1. Unit of Diagnostic and Therapeutic Neuroradiology, and Unit of Neurosurgery, Department of Neurosciences and Interdepartmental Centre of Nuclear Magnetic Resonance, and Department of Human Pathology, Section of Pathologic Anatomy, Azienda Ospedaliera Universitaria Senese, Policlinico “Santa Maria alle Scotte,” Siena, Italy; and Unit of Neuroradiology, Department of Radiology, Ospedale della Misericordia, Grosseto, Italy