Signal Enhancement of Low Magnetic Field Magnetic Resonance Image Using a Conventional- and Cyclic-Generative Adversarial Network Models With Unpaired Image Sets

Denis Yoo; Yuni Annette Choi; C J Rah; Eric Lee; Jing Cai; Byung Jun Min; Eun Ho Kim

doi:10.3389/fonc.2021.660284

Signal Enhancement of Low Magnetic Field Magnetic Resonance Image Using a Conventional- and Cyclic-Generative Adversarial Network Models With Unpaired Image Sets

Front Oncol. 2021 May 11:11:660284. doi: 10.3389/fonc.2021.660284. eCollection 2021.

Authors

Denis Yoo¹, Yuni Annette Choi¹, C J Rah¹, Eric Lee¹, Jing Cai², Byung Jun Min³, Eun Ho Kim⁴

Affiliations

¹ Artificial Intelligence Research Lab, Talos, Sheung Wan, Hong Kong.
² Department of Health Technology & Informatics, Hong Kong Polytechnic University, Hung Hom, Hong Kong.
³ Department of Radiation Oncology, Chungbuk National University Hospital, Cheongju, South Korea.
⁴ Department of Biochemistry, School of Medicine, Daegu Catholic University, Daegu, South Korea.

Abstract

In this study, the signal enhancement ratio of low-field magnetic resonance (MR) images was investigated using a deep learning-based algorithm. Unpaired image sets (0.06 Tesla and 1.5 Tesla MR images for different patients) were used in this study following three steps workflow. In the first step, the deformable registration of a 1.5 Tesla MR image into a 0.06 Tesla MR image was performed to ensure that the shapes of the unpaired set matched. In the second step, a cyclic-generative adversarial network (GAN) was used to generate a synthetic MR image of the original 0.06 Tesla MR image based on the deformed or original 1.5 Tesla MR image. Finally, an enhanced 0.06 Tesla MR image could be generated using the conventional-GAN with the deformed or synthetic MR image. The results from the optimized flow and enhanced MR images showed significant signal enhancement of the anatomical view, especially in the nasal septum, inferior nasal choncha, nasopharyngeal fossa, and eye lens. The signal enhancement ratio, signal-to-noise ratio (SNR) and correlation factor between the original and enhanced MR images were analyzed for the evaluation of the image quality. A combined method using conventional- and cyclic-GANs is a promising approach for generating enhanced MR images from low-magnetic-field MR.

Keywords: Magnetic Resonance Image (MRI); conventional-GAN; cyclic-GAN; enhancement of MR image; low magnetic field.