Bridging veins at the craniocervical junction: from anatomy to clinical significance in dural arteriovenous shunts.

PURPOSE: Bridging veins (BVs) serve as a route of pial venous reflux, and its anatomy is essential to understand the pathophysiology of dural arteriovenous shunts (dAVSs) around the craniocervical junction (CCJ) (from the jugular foramen level to the atlantal level). However, the anatomical variations of the BVs and their proximal connections remained poorly elucidated. This study aimed to radiologically investigate the anatomy of the bridging veins around CCJ and discuss the clinical significance of these BVs in the dAVS. METHODS: We investigated normal venous anatomy of the BVs from the jugular foramen level to the atlantal level using preoperative computed tomography digital subtraction venography in patients undergoing elective neurosurgery. BVs affected by the dAVSs in the same region were also evaluated. The three types of dAVS, craniocervical junction, anterior condylar, and proximal sigmoid sinus, were investigated. RESULTS: We identified six BV groups: superolateral, anterolateral, lateral, posterior, inferolateral, and inferoposterior. The superolateral and inferolateral groups, connected with the proximal sigmoid sinus and suboccipital cavernous sinus, respectively, were the largest groups. Each group has a specific downstream venous connection. The association with dVASs was observed only in the inferolateral group, which was typically the sole venous drainage in most dAVSs at the CCJ. CONCLUSION: We reported detailed anatomy of BVs from the jugular level to the atlantal level, which enhanced our understanding of the pathophysiology of dAVSs in the corresponding region.

Exploration of postural effects on the external jugular and diploic venous system using upright computed tomography scanning.

PURPOSE: Few studies have investigated the influence of posture on the external jugular and diploic venous systems in the head and cranial region. In this study, we aimed to investigate the effects of posture on these systems using upright computed tomography (CT) scanning. METHODS: This study retrospectively analysed an upright CT dataset from a previous prospective study. In each patient, the diameters of the vessels in three external jugular tributaries and four diploic veins were measured using CT digital subtraction venography in both supine and sitting positions. RESULTS: Amongst the 20 cases in the original dataset, we eventually investigated 19 cases due to motion artifacts in 1 case. Compared with the supine position, most of the external jugular tributaries collapsed, and the average size significantly decreased in the sitting position (decreased by 22-49% on average). In contrast, most of the diploic veins, except the occipital diploic veins, tended to increase or remain unchanged (increased by 12-101% on average) in size in the sitting position compared with the supine position. However, the changes in the veins associated with this positional shift were not uniform; in approximately 5-30% of the cases, depending on each vein, an opposite trend was observed. CONCLUSION: Compared to the supine position, the contribution of external jugular tributaries to head venous drainage decreased in the sitting position, whilst most diploic veins maintained their contribution. These results could enhance our understanding of the physiology and pathophysiology of the head region in upright and sitting positions.

Aneurysmal subarachnoid hemorrhage occurring during sleep: Clinical characteristics and risk factors.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is known to be triggered by several specific human activities. Sleep, by contrast, has not been considered a triggering activity for aSAH, and clinical characteristics of patients who sustain aSAH during sleep have rarely been reported in the literature. METHODS: This is a retrospective analysis on the data acquired through a multicenter aSAH registry. Between January 2019 and December 2021, a total of 732 aSAH patients had been registered into our database. After excluding 109 patients whose activities at aSAH onset had been unidentifiable, the remaining 623 aSAH patients were dichotomized to 59 patients who sustained aSAH during sleep (Sleep group) and 564 patients who sustained aSAH during daytime activities (Awake group). Two-group comparison of demographic variables and multivariate logistic regression analysis were performed to clarify their clinical characteristics and identify potential risk factors. RESULTS: The Sleep group exhibited significantly higher frequencies of diabetes (15.5 % vs. 6.4 %, p = 0.01) and antiplatelet use (13.8 % vs. 4.6 %, p=0.004) than the Awake group. Furthermore, multivariate logistic regression analysis showed that diabetes (OR, 3.051; 95 % CI, 1.281-7.268; p = 0.012) and antiplatelet use (OR, 3.640; 95 % CI, 1.422-9.316; p = 0.007) were correlated with aSAH occurring during sleep. There were no significant inter-group differences in the patient outcomes evaluated at discharge. CONCLUSION: The current results indicate that risk factors may exist for aSAH occurring during sleep. Further investigations on how comorbidities such as diabetes, antiplatelet use and sleep apnea affect human hemodynamic and hemostatic parameters during sleep is warranted to better understand those relationships.

[Inferior Petrosal Sinus and Anterior Condylar Confluence and Surrounding Venous Anatomy].

Veins at the craniocervical junction are complex network structures. They empty into two main brain venous drainages, the internal jugular vein and internal vertebral venous plexus, and reroute venous blood according to postural changes. They are also involved in the etiology of dural arteriovenous shunts in this region. Hence, regional venous anatomy is crucial for interventional neuroradiologists to understand the pathophysiology and formulate therapeutic strategies. This article aims to provide a summary on venous anatomy, radiological findings, and related pathological conditions, especially for young and inexperienced interventional neuroradiologists.

"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

Role of endovascular treatment for ruptured aneurysms involving the anterior spinal artery at the craniocervical junction.

Ruptured aneurysms at the craniocervical junction (CCJ) involving the anterior spinal artery (ASA) are rare and consist of heterogenous lesions with variable clinical entities. However, the standard therapeutic strategy for the lesions has not been well-established. Moreover, despite advances in modern neurointervention, reports describing endovascular treatment for this specific lesion have been few. Here, we report three cases of ruptured aneurysms on the pial tributary of the ASA at the CCJ, which were subsequently treated by transarterial glue injection or coil embolization. Endovascular treatment can be a therapeutic option, particularly for these ruptured aneurysms. Either transarterial glue injection or coil embolization can be effective depending on the type of etiology and the surrounding vasculature anatomy.

Extracranial prevertebral venous network of the craniocervical junction: CT-digital subtraction venography analysis.

PURPOSE: Although the craniocervical junction has a complex anatomical structure associated with clinical diseases, its ventral venous network has not been well studied. This study aimed to clarify the extracranial ventral venous structure at the craniocervical junction. METHODS: Head computed tomography digital subtraction venography (CT-DSV) images of 273 patients (age 6 months to 93 years) taken at our department were retrospectively analyzed. We analyzed the frequency and anatomical features of the venous channels, as well as their upstream and downstream connections with the surrounding channels at the ventral craniocervical junction, from the level of the hypoglossal canal to the second cervical vertebra. RESULTS: In 54% of the cases, the vein descended from the anterior condylar confluence, running medially along the basioccipital and fusing with its counterpart in the midline at the level of the atlanto-occipital membrane. Furthermore, 24% of this vein was connected caudally to the anterior external vertebral venous plexus. We also identified venous channels, either as a sole vein or venous plexus, on the tip of the odontoid process (10%), which has not been well described previously. The vein around the odontoid process was connected to several veins, including the aforementioned vein anterior to the condyle and the anterior internal vertebral venous plexus. CONCLUSIONS: CT-DSV analysis revealed a detailed venous architecture ventral to the craniocervical junction. Venous structures identified in this study may be involved in diseases in this area.

Imaging of the venous plexus of Rektorzik using CT-digital subtraction venography: a retrospective study.

PURPOSE: The venous plexus of Rektorzik (VPR), first described by Rektorzik in 1858, is a venous plexus around the internal carotid artery in the carotid canal. However, the VPR has never been investigated using the recently developed imaging modalities. In this study, we analyzed the VPR using computed tomography-digital subtraction venography (CT-DSV). METHODS: This study included 253 patients who had undergone head CT-DSV. The presence or absence of the right and left VPRs and their connecting veins were visually examined by two researchers. RESULTS: The VPR was observed in 60 patients (24%), 39 of which showed VPR only on the right side, 10 only on the left side, and 11 on both sides. VPR was significantly more common on the right side (p = 0.0002) and was observed more frequently around the horizontal segment of the internal carotid artery than around the vertical segment. The most common veins identified as distal and proximal VPR connections were the cavernous sinus (63/71, 89%) and the anterior condylar confluence (27/71, 38%), respectively. The mean age was significantly lower in patients with the VPR than in those without (53 vs. 57 years, p = 0.02). CONCLUSION: The VPR was significantly more frequent on the right side and in younger patients but was not a radiographically constant structure. In most cases, the VPR connected the cavernous sinus and anterior condylar confluence. Preoperative evaluation of VPR may lead to refined surgical procedures.

Application of Deep Learning Techniques for Automated Diagnosis of Non-Syndromic Craniosynostosis Using Skull.

ABSTRACT: Non-syndromic craniosynostosis (NSCS) is a disease, in which a single cranial bone suture is prematurely fused. The early intervention of the disease is associated with a favorable outcome at a later age, so appropriate screening of NSCS is essential for its clinical management. The present study aims to develop a classification and detection system of NSCS using skull X-ray images and a convolutional neural network (CNN) deep learning framework. A total of 56 NSCS cases (scaphocephaly [ n = 17], trigonocephaly [n = 28], anterior plagiocephaly [n = 8], and posterior plagiocephaly [n = 3]) and 25 healthy control infants were included in the study. All the cases underwent skull X-rays and computed tomography scan for diagnosis in our institution. The lateral views obtained from the patients were retrospectively examined using a CNN framework. Our CNN model classified the 4 NSCS types and control with high accuracy (100%). All the cases were correctly classified. The proposed CNN model may offer a safe and high-sensitivity screening of NSCS and facilitate early diagnosis of the disease and better neurocognitive outcome for patients.

De novo arteriovenous shunts after endovascular cure of cerebrospinal macro arteriovenous fistulas. A role for the vasa vasorum?

BACKGROUND AND PURPOSE: Macro-arteriovenous fistulas (MAVFs) are arteriovenous shunts draining into a giant venous ectasia. They can be treated by surgery or embolisation. Angiographic controls are usually performed rapidly after treatment in order to prove the cure of the lesion but no long term angiographies are generally scheduled. We wanted to control the stabilities of such lesions at follow-up. METHOD: Clinical history and imaging of ninety-five patients with high flow shunts draining into venous ectasias (MAVFs, Vein of Galen malformations and dilatations) were reviewed. RESULTS: De novo arteriovenous shunts related to angiogenesis involving vasa vasorum developed in three patients with MAVFs at various intervals. Genetic underlying conditions as HHT or RASA 1 mutations were suspected in each patient. CONCLUSIONS: Neo-angiogenesis can occur after cure of MAVFs. Long term imaging follow-ups should be considered as the natural history of such recurrent shunts is currently unknown.

Novel method to evaluate the risk of tumor adhesions and post-operative hemorrhage of meningiomas using 320 row CT-DSA: A clinical research study.

OBJECTIVE: Meningioma is an extra-axial tumor that forms adhesions toward the brain surface in the course of its growth. Predicting adhesions between the tumor and the brain surface leads to better predictions of surgical results. There are few studies on brain-tumor adhesions or postoperative hemorrhage. This study aimed to assess tumor vascularity of the dura and cerebral surface, and predict surgical outcomes using four-dimensional computed tomography angiography (4D CTA). PATIENTS AND METHODS: Using a dynamic contrast CT, we conducted a retrospective study of 27 patients with convexity (n = 15), falx (n = 6), and parasagittal (n = 6) meningiomas treated in our hospital from January 2016 to September 2018. We set the region of interest on the dural layer and cerebral surface side of meningiomas and calculated the mean CT value in each region. Distribution of blood flow in the tumor was classified into two groups: A, which has a higher CT value of the dural side than that of the brain surface side at every timing, and B, which meets the criteria other than those in group A. Demographic data, preoperative characteristic images, and postoperative complications were compared between the groups. RESULTS: Twelve and 15 patients were classified into groups A and B, respectively. The extent of adhesions against the cerebral cortex in group A was significantly less severe compared with that in group B (p = 0.038). The rate of postoperative hemorrhage occurrence in group B (53%) was significantly higher than that in group A (8%) (p = 0.04). There were no significant differences in the other preoperative characteristic images or perioperative parameters between groups A and B. CONCLUSION: A 320-row dynamic contrast CT scanner can detect meningiomas with a high probability of severe adhesion toward the brain surface and postoperative intraparenchymal hematoma.

Benefits and Safety of Periprocedural Heparin During Thrombectomy in Patients Contra-Indicated for Alteplase.

BACKROUND AND PURPOSE: Role of peri-procedural heparin as an adjuvant treatment during mechanical thrombectomy (MT) for patients contra-indicated for alteplase remains a source of debate. METHODS: We included patients from the multicenter French register ETIS that underwent MT without administration of alteplase, and compared patients who received heparin during MT with patients who did not. Heparin impact on outcome were analyzed regarding final TICI score, NIHSS at day one, modified rankin scale (mRS) and intracranial hemorrhagic transformation on imaging at day one. RESULTS: Over 1031 patients, 751 were included between January 2015 and June 2018 in 6 different centers, and 223 (26.69%) received heparin. Heparin administration was associated with a significant deleterious effect on NIHSS at 24h [adjusted OR = 1.2; p = 0.02], mRS at 3 months [adjusted OR 1.58; p = 0.03], and on complete reperfusion [TICI 3 adjusted OR 0.68; p = 0.02]. Heparin administration was associated with a significant reduction of hemorrhagic transformation [adjusted OR 0.48; p = 0.00005]. CONCLUSIONS: Heparin administration during MT seems deleterious for reperfusion and functional outcome. Randomized trials are needed to identify the role of antithrombotic treatments, such as heparin, in the setting of acute ischemic stroke management.

Aberrant trans-osseous venous drainage of the superficial middle cerebral vein: case report.

The superficial middle cerebral veins (SMCVs) are large veins to drain the brain and therefore anatomical knowledge of them is important for neurosurgeons and neuroradiologists. In a patient with a ruptured blister aneurysm, we incidentally found during angiography an aberrant drainage of the SMCVs, which penetrated the lateral part of the greater sphenoid wing and directly connected the SMCVs with the deep facial vein. Neurosurgeons usually need to remove that part of the greater sphenoid wing during the fronto-temporal approach. The existence of a well-developed current channel could be a contraindication for this type of procedure.

Thrombosis of the draining vein causes intracranial haemorrhage in the natural history of brain arteriovenous malformation: case report.

Rupture of arteriovenous malformations (AVM) may be caused by venous outflow restriction, but there is no radiographic evidence of this. We report a case showing only a venous thrombus preceding intracranial haemorrhage from AVM. This is the first evidence that venous thrombus results in AVM rupture in its natural history.

Intraosseous venous structures adjacent to the jugular tubercle associated with an anterior condylar dural arteriovenous fistula.

PURPOSE: Although involvement of the osseous component with an anterior condylar dural arteriovenous fistula (AC-DAVF) has been frequently described, osseous venous structures in which AC-DAVFs develop have not been fully elucidated. We investigated osseous venous structures adjacent to the hypoglossal canal in normal controls and patients with AC-DAVFs. METHODS: The study included 50 individuals with unruptured aneurysms as normal controls and seven patients with AC-DAVFs. Osseous venous structures adjacent to the hypoglossal canal in normal controls were analyzed using computed tomography (CT) digital subtraction venography. In patients with AC-DAVFs, the fistulous pouches, draining veins, and surrounding venous structures were examined using cone beam CT. RESULTS: In 46.0% of laterals in normal controls, osseous venous structures were visualized within the jugular tubercle superomedially to the hypoglossal canal. We named these structures the jugular tubercle venous complex (JTVC). The JTVC was always continuous with the anterior condylar vein and was sometimes connected to surrounding venous channels. We detected nine fistulous pouches in the seven patients with AC-DAVFs. The fistulous pouches were in the JTVC (33.3%), anterior condylar vein (33.3%), and other venous channels within the exoccipital region (33.3%). CONCLUSION: Although the JTVC is a venous structure frequently found in normal people, it had not been investigated until now. The venous channel between the anterior condylar vein and JTVC is a common origin site for AC-DAVFs, and it was associated with 66.6% of the AC-DAVF cases in the current study.

Fate of the three embryonic dural sinuses in infants: the primitive tentorial sinus, occipital sinus, and falcine sinus.

PURPOSE: The primitive tentorial, occipital, and falcine sinuses are thought to attain the adult pattern or regress between the fetal stage and adulthood. The anatomy of these three primitive dural sinuses has seldom been studied in the infant population, and it remains unclear when these dural sinuses reach the adult condition. Using computed tomography digital subtraction venography (CT-DSV), we analyzed the anatomy of these embryonic dural sinuses in infants. METHODS: We included 13 infants who underwent CT-DSV prior to neurosurgery and 35 cases with unruptured cerebral aneurysms as normal adult controls. Three embryonic dural sinuses, i.e., the primitive tentorial, occipital, and falcine sinuses, were retrospectively analyzed in CT-DSV images of infants and adults. We also analyzed the drainage patterns of the superficial middle cerebral vein (SMCV), determined by the connection between the primitive tentorial sinus and the cavernous sinus. RESULTS: The primitive tentorial, occipital, and falcine sinuses were present in 15.4%, 46.2%, and none of the infants, respectively, and in 10.0, 8.6, and 2.9% of the adults, respectively. The difference in SMCV draining pattern between infants and adults was insignificant. The incidence of the occipital sinus was significantly higher in infants than in adults. CONCLUSIONS: The connection between the primitive tentorial sinus and the cavernous sinus appears to be established before birth. The occipital sinus is formed at the embryonic stage and mostly regresses after infancy. The falcine sinus is usually obliterated prenatally. Our findings form the basis for interventions by pediatric interventional neuroradiologists and neurosurgeons.

Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography.

PURPOSE: Although neuroradiologists and skull base neurosurgeons are aware of the existence of veins within the clivus, such vessels have seldom been described in the literature. The aim of the present study is to elucidate the detailed venous structure of the clivus. METHODS: Computed tomography digital subtraction venography (CT-DSV) images of 50 unruptured aneurysm cases were examined retrospectively. RESULTS: Eighteen emissary veins were identified in 14 (28.0%) cases. A half of the emissary veins connected the inferior petrosal sinus with the inferior petro-occipital vein (IPOV) in the middle clivus. The clival diploic vein (CDV) was identified in 14.0% of cases, 42.9% of which had the clivus of the presellar type. The CDV was connected to the posterior intercavernous sinus or the rostral end of the basilar plexus superiorly, and was connected to the IPOV, anterior condylar vein, marginal sinus, or the anterior condylar confluence. CONCLUSION: The CDV provides collateral channels between the cavernous sinus and the internal jugular vein and the inferior petrosal sinus and the IPOV. Understanding of the emissary veins in the clivus and the CDV is valuable for skull base surgery, especially for endonasal endoscopic skull base procedures.

The importance of amyloid ß protein in cerebrospinal fluid when you recognize convexal subarachnoid hemorrhage.

BACKGROUND: Convexal subarachnoid hemorrhage (cSAH) is sometimes experienced in cerebral amyloid angiopathy (CAA), but ones that are repeated within a brief time period are not common. Also, it is often difficult to diagnose CAA when you experience a case of cSAH. METHODS: We examined the clinical course of 2 cases that showed cSAH repeatedly. We examined cerebrospinal fluid (CSF) concentrations of amyloid ß protein (Aß) 40 and 42 and tau protein as additional evidence for a diagnosis of CAA. RESULTS: Case 1 presented with transient motor paresis of the left hand and case 2 with transient sensory disturbance of the left hand. CT scans showed cSAH on the right central sulcus in both patients. Case 1 showed development of intracerebral hemorrhage on the frontal lobe near the right central sulcus. Case 2 showed relapse of cSAH with recurrence of the same symptoms. These cases could not be diagnosed by image analysis, but were considered CAA by Aß40, Aß42 and tau protein in CSF. CONCLUSION: Aß in CSF can be presented here as support for the diagnosis of CAA that is difficult to diagnose by Boston criteria.

Vasa vasorum: The role in intracranial physiology and pathophysiology.

Background: Vasa vasorum (VVs) is a Latin word representing vessels of vessels. VVs are usually found on the adventitia of the parent vessel and infrequently reach the media and intima, depending on the size and type of the parent vessels and physiological and pathological conditions. The VVs include arteries, capillaries, veins, and lymphatic vessels, involving the oxygenation and nourishment of the vessel's wall to sustain its healthy state. Accumulated studies have revealed that VVs are involved in various intracranial lesions, including atherosclerotic diseases, aneurysms, and shunt diseases. The current review aims to review and integrate past and recent findings and knowledge on VVs and to facilitate our understanding of VVs and intracranial pathology involving VVs. Methods: A literature review was carried out with a focus on the role of VVs by searching the Pubmed database. Results: We identified 71 articles that discuss the role of VVs. We discussed the anatomical structure, physiological significance, and pathological significance of the VV. Conclusion: VV is not only involved in the nutrition and metabolism of the vascular wall but is also deeply involved in the pathogenesis of inflammation, ischemia, and thrombosis of the vascular wall. In addition, in the central nervous system, intracranial vascular wall nutrient particularities and VVs are closely related to the pathogenesis of cerebral aneurysms, subarachnoid hemorrhage, arteriovenous shunt disease, atherosclerotic lesions, and other conditions.