Enhanced glioma semantic segmentation using U-net and pre-trained backbone U-net architectures Amir Khorasani1, 1Medical Image and Signal Processing Research Center, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 2Department of Bioimaging, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran. email: a.khorasani@resident.mui.ac.ir; amir69k@yahoo.com