1. Department of Neurosurgery, Brigham and Women's HospitalHarvard Medical School Boston MA
2. Department of Radiology, Brigham and Women's HospitalHarvard Medical School Boston MA
3. School of Medicine and SurgeryUniversità degli Studi di Milano‐Bicocca Milan Italy
4. Department of Radiology, Massachusetts General HospitalHarvard Medical School Boston MA