1. Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
2. Neurological Institute of Athens, Athens, Greece
3. Institute of Radiology, Department of Clinical Surgical Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
4. Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
5. Division of Neuroradiology, Department of Radiology, University of California, San Francisco (UCSF), California