Martin Paucar1,2, Håkan Almqvist2,3, Ingemar Björkhem4, Per Svenningsson1,2. 1. Department of Neurology, Karolinska University Hospital, Stockholm, Sweden. 2. Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden. 3. Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden. 4. Department of Laboratory Medicine, Karolinska University Hospital, Stockholm, Sweden.