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T1-weighting in Steady-State FLASH MRI-Diffusion Is Not Only Supportive but Mandatory for the Contrast.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος: T1-weighting in Steady-State FLASH MRI-Diffusion Is Not Only Supportive but Mandatory for the Contrast.
Συγγραφείς: Weinmüller S; Institute of Neuroradiology, Uniklinikum Erlangen, Erlangen, Germany., Chellapandian DC; Institute of Neuroradiology, Uniklinikum Erlangen, Erlangen, Germany.; Department of Artificial Intelligence in Biomedical Engineering (AIBE), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.; Magnetic Resonance, Siemens Healthineers AG, Erlangen, Germany., Endres J; Institute of Neuroradiology, Uniklinikum Erlangen, Erlangen, Germany., Leupold J; Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany., Gritsch F; Institute of Neuroradiology, Uniklinikum Erlangen, Erlangen, Germany., Wagner F; Magnetic Resonance, Siemens Healthineers AG, Erlangen, Germany., Schneider R; Magnetic Resonance, Siemens Healthineers AG, Erlangen, Germany., Zaiss M; Institute of Neuroradiology, Uniklinikum Erlangen, Erlangen, Germany.; Department of Artificial Intelligence in Biomedical Engineering (AIBE), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Πηγή: Magnetic resonance in medicine [Magn Reson Med] 2026 Oct; Vol. 96 (4), pp. 1789-1797. Date of Electronic Publication: 2026 Jun 21.
Τύπος έκδοσης: Journal Article
Γλώσσα: English
Στοιχεία περιοδικού: Publisher: Wiley Country of Publication: United States NLM ID: 8505245 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1522-2594 (Electronic) Linking ISSN: 07403194 NLM ISO Abbreviation: Magn Reson Med Subsets: MEDLINE
Imprint Name(s): Publication: 1999- : New York, NY : Wiley
Original Publication: San Diego : Academic Press
Ιατρικοί όροι (MeSH): Brain*/diagnostic imaging , Diffusion Magnetic Resonance Imaging*/methods , Image Processing, Computer-Assisted*/methods , Magnetic Resonance Imaging*/methods, Silicone Oils/chemistry ; Cerebrospinal Fluid/diagnostic imaging ; Phantoms, Imaging ; Computer Simulation ; Humans ; Algorithms ; Diffusion ; Printing, Three-Dimensional
Περίληψη: Purpose: FLASH imaging is widely assumed to produce a T1-weighted steady-state contrast using RF- and gradient-spoiling. We observed substantial overestimation of CSF signals in simulations, when diffusion was neglected and realistic proton density was applied. This work investigates the role of diffusion in steady-state FLASH contrast formation and its implications for simulation-based modeling and measurement.
Methods: FLASH sequences were simulated using phase graph simulations using a synthetic brain phantom with and without diffusion and realistic PD values to show the contrast change. The impact of neglecting diffusion in synthetic training data was evaluated using a segmentation network trained on simulated data and tested on in vivo measurement. Experimental validation of the contrast change was performed using a 3D-printed brain phantom using silicone oil as a low-diffusivity compartment.
Results: Without diffusion, simulations showed CSF signal intensities higher than WM, resulting in a contrast change. Diffusion suppresses higher-order echoes in long T2 tissues and is essential for achieving the T1-weighted steady-state contrast. A NN trained without diffusion fails to generalize to in vivo data and measurements with silicone oil compartments confirm the contrast changes in low-diffusivity media.
Conclusion: Diffusion is essential for realistic FLASH simulations of long T2 tissues such as CSF. Steady-state FLASH contrast arises from the interplay of RF-, gradient-spoiling, and "multi-TR-relaxation-spoiling" governed by T2-decay and diffusion effects. For many quadratic phase cycling schemes, diffusion is required to obtain realistic T1-weighted contrast in MR simulations and should not be neglected in simulations or simulation-based deep learning applications.
(© 2026 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)
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Grant Information: d.hip Campus - Bavarian AIM; 500888779 Deutsche Forschungsgemeinschaft; 16SV9585 Bundesministerium für Bildung und Forschung; Competence Network for Scientific High Performance Computing in Bavaria (KONWIHR)
Contributed Indexing: Keywords: RF‐spoiling; T1‐weighted FLASH; TR‐spoiling; diffusion; gradient‐spoiling; steady‐state
Substance Nomenclature: 0 (Silicone Oils)
Entry Date(s): Date Created: 20260622 Date Completed: 20260729 Latest Revision: 20260801
Update Code: 20260801
PubMed Central ID: PMC13421012
DOI: 10.1002/mrm.70443
PMID: 42324643
Βάση Δεδομένων: MEDLINE
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