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Your search keyword '"Schakel, Tim"' showing total 8 results
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8 results on '"Schakel, Tim"'

2. Towards retrospective motion correction and reconstruction for clinical 3D brain MRI protocols with a reference contrast

Author

Rizzuti, Gabrio, Schakel, Tim, Huttinga, Niek R. F., Dankbaar, Jan Willem, van Leeuwen, Tristan, and Sbrizzi, Alessandro

Subjects
Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Motion artifacts often spoil the radiological interpretation of MR images, and in the most severe cases the scan needs be repeated, with additional costs for the provider. We discuss the application of a novel 3D retrospective rigid motion correction and reconstruction scheme for MRI, which leverages multiple scans contained in a MR session. Typically, in a multi-contrast MR session, motion does not equally affect all the scans, and some motion-free scans are generally available, so that we can exploit their anatomic similarity. The uncorrupted scan is used as a reference in a generalized rigid-motion registration problem to remove the motion artifacts affecting the corrupted scans. We discuss the potential of the proposed algorithm with a prospective in-vivo study and clinical 3D brain protocols. This framework can be easily incorporated into the existing clinical practice with no disruption to the conventional workflow.

Published
2023

5. Improved Delineation with Diffusion Weighted Imaging for Laryngeal and Hypopharyngeal Tumors Validated with Pathology

Author

Smits, Hilde J.G., primary, Raaijmakers, Cornelis P. J., additional, de Ridder, Mischa, additional, Gouw, Zeno A. R., additional, Doornaert, Patricia A. H., additional, Pameijer, Frank A., additional, Lodeweges, Joyce E., additional, Ruiter, Lilian N., additional, Kuijer, Koen M., additional, Schakel, Tim, additional, de Bree, Remco, additional, Dankbaar, Jan W., additional, Breimer, Gerben E., additional, Terhaard, Chris H.J., additional, Willems, Stefan M., additional, and Philippens, Marielle E. P., additional

Published
2024
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6. Towards retrospective motion correction and reconstruction for clinical 3D brain MRI protocols with a reference contrast

Author

Gabrio Rizzuti, Schakel, Tim, Huttinga, Niek R F, Dankbaar, Jan Willem, Van Leeuwen, Tristan, and Sbrizzi, Alessandro

Subjects
Image and Video Processing (eess.IV), FOS: Electrical engineering, electronic engineering, information engineering, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Motion artifacts often spoil the radiological interpretation of MR images, and in the most severe cases the scan needs be repeated, with additional costs for the provider. We discuss the application of a novel 3D retrospective rigid motion correction and reconstruction scheme for MRI, which leverages multiple scans contained in a MR session. Typically, in a multi-contrast MR session, motion does not equally affect all the scans, and some motion-free scans are generally available, so that we can exploit their anatomic similarity. The uncorrupted scan is used as a reference in a generalized rigid-motion registration problem to remove the motion artifacts affecting the corrupted scans. We discuss the potential of the proposed algorithm with a prospective in-vivo study and clinical 3D brain protocols. This framework can be easily incorporated into the existing clinical practice with no disruption to the conventional workflow.

Published
2023

8. Optimized flip angle schemes for the split acquisition of fast spin‐echo signals (SPLICE) sequence and application to diffusion‐weighted imaging.

Author

Rahbek, Sofie, Schakel, Tim, Mahmood, Faisal, Madsen, Kristoffer H., Philippens, Marielle E.P., and Hanson, Lars G.

Subjects
ECHO-planar imaging, DIFFUSION magnetic resonance imaging, STEREOTAXIC techniques, MAGNETIC resonance imaging
Abstract

Purpose: The diffusion‐weighted SPLICE (split acquisition of fast spin‐echo signals) sequence employs split‐echo rapid acquisition with relaxation enhancement (RARE) readout to provide images almost free of geometric distortions. However, due to the varying T2$$ {}_2 $$‐weighting during k‐space traversal, SPLICE suffers from blurring. This work extends a method for controlling the spatial point spread function (PSF) while optimizing the signal‐to‐noise ratio (SNR) achieved by adjusting the flip angles in the refocusing pulse train of SPLICE. Methods: An algorithm based on extended phase graph (EPG) simulations optimizes the flip angles by maximizing SNR for a flexibly chosen predefined target PSF that describes the desired k‐space density weighting and spatial resolution. An optimized flip angle scheme and a corresponding post‐processing correction filter which together achieve the target PSF was tested by healthy subject brain imaging using a clinical 1.5 T scanner. Results: Brain images showed a clear and consistent improvement over those obtained with a standard constant flip angle scheme. SNR was increased and apparent diffusion coefficient estimates were more accurate. For a modified Hann k‐space weighting example, considerable benefits resulted from acquisition weighting by flip angle control. Conclusion: The presented flexible method for optimizing SPLICE flip angle schemes offers improved MR image quality of geometrically accurate diffusion‐weighted images that makes the sequence a strong candidate for radiotherapy planning or stereotactic surgery. [ABSTRACT FROM AUTHOR]

Published
2023
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