1. Department of Neurological Surgery, Oregon Health and Science University, Portland, Oregon, USA
2. Department of Neurology, Oregon Health and Science University, Portland, Oregon, USA
3. Department of Neuroradiology, Universitätsklinikum Würzburg, Würzburg, Germany
4. Department of Radiology, Oregon Health and Science University, Portland, Oregon, USA
5. Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, USA
6. Portland Veterans Affairs Medical Center, Portland, Oregon, USA