1. Department of Cardiology, Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland;
2. Clinical Neurosciences, Department of Neurology, University of Helsinki and Department of Neurology, Helsinki University Hospital, Helsinki, Finland;
3. Department of Clinical Physiology and Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland;
4. Department of Neurology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden