1. Radiology Department, UH St Ivan Rilski, Sofia, Bulgaria
2. Neurosurgery Department, UH St Ivan Rilski, Sofia, Bulgaria
3. Department of Interventional Neuroradiology and Neurosurgery, Meshalkin National Medical Research Center, Novosibirsk, Russia
4. Department of Neurology and Comprehensive Stroke Center, University of California Los Angeles David Geffen School of Medicine, Los Angeles, USA