Searched for: subject%3A%22Low%255C-field%255C%2BMRI%22
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Bekkering, Aleid (author)
MRI has been used worldwide as an imaging modality for decades due to its ability to distinguish between soft tissues. However, MRIs cannot be used in all situations due to their extensive hard- and software. For this reason, research in the field of low-field MRI has been conducted. Low-field MRI systems do not use superconducting magnets but...
master thesis 2022
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Shan, X. (author), van Gijzen, M.B. (author)
We study efficient implicit methods to denoise low-field MR images using a nonlinear diffusion operator as a regularizer. This problem can be formulated as solving a nonlinear reaction–diffusion equation. After discretization, a lagged-diffusion approach is used which requires a linear system solve in every nonlinear iteration. The choice of...
journal article 2022
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van der Werff, Karen (author)
Magnetic Resonance Imaging (MRI) is a non-invasive, non-ionizing imaging modality that is commonly used in the clinic today. However, it is an expensive technique. The high purchase, operational and maintenance costs, as well as the need for trained staff with technical expertise, put this technique out of reach for a large part of the world...
master thesis 2021
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de Vos, B. (author), Parsa, Javad (author), Abdulrazaq, Zaynab (author), Teeuwisse, Wouter M. (author), Van Speybroeck, Camille D.E. (author), de Gans, D.H. (author), Remis, R.F. (author), O’Reilly, Tom (author), Webb, A. (author)
Low-field permanent magnet-based MRI systems are finding increasing use in portable, sustainable and point-of-care applications. In order to maximize performance while minimizing cost many components of such a system should ideally be designed specifically for low frequency operation. In this paper we describe recent developments in...
journal article 2021
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de Leeuw den Bouter, M.L. (author), van Gijzen, M.B. (author), Remis, R.F. (author)
In this paper we present a magnetic resonance imaging (MRI) technique that is based on multiplicative regularization. Instead of adding a regularizing objective function to a data fidelity term, we multiply by such a regularizing function. By following this approach, no regularization parameter needs to be determined for each new data set...
journal article 2021
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de Leeuw den Bouter, M.L. (author), van den Berg, P.M. (author), Remis, R.F. (author)
In this paper we discuss an imaging method when the object has known support and its spatial Fourier transform is only known on a certain k-space undersampled pattern. The simple conjugate gradient least squares algorithm applied to the corresponding truncated Fourier transform equation produces reconstructions that are basically of a similar...
journal article 2021
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Ahishakiye, Emmanuel (author), van Gijzen, M.B. (author), Shan, X. (author), Tumwiine, Julius (author), Obungoloch, Johnes (author)
Currently, many children with hydrocephalus in East Africa and other resource-constrained countries do not have access to Magnetic Resonance Imaging (MRI) scanners, the preferred imaging tool during the disease administration and treatment. Conventional MRI scanners are costly to buy and manage, which limits their utilization in low-income...
conference paper 2021
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O’Reilly, Thomas (author), Teeuwisse, Wouter M. (author), de Gans, D.H. (author), Koolstra, Kirsten (author), Webb, A. (author)
Purpose: To design a low-cost, portable permanent magnet-based MRI system capable of obtaining in vivo MR images within a reasonable scan time. Methods: A discretized Halbach permanent magnet array with a clear bore diameter of 27 cm was designed for operation at 50 mT. Custom-built gradient coils, RF coil, gradient amplifiers, and RF...
journal article 2021
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de Leeuw den Bouter, M.L. (author), Gecmen, Dilan (author), Meijer, Angeline (author), de Gans, D.H. (author), Middelplaats, L.N.M. (author), Remis, R.F. (author), van Gijzen, M.B. (author)
More than 6,000 infants develop hydrocephalus in East Africa every year. Magnetic Resonance Imaging is the preferred technique to diagnose hydrocephalus. In countries such as Uganda, MRI is unaffordable at even major referral hospitals. In order to provide a sustainable diagnostic tool we are developing an inexpensive and easy-to-use MRI...
conference paper 2020
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Ahishakiye, Emmanuel (author), van Gijzen, M.B. (author), Tumwiine, Julius (author), Obungoloch, Johnes (author)
Background: Magnetic resonance imaging (MRI) is a safe non-invasive and nonionizing medical imaging modality that is used to visualize the structure of human anatomy. Conventional (high-field) MRI scanners are very expensive to purchase, operate and maintain, which limit their use in many developing countries. This study is part of a project...
journal article 2020
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Ahishakiye, Emmanuel (author), van Gijzen, M.B. (author), Tumwiine, Julius (author), Obungoloch, Johnes (author)
Objective: Image denoising has been considered as a separate procedure from image reconstruction which could otherwise be combined with acquisition and reconstruction. This paper discusses a joint image reconstruction and denoising algorithm in low-field MRI using a dictionary learning approach. Method: Our proposed algorithm uses a two-level...
conference paper 2020
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de Leeuw den Bouter, M.L. (author), van Gijzen, M.B. (author), Remis, R.F. (author)
We consider the MRI physics in a low-field MRI scanner, in which permanent magnets are used to generate a magnetic field in the millitesla range. A model describing the relationship between measured signal and image is derived, resulting in an ill-posed inverse problem. In order to solve it, a regularization penalty is added to the least...
journal article 2019
Searched for: subject%3A%22Low%255C-field%255C%2BMRI%22
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