Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related differences and causes each individual galenic venous system to be unique. Therefore, modern neurosurgical procedures require anatomical information on individual differences. Current radiological methods of digital substraction angiography and magnetic resonance venography fail short of providing the necessary information. New and more sophisticated Magnetic resonance imaging (MRI) technology may fulfill this need ¹⁾.