1. Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
2. Department of Applied Physics, University of Eastern Finland, Finland
3. Department of Clinical Radiology, Kuopio University Hospital, Finland
4. Department of Physical and Rehabilitation Medicine, Helsinki University Hospital and University of Helsinki, Finland
5. Griffith Centre of Biomedical and Rehabilitation Engineering (GCORE), Menzies Health Institute, Queensland and Advanced Design and Prototyping Technologies Institute (ADAPT), Australia