Pulseq-CEST: Towards multi-site multi-vendor compatibility and reproducibility of CEST experiments using an open-source sequence standard

• Type of Material: Article
• Authors: Kai Herz, Max Planck Institute for Biological Cybernetics; Sebastian Mueller, Max Planck Institute for Biological Cybernetics; Or Perlman, Massachusetts General Hospital; Maxim Zaitsev, Medical University of Vienna; Phillip Zhe Sun, Emory University; Linda Knutsson, Lund University; Jinyuan Zhou, Johns Hopkins University; Peter van Zijl, Johns Hopkins University; Kerstin Heinecke, Phys Tech Bundesanstalt; Patrick Schuenke, Phys Tech Bundesanstalt; Christian T Farrar, Massachusetts General Hospital; Manuel Schmidt, Friedrich Alexander Univ Erlangen Nurnberg; Arnd Dörfler, Friedrich Alexander Univ Erlangen Nurnberg; Klaus Scheffler, Max Planck Institute for Biological Cybernetics; Moritz Zaiss, Max Planck Institute for Biological Cybernetics
• Language: English
• Date: 2021-10-01
• Publisher: WILEY
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2021 International Society for Magnetic Resonance in Medicine
• Final Published Version (URL): http://dx.doi.org/10.1002/mrm.28825
• Title of Journal or Parent Work: MAGNETIC RESONANCE IN MEDICINE
• Volume: 86
• Issue: 4
• Start Page: 1845
• End Page: 1858
• Keywords: Pulseq; Radiology, Nuclear Medicine & Medical Imaging; SATURATION-TRANSFER CEST; MAGNETIZATION-TRANSFER; open-source; Science & Technology; PH; HUMAN BRAIN; standardization; Life Sciences & Biomedicine; MRI; CEST; IN-VIVO; CONTRAST

Abstract

Purpose: As the field of CEST grows, various novel preparation periods using different parameters are being introduced. At the same time, large, multisite clinical studies require clearly defined protocols, especially across different vendors. Here, we propose a CEST definition standard using the open Pulseq format for a shareable, simple, and exact definition of CEST protocols. Methods: We present the benefits of such a standard in three ways: (1) an open database on GitHub, where fully defined, human-readable CEST protocols can be shared; (2) an open-source Bloch-McConnell simulation to test and optimize CEST preparation periods in silico; and (3) a hybrid MR sequence that plays out the CEST preparation period and can be combined with any existing readout module. Results: The exact definition of the CEST preparation period, in combination with the flexible simulation, leads to a good match between simulations and measurements. The standard allowed finding consensus on three amide proton transfer–weighted protocols that could be compared in healthy subjects and a tumor patient. In addition, we could show coherent multisite results for a sophisticated CEST method, highlighting the benefits regarding protocol sharing and reproducibility. Conclusion: With Pulseq-CEST, we provide a straightforward approach to standardize, share, simulate, and measure different CEST preparation schemes, which are inherently completely defined.