Introduction: Onyx embolization is a well-established treatment of especially large brain arterio venous malformations (AVM). However, assessment of the extent of obliteration of the nidus after each stage is often a challenge. Superimposing the onyx mass mass over the feeding arteries or darning veins, makes their visualization difficult. Moreover, estimation of the volume of remaining live nidus is very important both for possible surgical resection or radiosurgery.
Methods: Data were prospectively collected. After each stage of embolization of AVM using Onyx liquid embolic system, a rotational cerebral angiography was also obtained and tri-dimensional reconstruction (3DR) of these data was performed on Leonardo workstation with both single volume (SV) and dual volume (DV) techniques. AVM obliteration status, visibility of live and occluded feeders, position of the onyx mass with respect to residual nidus and darning veins were compared using two methods. Finally, using volume-rendering technique, a volumetric study of the size of live and embolized nidus was performed. The Sørensen–Dice index was used to compare the correspondence between dual volume technique and angiography.
Results: Six adult patients with large brain AVMs were included. The average age was 45+6 years. AVMs were located in the following lobes: parieto-occipital (2), temporo-parietal (2), fronto-parietal (1), and frontal (1). For arterial feeder evaluation, dual volume reconstruction perfectly matched with cerebral angiography for their contribution into the nidus (Sørensen–Dice index =1). Volumetric study showed consecutive volume reduction after each stage of embolization, which was confirmed by detailed angiographic evaluation.
Conclusions: To our knowledge, this is the first case series introducing this method for increasing the chance of finding real attributing feeders of the AVM and differentiating them from en passage arteries in the literature. Dual-volume reconstruction is a promising method for performing a semi-quantitative measurement after AVM embolization, improving the visualization, and surgical planning.
Patient Care: Better visulization of the feeders, treatment planning, measuring the volume of residual AVM and treatment based on that.
Learning Objectives: this method increases the chance of finding real attributing feeders of the AVM and differentiating them from en passage arteries. Dual-volume reconstruction is a promising method for performing a semi-quantitative measurement after AVM embolization, improving the visualization, and surgical planning