Diploic Veins Research Articles

Comparison of a Novel Liquid Embolic System with Commonly Used Embolic Agents in the Endovascular Treatment of Intracranial Dural Arteriovenous Fistulas: A Single-Center Experience

Background/Objectives: Endovascular embolization is an effective treatment option for cerebral arteriovenous malformation (AVM) and dural arteriovenous fistulas (DAVFs). The objective of this study was to assess the safety and efficacy of MenoxTM in patients with cranial dural arteriovenous fistulas. Methods: From January 2021 to January 2023, 19 patients with intracranial DAVFs underwent embolization procedures. All patients were treated by embolization with MenoxTM or/and in combination with other embolization products such as Onyx (Covidien, Irvine, California), PHIL (MicroVention, Tustin, California), and Squid (Balt Extrusion, Montmorency, France). Treatment approaches were selected depending on the anatomical location of the fistula. Patients were monitored and followed-up for 12 months. Results: The patients’ mean age was 56.26 ± 16.49 years. Of these 19 patients, 58% (n = 11) were treated with the MenoxTM liquid embolizing agent (LEA) alone or in combination with different LEAs, while n = 7 were treated with other LEAs and 1 patient was treated solely with coils. Complete occlusion of DAVFs with MenoxTM and other agents was evident in 68.4% (n = 13/19) of patients. Complete occlusion (100%) was observed in the sinus rectus, transverse sinus, and diploic veins of the orbital roof, while complete occlusion was observed in 50% of falcotentorial patients and 60% of superior sagittal sinus patients. The lowest rate of complete fistula obliteration was observed in the dural carotid cavernous fistula (CCF) group (25%). An intra-procedural adverse event occurred in one patient. No other post-procedural adverse events were noted. Furthermore, in patients treated with MenoxTM, total occlusion was achieved in 72.7% (n = 8) of patients, whereas the non-MenoxTM group had 62.5% (n = 5) of patients with 100% occlusion and 37.5% (n = 3) of patients with subtotal occlusion. Conclusions: Outcomes using MenoxTM alone and in combination with other agents were effective, and it is safe for the treatment of dural arteriovenous fistulas.

Venous Anatomy of the Superior and Inferior Sagittal Sinuses

The superior sagittal sinus(SSS)is contained within the dura, which consists of the dura propria and osteal dura at the junction of the falx cerebri, in addition to the attachment of the falx to the cranial vault. The SSS extends anteriorly from the foramen cecum and posteriorly to the torcular Herophili. The superior cerebral veins flow into the SSS, coursing under the lateral venous lacunae via bridging veins. Most of the bridging veins reach the dura and empty directly into the SSS. However, some are attached to the dural or existed in it for some distance before their sinus entrance. The venous structures of the junctional zone between the bridging vein and the SSS existed in the dura are referred to as dural venous channels. The SSS communicates with the lateral venous lacunae connecting the meningeal and diploic veins, as well as the emissary veins. These anatomical variations of the SSS are defined by the embryological processes of fusion and withdrawal of the sagittal plexus and marginal sinus.

Imaging evaluation and volumetric measurement of the space surrounding the diploic veins

PurposeThe diploic veins have been suggested to be involved in the excretion of cerebrospinal fluid and intracranial waste products; however, to date, there have been no reports evaluating the space surrounding the diploic veins. Therefore, we aimed to visualize the distribution of gadolinium-based contrast agent (GBCA) in the space surrounding the diploic veins and to evaluate the spatial characteristics.Materials and methodsNinety-eight participants (aged 14–84 years) were scanned 4 h after intravenous GBCA injection at Nagoya University Hospital between April 2021 and December 2022. The volume of the space surrounding the diploic veins where the GBCA was distributed was measured using contrast-enhanced T1-weighted images with the application of three-axis motion-sensitized driven equilibrium. The parasagittal dura (PSD) volume adjacent to the superior sagittal sinus was also measured using the same images. Both volumes were corrected for intracranial volume. The correlation between age and the corrected volume was examined using Spearman’s rank correlation coefficient; the relationship between the corrected volume and sex was assessed using the Mann–Whitney U test.ResultsA significant weak negative correlation was observed between the volume of the space surrounding the diploic veins and age (r = −0.330, p < 0.001). Furthermore, there was a significant weak positive correlation between the PSD volume and age (r = 0.385, p < 0.001). Both volumes were significantly greater in men than in women. There was no correlation between the volume of the space surrounding the diploic veins and the volume of the PSD.ConclusionThe volume of the space surrounding the diploic veins was measurable and, in contrast to the volume of the PSD, was greater in younger participants. This space may be related to intracranial excretory mechanisms and immune responses during youth, requiring further research.

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

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. 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. 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. 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.

Investigating the relationship between cranial bone thickness and diploic channels: A first comparison between fossil Homo sapiens and Homo neanderthalensis.

Diploic veins are part of the circulatory system of the head. They transport venous blood and cerebrospinal fluid and are housed in diploic channels (DCs). DCs are highly variable in terms of their position, extension, and size. These parameters were hypothesized to be related to the variations in cranial vault thickness (CVT). For the first time, we analyzed the spatial relationship between CVT and DCs in a sample of eight H. neanderthalensis and H. sapiens cranial fossils. Using micro-CT scanning data, we constructed color maps of the CVT and visually inspected whether the regional thickness variation was associated with the morphology and distribution of the DC branches. The results showed that when regional bone thickness was below a certain threshold, no DCs or scattered small DC branches were present. Larger DC branches appeared only when the thickness exceeded the threshold. However, once the threshold was reached, further increases in thickness no longer resulted in more or larger DCs. This study also found that our sample of H. neanderthalensis and H. sapiens have different distribution patterns in thin areas, which may affect how their DCs connect with different branches of the middle meningeal vessels. This preliminary study provides evidence for the discussion on the interaction between the cranium, brain, and blood vessels. Future research should include more hominin fossils to better document the variation within each species and possible evolutionary trends among hominin lineages.

Adaptative Diploic Vein Bypass of the Superior Sagittal Sinus in a Large Falcine Meningioma

We describe an adaptative bypass at the posterior third of the superior sagittal sinus (SSS) through the parietal diploe veins related to a large falcine meningioma on a 55-year-old lady with progressive headaches and mild left hemiparesis. Cranial imaging revealed a large tumor at the posterior third of the cerebral falx, compatible with meningioma. Imaging also revealed lack of continuity of the superior sagittal sinus at that region. Large diploic veins were seen bypassing the segment of the SSS affected by the tumor. An "L"-shaped modified posterior interhemispheric craniotomy was performed to avoid traversing the diploic veins. Near-total resection of the meningioma was accomplished. Postoperative imaging revealed a small remnant invading the SSS, which was treated with adjuvant radiotherapy. The patient tolerated the procedure well and was discharged to rehabilitation unit on postoperative day 5 with no neurologic deficits.

Cranial diploic channels and their veins - a review of literature.

The current paper is a review of the results attained in the past and current anatomical studies, aimed at understanding the variability and function of the diploic venous system of the human skull. The diploic veins can serve as transit for infections from the scalp to the structures contained within the cranial cavity via the emissary veins, due to their interconnections with the pericranial veins, meningeal veins and dural sinuses. Thereby this clinical aspect has also been discussed.

Use of Compressed Sensing Accelerated, Low-Velocity Encoded, Isotropic Resolution, Phase Contrast Magnetic Resonance Angiography for SEEG Electrode Implantation

We assessed the feasibility of using compressed sensing accelerated, low-velocity encoded, isotropic resolution phase contrast (CLIP) magnetic resonance angiography (MRA) for avascular trajectory planning of stereoelectroencephalography. Ten healthy subjects (1 woman and 9 men; age, 33.6 ± 9.0 years) and 20 consecutive patients (12 female patients; age, 22 ± 13.6 years) were enrolled in the present study. The healthy subjects underwent CLIP-MRA, and 3 other phase contrast MRA protocols with conventional parallel imaging (PI) acceleration, including low resolution with twofold PI (PI2), high resolution (HR) with fivefold PI (PI5), and HR-PI2. The patients underwent CLIP-MRA and computed tomography angiography (CTA). The image qualities were evaluated. The numbers and locations of trajectory-vessel conflict detected using CLIP-MRA were noted. With similar scan durations, CLIP-MRA achieved higher spatial resolution compared with low resolution with PI2 and detected significantly more branches compared with HR-PI5. With the same spatial resolution, the signal/noise and contrast/noise ratios of CLIP-MRA were higher than those with HR-PI2 with a shorter scan duration. For the 12 adult patients (10 female patients; 28.8 ± 12.7 years), CLIP-MRA had better signal/noise and contrast/noise ratios than CTA. The trajectory had required modification for 14 of the 20 patients (70%), with a proportion of trajectory modification of 10.7% (23 of 215 electrodes). The middle meningeal artery, cortical vessel, and skull vessel were the main vessels with conflict (n= 11, n= 7, and n= 5, respectively). In the present study, CLIP-MRA provided a clear cortical vascular display noninvasively without intravascular contrast and radiation. The middle meningeal artery and diploic and emissary veins were the main conflict vessels and could be clearly displayed using CLIP-MRA but not CTA.

Does diploic venous flow drain extracranially in the pterional area? A magnetic resonance imaging study.

To the best of our knowledge, no study using neuroimaging modalities has documented calvarial diploic veins (DVs) connected to the extracranial sites. This study aimed to characterize them using magnetic resonance imaging (MRI). A total of 88 patients underwent thin-sliced contrast MRI. In addition, the DVs coursing through the pterional area were observed on three injected cadaver heads. On postcontrast MRI, the DVs of the pterional area directly drained into the temporalis muscle or supplied branches coursing into the muscle in 43% on the right side and 40% on the left. The DVs and their branches were highly variable in diameter and number. In 9% of cases, the DV of the pterional area was found to drain into an extracranial site and connected to large venous channels distributed in the temporalis muscle. Furthermore, in 17% of cases, the DVs drained into the extracranial sites in the frontal skull region, followed by 9% in the parietal, 2% in the occipital, and 1% in the temporal regions. The DVs coursed superficially in the pterional area on both sides of all three cadaver heads. On one side, the DV in the area was open to an extracranial site. Part of the diploic venous flow drains extracranially in the pterional area. This area may provide an important interface between the calvarial DVs and the extracranial venous system.

Diploic vein morphology in normal and craniosynostotic adult human skulls.

Diploic veins (DV) run within the cranial diploe, where they leave channels that can be studied in osteological samples. This study investigates overall DV variability in human adults and the effects of sex, age, cranial dimensions, and dysmorphogenesis associated with craniosynostosis (CS). The morphology of macroscopic diploic channels was analyzed in a set of the qualitative and quantitative variables in computed tomography-images of crania of anatomically normal and craniosynostotic adult individuals. Macroscopic diploic channels occur most frequently in the frontal and parietal bones, often with a bilaterally symmetrical pattern. DV-features (especially DV-pattern) are characterized by high individual diversity. On average, there are 5.4 ± 3.5 large macroscopic channels (with diameters &gt;1 mm) per individual, with a mean diameter of 1.7 ± 0.4 mm. Age and sex have minor effects on DV, and cranial proportions significantly influence DV only in CS skulls. CS is associated with changes in the DV numbers, distributions, and diameters. Craniosynostotic skulls, especially brachycephalic skulls, generally present smaller DV diameters, and dolichocephalic skulls display increased number of frontal DV. CS, associated with altered cranial dimensions, suture imbalance, increased intracranial pressure, and with changes of the endocranial craniovascular system, significantly also affects the macroscopic morphology of DV in adults, in terms of both structural (topological redistribution) and functional factors. The research on craniovascular morphology and CS may be of interest in biological anthropology, paleopathology, medicine (e.g., surgical planning), but also in zoology and paleontology.

Evaluating diploic vein blood flow using time-resolved whole-head computed tomography angiography and determining the positional relationship between typical craniotomy approaches and diploic veins in patients with meningioma.

Diploic veins may act as collateral venous pathways in cases of meningioma with venous sinus invasion. Diploic vein blood flow should be preoperatively evaluated to consider preserving the veins. In this study, we evaluated the use of time-resolved whole-head computed tomography angiography (4D-CTA)-which is less patient-intensive than digital subtraction angiography (DSA)-for assessing diploic vein blood flow and the positional relationship between typical craniotomy approaches and diploic veins. We retrospectively examined 231 patients who underwent surgery for intracranial meningioma. We performed contrast-enhanced magnetic resonance imaging (MRI) to evaluate diploic vein pathways and compared the visualization rates of diploic vein blood flow assessed using 4D-CTA and DSA. Subsequently, we evaluated the rates of the diploic veins transected during craniotomy by comparing the pre- and postoperative contrast-enhanced MRI. The diagnostic performance of 4D-CTA was assessed in 45 patients. Of the 320 diploic veins identified in these patients, blood flow in 70 (21.9%) diploic veins was identified by 4D-CTA and DSA, and both results were consistent. To assess the transection rates of the diploic veins, 150 patients were included. A trend towards a high transection rate of the diploic vein in the basal interhemispheric, frontotemporal, orbitozygomatic, combined transpetrosal, and convexity craniotomy approaches was observed. In patients with meningiomas, both 4D-CTA and DSA are useful in evaluating diploic vein blood flow. In meningiomas with venous sinus invasion, determining the extent of craniotomy after understanding the pathways and blood flow of diploic veins is recommended.

Analysis of Revision Surgery Following Surgical Reconstruction of the Sigmoid Sinus Wall in Patients with Pulsatile Tinnitus.

Background:To explore potential causes leading to the failure of the surgical reconstruction of sigmoid sinus wall in patients with pulsatile tinnitus.Methods:This study retrospectively analyzed pulsatile tinnitus patients with sigmoid sinus wall dehiscence and/or sigmoid sinus diverticulum, who underwent revision surgeries following the surgical reconstruction of the sigmoid sinus wall.Results:A total of 7 pulsatile tinnitus patients were included. After the first surgery, 5 of 7 patients showed varying degrees of remission in pulsatile tinnitus, but pulsatile tinnitus gradually recurred. The other 2 patients experienced no change in pulsatile tinnitus. Images after the first surgeries revealed that the surgical failure of Patients 1-5 was caused by incompleted elimination of sigmoid sinus wall dehiscence and sigmoid sinus diverticulum. Following revision surgeries, they all acquired great or complete resolution of pulsatile tinnitus. In Patient 6, an abnormal diploic vein entering the sigmoid sinus was overlooked during the first surgery for repairing sigmoid sinus wall dehiscence. As soon as the diploic vein was blocked during the revision surgery, the patient’s pulsatile tinnitus was alleviated significantly. Patient 7 had a recurrence of pulsatile tinnitus after transient improvement following the first surgery, and still experienced no change in pulsatile tinnitus after the revision surgery. However, after venous sinus stenting in the stenosis of transverse-sigmoid sinus junction, she got complete resolution of pulsatile tinnitus. It suggested that the unresolved stenosis of the venous sinus was the cause of the surgical failure.Conclusions:Both sigmoid sinus diverticulum and sigmoid sinus wall dehiscence are recommended to be resolved during surgery. Abnormal diploic veins and venous sinus stenosis are potential causes of pulsatile tinnitus.

Percutaneous transosseous embolization of a diploic vein arteriovenous fistula with intracranial and extracranial shunting.

Transosseous embolization of diploic vein arteriovenous fistula is feasible when necessary in select cases.

Evaluation of Bone Wax Coated Bipolar Coagulation Forceps: Performance and Safety Assessment.

BackgroundImproving the performance of bipolar coagulation forceps is crucial for safer and more accurate neurosurgery. In our department, we found that bone wax (BW) melted by thermal effect of bipolar electrocoagulation can achieve more efficient hemostasis and reduce the amount of BW in neurosurgical procedures associated with bleeding from emissary and diploic veins. Nevertheless, relevant studies are still lacking to verify our finding.ObjectiveThe study objectives were to evaluate the performance and safety in electrocoagulation: (1) compare the performance of BW coated bipolar coagulation forceps and the conventional anti-stick forceps in vivo, and (2) assess the safety of electrocoagulation with BW coated bipolar coagulation forceps in rat primary motor cortex.MethodsTissue adhesion was evaluated by comparing the wetting tension and the amount of protein adhered to the forceps tips after electrocoagulation. Thermal damage was assessed by analyzing the thermography and H&E staining of coagulated rat brain tissues. The hemostatic efficiency was reflected by the number of electrocoagulation until complete hemostasis and the condition of damaged common carotid arteries. The safety of BW coated forceps in electrocoagulation was assessed by evaluating the inflammation of coagulated rat primary motor cortex and the motor functions at the 7th day postoperatively.ResultsBone wax coated forceps had a significantly higher contact angle and adhered less coagulum. Thermography was acquired at 3 s, 6 W units in rat primary motor cortex in vivo. The highest temperature recorded during BW coated tips application was significantly lower than the uncoated. In addition, there was a relatively smaller tissue injury area produced by the BW coated forceps. Additionally, BW coated forceps improved the hemostatic efficiency and caused fewer injuries on the damaged arteries (3 s, 10 W units). More importantly, electrocoagulation with BW coated forceps led to no significant motor function impairments and less glial and microglia responses.ConclusionThis study reveals that BW coated bipolar coagulation forceps can provide a convenient, cost-efficient, safer, and more efficient way for hemostasis. More research is needed to evaluate the electrocoagulation with BW in the long term and verify our finding in human beings.

Diploic Veins as Collateral Venous Pathway in Patients with Superior Sagittal Sinus Obstruction caused by Large Size Meningioma

Diploic Veins as Collateral Venous Pathway in Patients with Superior Sagittal Sinus Obstruction caused by Large Size Meningioma

Late venous air embolism following insertion of Mayfield head pins.

Dear Editor, Venous air embolism (VAE) is not an uncommon event during neurosurgical procedures. It is an iatrogenic complication that occurs when air from the atmosphere enters into the systemic circulation specifically when the surgical site is above the level of heart producing a sub-atmospheric pressure in the open veins. A 27-year-old male diagnosed as a case of fronto-temporo-parietal meningioma was posted for craniotomy and excision under general anesthesia. His Glasgow Coma Scale [GCS] was 15, and no neurological deficit was present. All laboratory investigations were within normal limits. His magnetic resonance imaging was suggestive of large well-defined lesion in left Sylvian fissure, extending into left basal cistern with mass effect. Following anesthesia induction, a Mayfield pin was used to stabilize the head of the patient in a supine position. The pin was removed and reinserted by the surgeon to improve the surgical access. Half an hour later, the surgeon repositioned the patient with head end elevated by 30 degree. We observe a sudden fall in end-tidal carbon dioxide concentration [EtCO2] from 30 to 19 mmHg with a drop of oxygen saturation from 100% to 95%. Rest of the vital parameters including heart rate and blood pressure demonstrated no change from baseline. We started the management with administration of 100% oxygen and intravenous fluids. We could aspirate 4–5 ml of air through the central venous line catheter [Arrow triple lumen central venous catheter, 7 French sizes, and 16-centimeter length]. We confirmed the central venous line position with electrocardiogram as a guide. The superior vena cava – right atrium junction positioning of the central venous line was confirmed with a tall P wave, which was equal to R wave height. The time frame between the event and air aspiration was one and half minutes. Within 1–2 min of air aspiration, oxygen saturation returned back to normal and EtCO2 rose up to 25 mmHg from 19 mmHg. No further episodes of VAE occurred during surgery. Mayfield head pin is commonly used in neurosurgical patients to keep the head stable during surgery. The literature is scarce in case reports showing an association of VAE and Mayfield head pins in adult patients.[12] Ture H et al. observed that the rate and severity of VAE were significantly lower in patients with 30-degree head elevation than in patients with 45-degree head elevation undergoing craniotomy in semi-sitting position.[3] This was a case of late VAE during repositioning of patient possibly following air entrainment through diploic veins injured at first attempt of pin insertion. In our case, we could not find any other possible explanation for this sudden decrease in EtCO2 except for the traumatized initial skull pin site being culprit for air entrainment after a change in position. At this time point, the surgery was not started and anesthetic depth was well maintained. The proper scanning of the surgical site by a surgeon before pin insertion, avoidance of sudden change in patient positioning, and proper suturing of the initial traumatized pin insertion site could avert this iatrogenic complication. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Magnetic resonance imaging analysis of human skull diploic venous anatomy.

Background: The skull diploic venous space (DVS) represents a potential route for cerebrospinal fluid (CSF) diversion and absorption in the treatment of hydrocephalus. The goal of this study was to carry out a detailed characterization of the drainage pattern of the DVS of the skull using high-resolution MRI, especially the diploic veins draining to the lacunae laterales (LLs) since the LLs constitute an important channel for the CSF to access the superior sagittal sinus and subsequently the systemic circulation. The objective was to identify those skull regions optimally suited for an intraosseous CSF diversion system.Methods: High-resolution, T1-weighted MRI scans from 20 adult and 16 pediatric subjects were selected for analysis. Skulls were divided into four regions, that is, frontal, parietal, temporal, and occipital. On each scan, a trained observer counted all diploic veins in every skull region. Each diploic vein was also followed to determine its final drainage pathway (i.e., dural venous sinus, dural vein, LL, or indeterminate).Results: In the adult age group, the frontal and occipital skull regions showed the highest number of diploic veins. However, the highest number of draining diploic veins connecting to the lacunae lateralis was found in the frontal and parietal skull region, just anterior and just posterior to the coronal suture. In the pediatric age group, the parietal skull region, just posterior to the coronal suture, showed the highest overall number of diploic veins and also the highest number of draining diploic veins connecting to the LL.Conclusion: This study suggested that diploic venous density across the skull varies with age, with more parietal diploic veins in the pediatric age range, and more occipital and frontal diploic veins in adults. If the DVS is ultimately used for CSF diversion, our anatomical data point to optimal sites for the insertion of specially designed intraosseous infusion devices for the treatment of hydrocephalus. Likely the optimal sites for CSF diversion would be the parietal region just posterior to the coronal suture in children, and in adults, frontal and/or parietal just anterior or just posterior to the coronal suture.

Chronic Epidural Hematoma: Still a Rare Entity?

Abstract Introduction Extradural hematoma diagnosed more than 14 days after head injury is classified as a chronic extradural hematoma (CEDH). In the present study, we presented a series of 8 patients with CEDH in a span of 6 months. Materials and Methods In this article, we reported 8 cases of CEDH who presented to Nil Ratan Sircar Medical College, Kolkata, West Bengal, India, within a span of 6 months. Discussion Extratemporal epidural hematomas (EDHs) are often due to venous bleeding from the diploic veins or dural sinuses or to delayed rupture of a middle meningeal pseudoaneurysm. In these cases, cerebrospinal fluid may redistribute from the lateral ventricles and thus allowing room for the enlarging hematoma producing vague neurological symptoms and signs. The incidence rate of CEDH reported in the literature ranges from 3.9 to 30% of all EDHs. Computed tomography (CT) scan in CEDH often shows a low-density center surrounded by a high-density margin. Calcification of the displaced dura mater may also occur. Some are identified incidentally, whereas others are diagnosed when investigating for persistent and/or progressive neurological symptoms. Symptomatic CEDH should be surgically evacuated and has an excellent outcome the earlier it is done. In patients with no or mild symptoms, normal neurological status, and a small-sized CEDH spontaneous resolution may be expected. Conclusion In the post-CT era, it is always said that CEDH is a rare entity. However, in developing countries we still encounter a large number of such cases and the question arises whether CEDH is still a rare entity.

Dural venous system: angiographic technique and correlation with ex vivo investigations

BackgroundThe dural vasculature plays a key role in several important conditions, including dural fistulas and subdural collections. While in vivo investigations of intrinsic dural arterial angioarchitecture are rare, no angiographic...

Calvarial diploic venous channels: delineation with maximal intensity projection technique.

To date, very few studies have explored the three-dimensional architecture of calvarial diploic venous channels (CDVCs). This study aimed to characterize the three-dimensional architecture of CDVCs using maximum intensity projection (MIP) images based on contrast-enhanced magnetic resonance imaging (MRI). A total of 77 patients with intact calvarial hemispheres and underlying dura mater and dural sinuses underwent contrast-enhanced MRI. Among them, we extracted the data of 49 with at least a part of the major CDVC pathways identified on the MIP images for analysis. On serial contrast-enhanced MRI images, the CDVCs were commonly detected as curvilinear structures with inhomogeneous diameters and tributaries, while the MIP images delineated the three-dimensional architecture of the developed CDVC pathways. More than such CDVC pathway was entirely delineated on the right in 67.3% and on the left in 71.4%, most frequently in the frontal and temporal regions, with their connecting sites to the sphenoparietal and superior sagittal sinuses. The morphology, distribution, and course of the identified CDVCs were highly variable. In 55.1%, the CDVCs formed fenestrations that were variable in size, shape, and number. The developed CDVC pathways may be characterized by morphological variability and fenestrations. Thin-sliced, contrast-enhanced MRI is useful to depict diploic veins, while MIP images allow for better appreciation of the entire course of the developed CDVC pathways. Traumatic and intraoperative disconnection between the dura mater overlying the dural sinuses and the adjacent inner table of the skull can cause epidural venous bleeding.