1. Department of Medicine, Duke University Medical Center, Durham, North Carolina.
2. Department of Radiology, Division of Neuroradiology, Loma Linda University Medical Center, Loma Linda, California.
3. Department of Radiology, University of Southern California Keck School of Medicine, Los Angeles, California.
4. Department of Medicine, Loma Linda University Medical Center, Loma Linda, California.
5. Department of Pediatrics, Division of Child Neurology, Loma Linda University Children's Hospital, Loma Linda, California.
6. Departments of Neurosurgery and Neurology, University of Cincinnati, Cincinnati, Ohio.