Search

Arteriovenous malformation (AVM) is an abnormal connection between arteries and veins, bypassing the capillary system. In most cases, the disorder may be asymptomatic. The objective of endovascular AVM treatment is set individually for each case upon consultations with a neurosurgeon and a neurologist. The endpoint of the treatment should consist in prevention of AVM bleeding in a management procedure characterized by a significantly lower risk of complications as compared to the natural history of AVM. Endovascular interventions within AVM may include curative exclusion of AVM from circulation, embolization adjuvant to resection or radiation therapy, targeted closure of a previously identified bleeding site as well as palliative embolization. Onyx was first described in the 1990s. It is a non-adhesive and radiolucent compound. Onyx-based closure of the lumen of the targeted vessel is obtained by means of precipitation. The process is enhanced peripherally to the main flux of the injected mixture. This facilitates angiographic monitoring of embolization at any stage. The degree of lumen closure is associated with the location of the vessel. Supratentorial and cortical locations are most advantageous. Dense and plexiform structure of AVM nidus as well as a low number of supplying vessels and a single superficial drainage vein are usually advantageous for Onyx administration. Unfavorable factors include nidus drainage into multiple compartments as well as multiarterial supply of the AVM, particularly from meningeal arteries, en-passant arteries or perforating feeders. Onyx appears to be a safe and efficient material for embolization of cerebral AVMs, also in cases of intracranial bleeding associated with AVM. Curative embolization of small cerebral AVMs is an efficient and safe alternative to neurosurgical and radiosurgical methods. Careful angiographic assessment of individual arteriovenous malformations should be performed before each Onyx administration.

Background: Arteriovenous malformations (AVM) markedly alter the distribution of the regional cerebral blood flow, as they consist of abnormal arteries and veins with no resistance vessels between them. The aim of this study was to the evaluate diagnostic utility of cerebral perfusion scintigraphy (dynamic phase and SPECT) in patients with AVM., Material and Methods: Nineteen patients were examined. All the patients had been previously diagnosed with AVM and qualified for intravascular embolization. Brain scintigraphy was performed with 99mTc-ECD and included dynamic phase and SPECT imaging. The regional blood flow was evaluated visually and semi quantitatively, based on comparison between the activity in the two symmetrical regions of interest. Differences higher than 10% were considered significant. Cerebral angiography combined with intravascular embolization was carried out after a scitigraphic examination., Results: Based on angiograms, the diameter of the AVM nidus was estimated and varied from 1.0 cm to 9.0 cm. In 13 cases, AVM were visible in the dynamic scintigraphy as areas of increased tracer activity. In each case, SPECT images showed the AVM nidus as a region of decreased tracer accumulation. Hypoperfusion in the brain tissue adjacent to the nidus was seen in 15 subjects. In one patient cerebellar diaschisis was present. The average ratio of activity in the region of AVM to activity in the normally perfused tissue calculated by semiquantitative analysis was 77.5 +/- 10.9%., Conclusion: Cerebral perfusion scintigraphy (SPECT images and dynamic scintigraphy) allows one to identify perfusion disturbances caused by the presence of intracranial AVM.

We describe a cervical congenital paraspinal arteriovenous malformation (AVM) drained by paraspinal and epidural ectatic veins, which caused massive erosion of the C6 and C7 vertebral bodies, threatening the cervical stability and necessitating treatment. During the first session, six arterial embolizations were performed to reduce the size and the flow of the AVM. Two months later, a venous approach was used to occlude the remnant venous exit of the AVM and achieve a complete cure. All embolizations were performed using N-butylcyanoacrylate.