BraSyn 2023 challenge: Missing MRI synthesis and the effect of different learning objectives

This work is addressing the Brain Magnetic Resonance Image Synthesis for Tumor Segmentation (BraSyn) challenge which was hosted as part of the Brain Tumor Segmentation challenge (BraTS) 2023. In this challenge researchers are invited to work on synthesizing a missing magnetic resonance image sequence given other available sequences to facilitate tumor segmentation pipelines trained on complete sets of image sequences. This problem can be addressed using deep learning in the framework of paired images-to-image translation. In this work, we proposed to investigate the effectiveness of a commonly-used deep learning framework such as Pix2Pix trained under supervision of different image-quality loss functions. Our results indicate that using different loss functions significantly affects the synthesis quality. We systematically study the impact of different loss functions in the multi-sequence MR image synthesis setting of the BraSyn challenge. Furthermore, we show how image synthesis performance can be optimized by beneficially combining different learning objectives.