We investigated the number and possible causes of clinically silent lesions seen in diffusion-weighted magnetic resonance imaging after embolization of arteriovenous malformations (AVMs) and fistulas using acrylate only or in combination with coils. Included were 19 patients with 18 AVMs and one case of a vein of Galen aneurysm in which 25 interventions were carried out. Results of diffusion-weighted imaging, the appearance of perinidal and distant lesions, were correlated to Spetzler grade, nidus size, flow, number of feeders occluded, rate of nidus occlusion and duration of the intervention. We found seven distant lesions corresponding to non-symptomatic infarcts in the given clinical setting. The only significant correlation between lesion size and parameters analyzed was the degree of nidus occlusion achieved during the intervention. Because most of the lesions presented in cases with a high occlusion rate, they appear to be related to the intention to reach a complete occlusion of the nidus. These results emphasize that the risk involved in eliminating the nidus completely must be reconsidered with special care, particularly in a situation where most high-flow feeders have been occluded.

Pediatric neurovascular malformations are rare. However, proper diagnosis and management are mandatory to achieve a good neurocognitive outcome. Among them several types can be identified with specificities for each. In the newborn and infancy, the most frequent cerebral venous malformation is vein of Galen aneurysmal malformation. It can be discovered antenatally, in neonates (mainly in cases with hemodynamic impact), or in infants presenting with macrocrania and hydrocephalus. Treatment of choice is endovascular, by transarterial selective occlusion of pathological vessels. Interventions are staged with a first session at around 5 months, adjusted to neurological development. Late consequences, especially if left untreated or treated outside the therapeutic window, are delayed neurocognitive development and seizures. Pial arteriovenous malformation can also be diagnosed antenatally. Regional parenchymal destruction could occur in the first months of life, requiring early endovascular treatment. Dural sinus malformations are the third main type of neurovascular malformation, and are also diagnosed antenatally or in the first months of life. Cardiac tolerance is usually good. Adverse consequences are mainly neurocognitive delay due to chronic venous hyperpressure or acute hemorrhage due to thrombosis of the pathological sinuses. Nidal-type brain arteriovenous malformation and cavernous angioma are usually seen later in children, with hemorrhage often being the first presenting symptom.

Brain arteriovenous malformations (AVMs) produce circulatory and functional disturbances in adjacent as well as in remote areas of the brain, but their physiological effect on the cerebrospinal fluid (CSF) pressure is not well known.The hypothesis of an intrinsic disease mechanism leading to increased CSF pressure in all patients with brain AVM is outlined, based on a theory of hemodynamic control of intracranial pressure that asserts that CSF pressure is a fraction of the systemic arterial pressure as predicted by a two-resistor series circuit hydraulic model. The resistors are the arteriolar resistance (that is regulated by vasomotor tonus), and the venous resistance (which is mechanically passive as a Starling resistor). This theory is discussed and compared with the knowledge accumulated by now on intravasal pressures and CSF pressure measured in patients with brain AVM.The theory provides a basis for understanding the occurrence of pseudotumor cerebri syndrome in patients with nonhemorrhagic brain AVMs, for the occurrence of local mass effect and brain edema bordering unruptured AVMs, and for the development of hydrocephalus in patients with unruptured AVMs. The theory also contributes to a better appreciation of the pathophysiology of dural arteriovenous fistulas, of vein of Galen aneurismal malformation, and of autoregulation-related disorders in AVM patients.The hydraulic hypothesis provides a comprehensive frame to understand brain AVM hemodynamics and its effect on the CSF dynamics.

BACKGROUND

/

OBJECTIVE:

Transarterial infusion of Onyx is now widely used in the treatment of arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Transvenous Onyx embolization is rarely performed, and usually in cases of carotid cavernous fistulas. We describe a novel technique of transvenous Onyx embolization in the treatment of three high risk DAVFs and one vein of Galen (VOG) AVM.

METHODS:

Cases were evaluated with specific attention to technical caveats, clinical indications, and complications. Patients were treated during 2011-2012 by two operators (FCA and CGM). Standard transfemoral venous approaches were employed in order to obtain access into the draining venous system in all cases.

RESULTS:

Four female patients, aged 5 months to 68 years, were treated. Two patients, one presenting with headache and the other with a bruit, demonstrated high risk DAVFs involving the transverse-sigmoid sinuses. One patient, who was asymptomatic, manifested a high risk ethmoidal DAVF that was discovered incidentally during treatment of a basilar aneurysm. The final patient presented with symptoms of a pineal region mass and was found to have a VOG AVM. In all cases, a microcatheter was navigated through the draining venous pouch and into the ostium of an arterial feeder. A single Onyx infusion from this position filled multiple arterial feeders and resulted in cures in the first three patients and a significant reduction in AVM nidus in the fourth patient. No complications occurred.

CONCLUSIONS:

Transvenous Onyx infusion into a single arterial feeder can produce retrograde embolization of numerous other arterial feeders supplying high risk DAVFs and complex cerebral AVMs. This technique appears to be safe and potentially curative in select cases.

Acquired central nervous system (CNS) lesions are often subtle; therefore, the prenatal diagnosis of these lesions is extremely important. The fetal ultrasound examination and magnetic resonance imaging (MRI) are two important imaging methods that give an insight into these types lesions. The method of choice during pregnancy is still fetal ultrasound; however, fetal MRI is important when there are certain pathologies, e.g. periventricular leukomalacia (PVL) or malformations of the vein of Galen. In this manner clinicians can plan further therapy after childbirth in advance (e.g. cerebral angiography or embolization).

Vein of galen malformation (VOGM) is a very rare disease which affects blood vessels of the brain. In general population the incidence is estimated at 1%. Treatment of choice is transluminal embolization. We present the case of five-month-old child with low degree heart failure, hydrocephalus and significantly delayed psychomotor development. MR examination reveals a vein of Galen malformations, wall type (type I according to Yasargil) 6 cm in diameter, with venous drainage to the sinus rectus. The enlarged vein filled with thrombus. It causes brain stem compression. Angiography shows one feeder leading to the VOGM, from right posterior brain artery. Lesion was treated with two embolic materials: 5 coils and 2 ml of ONYX. Angiography confirmed total exclusion of the fistula and the circulation in the vein of Galen. One of the most important elements of treatment is to perform a proper diagnosis and evaluation of lesions morphology. With proper technique, high skills and proper equipment, intravascular embolization of vein of Galen malformation is an effective treatment.

Three types of brain arteriovenous vascular malformations can be found during the neonatal period, according to their anatomical location. Vein of Galen malformations are the most common. The others are pial arteriovenous malformations or dural arteriovenous malformations, which include dural sinus malformations. They can be asymptomatic, but most often they are associated with different symptoms, related to their angioarchitecture or their effect on the brain. High-flow arteriovenous malformations can thus be responsible for heart failure. Local or regional venous hyperpressure exposes the patient to subacute or chronic brain lesions, or to hydrovenous disorders such as hydrocephalus. Some types of venous reflux can expose patients to brain hemorrhage. The treatment chosen for these vascular malformations and their consequences is transarterial or transvenous embolization, depending on the angioarchitecture and type of lesion. The schedule for the treatment will be determined according to the malformation type and its local or general effects on the brain. The aim of this article is to present the recommendations of the French National Referral Center for neurovascular malformations in children, in order to help clinicians and radiologists treat these patients during pre- or neonatal period.

Vein of Galen malformations (VGM) are rare intracranial vascular anomalies that constitute 1% of all intracranial vascular malformations. Untreated VGM have a very poor prognosis. A high proportion of patients who present in the neonatal period rapidly deteriorate and succumb to congestive cardiac failure. The prenatal diagnosis and possible in utero referral to highly specialised centre of postnatal care have resulted in considerable improvement in prognosis. The authors present a case of a postnatally diagnosed VGM in a full-term infant presenting with progressive cardiac failure and necrotising enterocolitis secondary to gut hypoperfusion. They emphasise the importance of prenatal diagnosis by pulsed wave Doppler and colour-velocity imaging for subsequent referral to a centre of excellence in a multidisciplinary approach involving neonatologists, paediatric cardiologists and interventional radiologists in order to optimise the management and limit the neurological sequelae in children with this type of malformation.

Background.

The Vein of Galen aneurysmal malformation (VGAM) is a rare congenital, cerebral, arteriovenous deformity. Good cross-discipline cooperation is in demand because of associated complications and high mortality. The recognition of the optimal therapeutic window is useful to allow proper management. Case Report. We report on the successful treatment of a 2-week-old, healthy girl with a VGAM, which came across in the context of the newborn ultrasonographic screening. After interdisciplinary discussion, 2 embolizations of the VGAM followed without complications-the first in the age of 6 months and the second at 12 months of life. Before and after the intervention, the patient had an age-appropriate development without neurological deficits.

Conclusion.

The endovascular transarterial embolization is described as the treatment of choice. Time and method of intervention depend on clinical signs of the patient. In our case the patient was asymptomatic. So the arteriovenous abnormality was an incidental finding by ultrasound. Because of the natural history of the disease, and the potential severe neurocognitive consequences at long-term followup if left untreated, it was decided to embolize the lesion. Thanks to embolization with glue, good therapeutical and clinical results could be obtained with normal neurological development.