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.
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Data availability
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Code availability
The source code of our method is made publicly available at https://github.com/hb-liu/cest-cu.
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Acknowledgements
Authors would like to acknowledge the funding supports from Research Grants Council of the Hong Kong Special Administrative Region, China (11206325, 11102218, 11200422, CityUHK RFS2223-1S02); HMRF (21222621); ITF-MHKJFS (MHP/076/23); InnoHK initiative of the Innovation and Technology Commission of the Hong Kong Special Administrative Region Government - Hong Kong Centre for Cerebro-cardiovascular Health Engineering; City University of Hong Kong (7030012, 9678372, 9229504, 9609321 and 9610616), Institute of Digital Medicine, Tung Biomedical Sciences Centre; State Key Laboratory of Terahertz and Millimeter Waves; The University of Hong Kong (109000487, 204610401 and 204610519); National Key Research and Development Program of China: 2023YFE0210300.
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H.L.: Conceptualization, Methodology, and Writing – original draft. Z.C., L.H.L., Y.L., Z.W., and J.W.: Data curation and Visualization. Y.Z., D.S., J.H., and K.C.: Supervision, Funding acquisition, and Writing – review & editing.
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Liu, H., Chen, Z., Law, L.H. et al. Accelerating CEST MRI through complementary undersampling and multi-offset transformer reconstruction. Commun Eng (2026). https://doi.org/10.1038/s44172-025-00580-6
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DOI: https://doi.org/10.1038/s44172-025-00580-6
