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Adaptive 4D MR imaging using navigator‐based respiratory signal for MRI‐guided therapy
Author(s) -
Tokuda Junichi,
Morikawa Shigehiro,
Haque Hasnine A.,
Tsukamoto Tetsuji,
Matsumiya Kiyoshi,
Liao Hongen,
Masamune Ken,
Dohi Takeyoshi
Publication year - 2008
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21436
Subject(s) - imaging phantom , computer science , computer vision , real time mri , image quality , scanner , artificial intelligence , visualization , orientation (vector space) , dynamic contrast enhanced mri , magnetic resonance imaging , medicine , nuclear medicine , image (mathematics) , radiology , mathematics , geometry
For real‐time 3D visualization of respiratory organ motion for MRI‐guided therapy, a new adaptive 4D MR imaging method based on navigator echo and multiple gating windows was developed. This method was designed to acquire a time series of volumetric 3D images of a cyclically moving organ, enabling therapy to be guided by synchronizing the 4D image with the actual organ motion in real time. The proposed method was implemented in an open‐configuration 0.5T clinical MR scanner. To evaluate the feasibility and determine optimal imaging conditions, studies were conducted with a phantom, volunteers, and a patient. In the phantom study the root mean square (RMS) position error in the 4D image of the cyclically moving phantom was 1.9 mm and the imaging time was ≈10 min when the 4D image had six frames. In the patient study, 4D images were successfully acquired under clinical conditions and a liver tumor was discriminated in the series of frames. The image quality was affected by the relations among the encoding direction, the slice orientation, and the direction of motion of the target organ. In conclusion, this study has shown that the proposed method is feasible and capable of providing a real‐time dynamic 3D atlas for surgical navigation with sufficient accuracy and image quality. Magn Reson Med 59:1051–1061, 2008. © 2008 Wiley‐Liss, Inc.