Cerebral MR venography: normal anatomy and potential diagnostic pitfalls

BACKGROUND AND PURPOSE: MR venography is often used to examine the intracranial venous system, particularly in the evaluation of dural sinus thrombosis. The purpose of this study was to evaluate the use of MR venography in the depiction of the normal intracranial venous anatomy and its variants, to assess its potential pitfalls in the diagnosis of dural venous sinus thrombosis, and to compare the findings with those of conventional catheter angiography. METHODS: Cerebral MR venograms obtained in 100 persons with normal MR imaging studies were reviewed to determine the presence or absence of the dural sinuses and major intracranial veins. RESULTS: Systematic review of the 100 cases revealed transverse sinus flow gaps in 31% of the cases, with 90% of these occurring in the nondominant transverse sinus and 10% in the codominant transverse sinuses. No flow gaps occurred in the dominant transverse sinuses. The superior sagittal and straight sinuses were seen in every venogram; the occipital sinus was seen in only 10%. The vein of Galen and internal cerebral veins were also seen in every case; the basal veins of Rosenthal were present in 91%. CONCLUSIONS: Transverse sinus flow gaps can be observed in as many as 31% of patients with normal MR imaging findings; these gaps should not be mistaken for dural sinus thrombosis.     

脑磁共振静脉成像

目的：磁共振静脉成像(MRV)已被广泛应用于颅内静脉系统检查，特别是用来评价静脉窦血栓形成。本研究的目的是评价脑MRV描述正常颅内静脉系统解剖和变异的作用，评价它在诊断硬脑膜窦血栓形成过程中潜在的误诊因素。材料和方法：对79例常规磁共振表现正常的MRV图像进行分析，观察硬脑膜窦和主要静脉的表现和缺失情况。其中7例志愿者接受了MRV和3DPCMRA两种方法检查。结果：上矢状窦、直窦、Galen静脉和大脑内静脉显示率为100％，枕窦显示率为10％，基底静脉显示率为92％。横窦血流间隙显示率约为34％，均出现在非优势侧横窦，优势侧横窦没有出现流动间隙。结论：MRV是有效的评价颅内静脉系统方法。常规MR表现正常者中有34％可以发现横窦流动间隙，这些流动间隙不应被误诊为静脉窦血栓形成。     

Transtemporal power- and frequency-based color-coded duplex sonography of cerebral veins and sinuses.

PURPOSETo determine the ability of transtemporal power- and frequency-based transcranial color-coded duplex sonography to aid in the assessment of cerebral veins and sinuses, as well as to provide reference data for flow direction and velocity.METHODSUsing a color duplex device equipped with a 2.0/2.5-MHz sector scan, we insonated 120 healthy volunteers and three patients with cerebral venous thrombosis.RESULTSIn subjects 20 to 59 years old, deep middle cerebral veins were identified in 88%, basal veins in 97%, straight sinuses in 60%, and transverse sinuses in 42%. The corresponding values for subjects 60 to 79 years old were 53%, 86%, 23%, and 20%, respectively. Velocities were highest in transverse and straight sinuses, slower in basal veins, and slowest in deep middle cerebral veins. Flow was directed lateromedially in the deep middle cerebral vein, rostrocaudally in the basal vein and straight sinus, and mediolaterally in the transverse sinus. Two patients with straight sinus thromboses showed reversed flow direction in the basal veins, and one patient with superior sagittal sinus thrombosis showed elevated velocities in a deep middle cerebral vein.CONCLUSIONTranstemporal power- and frequency-based color-coded duplex sonography enabled imaging and velocity measurements in deep cerebral veins in subjects 20 to 59 years old, but detection of the straight and transverse sinuses was low. In older subjects, only the basal vein was regularly assessed.     

Endovascular thrombolysis in deep cerebral venous thrombosis.

We present two cases of acute thrombosis of the internal cerebral veins, vein of Galen, and straight sinus without sagittal sinus involvement. Both patients had hydrocephalus and severe edema of the basal ganglia and thalami, one with hemorrhagic infarction of the thalamus. Because both patients rapidly deteriorated to a comatose state, endovascular thrombolysis was performed with urokinase infusion of the deep venous structures. Thrombolysis was continued until a patent channel with brisk flow in the venous structures was achieved. Both patients survived with minimal neurologic deficits.     

CT scan of dural arteriovenous fistulas

Summary CT was performed on ten cases of dural intracranial arteriovenous fistulas. There were 3 fistulas of the transverse sinus draining directly into the homolateral jugular vein; 2 fistulas of the sinus with distal occlusion of the sinus and back flow into the cortical veins (one was on the transverse sinus, the other on the sagittal sinus); 2 fistulas of the middle fossa; 3 fistulas with direct venous drainage into the cortical veins, one of these forming a tumor process in the posterior fossa. Osseous abnormalities were seen in only one case. Cerebral CT abnormalities, such as patchy or vermicular enhancement, were seen in all the cases with fistulas draining into the cerebral veins. Cerebral CT was normal in cases of fistulas of the sinus without back flow into the cerebral veins.     

Intracranial MR venography in children: normal anatomy and variations

BACKGROUND AND PURPOSE: Little information is available regarding the anatomy of the intracranial veins and sinuses that can be shown on MR venograms of children. The aim of this study was to determine the normal venous anatomy and anatomic variants. METHODS: Fifty children who were referred for investigation of developmental delay and who had normal results of MR imaging of the brain were recruited into the study. The cerebral veins and sinuses, including the occipital sinuses, were assessed by using 2D time-of-flight venography. Particular attention was paid to the anatomy of the venous confluence. RESULTS: Twenty-seven cases had dominant right transverse sinuses, 18 had dominant left transverse sinuses, four had co-dominant transverse sinuses, and one had absence of both transverse sinuses. In 21 (51%) of 41 cases without occipital sinuses, absent or hypoplastic transverse sinuses were found. Nine patients had occipital sinuses. Five (56%) of nine patients with occipital sinuses were younger than 2 years, and patients younger than 2 years accounted for 24% of all patients (12 of 50 patients) in the study. In six (67%) of nine patients with occipital sinuses, absent or hypoplastic transverse sinuses were shown. Two patients had bulbous prominence of the vein of Galen. One had foreshortened superior sagittal sinus, which in turn is drained by two paramedian cortical veins. CONCLUSION: Understanding the normal anatomy of the cerebral venous system and its variants by using MR venography in children provided the background to future studies on anomalous venous structure in malformations of the brain.     

Recanalization of the falcine sinus after venous sinus thrombosis.

Thrombosis of the straight and transverse sinuses associated with a large hemorrhagic venous infarct developed in an infant with large chronic subdural fluid collections after drainage of the subdurals. CT and MR studies obtained before and after the onset of venous sinus thrombosis showed interval widening of a segment of the posterior falx between the vein of Galen and the superior sagittal sinus. MR angiography confirmed a recanalized falcine sinus.     

Magnetic resonance imaging of cerebral venous thrombosis secondary to "low-dose" birth control pills

The clinical and radiographic features of cerebral deep venous thrombosis in a 21-year-old white woman are presented. This nulliparous patient presented with relatively mild clinical symptoms and progressing mental status changes. The only known risk factor was "low-dose" oral contraceptive pills. The magnetic resonance image (MRI) showed increased signal intensity from the internal cerebral veins, vein of Galen, and straight sinus. The diagnosis was confirmed by arterial angiography.     

Cerebral venography with MR

The authors describe a two-dimensional time-of-flight magnetic resonance (MR) angiography technique to create projection venograms of the head. The technique was applied to 27 healthy volunteers and 39 patients. The superior sagittal and straight sinuses, the internal cerebral veins, and the Galen vein were visualized in all the volunteers. Other veins were seen in a high percentage of subjects. Systematic comparison of digital subtraction angiography (DSA) after intraarterial contrast medium injection and MR venography in patients showed good correlation between the two techniques. MR venography proved helpful in identifying thrombosis or patency of cerebral veins and sinuses and showed collateral venous drainage and venous drainage from arteriovenous malformations. There was good correlation between conventional contrast angiography and MR venography. In conclusion, MR venography is considered reliable for showing the cerebral venous system and provides information additional to that of conventional spin-echo imaging.     

成人永存镰状窦的64层CTA诊断并复习文献

目的分析成人永存镰状窦的64层CTA表现,提高对大脑深静脉发育异常的进一步认识。方法对9例经CTA诊断为永存镰状窦的成人患者,采用MSCT重组技术对成像进行分析。结果 9例患者均因临床疑诊颅内动脉病变而接受CTA检查。永存镰状窦显示从大脑大静脉或直窦前部与上矢状窦中后1/3处或邻近的条带状血管样结构。结论 64层CTA是成人永存镰状窦无创、有效的检查方法。     

Consequences of the anatomy of deep venous outflow from the brain

The deep venous system is best defined as the entire territory served by the great vein of Galen and the basal veins. This comprises not only the choroid plexuses and the deep grey matter of the thalamus and striatum, but also the periventricular white matter and corpus callosum, hippocampus and the cortical areas of the limbic lobe including the cingulate and parahippocampal gyri, the visual cortex, the diencephalon and rostral brain stem, and part of the cerebellum. The superficial venous system comprises the remaining neocortex (with the cortex of the entire convexity) together with a layer of subcortical white matter, separated from the periventricular white matter by a venous watershed. Outflow towards the great vein of Galen and straight sinus can be substituted by collateral channels towards the basal vein. The basal vein in turn is connected not only to the great vein of Galen, but also to the superior petrosal sinus (via the lateral mesencephalic vein), and in the adult configuration to the cavernous sinus and pterygoid plexus (via the deep and superficial sylvian veins). Evidence from pathological anatomy indicates that the venous watershed exists not only in the white matter of the hemispheres, but between the entire territories of the deep and superficial venous systems. Because of their anastomotic interconnections, only simultaneous obstruction of veins of Galen and basal veins wil effectively obstruct deep venous outflow. This can occur in the tentorial incisura, from swelling or displacement of the midbrain due to brain oedema, haematoma or tumour. Complete obstruction of great vein of Galen and basal veins leads to rapid death. In patients who survive incomplete obstruction, various combinations of damage to parts of the deep venous territory exist. This is possible because very many tributaries of the deep system unite below and sometimes above the tentorial incisura. The hallmarks these varying deep venous obstructions have in common are sparing of the subcortical white matter of the convexity, and cortical involvement limited to the limbic lobe and visual cortex. Obstruction of cerebral venous outflow explains many pathological phenomena. Treatment must aim at relieving this obstacle to blood flow. Received: 17 August 1998 Accepted: 1 September 1998     

Cerebral MR venography in children: comparison of 2D time-of-flight and gadolinium-enhanced 3D gradient-echo techniques

PURPOSE: To prospectively compare two-dimensional (2D) time-of-flight cerebral magnetic resonance (MR) venography with gadolinium-enhanced three-dimensional (3D) gradient-echo cerebral MR venography in children. MATERIALS AND METHODS: This investigation had investigational review board approval and was Health Insurance Portability and Accountability Act compliant; parental informed consent was obtained. Thirty-seven patients (20 boys, 17 girls) who ranged in age from 4 days to 15 years underwent 2D and 3D MR venography. Two pediatric neuroradiologists compared the visibility of the superior sagittal, straight, transverse, and sigmoid sinuses and the internal jugular veins on images obtained with the two sequences. RESULTS: In 17 (46%) of the 37 patients, the sequences were equivalent in terms of their depiction of venous anatomy. In 19 (51%) of the 37 patients, 3D MR venography was superior to 2D MR venography. Suboptimal enhancement of veins occurred in one (3%) patient at 3D MR venography. Venous anomalies suggested at 2D MR venography but not present at 3D MR venography included flow gaps in the nondominant transverse sinuses of four patients, unilateral transverse sinus atresia in eight, and a narrowed superior sagittal sinus in two. Two-dimensional MR venography results failed to reveal a persistent falcine sinus associated with straight sinus atresia in one patient and suggested transverse sinus thrombosis in two patients in whom 3D MR venography results were normal. Additionally, the extent of dural thrombosis was overestimated at 2D MR venography in one patient. As compared with 3D MR venography, 2D MR venography failed to reveal sigmoid sinus stenosis in one patient and poorly depicted posterior fossa dural sinus anatomy in two patients with dural arteriovenous fistula. CONCLUSION: Three-dimensional MR venography is often superior to 2D MR venography in the delineation of major cerebral venous structures in children. Most of the artifactual loss of vascular signal seen with the use of 2D MR venography occurred in nondominant transverse sinuses.     

Deep venous drainage in great cerebral vein (vein of Galen) absence and malformations

Summary We report two types of venous patterns associated with great cerebral vein (vein of Galen) absence or unavailability. Developmental venous anomalies or vein of Galen arteriovenous malformations (VGAM) serve as an illustrative material. A diencephalic pattern that collects the thalamo-striate veins into the tentorial sinus is recognized in most VGAM. A telencephalic arrangement connecting the striate veins with the rostral afferents to the basal vein is less frequent. Both patterns reproduce embryonic stages preceeding the development of the great cerebral vein, thus confirming Raybaud's hypothesis that in VGAM the pouch is not the vein of Galen but the medial vein of the prosencephalon. The prognostic value of each pattern can then be appreciated and the therapeutic strategies rationalized; some unexplained complications of the venous approach for non selected VGAM can thus be avoided.     

脑静脉窦栓塞动物模型的建立方法

目的:探讨经皮穿刺静脉插管静脉窦内弹簧圈或/和明胶海绵植入致脑静脉窦急性栓塞动物模型的建立方法,评价其有效性、可行性、优缺点。方法:采用经静脉插管的介入方法将弹簧圈和/或明胶海绵放置在实验小型猪脑静脉窦的不同位置达到静脉窦完全或不完全栓塞的效果。结果:9例实验动物均成功的完全或不完全栓塞上矢状窦、直窦、乙状窦。右侧乙状窦栓塞1例,上矢状窦中后1/3 Rolandic静脉前1~2cm处1例,Rolandic静脉处栓塞3例,Rolandic静脉后1~2cm处栓塞2例,直窦栓塞1例,窦汇和直窦栓塞1例。结论:经皮穿刺静脉插管脑静脉窦内弹簧圈、明胶海绵植入致脑静脉窦急性栓塞动物模型的实验方法有效可行,此方法不开颅,脑组织无人为损伤,更加接近实际发病状况。     

More reliable noninvasive visualization of the cerebral veins and dural sinuses: comparison of three MR angiographic techniques

PURPOSE: To compare the visualization of cerebral veins and dural sinuses at contrast material-enhanced three-dimensional (3D) fast low-angle shot (FLASH) magnetic resonance (MR) angiography, time-of-flight (TOF) MR angiography, and phase-contrast MR angiography. MATERIALS AND METHODS: The authors prospectively compared the two-dimensional source images, multiplanar reconstructed images, and maximum intensity projection angiograms obtained at contrast-enhanced 3D radio-frequency-spoiled FLASH MR angiography in 20 patients with those obtained at TOF and phase-contrast MR angiographic examinations. Two neuroradiologists in consensus determined the number of visualized cortical veins and graded the quality of visualization of veins and sinuses as intense and continuous, faint and continuous, or noncontinuous. Statistical analysis was performed with the nonparametric sign test and the Wilcoxon matched pairs sign rank test. RESULTS: The cortical veins, inferior sagittal sinus, and cavernous sinuses were visualized best with FLASH MR angiography (P <.003). The Trolard and Labbé veins were visualized equally well with the FLASH and TOF sequences. For septal, internal cerebral, and Rosenthal left basal vein visualization, phase-contrast MR angiography was inferior to the FLASH and TOF MR angiographic examinations (P <.05). The quality of visualization of the thalamostriate and Galen veins and of the superior sagittal, rectal, and transverse sinuses was the same at all MR angiographic examinations. CONCLUSION: Three-dimensional FLASH MR angiography depicts some venous structures better than do TOF and phase-contrast MR angiographic examinations. The depiction of other veins is the same with 3D FLASH and TOF sequences.     

Sixteen-detector row CT angiography of the brain: comparison of 3 different volumes of the contrast material

OBJECTIVE: The aim of this prospective study was to investigate the effect of different volumes of contrast material on vascular enhancement in 16-channel multi-detector row computed tomographic angiography of the brain. METHODS: A total of 194 patients were divided into 3 groups who received different volumes of contrast material: 100 (n = 62), 80 (n = 72), and 60 mL (n = 60). The attenuation values were measured on transverse images at 12 different intracranial vessels (right and left internal carotid arteries, A2s, M2s, and P2s, basilar artery, vein of Galen, superior sagittal sinus, and dominant sigmoid sinus). The image quality parameters (intra-arterial contrast, arterial delineation, venous contamination, and confidence in diagnosis) were graded by 2 observers in consensus using a 5-point scale. RESULTS: The attenuation values at the left A2 segment, superior sagittal sinus, and sigmoid sinus were significantly lower in the 60-mL group than those in other groups, whereas no significant differences were found between the 3 groups for the remaining intracranial vessels. For qualitative evaluation, arterial delineation was rated higher in the 100- and 80-mL groups, whereas less venous contamination was found in the 60-mL group. There was no significant difference in overall image quality (the sum of the scores for 4 image quality parameters) between the 3 groups. CONCLUSIONS: A contrast material volume of 60 mL (18 g iodine) provides excellent image quality of cerebral multi-detector row computed tomographic angiography comparable to those achievable with 100 and 80 mL.     

以颅内出血为表现的脑静脉系统血栓的DSA诊断

目的 :探讨以颅内出血为首发症状的脑静脉系统血栓患者的DSA影像特征。材料和方法 :对同期 2 76例颅内出血患者的脑DSA影像进行分析并总结以颅内出血发病的脑静脉系统血栓的DSA影像学特点。结果 :2 76例颅内出血患者经DSA全脑血管造影确诊为脑静脉系统血栓 3 6例。其DSA影像学主要表现为 :全脑小静脉扩张、迂曲、数目明显增多 ;全脑动静脉循环时间延长 ;丘纹静脉和大脑内静脉系统显影增粗、扩张 ,并发生深静脉滞流 ,呈现出“雪花样”表现 ;静脉窦内对比剂滞留、显影延迟或残缺不全。结论 :DSA全脑血管造影是诊断脑静脉系统血栓的可靠方法。     

Cerebral venous sinus thrombosis presenting with excessive subarachnoid hemorrhage in a 14-year-old boy

Cerebral venous thrombosis presenting with subarachnoid hemorrhage (SAH) is very rare. We report a case of cerebral venous sinus thrombosis as an initial manifestation of SAH. A 14-year-old boy was admitted with progressive headache, nausea, vomiting, diplopia, and gait disturbance. Cerebral computed tomography scan showed a widely SAH in the basal cisterns, bilateral sylvian fissures, and anterior interhemispheric fissure. Cerebral angiography was performed to detect any aneurysm in intracranial vasculature as a cause of SAH; however, the totally thrombosed superior sagittal sinus, galenic vein, and straight sinus were the sole abnormal findings.     

静脉性脑梗死MR影像特点

目的回顾总结静脉性脑梗死MRI及MRV影像表现,旨在提高影像诊断水平。方法对15例静脉性脑梗死的MR表现进行了回顾性分析,其中9例临床治疗后复查MR表现明显好转,临床症状明显改善。15例均行常规MRI平扫,其中9例同时进行MR增强及3DCE-MRV,6例行2DTOF MRV。结果 15例脑内多发病灶9例,单发病灶6例,其中2例脑梗死伴出血改变。15例中发生于额叶4例,顶叶6例,颞叶3例,枕叶1例,小脑1例。静脉栓塞部位11例为上矢状窦,1例直窦及左横窦,1例右侧横窦及乙状窦,2例皮层大脑浅静脉。9例行增强扫描,5例病灶内不规则强化,2例脑膜强化,3例无强化.7例MRV均显示栓塞的静脉血流信号丢失或缺损,3例出现异常静脉侧支或引流静脉异常扩张。结论静脉性脑梗死MR影像表现具有特征性,MRI结合MRV可以作为首选的无创检查方法,对静脉栓塞早期诊断和治疗有重要作用。     

Development of posterior fossa dural sinuses,emissary veins,and jugular bulb: morphological and radiologic study.

PURPOSETo report the anatomic and radiologic development of the transverse, sigmoid, and occipital sinuses, the emissary veins, and the jugular bulb formation from the jugular sinus in humans before and after birth.METHODSRoentgenograms of 33 injected brains showing the cranial venous system in human fetuses from 3 to 7 months of gestational age and cerebral angiograms of newborns and infants up to 6 years of age (23 clinical cases) were made and analyzed in detail. Special attention was focused on the inner diameters of the transverse and sigmoid sinuses and of the internal jugular veins, particularly at the sigmoid sinus-internal jugular vein junction.RESULTSMarked increase in venous flow from the rapidly growing cerebral hemispheres leads to ballooning of the transverse sinuses in the absence of an increase in the inner diameters of the sigmoid and jugular sinuses. The ballooning also results in formation of the occipital sinus, marginal sinus around the foramen magnum, and emissary veins. The formation of the jugular bulbs from the jugular sinuses begins after birth when a shift from a fetal to a postnatal type of circulation (or from a lying-down position to an erect posture) takes place.CONCLUSIONThe morphological changes of the posterior fossa dural sinuses, emissary veins, and jugular bulb are closely related to the development of the brain, shift to postnatal type of circulation, and postural hemodynamic changes.