Meningioma of the third ventricle

Summary Meningiomas of the third ventricle are rare intracranial neoplasms. We reported such a case in a 42 years old man without clinical evidence of increased intracranial pressure. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the tumour sitting in the superior and anterior part of the third ventricle, bulging into the lateral ventricles. CT was more effective than MRI in the demonstration of calcifications whereas MRI proved to be superior in delineation of the tumour and its relation with surrounding structures.     

Anterior cranial fossa dural arteriovenous fistula with a varix mimicking an anterior communicating artery aneurysm

We report an anterior cranial fossa dural arteriovenous fistula with a varix mimicking an aneurysm on CT and MRI.     

A standardized method for computed tomography of the orbits

Summary A standardized method for the CT exploration of the orbital region has been searched for. This method makes it possible to visualize the entire orbital region with a minimum of 4 tomographic scans, each section 6 mm thick. The reference line chosen for this exploration is parallel to the optic nerve and joins the projection of the inferior border of the orbit on the lateral view with the upper border of the ear to the scalp. After each tomographic scan the patient is moved so that the new scanning line is still parallel to the reference line but distant by 9 mm from the previous one.     

CT appearances of chronically retained wooden intraorbital foreign bodies

Identification of wooden intraorbital foreign bodies (WIOFB) is crucial for avoiding severe orbital infection. Despite careful clinical examination, WIOFB are often not recognised. We report the CT findings in chronically retained WIOFB. When not initially diagnosed, WIOFB create a granulomatous inflammatory foreign-body reaction. CT demonstrates the WIOFB as a linear dense structure surrounded by a soft-tissue mass with density similar to that of muscle, corresponding to the foreign-body reaction.     

Ependymomas of the posterior cranial fossa: CT and MRI findings

We studied nine children with posterior cranial fossa ependymomas to identify specific neuroradiological features. Patients were studied preoperatively with CT and MRI; T1-, T2-and proton-density (PD)-weighted images were obtained. All children underwent surgery and a definite histopathological diagnosis was made. All the tumours grew into the fourth ventricle and caused dilatation of its upper part, which resembled a cap. All but one were separated from the vermis by a cleavage plane. In eight cases there was desmoplastic development through the foramina of the fourth ventricle, and five were heterogeneous due to necrosis and cystic change; one had a haemorrhagic area. In most cases the solid portion was isointense with grey matter on T1-weighted images, hyperintense on PD weighting, and isointense on T2-weighted images. On CT the tumour was isodense in six cases and calcification was detected in four. The presence of both desmoplastic development and a tumour/vermis cleavage plane in a posterior cranial fossa tumour isodense on CT is highly suggestive of ependymoma.     

Arachnoid cysts of the middle cranial fossa: a consideration of their origins based on imaging

Arachnoid cysts situated in the middle cranial fossa constitute the largest group of this type of lesion. Their origin has been the subject of debate since they were first described. There is still controversy as to whether they originate directly from the meninges adjacent to the temporal pole or whether partial agenesis of the temporal lobe favours secondary formation of the cyst. We assessed the morphology of the temporal lobe and the bulging of the squamous temporal bone. Paradoxical changes in adjacent-bone, described as very rare findings in arachnoid cysts of the middle cranial fossa, were common in our study and suggest, in association with direct signs of temporal atrophy, that this atrophy precedes, or is at least coexistent with, the formation of the cyst. The importance of being able to determine the origin of the cyst lies in its being a factor to assess as regards treatment.     

Posterior cranial fossa tumours in childhood

We reviewed clinical and CT findings in 133 posterior cranial fossa tumours in children. All had histological diagnosis, apart from 20 cases of brain stem glioma. The majority were intra-axial tumours, including 53 medulloblastomas (40%), 31 cerebellar astrocytomas (23%), 28 brain stem gliomas (21%), 14 ependymomas (11%), and single cases of ganglioglioma, haemangioblastoma and teratoma. Extra-axial tumours formed only 3%, including 2 chordomas and 2 schwannomas. The clinical data and CT findings are reviewed. Cerebellar astrocytoma involved the sexes equally, while medulloblastoma, brain stem glioma, and ependymoma were more common in males. Most cerebellar astrocytomas were in the midline, and presumably arose from the vermis. The frequency of calcification was similar to that in previous reports, being highest in ependymoma (69%), followed my medulloblastoma (29%), cerebellar astrocytoma (17%), and brain stem glioma (8%).     

Primary myxoma of the posterior fossa

Summary A rare case of primary intracranial myxoma of the posterior fossa is described in a 32-year old woman. The patient presented with a history of headaches, disequilibrium, nausea and abnormal vision for several months. Computed tomography (CT) showed a well-demarcated hypodense mass. After contrast administration the mass appeared as an inhomogeneously enhancing lesion surrounded by a small rim of edema. The mass was surgically excised with histological examination revealing a true myxoma. Echocardiography revealed no evidence of a cardiac myxoma. The CT appearance of other case reports of non-cardiac myxomas in the literature is reviewed.Recipient of fellowship J0283M (Erwin Schroedinger Stipendium), Austria     

Recurrent craniopharyngioma invading the orbit,cavernous sinus and skull base: a case report

A case is described in which a recurrent craniopharyngioma extended into the sphenoid bone, posterior ethmoid cells, cavernous sinus and orbit.     

脊膜瘤的低场MR诊断

目的 总结脊膜瘤的低场MRI表现，资料与方法 搜集经手术病理证实的脊膜瘤27例，使用开放式0.23TMR扫描仪，行常规矢状位扫描，增强加轴位和冠状位扫描。对肿瘤的部位，形态，大小，边缘，信号，椎间孔改变及增强情况等进行总结分析。结果 颈椎7例，胸椎20例，肿瘤大多呈椭圆形或圆形，平均直径为1.92cm，呈均匀等T1等T2信号19例，5例呈略短T1信号，3例信号欠均匀。25例增强扫描患者，22例均匀强化，2例强化略不均匀，1例不强化，结论 脊髓瘤的低场MRI表现与高场MR一样，具有诸多特征性表现，认真观察分析，一般均可做出准确诊断。     

Comparison of consistency of meningiomas and CT appearances

Summary Computed tomograms of meningiomas in which the consistency of the tumour had been specifically noted at surgery were reviewed. Those showing diffuse calcification or evidence of marked cystic or necrotic changes were excluded, leaving 77 tumours of which 46 were hard and 31 soft. Ninety per cent of the hard tumours were of increased attenuation; the other 10% were isodense with brain. Forty-nine per cent of the soft meningiomas were of high attenuation, but 35% were isodense and 16% were of lower than brain attenuation. There was a greater incidence of marked intracerebral oedema around the hard tumours. All hypodense tumours enhanced to greater than brain attenuation; mean enhancement was relatively less in the tumours of high plain scan attenuation regardless of consistency and there was no relationship between degree of enhancement and either the consistency or with the amount of vascularity as estimated by the surgeon or histologist.     

前颅凹底神经纤维瘤1例

患者 男,42 岁,因头痛、头晕、嗅觉丧失 4 个月入院.体格检查:神志清楚,对答切题,嗅觉丧失,双侧瞳孔等大等圆,双侧面部感觉正常. 影像检查:CT示前颅窝底见类圆形稍低、等、高混杂密度肿块,大小约4.8 cm ×3.5 cm×5.6 cm,边缘清晰,邻近骨质压迫吸收变薄,肿块向下突破颅底骨质延伸至双侧后组筛窦,向上推压双侧额叶,向两侧推挤双侧眼眶内壁及内直肌(图 1);增强见肿块明显不均匀强化,内可见低密度无强化区.MRI检查见前颅凹底长T1、T2 信号为主混杂信号肿块,边缘见短 T2 信号环,DWI上呈等/稍低信号,增强肿块不均匀强化,内见多发片状不强化囊变区(图 2～5).     

Hypodense area within a meningioma: Metastasis from breast cancer

Summary A case of an intracranial meningioma containing a metastasis from breast cancer is reported. CT demonstrated a hypodense area within the meningioma and angiography showed a relatively less evident blush in the same area. The correlation of the neuroradiological with the pathological findings is discussed.     

Posterior cranial fossa dural arteriovenous malformation with a varix mimicking a thrombosed aneurysm: case report

Summary Dural arteriovenous malformations (AVMs) in the posterior cranial fossa are relatively infrequent. Intradural haemorrhage is one of their specific complications. Angiographic demonstration of varices or aneurysmal structures is one of the hallmarks of severe cases. We report a patient with posterior cranial fossa dural AVM associated with a varix mimicking a thrombosed aneurysm on CT and MRI. Internal carotid and vertebral angiography failed to demonstrate an aneurysm, but external carotid injection revealed a dural AVM affecting the sigmoid sinus, and a varix. The AVM was completely eliminated by embolization. When a dural AVM is suspected clinically selctive angiography should be performed to confirm the diagnosis even when CT or MRI do not show dilated vessels.     

A case of microcystic meningioma associated with acute subdural hematoma in the posterior cranial fossa

A 53-year-old woman was brought to the emergency room with headache and progressive deterioration of consciousness. Radiological examinations revealed acute subdural hematoma extending along the cerebellar tentorium to the falx cerebri, and a mass lesion with hemorrhage in the left cerebellum, with acute hydrocephalus. Emergency tumor and hematoma removal with decompressive craniectomy of the occiput was performed. Histopathological diagnosis was microcystic meningioma. Postoperatively, the patient recovered to clear consciousness with sequelae of left cerebellar ataxia, cerebellar dysarthria, and vertigo. This case of tentorial microcystic meningioma associated with acute subdural hematoma in the posterior cranial fossa is extremely rare, with only reported 4 similar cases.     

Solitary fibrous tumor of the orbit: CT and pathologic correlation

We report the CT findings of a solitary fibrous tumor of the orbit. The radiologic features included relatively homogeneous contrast enhancement and smooth remodelling of the bones of the orbit, findings consistent with the benign nature of this relatively rare tumor. Received: 30 December 1997 Accepted: 10 June 1998     

Meningioma of the scapula

Meningiomas account for approximately 15% of all intracranial tumors and are the most common non-glial primary tumors of the central nervous system. Most meningiomas are benign neoplasms with characteristic imaging features. Primary extradural meningiomas account for only 1–2% of all meningiomas. They must be differentiated from intradural meningiomas with secondary extradural extension and/or metastases. The vast majority of extradural meningiomas are found in the skull or in the head and neck region. We report on an extremely rare case of primary extradural meningioma that was located in the scapula. The lesion was resected. Radiographic findings and pathologic features are discussed. To the best of our knowledge, this form of presentation of an extradural meningioma has not been previously described.     

Endovascular treatment of anterior cranial fossa dural arteriovenous fistula

We describe the technique and results of the endovascular treatment of anterior cranial fossa dural arteriovenous fistulas (DAVF) in four symptomatic patients. Catheterization was via the superior sagittal sinus in two patients and via the ophthalmic artery in two patients. Embolization was performed using detachable platinum coils in the former two patients and a liquid embolic system (Onyx-18, MTI) in the latter. We were able to reach the fistula site and to embolize the arteriovenous shunting zone in all of the patients. The final angiogram showed complete occlusion of the DAVFs, and all patients recovered completely. No complications related to either approach were observed. Endovascular treatment of anterior cranial fossa DAVFs is feasible by either transvenous or transarterial access.     

Dural arteriovenous malformations of the base of the anterior cranial fossa

Two cases of dural arteriovenous malformation at the base of the anterior fossa are reported. The angiographic appearance in both cases is quite uniform and resembles the findings in 12 cases previously reported. Feeders are anterior and/or posterior ethmoidal arteries and the external carotid system also contributes. A drainage vein always shows aneurysmal dilatation of its proximal portion. CT findings are also mentioned and radiological literature reviewed.     

CT of meningiomas on the posterior surface of the petrous bone

Summary A detailed analysis of the CT findings in 16 surgically verified cases of meningioma of the posterior surface of the petrous bone is presented. The results indicate that a correct preoperative diagnosis is possible in almost every case. Frequently occuring specific CT criteria for meningioma of the posterior surface of the petrous bone include: hyperdense, homogeneously enhancing, extra-axial, CPA mass; inverse relationship between precontrast attenuation value and degree of contrast enhancement of the tumor; oval shape; obtuse angle between lateral tumor border and posterior surface of petrous bone, and evidence of transcisternal supratentorial tumor extension. Infrequently occuring specific CT criteria include: tumor calcification; hyperostosis or exostosis of the posterior surface of the petrous bone; a comma-shaped tumor configuration in cases with transcisternal tumor extension and evidence of transtentorial tumor extension. Oxygen CT cisternography is the most sensitive and reliable technique for detecting small tumors. The CT differential diagnosis of meningioma of the posterior surface of the petrous bone is discussed.