1. Division of Interventional Neuroradiology, University of California at Los Angeles Medical Center, Los Angeles, California
2. Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
3. Divisions of Interventional Neuroradiology and Neurosurgery, University of California at Los Angeles Medical Center, Los Angeles, California
4. Department of Diagnostic Imaging, Kaiser Permanente Medical Center, Los Angeles, California