Ruibin Liu1, Hongxi Zhang2, Yue Qian3, Yi-Cheng Hsu4, Caixia Fu5, Yi Sun4, Dan Wu1, Yi Zhang1. 1. Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China. 2. Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. 3. Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. 4. MR Collaboration, Siemens Healthcare Ltd., Shanghai, China. 5. Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China.
Abstract
PURPOSE: To correct the temporal B0 drift in chemical exchange saturation transfer (CEST) imaging in real-time with extra free-induction-decay (FID) readout. THEORY AND METHODS: The frequency stabilization module of the recently proposed frequency-stabilized CEST (FS-CEST) sequence was further simplified by replacing the original three k-space lines of gradient-echo (GRE) readout with a single k-space line of FID readout. The B0 drift was quantified using the phase difference between the odd and even parts of the FID signal in the frequency stabilization module and then used to update the B0 frequency in the succeeding modules. The proposed FS-CEST sequence with FID readout (FID FS-CEST) was validated in phantoms and 16 human subjects on cross-vendor scanners. RESULTS: In the Siemens experiments, the FID FS-CEST sequence successfully corrected the user-induced B0 drift, generating consistent amide proton transfer-weighted (APTw) images and magnetization transfer ratio asymmetry (MTRasym ) spectra with those from the non-frequency-stabilized CEST (NFS-CEST) sequence without B0 drift. In the Philips experiments, the FID FS-CEST sequence produced more stable APTw images and MTRasym spectra than the NFS-CEST sequence in the presence of practical B0 drift. Quantitatively, the SD of the APTw signal values in the deep gray matter from 15 subjects was 0.26% for the FID FS-CEST sequence compared to 1.03% for the NFS-CEST sequences, with the fluctuations reduced by nearly three-quarters. CONCLUSIONS: The proposed FS-CEST sequence with FID readout can effectively correct the temporal B0 drift on cross-vendor scanners.
PURPOSE: To correct the temporal B0 drift in chemical exchange saturation transfer (CEST) imaging in real-time with extra free-induction-decay (FID) readout. THEORY AND METHODS: The frequency stabilization module of the recently proposed frequency-stabilized CEST (FS-CEST) sequence was further simplified by replacing the original three k-space lines of gradient-echo (GRE) readout with a single k-space line of FID readout. The B0 drift was quantified using the phase difference between the odd and even parts of the FID signal in the frequency stabilization module and then used to update the B0 frequency in the succeeding modules. The proposed FS-CEST sequence with FID readout (FID FS-CEST) was validated in phantoms and 16 human subjects on cross-vendor scanners. RESULTS: In the Siemens experiments, the FID FS-CEST sequence successfully corrected the user-induced B0 drift, generating consistent amide proton transfer-weighted (APTw) images and magnetization transfer ratio asymmetry (MTRasym ) spectra with those from the non-frequency-stabilized CEST (NFS-CEST) sequence without B0 drift. In the Philips experiments, the FID FS-CEST sequence produced more stable APTw images and MTRasym spectra than the NFS-CEST sequence in the presence of practical B0 drift. Quantitatively, the SD of the APTw signal values in the deep gray matter from 15 subjects was 0.26% for the FID FS-CEST sequence compared to 1.03% for the NFS-CEST sequences, with the fluctuations reduced by nearly three-quarters. CONCLUSIONS: The proposed FS-CEST sequence with FID readout can effectively correct the temporal B0 drift on cross-vendor scanners.
Authors: Jinyuan Zhou; Moritz Zaiss; Linda Knutsson; Phillip Zhe Sun; Sung Soo Ahn; Silvio Aime; Peter Bachert; Jaishri O Blakeley; Kejia Cai; Michael A Chappell; Min Chen; Daniel F Gochberg; Steffen Goerke; Hye-Young Heo; Shanshan Jiang; Tao Jin; Seong-Gi Kim; John Laterra; Daniel Paech; Mark D Pagel; Ji Eun Park; Ravinder Reddy; Akihiko Sakata; Sabine Sartoretti-Schefer; A Dean Sherry; Seth A Smith; Greg J Stanisz; Pia C Sundgren; Osamu Togao; Moriel Vandsburger; Zhibo Wen; Yin Wu; Yi Zhang; Wenzhen Zhu; Zhongliang Zu; Peter C M van Zijl Journal: Magn Reson Med Date: 2022-04-22 Impact factor: 3.737