Accelerating CEST MRI through complementary undersampling and multi-offset transformer reconstruction.
Authors
Affiliations (13)
Affiliations (13)
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China.
- Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China.
- School of Biomedical Engineering & State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai, China.
- Shanghai United Imaging Intelligence Co. Ltd., Shanghai, China.
- Shanghai Clinical Research and Trial Center, Shanghai, China.
- Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. [email protected].
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China. [email protected].
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China. [email protected].
- Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins Medicine, Baltimore, MD, USA. [email protected].
- State Key Laboratory of Terahertz and Millimeter Waves & Institute of Digital Medicine & Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong, China. [email protected].
- Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China. [email protected].
Abstract
Chemical exchange saturation transfer (CEST) is a promising magnetic resonance imaging (MRI) technique that provides molecular-level information in vivo. To obtain this unique contrast, repeated acquisition at multiple frequency offsets is needed, resulting a long scanning time. In this study, we propose a hybrid strategy at k-space and image domain to accelerate CEST MRI to facilitate its wider application. In k-space, we developed a complementary undersampling strategy which enforces adjacent frequency offsets by acquiring different subregions of k-space. Both Cartesian and spiral k-space trajectories were applied to validate its effectiveness. In the image domain, we developed a multi-offset transformer reconstruction network that uses complementary information from adjacent frequency offsets to improve reconstruction performance. Additionally, we introduced a data consistency layer to preserve undersampled k-space and a differentiable coil combination layer to leverage multi-coil information. The proposed method was evaluated on rodent brain and multi-coil human brain CEST images from both pre-clinical and clinical 3 T MRI scanners. Compared to fully-sampled images, our method outperforms a number of state-of-the-art CEST MRI reconstruction methods in both accuracy and image fidelity. CEST maps, including amide proton transfer (APT) and relayed nuclear Overhauser enhancement (rNOE), were calculated. The results also showed close agreement with fully-sampled ones.