑膜瘤术前静脉窦侵犯评估的应用价值。方法回顾性分析经手术治疗的上矢状窦旁脑膜瘤患者26例,共26枚肿瘤,所有患者术前行三维对比增强MR静脉血管成像(three dimensional contrast enhance magnetic resonance venography,3D-CE-MRV)及3D-CE-TOF-MRV检查。对比观察其在显示肿瘤染色、与上矢状窦关系的差异。以术中所见肿瘤侵犯静脉窦的程度为标准,计算诊断准确度,并采用配对2检验比较3D-CE-MRV及3D-CE-TOF-MRV在评估肿瘤对上矢状窦侵犯程度的差异的统计学意义。结果19枚肿瘤在3D-CE-MRV上可见肿瘤染色,26枚在3D-CE-TOF-MRV显示清晰的肿瘤染色。术中见5枚肿瘤与上矢状窦分离(0级),9枚与上矢状窦壁黏连(1级),9枚突入上矢状窦腔(2级),3枚填满上矢状窦腔(3级),3D-CE-MRV假阴性1例,假阳性8例,准确度65%,3D-CE-TOF-MRV假阴性2例,假阳性1例,准确度88%,差异有统计学意义,P=0.021。结论3D-CE-TOF-MRV技术清晰显示其对相邻静脉窦侵犯程度,在显示肿瘤对上矢状窦侵犯程度方面优于3D-CE-MRV,可以为脑膜瘤术前评估提供准确的影像信息。     

The role of advanced MRI techniques in differentiating typical,from atypical and malignant meningiomas

Background

Meningiomas are the commonest primary, non-glial intracranial tumors. The diagnosis is often correctly predicted from characteristic imaging appearances. Some meningiomas have atypical imaging appearance that may cause diagnostic confusion.

Aim

Is to evaluate the role of advanced MR imaging techniques in differentiating typical from atypical and malignant meningiomas before surgery.

Patient

Thirty patients were retrospectively included in this study. They were referred from Neurosurgery Department and all of them suspected to have intracranial meningioma according to the contrast enhanced CT.

Methods

All patients were subjected to conventional magnetic resonance imaging followed by advanced magnetic resonance imaging in the form of diffusion weighted imaging, perfusion weighted imaging and MR spectroscopy by single-voxel techniques.

Results

The overall results based on differentiation of typical from atypical and malignant meningiomas by advanced MRI techniques. Twenty four patients had typical meningioma and 6 patients had atypical and malignant Meningiomas by advanced MRI techniques.

Conclusion

Appearance of meningiomas on DWIs and the calculation of ADC values could be correlated with their histopathological grading. On MRS, alanine was not found to be increased in all meningiomas, so MRS cannot reliably differentiate typical intracranial meningomas from atypical meningiomas.     

Multiple pulmonary metastases from intracranial meningioma: MR imaging findings (case report)

Extracranial metastases from meningioma are very rare and among those the lungs are the most common metastatic site. In the literature, pulmonary metastases of meningiomas have been emphasized on their rarity, non-specific imaging findings, and cytologic features. Some definitive MR imaging features of intracranial meningiomas have been described. However, MR imaging findings of the lung metastases of meningiomas have not been investigated with regard to these diagnostic imaging features. In this report, similarities between MR imaging features of primary intracranial meningioma and its rare lung metastases are presented.     

联合MRI和CT诊断微小脑膜瘤

目的 探讨微小脑膜瘤CT和MRI早期敏感征象,提高其检出率.方法 回顾性分析41例经临床随访及病理确诊为微小脑膜瘤的临床及影像学资料,观察并记录微小脑膜瘤发生部位、CT密度、MRI信号特点,对结果进行统计学分析.结果 21例患者行CT平扫检查,其中5例呈钙化密度,12例呈高/稍高密度,4例呈等密度.41例患者均行MRI检查,T1 WI:37例呈等信号,4例呈低信号;T2 WI:33例呈等信号,4例呈高信号,4例呈低信号;FLAIR:14例呈略高信号,27例呈等信号.13例患者行扩散加权成像(DWI)检查,其中5例呈高/稍高信号.MR增强扫描病变均呈明显强化.结论 MR多序列(FLAIR、DWI)、多方位(矢状面)结合增强扫描、薄层扫描并联合CT平扫可极大地减少微小脑膜瘤的漏诊率.     

MRI of primary meningeal tumours in children

Childhood meningeal tumours are uncommon and mostly meningiomas. We reviewed the histological and radiological findings in meningeal tumours in six children aged 12 years or less (four benign meningiomas, one malignant meningioma and one haemangiopericytoma). Compared to the adult counterpart, childhood meningiomas showed atypical features: cysts, haemorrhage, aggressiveness and unusual location. MRI features varied according to the site of the tumour, histology, haemorrhage, and presence of intra- or peritumoral cysts. Diagnosis of the extra-axial tumour was relatively easy in two patients with meningiomas, one malignant meningioma and one haemangiopericytoma. MRI findings strongly suggested an intra-axial tumour in two patients with benign meningiomas, because of severe adjacent edema. Awareness of the variable findings of childhood meningiomas and similar tumours may help in differentiation from brain tumours. Received: 22 September 1998 Accepted: 18 November 1998