Absence of the torcular, review of venous sinus anatomy, and the simplified dural sinus classification.

BACKGROUND: Classically, the torcular Herophili is described as the symmetric junction between the superior sagittal sinus (SSS), transverse sinuses (TSs), and straight sinus (SS). However, finding this pattern in practice is not standard. Anatomical variations are common, and different drainage patterns should be expected. Existing literature proposes highly detailed descriptions and classifications of this region. Still, a simplified and practical categorization is not available. METHODS: We present an anatomical finding of the torcular Herophili discovered on a cadaveric dissection. Then, we conducted a retrospective study examining the 100 most recent cranial magnetic resonance venographies (MRVs) from the Mayo Clinic, labeling them with a new proposed dural sinus classification system. Images were initially classified by two authors and further validated by a board-certified neurosurgeon and a board-certified neuroradiologist from our institution. To measure consistency in image identification, two additional international neurosurgeons were asked to classify a subset of the same MRV images, and their answers were compared. RESULTS: Of the MRV cohort, 33 patients were male and 67 were female. Their ages ranged from 18 to 86 years, with a mean of 47.35 years and a median of 49 years. Upon examination, 53 patients presented as confluent (53%), 9 as SSS divergent (9%), 25 as SS divergent (25%), 11 as circular (11%), and 2 as trifurcated (2%). The inter-rater reliability ranked very good; agreement between the two neurosurgeons was 83% (κ = 0.830, p < 0.0005). CONCLUSION: The confluence of the venous sinuses is a highly variable anatomical area that is rarely evaluated with neuroimaging before surgery. The classic textbook configuration is not the rule. Using a simplified classification system may increase awareness and hopefully patient safety by preparing the physician for anatomical variations that they will encounter in a surgical or clinical scenario.

A clinico-radiological study of deep cerebral venous thrombosis.

PURPOSE: Isolated deep cerebral venous thrombosis (DCVT) may have different presentation and outcome compared to DCVT with additional sinus thrombosis. We compare clinico-radiological findings and outcomes of patients with isolated DCVT with those having additional sinus thrombosis. METHODS: Forty-one DCVT patients with or without additional sinus thrombosis were included. Deep CVT was diagnosed if there was thrombosis of straight sinus, vein of Galen, internal cerebral vein, or basal vein of Rosenthal on MR venography (MRV). Isolated DCVT patients were classified as Group A and those with additional sinus thrombosis as Group B. The clinical features, risk factors, MRI findings, and outcomes at 1, 3, and 6 months were compared between Groups A and B. RESULTS: Median age was 28 years, and 22 (54%) were females. Eight (19.5%) patients were in Group A and 33 (80.5%) in Group B. Group B patients had shorter duration of illness (7 vs 30 days; p = 0.01), frequent vomiting [25 (75.7%) vs 2 (25%); p = 0.01], and papilledema [13 (39%) vs 0 (0%); p = 0.04]. Risk factors were comparable. MRI revealed bilateral thalamic [5 (62.5%) vs 6 (18.2%)] and basal ganglia [(4 (50%) vs 6 (18.2%)] lesions more frequently in Group A. At 1 month, 2 (6%) patients died in Group B and none in Group A, and 24 had good outcome (50% Group A and 60.6% in Group B). At 3 months, 30 had good outcome (62.5% Group A and 80.6% in Group B). Improvement after 3 months was negligible. CONCLUSION: Isolated DCVT is rare, and additional sinus thrombosis is associated with more severe illness and death. However, long-term outcomes in the survivors are similar between the two groups.

CT angiographic study of the cerebral deep veins around the vein of Galen.

Research on the anatomy of cerebral deep veins (CDVs) around the vein of Galen (VG) is very important and has fundamental clinical significance. Large-scale anatomical studies of CDVs using computed tomography angiography (CTA) are rarely reported. A retrospective study of the CDVs around the VG was conducted in Chinese patients of Han nationality. One hundred cases were included in the final analysis. The patients were aged from 17 to 78 years (mean: 42.3 years). Also, 46% of the patients were female. The diameter of the internal cerebral vein (ICV) at its beginning and termination points ranged from 0.4 to 2.8 mm (1.49 ± 0.39 mm) and 0.4 to 3.5 mm (2.05 ± 0.47 mm), respectively. There was statistical significance regarding the diameter of the ICV at its beginning and termination points (P <0.01). The ICV length ranged from 28.5 to 47.9 mm (36.86 ± 3.74 mm). The length of the straight sinus (SS) ranged from 30.2 to 57.8 mm (43.6 ± 6.37 mm). The length of the VG ranged from 1.5 to 41.8 mm (9.30 ± 4.76 mm). The angle at the VG and SS transition area ranged from 25.4 to 110.6° (77.2 ± 18.0°). This study was a meaningful attempt to conduct anatomical research of CDVs using CTA. Preoperative familiarity with the normal venous structure and its variation around the VG would be helpful for endovascular treatment.

Persistent falcine sinus with temporo-occipital schizencephaly: case report with a review of literature in relation to the undeveloped vein of Galen and/or straight sinus.

Falcine sinus is a normal midline embryonic venous sinus present in the fetal brain and usually disappears by birth. Persistent falcine sinus (PFS) has been reported as a normal variant or along with vein of Galen (VOG) malformation, encephalocele, and other abnormalities. Schizencephaly, either closed or open type, has been reported with other associated vascular anomalies. We report a 22-month-old child, who presented with delayed milestones and referred for magnetic resonance (MR) imaging, and the child was found to have PFS with associated bilateral temporo-occipital closed-lip schizencephaly, hippocampal abnormalities, falco-tentorial dehiscence, and white matter abnormalities. The vein of Galen and straight sinus were absent, and the internal cerebral veins were seen draining into superior sagittal sinus via the falcine sinus. These set of abnormalities are unique from abnormalities reported previously in association with the falcine sinus.

MRI Findings of Spontaneous Intracranial Hypotension: Usefulness of Straight Sinus Distention.

OBJECTIVE. Spontaneous intracranial hypotension (SIH) shows various characteristic MRI findings. We evaluated the usefulness of straight sinus distention compared with transverse sinus distention and also evaluated other MRI findings of SIH. MATERIALS AND METHODS. Forty-three consecutive patients (28 female and 15 male patients) treated for SIH and 43 age- and sex-matched control subjects at two institutions from 2012 through 2014 were included in this study. Two reviewers determined whether the transverse sinus distention sign and straight sinus distention sign were present on MRI. Diagnostic performance values and interobserver agreement were calculated. Reviewers also assessed MRI examinations in consensus for the presence of the following findings: pachymeningeal enhancement, subdural effusion or hematoma, enlargement of the pituitary gland, and downward displacement of the brainstem and tonsils. RESULTS. The sensitivity, specificity, and diagnostic accuracy of the transverse sinus distention sign for SIH were 76.7%, 83.7%, and 80.2%, whereas those of the straight sinus distention sign were 79.1%, 95.4%, and 87.2%, respectively. The specificity of the straight sinus distention sign for SIH was significantly higher (p = 0.025) than that of the transverse sinus distention sign. In addition, the straight sinus distention sign showed substantial agreement (κ = 0.79), whereas the transverse sinus distention sign showed moderate agreement (κ = 0.60). The diagnostic accuracy of the presence of either transverse or straight sinus distention (83.7%) was significantly higher than that of pachymeningeal enhancement (80.2%, p = 0.032). CONCLUSION. The straight sinus distention sign could be helpful for the diagnosis of SIH because it has sensitivity comparable to other imaging findings and higher specificity and higher level of interobserver agreement than other imaging findings.

Visualization of the tentorial innervation of human dura mater.

Posterior projections of the ophthalmic division of the trigeminal nerve (the ophthalmic nerve) are distributed in the tentorium cerebelli as recurrent meningeal branches. We investigated the morphological tentorial distribution of the ophthalmic nerve. Fifty-two sides of the tentorium cerebelli and adjacent dura mater obtained from 29 human specimens were stained using Sihler's method to examine the nerve fibres in the dural sheets. The innervation patterns of the tentorium cerebelli were classified into the following four types according to their distributions: Type 1, where nerve fibres projected to both the straight and transverse sinuses; Type 2, where nerve fibres projected only to the transverse sinus and lateral convexity; Type 3, where nerve fibres projected medially only to the straight sinus and the posterior part of the falx cerebri; and Type 4, where the nerve fibres terminated within the tentorium cerebelli. Images of the tentorium cerebelli were superimposed to identify areas of dense innervation. The incidence rates of Types 1-4 were 71.2% (n = 37), 21.2% (n = 11), 3.8% (n = 2) and 3.8% (n = 2), respectively. More branches of nerve fibres traversed towards the transverse sinus posterolaterally than towards the straight sinus medially. The space between the anterior half of the straight sinus and the medial tentorial notch can be considered a safe surgical area where innervation is scarce. The posterior part of the falx cerebri was innervated by the ophthalmic nerve that traversed to the straight sinus. The parietal branches of the middle meningeal artery in the lateral convexity that were projected orthogonally by the ophthalmic nerve traversed the transverse sinus, implicating their vulnerability and possible sensitivity under physiological or neurosurgical conditions. This study has revealed the macroscopic tentorial innervation of the dura mater in humans, which could be useful information for both neurosurgeons and neurologists.

Single-session, transarterial complete embolization of Galenic dural AV fistula.

Galenic dural arteriovenous fistula (DAVF) represents a unique, hard to treat subgroup of tentorial DAVFs. We present an unusual case of hemorrhagic Galenic DAVF in a 54-year-old woman. The fistula drained directly to the vein of Galen through multiple feeders. Complete occlusion of the fistula was achieved through transarterial embolization. Deep venous drainage remained intact and the patient recovered well. To our knowledge, this is the first report on complete closure of hemorrhagic Galenic DAVF using transarterial embolization with complete obliteration of vein of Galen. The presence of nonfunctioning straight sinus may have contributed to the success of treatment and it may be considered as a predictive marker for endovascular embolization.

Multiple Deep White Matter Hyperintense Lesions on Diffusion-Weighted Imaging: Early Sign of Straight Sinus Thrombosis.

Straight sinus thrombosis (SST) is a rare type of cerebral venous sinus thromboses and is extremely difficult to diagnose, especially at its acute stage. The diagnosis is often delayed in many cases of SST that leads to treatment delay and a poor prognosis. We report the case of a 67-year-old patient who had multiple deep white matter (DWM) hyperintense signals on diffusion-weighted imaging (DWI) immediately after the onset of SST. This DWM hyperintense signal on DWI was the only abnormality at the acute stage, the underlying cause of which was congestive cerebral ischemia. Taken together, DWM hyperintense signals on DWI could be a useful diagnostic imaging marker for the early detection of SST.

Eclipse balloon-assisted straight sinus thrombectomy: A novel technique.

Cerebral venous sinus thrombosis comprises 0.5% of all strokes and usually affects young adults. Straight sinus involvement is relatively rare, and it is associated with poor prognosis. Intravenous anticoagulation is considered the first line of treatment. Endovascular approaches such as direct catheter thrombolysis, balloon-assisted thrombolysis, and mechanical thrombectomy may be more efficient and should be considered in cases in which there is involvement of the deep venous system, declining neurological status, or less invasive treatment options have failed. In this work, we describe a novel technique of ECLIPSE 2L balloon (Balt, Irvine, CA) assisted mechanical thrombectomy for straight sinus thrombosis and a review of dural sinus thrombosis management.

Combined Mechanical Thrombectomy for Multiple Cerebral Venous Sinus Thrombosis Involving the Straight Sinus: A Case Report.

The proportion of cerebral venous sinus thrombosis involving the straight sinus (StS) is low, and the prognosis is poor. We report a case of multiple sinus thrombosis involving StS in which the patient underwent mechanical thrombectomy (MT) using a stent retriever and an aspiration catheter (combined MT) with a good postoperative course. A 15-year-old girl was admitted to our hospital with rapid loss of consciousness. Magnetic resonance imaging (MRI) revealed thrombosis of the bilateral internal cerebral veins, vein of Galen, StS, torcular herophili (TH), and right transverse sinus (TS), as well as edema mainly in the left thalamus, basal ganglia, and corpus callosum. Systemic heparinization was initiated, and combined MT was performed. Although complete recanalization of the TH and right TS via the left internal jugular vein was achieved, the microwire could not be advanced to the StS. Hence, the approach route was changed to remove the thrombus from the superior sagittal sinus and successfully reach the StS via the right TS. Partial recanalization of the StS was achieved, and venous congestion was improved. Two months after MT, the patient returned to school without neurological deficits. MRI performed 3 months after MT revealed disappearance of the edema and complete recanalization of the StS. In this case, StS catheterization via the left TS was not possible. However, we could reach the right TS, which were recanalized first. Partial recanalization of the StS can be expected a good prognosis under the patency of the TH and TS.

A retrospective study of 78 adult tentorial middle line region dural arteriovenous fistulae.

OBJECTIVE: Dural arteriovenous fistulae (DAVF) in the tentorial middle line region are uncommon with specific features and more cognitive disorders than any other region. The purpose of this study is to present clinical characteristics and our experience with endovascular treatment in this specific region. METHODS: During a 20-year period, 94.9% of patients (74/78) underwent endovascular treatment (36 in galenic, 48.6%) (12 in straight sinus, 16.2%) (26 in torcular, 35.1%). There were 63 males and 15 females with mean age of 50 (50 ± 12) years in total of 78 patients. The clinical presentation, angiographic features, treatment strategy, and clinical outcomes were recorded. RESULTS: Transarterial embolization (TAE) was performed in 89.2% of the 74 patients (66/74), transvenous embolization alone in one patient and mixed approach in seven. Complete obliteration of the fistulas was obtained in 87.5% of the patients (64/74). 71 patients (mean, 56 months) had phone, outpatient, or admission follow-up. The digital subtraction angiography (DSA) follow-up period (25/78, 32.1%) was 13.8 (6-21) months. Two of them (2/25, 8%) had fistula recurrences after complete embolization and were embolized again. The phone follow-up period (70/78, 89.7%) was 76.6 (40-92.3) months. Pre-embolization and post-embolization mRS ≥ 2 were in 44 patients (44/78) and 15 (15/71) patients, respectively. DAVF with internal cerebral vein drainage (OR 6.514, 95% Cl 1.201-35.317) and intracranial hemorrhage (OR 17.034, 95% Cl 1.122-258.612) during TAE were the risk factors for predicting poor outcomes (followed up mRS ≥ 2). CONCLUSIONS: TAE is the first-line treatment for tentorial middle line region DAVF. When pial feeders' obliteration is difficult to achieve, it should not be forced due to the poor outcomes after intracranial hemorrhage. The cognitive disorders caused by this region were not reversible as reported. It is imperative to enhance the care provided to these patients with cognitive disorders.

Atretic cephaloceles with different imaging phenotypes - Case series with review of literature.

Atretic cephaloceles (ACs) are congenital skull defects with herniation of rudimentary intracranial structures through the defect and associated with persistent falcine sinus or embryonic positioning of straight sinus. We describe five cases of ACs, out of which only one had embryonic straight sinus. Three cases had other intracranial malformations such as hypoplasia of corpus callosum, dysplastic tectum in one child and parieto-occipital polymicrogyria with falcotentorial dehiscence in the other, and frontal horn deformity and cortical dysplasia in the third. The prognosis of AC depends on the coexistent intracranial abnormalities and this highlights the role of magnetic resonance imaging in diagnosing the other associated anomalies for prediction of prognosis and planning of necessary surgical management.

Case report: Transvenous coil embolization of a high-grade Galenic dural arteriovenous fistula.

Introduction: Galenic dural arteriovenous fistulas (dAVFs) are a rare form of dAVF and rarely described in the literature. Their distinct location requires different surgical approaches than dAVFs occurring at the nearby sites of the straight sinus and torcular Herophili, and their high risk of hemorrhage makes these dAVFs very challenging to approach surgically. In this report, we present a unique case of Galenic dAVF. Case description: The patient is a 54-year-old female who presented with a 2-year history of progressive headaches, cognitive decline, and papilledema. A cerebral angiogram demonstrated a complex dAVF to the vein of Galen (VoG). She underwent transarterial embolization with Onyx-18 which resulted in minimal reduction in arterial venous shunting. She subsequently underwent a successful transvenous coil embolization resulting in complete occlusion of dAVF. The patient's postoperative course was complicated by interventricular hemorrhage; however, she had a remarkable clinical recovery with resolution of headaches and improvement in cognitive function. A follow-up angiogram completed 6 months post-embolization demonstrated very mild residual shunting. Conclusion: In the unique case presented here, we demonstrate the efficacy of transvenous embolization via an occluded straight sinus as an alternative therapeutic option to eliminate cortical venous reflux.

A Transvenous Endovascular Approach in Straight Sinus Has Minor Impacts on Chordae Willisii.

Cerebral dural sinuses contain different types of chordae willisii (CW). The transvenous endovascular approach, which has become an optimal method for the treatment of cerebrovascular diseases, such as malformation, fistula, and chronic intracranial hypertension, due to sinus thromboses, frequently uses retrograde navigation through dural sinuses. Whether or how much the endoscopic procedure damages the chordae willisii is often not well-assessed. In our study, an overall number of 38 cadaveric heads were analyzed for the distribution and features of the chordae willisii in the straight sinus. We used an endoscope on these samples mimicking a mechanical thrombectomy procedure performed in the straight sinus. Both endoscopic gross observation and light microscopic histological examination were used to assess the damages to the chordae willisii by the procedure. We found that the valve-like lamellae and longitudinal lamellae structures were mainly found in the posterior part of straight sinus whereas trabeculae were present in both anterior and posterior portions. We treated a group of samples with a stent and another with a balloon. The stent-treated group had a significantly higher rate of Grade 1 damage comparing with the balloon-treated group (p = 0.02). The incidence of damage to the surface of chordae willisii was also higher in the stent-treated group (p = 0.00). Neither the use of stent nor of balloon increased the rate of damage to chordae willisii during repeated experiments. These findings indicated that stent or balloon navigation through the straight sinus can cause minor damages to the chordae willisii and frequent uses of retrograde navigation through the straight sinus do not appear to increase the rates of damage to chordae willisii.

A Transvenous Endovascular Approach in Straight Sinus has Minor Impacts on Chordae Willisii.

Background: The transvenous endovascular approach has become an optimal method for the treatment of cerebrovascular diseases. This procedure might cause iatrogenic damage to the chordae willisii (CW) in the straight sinus. However, little literature has been found to support this hypothesis. Objective: To investigate the possible damage of CW in the straight sinus during a transvenous endovascular procedure. Materials and Methods: The features of the CW from 38 cadaveric heads were observed via an endoscope mimicking a mechanical thrombectomy procedure in the straight sinus. Endoscopic observation and light microscopy examination were used to assess the damage of the CW throughout the procedure. Results: Valve-like lamellae and longitudinal lamellae were found predominantly in the posterior portion of the straight sinus. Trabeculae were present in both the anterior and posterior portions of the straight sinus. Samples treated with a stent had a significantly higher rate of Grade 1 damage during the eight procedures compared with samples treated with a balloon (P = 0.02). The incidence of damage to the CW surface was higher in the stent group than in the balloon group (P = 0.00). The use of stent or balloon did not increase the rate of CW damage during repeated experiments. Conclusions: The stent or balloon navigation through the straight sinus can cause minor damage to the CW. Frequent uses of retrograde navigation through the straight sinus do not seem to increase the possibility of damage to CW.

Recanalization for straight sinus thrombosis through combined mechanical thrombectomy: A case report.

Background: Systemic anticoagulation has been the standard treatment for cerebral venous sinus thrombosis (CVT). Although endovascular treatments, including mechanical thrombectomy (MT), have been reported to be effective for CVT, no clear evidence has been established. Case Description: A 51-year-old woman who had been administered oral contraceptive pills was transferred to our hospital with altered consciousness and disorientation. Computed tomography (CT) revealed a hyperdense signal in the straight sinus (StS), and CT angiography revealed a defect in the basal vein and StS, leading to a diagnosis of StS thrombosis. Although systemic anticoagulation through unfractionated heparin was performed, her neurological condition deteriorated, and venous ischemia was observed on CT the next day. She then underwent MT. Partial recanalization was achieved with an aspiration catheter and a stent retriever. Her neurological condition improved tremendously, and venous ischemia was reversed following MT. She was discharged 3 weeks later without neurological deficits with oral anticoagulant. Conclusion: This was a relatively rare case with CVT confined to StS. Immediate combined MT for StS thrombosis can improve venous circulation, make the venous ischemia reversible, and improve patient outcomes, even if it results in partial recanalization.

Quantitative Evaluation of a Cross-Sectional Area of the Fetal Straight Sinus by Magnetic Resonance Imaging and Its Clinical Value.

Objective: The intracranial venous system plays an important role in ensuring blood circulation and a stable blood supply to the fetal brain. In the present study, a cross-sectional area of the fetal straight sinus was quantitatively evaluated by fetal magnetic resonance imaging (MRI) to explore the method's clinical value. Methods: The clinical and MRI data of 126 normal fetuses in mid-to-late stage pregnancies were retrospectively analyzed. The "dominant" sequence of the fetal straight sinus was selected, and the cross-sectional area of the lumen was measured at each gestational age to obtain the normal range at different ages and to analyze the developmental pattern and characteristics of the fetal straight sinus. Results: There were statistically significant differences in the cross-sectional area of the fetal straight sinus among different gestational ages (P < 0.05). The cross-sectional area of the fetal straight sinus was positively correlated with gestational age (coefficient of determination = 0.6892, P < 0.05). That is, the cross-sectional area of the fetal straight sinus grew with increasing gestational age, and the regression equation was y = 0.27 x - 2.14 (P < 0.05). Additionally, there were five fetuses with cerebral venous abnormalities, including four with heart failure and one with venous sinus thrombosis. Conclusion: Quantitative measurement of a cross-sectional area of the fetal straight sinus by MRI enhanced understanding of the anatomical features and developmental pattern of fetal cerebral veins and provided a reference for the clinical diagnosis of related diseases and investigation concerning pathogenesis.

Topographical anatomy of the tentorium cerebelli and venous confluences in human midterm fetuses.

Early development of veins and sinuses at and around the posterior cranial fossa seemed not to be shown by photographs except for our recent study (Ann Anat, 2020). Examination of histological sections of 38 fetuses at 10-16 weeks gestational age (GA) demonstrated that: (1) the superior petrosal sinus passed posterosuperiorly through the tentorium cerebelli and, distant and lateral to both the cerebellum and internal ear, drained into the transverse sinus; (2) the superior sagittal sinus was underdeveloped, and the inferior sagittal sinus was not yet evident; (3) the straight sinus (STS) originated from a joining of the bilateral pial veins from the lateral ventricular choroid plexus, passed through the inferoposterior part of the falx cerebri, reached the initial confluens sinuum, and then divided into the bilateral transverse sinuses. The STS origin was immediately behind the pineal body, and near the inferoposterior end of the third ventricle. The falx had a thick attachment to the tentorium below the entire course of the STS and was behind other parts of the brain. Therefore, the development and growth of the posterior dural system seemed to be independent from brain growth, and occurred well before the cerebellum grew to fill the posterior cranial fossa. A basic configuration of intracranial veins and sinuses, including embryonic transient veins (such as the vena capitis prima) seemed to be established by venous return from the choroid plexus and cranial wall, without greatly increasing the abundance of neuronal or glial cells in the brain.

Case report of a vertical straight sinus with hydrocephalus and Chiari I malformation.

The straight sinus is a division of the dural venous sinuses, found beneath the splenium of the corpus callosum. At the internal occipital protuberance, it comes together with the superior sagittal sinus and transverse sinus to form the torcular Herophili. It functions as a major site of venous drainage for the cerebellum, inferior sagittal sinus, and vein of Galen. Many morphological variations have been reported involving the angulation, positioning, and number of straight sinuses present. Patients with Chiari II and III malformations have been observed to have a high incidence of anatomical variation with their dural venous sinuses, including vertically oriented straight sinuses. Additionally, there is a high rate of hydrocephalus in this patient population. Herein, we report a vertically oriented straight sinus in a child.

Related Structures in the Straight Sinus: An Endoscopic Anatomy and Histological Study.

Some structure might be encountered with endovascular procedures within the straight sinus and is not now readily seen on digital subtraction angiography (DSA). We investigated the morphological and histological characteristics of the straight sinus, chordae willisii (CW), and junction between the great cerebral vein (GCV) and straight sinus. A total of 22 cadaveric heads and 135 patients were analyzed with either anatomic dissection or neuroimaging. The morphological features of the CW and the junction between the GCV and straight sinus were analyzed by endoscope. The histology of the junction between the GCV and straight sinus was evaluated under the microscope with staining for elastic fiber, Masson's, and immunohistochemistry. We found that fold, elevation, small bugle, or nodule and CW were detected by endoscope in the straight sinus. The most common type of CW was valve-like lamellae, which comprised 40.46% of all CW. Three different types of junctions between the GCV and straight sinus were identified: type 1 has folds in the GCV and elevation on the floor of the straight sinus; type 2 has folds and a small bugle; and type 3 presents with an intraluminal nodule located at the opening of the GCV. Compared with arachnoid granulation, the nodule consists of smooth muscle fibers and higher rate of elastic fibers. Understanding the detailed anatomy of the straight sinus may help surgeons to avoid procedural difficulties and to achieve higher success rate.