1. Department of Radiology, Neuroradiology Section; University of California; San Francisco CA
2. Department of Neurology, Cerebrovascular Unit; Neurological Institute Carlo Besta; Milan Italy
3. Department of Radiology, Nuclear Medicine Section; University of California; San Francisco CA
4. Department of Epidemiology and Biostatistics; University of California; San Francisco CA
5. Department of Radiology, Neuroradiology Division; University of Virginia