1Department of Radiology, Johns Hopkins University, Baltimore, MD, United States, 2Department of Radiology, Southern Medical University Zhujiang Hospital, Guangzhou, China, People's Republic of, 3Department of Neurology, Johns Hopkins University, Baltimore, MD, United States, 4Department of Pathology, Johns Hopkins University, Baltimore, MD, United States, 5Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States