Tips and tricks in the diagnosis of intracranial dural arteriovenous fistulas: A pictorial review

Endovascular treatment of intracranial dural arteriovenous fistulas with Onyx: A consecutive series of 62 patients from a single-center

OBJECTIVE

Intracranial intracranial dural arteriovenous fistulas (DAVFs) are mainly treated with an endovascular approach and various embolic agents. The aim of this study was to investigate the efficacy and safety of Onyx embolization in the treatment of DAVFs and characterize the factors as sociated with complete obliteration.

METHODS

This retrospective study was based on 62 patients with DAVFs who underwent endovascular treatment with Onyx alone or in combination with coils at our institution. Clinical and imaging data were collected and analyzed.

RESULTS

A total of 62 patients with 64 DAVFs were treated with endovascular embolization. The most common primary symptom was ophthalmological signs with a rate of 37.1%. Cognard type III was the most commonly seen subtype (32.8%). The immediate complete occlusion and follow-up rate was 92.2% and 93.5%, respectively. Transvenous balloon-assisted sinus protection was used in 12 patients (18.8%). The pressure cooker technique was used in eight patients (12.5%). Complications were seen in five patients including intracerebral hemorrhage (n = 2), venous thrombotic events (n = 2), and glued microcatheter (n = 1).

CONCLUSIONS

Endovascular Onyx alone or in combination with coils embolization is a safe and effective therapy for DAVFs. Favorable angiographic and clinical outcomes can be achieved using different endovascular approaches. Transvenous balloon-assisted sinus protection and the pressure cooker technique may help achieve complete occlusion of DAVFs.

Traumatic middle meningeal arteriovenous fistulas (MMAVFs): an exploratory systematic review

This study aims to systematically review case reports and case series in order to compare the postoperative course of conservative, endovascular and surgical treatments for traumatic dural arteriovenous fistulas predominantly supplied by the middle meningeal artery (MMAVFs), which usually occur following head trauma or iatrogenic causes. We conducted a comprehensive search of PubMed, Embase, Scopus, Web of Science, and Google Scholar until June 23rd, 2024. Three cohorts were defined based on the treatment modality employed. The primary outcomes were the rates of overall obliteration and postoperative complications, with all-cause mortlality considered as secondary outcome. A total of 61 studies encompassing 78 pooled MMAVFs were included in the qualitative analysis. The predominant demographic consisted of males (53.9%) with a median age of 50.5 (IQR: 33.5-67.5) years. The main etiologies for fistula formation were head trauma (75.6%), cranial neurosurgical procedures (11.5%) and endovascular embolization (8.97%). Venous drainage patterns were categorized as follows based on anatomical confluence: Class I (16.7%), II (14.1%), III (12.8%), IV (14.1%), V (7.7%), and VI (3.9%). Regarding treatment efficacy, the overall obliteration rate was 89.74%, achieved through endovascular (95.83%), surgical (64.29%) or conservative (93.75%) approaches. In terms of safety, the overall postoperative complication rate was 6.49% with an all-cause mortality rate of 8.97%, predominantly observed in the surgical group (35.71%). Our systematic review highlights the challenging management of traumatic MMAVFs, frequently associated with head injuries. Endovascular therapy has emerged as the predominant treatment modality, demonstrating markedly higher rates of fistula obliteration, reduced all-cause mortality, and fewer postoperative complications.

The "Hypointense Focal Brain" on susceptibility-weighted imaging as a sign of venous congestion in cranial dural arteriovenous fistulas

BACKGROUND

Cranial dural arteriovenous fistulas (dAVFs) are complex neurovascular malformations accounting for approximately 10%-15% of all intracranial arteriovenous malformations. The objective is to investigate the utility of susceptibility-weighted imaging (SWI) in identifying "hypointense focal brain" as an additional helpful sign of venous congestion in cranial dAVFs.

MATERIALS AND METHODS

A retrospective review of patients diagnosed with cranial dAVFs between January 2015 and June 2023 was conducted, and SWI was used to identify the "hypointense focal brain" sign within the venous drainage region of the dAVF. The "hypointense focal brain" on SWI was identified as a low-intensity signal within the venous drainage region, indicative of venous congestion. The presence of this imaging sign was assessed by two neuroradiologists and signal intensity measurements were performed to support the presence of the sign.

RESULTS

The study included six patients with cranial dAVFs exhibiting cortical venous retrograde drainage and the "hypointense focal brain" on SWI. Follow-up imaging post-treatment revealed resolution or improvement of the hypointense signal, confirming its association with venous congestion. Signal intensity measurements further supported the presence of this imaging sign in pre-treatment scans.

CONCLUSION

The study's findings demonstrate the presence of a reversible "hypointense focal brain" sign on SWI in patients with cranial dAVFs and CVR, which can be useful as an additional imaging sign for venous congestion.

An Uncommon Culprit: Dural Arteriovenous Fistula Presenting as Otodynia and Dizziness

Dural arteriovenous fistulas (DAVFs) are rare vascular abnormalities that can present with diverse neurological symptoms. We report a case of a woman in her early 60s who presented with pain in the left ear and dizziness. Neurological evaluation and imaging studies revealed a DAVF in the left cerebellopontine angle. This case underscores the importance of considering DAVF as a potential etiology in patients presenting with atypical otological symptoms.

Low-Frequency Air-Bone Gap and Pulsatile Tinnitus Due to a Dural Arteriovenous Fistula: Considerations upon Possible Pathomechanisms and Literature Review

Low-frequency air-bone gap (ABG) associated with pulsatile tinnitus (PT) and normal impedance audiometry represents a common finding in patients with third window syndromes. Other inner disorders, including Meniere's disease (MD), perilymphatic fistula and intralabyrinthine schwannoma, might sometimes result in a similar scenario. On the other hand, PT is frequently associated with dural arteriovenous fistula (DAVF), while conductive hearing loss (CHL) is extremely rare in this clinical setting. A 47-year-old patient was referred to our center with progressive left-sided PT alongside ipsilateral fullness and hearing loss. She also experienced headache and dizziness. Otoscopy and video-oculographic examination were unremarkable. Conversely, a detailed instrumental audio-vestibular assessment revealed low-frequency CHL with normal impedance audiometry, slight left-sided caloric weakness, slightly impaired vestibular-evoked myogenic potentials on the left and normal results on the video-head impulse test, consistent with an MD-like instrumental profile. Gadolinium-enhanced brain MRI revealed an early enhancement of the left transverse sinus, consistent with a left DAVF between the left occipital artery and the transverse sinus, which was then confirmed by angiography. A trans-arterial embolization with Onyx glue was performed, resulting in a complete recession of the symptoms. Post-operatively, the low-frequency ABG disappeared, supporting the possible role of venous intracranial hypertension and abnormal pressure of inner ear fluids in the onset of symptoms and offering new insights into the pathomechanism of inner ear CHL.

Vascular Myelopathies

There are many vascular disorders that can affect the spinal cord, and their prevalence and etiology are highly influenced by age, sex, and risk factors. This article reviews the embryology and anatomy of the spinal cord, as well as several vascular conditions, describing their clinical and imaging presentation, emphasizing the different imaging modalities' contributions to increasing specificity and better defining the most appropriate therapy strategy for improving the patient's prognosis.

Association between Dural AVFs and Cerebral Venous Thrombosis

BACKGROUND AND PURPOSE

Recent reports suggest an association between dural AVFs and cerebral venous thrombosis. We aimed to investigate the specific temporal and anatomic association between the 2 conditions.

MATERIALS AND METHODS

A consecutive cohort of adult patients with dural AVFs was seen at Amsterdam University Medical Centers (2007-2020). An experienced neuroradiologist re-evaluated the presence and imaging characteristics of dural AVFs and cerebral venous thrombosis on all available imaging. The temporal (previous/concurrent/subsequent) and anatomic (same/adjacent/unrelated venous sinus or vein) association between dural AVFs and cerebral venous thrombosis was determined.

RESULTS

Among 178 patients with dural AVFs, the mean age was 58.3 (SD, 13.2) years and 85 (48%) were women. Of 55 patients (31%) with cerebral venous thrombosis, 34 (62%) were women. Four patients (7%) had cerebral venous thrombosis before the development of a dural AVF, 33 (60%) had cerebral venous thrombosis at the time of dural AVF diagnosis (concurrent), and 18 (33%) developed cerebral venous thrombosis during follow-up after conservative treatment. The incidence rate of cerebral venous thrombosis after a dural AVF was 79 per 1000 person-years (95% CI, 50-124). In 45 (82%) patients with dural AVFs and cerebral venous thrombosis, the thrombosis was located in the same venous sinus as the dural AVF, whereas in 8 (15%) patients, thrombosis occurred in a venous sinus adjacent to the dural AVF.

CONCLUSIONS

One-third of patients with a dural AVF in this study were diagnosed with cerebral venous thrombosis. In almost two-thirds of patients, cerebral venous thrombosis was diagnosed prior to or concurrent with the dural AVF. In 97% of patients, there was an anatomic association between the dural AVF and cerebral venous thrombosis. These data support the hypothesis of a bidirectional association between the 2 diseases.

Differential subsampling with cartesian ordering: A high spatial-temporal resolution dixon imaging sequence for assessment of dural arteriovenous fistula

Objective

To evaluate the accuracy of differential subsampling with cartesian ordering (DISCO) in comparison to time of flight (TOF) in detecting dural arteriovenous fistulas (DAVF), cerebral venous thrombosis (CVT) and hemodynamics.

Methods

Sixty-two cases (24 female; aged 14–75; mean age, 51.3 years) were included in our study, with 42 positive and 20 negative cases via Digital Subtraction Angiography (DSA). Two neuroradiologists independently evaluated the DISCO and TOF. The sensitivity, specificity, and accuracy of the DISCO and TOF-MRA were individually calculated using DSA as the gold standard. Inter-observer reliability was assessed by using a weighted Cohen's kappa (κ) test; P < 0.05 was set as the threshold for statistical significance.

Results

Diagnostic sensitivities of DISCO and TOF for DAVF were 92.86 and 64.29%; specificities were 95.0% and 95.0%; while accuracies were 93.55 and 74.19% respectively. For detected CVT, sensitivities of DISCO and TOF were 100 and 92.31%; specificities were 96.55 and 93.10%; with accuracies 97.62 and 92.86% respectively. In hemodynamic analysis, sensitivity of DISCO for reflux was 95.45%; with a specificity of 95.0%; and accuracy 95.24%. The inter-observer kappa values were 0.857 for DISCO (P < 0.001).

Conclusion

DISCO showed a high degree of sensitivity and specificity, suggesting its effectiveness in detecting DAVF with or without CVT. Intracranial hemodynamics can be identified using DISCO in DAVF patients, providing accurate evaluation of cerebral blood flow dynamics during the pre-treatment phase.

[Cerebral dural arteriovenous fistulas]

CLINICAL ISSUE

The cerebral dural arteriovenous (AV) fistula is a rare cerebral vascular malformation. Clinical presentation varies from asymptomatic to acute intracranial bleeding. Classification is based on the venous drainage with a risk assessment of bleeding. The carotid-cavernous fistula is a subtype with its own classification and treatment approaches.

PRACTICAL RECOMMENDATIONS

Nowadays, dural fistulas can be diagnosed using high-resolution and time-resolved tomographic methods. Catheter angiography with subsequent interdisciplinary discussion should be performed for precise classification and therapy planning. Both endovascular and surgical treatment methods are available.

Results of transvenous embolization of intracranial dural arteriovenous fistula: a consecutive series of 136 patients with 142 fistulas

OBJECTIVE

Intracranial dural arteriovenous fistula (DAVF) is mainly treated with an endovascular approach. Two major treatment advances include transvenous embolization (TVE) with coils in 1989 and, more recently, transarterial embolization with Onyx. The aim of this study was to present a large monocentric series of patients with DAVF treated with TVE. This series reports more than 20 years of experience and describes the evolution of the medical management of these patients, as well as current indications for this treatment at the authors' center.

METHODS

Consecutive patients treated for intracranial DAVFs with TVE from 1995 to 2018 were included. Clinical and imaging data were systematically collected. Univariate and multivariate analyses were performed to identify factors that were significantly associated with adverse clinical course or complications.

RESULTS

In this study of 136 patients with 142 DAVFs treated with TVE, the occlusion rate was 90%. The median length of follow-up was 11 months. The rate of permanent complications was 5.1%, and the procedure-related mortality rate was 1.5%. Procedure-related mortality was associated with extension of thrombosis that was observed early in our experience. The introduction of a postoperative anticoagulation regimen has drastically decreased the occurrence of this complication. Other minor complications included cochleovestibular syndrome after embolization of lateral sinus DAVF and oculomotor nerve damage after embolization of cavernous sinus DAVF.

CONCLUSIONS

TVE allows efficient occlusion of DAVF. It remains a valid option for DAVF located on a sinus that does not participate in normal venous drainage of the brain.

Transarterial embolization of dural arteriovenous fistulas of the lateral sinuses with stent-assisted sinus protection

BACKGROUND

The balloon-assisted sinus protection technique has been described as a sinus-preserving technique during transarterial embolization (TAE) of dural arteriovenous fistulas (DAVFs). However, some serious complications of this technique have been documented.

OBJECTIVE

To describe our preliminary experience with a new technique called stent-assisted sinus protection (SSP).

METHODS

We performed a retrospective analysis of seven consecutive patients with type I or IIa DAVFs of the lateral sinus treated by TAE with a closed-cell stent temporarily deployed in the sinus.

RESULTS

Of the seven patients, four had type I DAVF, and three had type IIa DAVF. The patency of all involved sinuses and their tributaries (including the inferior anastomotic vein and the superior petrosal sinus) was preserved. At the end of the procedure, all stents were successfully retrieved with embolic particles trapped in their meshes. No procedural complications were noted. Clinical follow-up was satisfactory, with complete resolution or significant reduction of pulsatile tinnitus.

CONCLUSIONS

SSP appears to be feasible and probably safe. However, larger studies are needed to confirm these preliminary results.

Is the Middle Meningeal Artery the Optimal Path for Dural Arteriovenous Fistula Embolization?

Background: The middle meningeal artery (MMA) is the optimal arterial path for endovascular treatment (EVT) of dural arteriovenous fistulas (DAVFs). However, the details are not completely understood.

Materials and Methods: We performed a retrospective study of patients who were admitted to the First Hospital of Jilin University with a diagnosis of cranial DAVF with involvement of the MMA as a feeding artery. On the basis of the arterial path chosen and the role of the MMA in the first EVT procedure, EVT was divided into three types (I–III), each of which was further divided into two subclasses (a and b). The degree of embolization was analyzed.

Result: The 104 included patients ranged in age from 13 to 80 years (mean, 53.6 ± 11.8 years). There were 48 cases of hemorrhage (46.2%, 48/104). Complete embolization was achieved in the first procedure in 64.4% of cases, and success was eventually achieved using EVT (the first attempt or a subsequent attempt) in 74.1% of cases. EVT caused complications in 6.7% of cases. A modified Rankin scale score of 0 or 1 was achieved in 78.8% of patients. Statistical analyses revealed that type Ia and IIb EVTs had the lowest complete embolization rates, but no difference was found between type Ia and IIb EVTs. Types IIa and III EVT had the highest complete embolization rates. Most cases had a good prognosis.

Conclusion: These findings elucidate the features of the different EVT classes defined by the first EVT procedure and the role of the MMA. The delivery of treatment via slim and tortuous MMA branches increased the failure rate of EVT. A thick, straight MMA branch is the optimal path for treatment.

Detecting causes of pulsatile tinnitus on CT arteriography-venography: A pictorial review

Pulsatile tinnitus (PT) can be a mild or debilitating symptom. Following clinical examination and otoscopy, when the underlying aetiology is not apparent, radiological imaging can be used to evaluate further. CT arteriography-venography (CT A-V) of the head and neck has recently been introduced as a single 'one catch' modality for identifying the many causes of PT including those which are treatable and potentially serious whilst also providing reassurance through negative studies or studies with benign findings. CT A-V is performed as a single phase study allowing both arterial and venous assessment, hence limiting radiation exposure. Additional multiplanar reformats and bone reconstructions are desirable. Understanding the limitations of CT A-V is also required, with an awareness of the scenarios where other imaging modalities should be considered. The causes of PT can be divided into systemic and non-systemic categories. Non-systemic aetiologies in the head and neck should be carefully reviewed on CT A-V and include a variety of vascular causes (arteriovenous malformations/fistulas, venous or arterial aetiologies) and non-vascular causes (tumours and bony dysplasias). Venous causes (dominant, aberrant, stenosed or thrombosed venous vessels) are more common than arterial aetiologies (aberrant or stenosed internal carotid artery, aneurysms or a persistent stapedial artery). Glomus tumours that are not visible on otoscopy and osseous pathologies such as bony dehiscence and otospongiosis should also be excluded. Careful assessment of all the potential vascular and non-vascular causes should be reviewed in a systematic approach, with correlation made with the clinical history. A structured reporting template for the reporting radiologist is provided in this review to ensure all the potential causes of PT are considered on a CT A-V study. This will help in providing a comprehensive radiological evaluation, hence justifying the radiation dose and for patient assessment and prognostication.