Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr|Medical Image Processing and Analysis Group, Laboratory of Medical Physics, School of Medicine, University of Patras, 265 04 Rio, Greece. daskalakis@med.upatras.gr