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.     

三叉神经瘤的CT及MRI诊断(附27例分析)

目的提高三叉神经瘤的CT、MRI的诊断水平.材料与方法对经手术病理证实的27例三叉神经瘤行CT及MRI检查.结果颅后窝型12例,颅中窝型6例,跨颅窝型5例.位于颅中窝、颅后窝的肿瘤呈椭圆形;跨颅窝生长者呈哑铃形或不规则形.CT扫描显示稍高密度区、混合密度区、囊性低密度区,不均匀增强或环形增强.MRIT1WI呈不均匀低信号,T2WI呈不均匀高信号,肿瘤边缘清楚,有显著占位效应.结论CT、MRI定性诊断困难时,应结合临床三叉神经受损表现诊断.     

儿童后颅凹肿瘤的CT, MRI诊断

目的：分析儿童后颅凹常见肿瘤的ＣＴ和ＭＲＩ影像学表现,提高诊断该病的准确性。材料和方法：收集儿童后颅凹常见肿瘤４０例,其中髓母细胞瘤１８例,星形细胞瘤１３例,室管膜瘤９例。行ＣＴ和ＭＲＩ检查。ＣＴ平扫４０例,增强扫描３２例;ＭＲＩ平扫２８例,增强扫描１６例。将其结果与手术病理对照。结果：４０例儿童后颅凹常见肿瘤ＣＴ显示率为９７５％,ＭＲＩ显示率为１００％。术前ＣＴ定性误诊１１例,准确率为７２５％。术前ＭＲＩ定性误诊４例,准确率为８５７％。ＣＴ和ＭＲＩ联合检查,能对后颅凹多数常见肿瘤作出定位及定性诊断。ＭＲＩ能多方位成像,去除后颅凹颅骨伪影的干扰,对该病的定位定性诊断明显优于ＣＴ。结论：ＣＴ和ＭＲＩ检查相结合,能提高诊断儿童后颅凹常见肿瘤的准确率,为临床提供更准确的诊疗信息。     

Two cases of dural arteriovenous malformation occurring after intracranial surgery

Summary The occurrence of post-operative dural arteriovenous malformation (AVM) has rarely been proved angiographically. The authors report two such cases: in one, a pure dural AVM was located in the region of the cavernous sinus and in another a mixed pial and dural AVM was found in the posterior fossa. The literature about pathogenesis is reviewed.     

Cerebral haemorrhage from a remote varix in the venous outflow of an arteriovenous malformation treated successfully by embolisation

The “spot sign”, described in 2007, has shown that a focal area of contrast extravasation within an intracerebral haematoma (ICH) can be correlated with haematoma expansion. Here we describe a case where time-resolved dynamic CT angiography (dCTA) shows the appearance of the “spot sign” only in later images. This shows the importance of timing of static CT angiogram that, if performed too early, might result in a false negative diagnosis.Haemorrhage in patients with intracranial arteriovenous malformation (AVM) usually occurs from the AVM itself or from an associated arterial aneurysm. We report a case of intracerebral haemorrhage arising from a remote varix related to the venous outflow of an ipsilateral frontal AVM.     

Choroid plexus papilloma in the posterior cranial fossa: MR, CT, and angiographic findings.

In this study, we reviewed the magnetic resonance (MR, n=5), computed tomography (CT, n=3), and angiography (n=3) of six patients with pathologically confirmed choroid plexus papilloma (CPP) in the posterior cranial fossa. CPPs in the posterior cranial fossa have several features, including a propensity to arise at the foramen of Luschka with extraventricular extension, occasional peritumoral signal voids/cysts or calcification, weaker enhancement on MR or CT, and less strong tumor staining by the anterior or posterior inferior cerebellar artery or angiography.     

DSA全脑血管造影431例分析

目的:分析431例全脑血管造影,探讨颅内血管病变用DSA全脑血管造影的价值。材料和方法:92年至96年行DSA全脑血管造影431例。采用Seldinger技术,经股动脉穿刺置管行选择性或/和超选择性全脑血管造影。前交通及后交通动脉瘤经显微神经外科证实。结果:动脉瘤155例,血管畸形76例,占位性病变48例。颅内动脉瘤发生在大脑前动脉系统为42.58％,而前交通动脉瘤为大脑前动脉系统的74.24％。颅内动脉瘤为全脑血管造影阳性发现的首位,其次为血管畸形,颅内占位。本组阴性率为25.75％。结论:CT、MR发现颅内出血或血管畸形时,不一定全脑血管造影有阳性改变。     

Why should we report posterior fossa emissary veins?

Posterior fossa emissary veins are valveless veins that pass through cranial apertures. They participate in extracranial venous drainage of the posterior fossa dural sinuses. The mastoid emissary vein, condylar veins, occipital emissary vein, and petrosquamosal sinus are the major posterior fossa emissary veins. We believe that posterior fossa emissary veins can be detected by radiologists before surgery with a thorough understanding of their anatomy. Describing them using temporal bone computed tomography (CT), CT angiography, and cerebral magnetic resonance (MR) venography examinations results in more detailed and accurate preoperative radiological interpretation and has clinical importance. This pictorial essay reviews the anatomy of the major and clinically relevant posterior fossa emissary veins using high-resolution CT, CT angiography, and MR venography images and discusses the clinical importance of reporting these vascular variants.Posterior fossa emissary veins pass through cranial apertures and participate in extracranial venous drainage of the posterior fossa dural sinuses. These emissary veins are usually small and asymptomatic in healthy people. They protect the brain from increases in intracranial pressure in patients with lesions of the neck or skull base and obstructed internal jugular veins (1). They also help to cool venous blood circulating through cephalic structures (2). Emissary veins may be enlarged in patients with high-flow vascular malformations or severe hypoplasia or aplasia of the jugular veins. They are associated with craniofacial syndromes (1, 3). Dilated emissary veins may cause tinnitus (4, 5).We aim to emphasize the importance of reporting posterior fossa emissary veins prior to surgeries that are related to the posterior fossa and mastoid region. Here, we review their embryology and anatomy based on high-resolution computed tomography (CT), CT angiography, and magnetic resonance (MR) venography images.     

颅颈部血管多层螺旋减影CTA与DSA的比较研究

目的 评价减影CTA对检察颅颈部血管性病变的灵敏度和特异度及其临床应用价值.方法 对76例怀疑颅颈部血管疾病患者施行16层螺旋减影CTA检查,在保证增强前后所采集的数据参数一致的前提下用Neuro-DSA软件进行减影,其中30例与DSA作比较观察.减影CTA图像质量分为优良、一般、差;应用非参数统计检验、计算减影CTA显示病变的灵敏度和特异度.结果 以颈内动脉颅段、前后交通动脉、大脑前中后动脉近段、椎基动脉为观察对象,共观察血管段900段.减影CTA图像质量优良571段,为63.4%,一般有301段,为33.4%.但在显示颅颈部不同段血管的图像质量上有差异;减影CTA检出病变的灵敏度为84.4%,特异度为40%,检出动脉瘤的灵敏度和特异度均为100%.结论 16层螺旋减影CTA无创,快捷,简单易行,能提供较高分辨率的血管图像,可作为一种常规的方法应用于颅颈部血管疾病的筛查和诊断.     

Aqueduct stenosis due to venous ectasia with a dural arteriovenous fistula

We report aqueduct compression by venous ectasia in a 65-year-old man with a dural arterio-venous fistula in the posterior cranial fossa draining into a superior vermian vein. Conventional and phase-contrast MRI showed the aqueduct stenosis and the causative dilated vein. Received: 9 November 1998 Accepted: 2 August 1999     

颅底及颈段脊髓血管畸形的介入检查

目的 :为介入栓塞治疗及手术治疗提供重要依据 ,从而防止误诊、漏诊病例的发生。方法 :对我院近期 3 0例疑有颅底及颈段脊髓血管畸形患者的临床表现、MRI影像特点、介入检查资料进行分析。结果 :3 0例患者均具有颅底及颈段脊髓血管畸形的临床表现及磁共振影像特点 ,经行选择性全脊髓血管造影、必要时行全脑血管造影证实 2 9例为颅底及颈段脊髓血管畸形 (其中 2 7例畸形团来自颈部血管供血及胸段脊髓血管等多支血管供血 ;2例来自颈外动脉系统供血 )。另外 1例开始被误诊为颅底及颈段脊髓血管畸形 ,后进行全脑血管造影发现为由颈内动脉原始听动脉供血的硬脑膜动静脉瘘向脊髓髓周静脉引流而造成MRI的留空信号。结论 :为了防止误诊及漏诊病例的发生 ,应对双侧的锁骨下动脉、椎动脉、肋颈干、甲状颈干、上胸段肋间动脉或全脊髓血管及颈外动脉进行造影检查 ,必要时还应进行全脑血管造影。     

Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment

Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.     

Intracranial adenoid cystic carcinoma mimicking meningioma: report of two cases

Two cases of intracranial adenoid cystic carcinoma mimicking meningioma are reported. In one, MRI showed not only a homogeneously enhancing extra-axial tumour attached to the dura mater of the posterior cranial fossa, but also surrounding dural enhancement, the dural tail sign. In the second, CT demonstrated a well-demarcated enhancing extra-axial tumour, indistinguishable from a sphenoid ridge meningioma extending into the orbit. The neuroradiological features of intracranial adenoid cystic carcinoma may thus closely resemble those of meningioma.     

颅内硬膜外积脓的影像诊断

目的　评估MR和CT对颅内硬膜外积脓的诊断价值。方法　对 4例颅内硬膜外积脓的CT和MR表现进行分析。结果　 2例额部 ;1例额顶部 ;1例后颅窝。 4例颅内硬膜外积脓处硬膜明显增厚 ,均匀强化 ,局部骨板侵蚀破坏变薄或增生。结论　CT和MR可以清楚显示颅内硬膜外积脓的形态学和病理学改变 ,因此CT和MR是诊断颅内硬膜外积脓最有价值的方法     

Dural arteriovenous malformations at the base of the anterior cranial fossa: report of nine cases

Nine men with dural arteriovenous malformations (DAVM) at the base of the anterior cranial fossa are described. Four patients had intracerebral haemorrhage and four had seizures, associated with haemorrhage in two. In three cases the fistula was an incidental finding. In five cases the diagnosis could be made before angiography, on the basis of CT findings. Angiographically, venous drainage was always seen into ascending cortical veins. Five cases demonstrated drainage via the olfactory vein into the basal vein of Rosenthal; in four this way was the principal route of drainage. Five patients underwent surgery, the therapy of choice. One fistula closed spontaneously after angiography. Two patients refused treatment and one was not treated because of his poor general condition. Because arterial supply was usually bilateral, from small branches of the ophthalmic artery, embolisation seemed to be more dangerous. Compared to dural fistulae in other locations the DAVM of the anterior cranial fossa have a higher risk of complications and should be treated even if asymptomatic at the time of diagnosis.     

The craniocervical venous system in relation to cerebral venous drainage

BACKGROUND AND PURPOSE: Passing from the supine to the upright position favors cerebral venous outflow into vertebral venous systems rather than into the internal jugular veins. We sought to determine venous connections between dural venous sinuses of the posterior cranial fossa and craniocervical vertebral venous systems. METHODS: Corrosion casts of the cranial and cervical venous system were obtained from 12 fresh human cadavers, and anatomic confirmation was made by dissection of three previously injected fresh human specimens. MR venography was performed to provide radiologic correlation. RESULTS: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins were found to represent the venous connections between the dural venous sinuses of the posterior cranial fossa and the vertebral venous systems. This study revealed the nearly constant presence of the anterior condylar confluent (ACC) located on the external orifice of the canal of the hypoglossal nerve. The ACC offered multiple connections with the dural venous sinuses of the posterior cranial fossa, the internal jugular vein, and the vertebral venous system. All these structures were shown by MR venography. CONCLUSION: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins connect the dural venous sinuses of the posterior cranial fossa with the vertebral venous systems. These connections are clinically relevant, because encephalic drainage occurs preferentially through the vertebral venous system in the upright position. The ACC is a constant anatomic structure that may play an important role in the redirection of cerebral blood in the craniocervical region.     

MR 3D-CISS序列对脊髓AVM的诊断价值

目的：评价MR 3D稳态构成干扰序列(constructive interference in steady state，CISS)对脊髓AVM的诊断价值。方法：回顾性分析26例脊髓动静脉畸形(arteriovenous malformations，AVM)患者的3D-CISS成像表现，并与DSA结果进行对照。结果：DSA显示16例脊髓AVM表现为脊髓背侧一条稍粗大的畸形血管干和分布于硬脊膜内许多高度迁曲的细小分支，呈蚯蚓状、匐行状迂曲血管影，脊髓表面纹理被穿透；7例则显示为一条扩张的引流静脉；3例表现为球状局限性血管丛。23例3D-CISS表现与DSA结果基本一致，3例DSA证实为胸段AVM，而3D-CISS发现为全段脊髓AVM。根据手术病理和最终诊断结果，3D-CISS序列诊断脊髓AVM的敏感性和特异性分别为92％、98％。结论：3D．CISS序列对疑为脊髓AVM病人有很好的筛选作用，其敏感性较高。     

Spontaneous thrombosis of a giant intracavernous internal carotid artery aneurysm and ipsilateral internal carotid artery occlusion

A 75-year-old man who had suffered from right visual disturbance for 10 years suddenly experienced right cavernous sinus syndrome. Magnetic resonance imaging revealed a giant thrombosed aneurysm in the right cavernous sinus extending to the right middle cranial fossa. Digital subtraction angiography disclosed occlusion of the right internal carotid artery at the petrous portion and good cross filling in the right-sided circulation through the anterior communicating artery. There was no filling of the aneurysm. In this case, the mechanism of parent artery occlusion is unclear, but direct compression and stretching of the parent artery by the aneurysm may be involved.     

Preoperative embolization of intracranial meningiomas

The goal of preoperative embolization of intracranial meningiomas is to facilitate their surgical removal by reducing tumor vascularity and decreasing blood loss during surgery. This study is based on personal experience with about 100 embolized meningiomas and on the experience of others. Embolization is performed during the same session as diagnostic angiography. The appropriate embolic materials (absorbable or nonabsorbable) are chosen according to the location of the tumor, the size of the feeding arteries, the blood flow, and the presence of any potentially dangerous vessels (dangerous anastomoses between external carotid artery and internal carotid or vertebral arteries, arteries supplying the cranial nerves). Preoperative embolization appeared to be very useful in large tumors with pure or predominant external carotid artery supply (convexity meningiomas), in skull-base meningiomas, and in middle fossa and paracavernous meningiomas. It was also useful in falx and parasagittal meningiomas receiving blood supply from the opposite side and in posterior fossa meningiomas. CT low densities demonstrated after embolization did not always correlate with necrosis on microscopic examination, and large areas of infarction could be found despite normal CT. Embolic material was found on pathologic examination in 10%-30% of cases; fresh or recent ischemic and/or hemorrhagic necrosis consistent with technically successful embolization was demonstrated in 40%-60% of cases. With careful technique complications are rare.     

Endoscopic paranasal sinus surgery: radiographic evaluation of severe complications.

PURPOSE: To report our experience with the radiographic evaluation of severe complications resulting from the functional endoscopic sinus surgery (FESS) procedure. PATIENTS: Ten major complications were reviewed retrospectively. FINDINGS: Ten major complications occurred. Eight of 10 had injury to the floor of the anterior cranial fossa, fovea ethmoidalis (roof of the ethmoid sinus), or roof of the sphenoid sinus. Six patients presented with meningitis or rhinorrhea, two presented with headache and massive pneumocephalus; one patient who presented with meningitis had a large nasal frontal encephalocele. Noncontrast brain CT that included the paranasal sinuses adequately evaluated the source of pneumocephalus. Thin-section coronal CT accurately predicted the site of leak in five patients. Both coronal sinus CT and MR imaging were useful to confirm the nasal encephalocele. Two of 10 had vascular injury secondary to FESS. One patient presented with subarachnoid hemorrhage seen on noncontrast CT and cerebral angiography demonstrated an aneurysm of the anterior cerebral artery. The second patient suffered severe intraoperative hemorrhage. Emergency angiography revealed a pseudoaneurysm of the cavernous carotid artery, and balloon occlusion of the artery was performed. No deaths occurred in this series. CONCLUSION: Radiologists should be familiar with the rare, but potential complications of this commonly performed procedure in order to help direct the work-up in an efficacious manner.