FijiRelax: Fast and noise-corrected estimation of MRI
relaxation maps in 3D + t

Fernandez, Romain; Moisy, Cédric

doi:10.21105/joss.04981

Cited by 1 publication

(4 citation statements)

References 9 publications

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“…All simulations were performed on a server running Ubuntu 20.04.2 LTS operating system, with an Intel(R) Xeon(R) Gold 6248R CPU at 2.70GHz, 112 cores, 2 threads per core, and an NVIDIA A100 PCIe GPU with 40GB of memory. We used our custom integral equation methods which borrow some routines from the open‐source software MARIE 10 . The VIE was solved with the aid of the higher‐order singular value decomposition (HOSVD), 13 and the VSIE with the aid of the precorrected fast Fourier transform 51 .…”

Section: Methodsmentioning

confidence: 99%

“…We used our custom integral equation methods which borrow some routines from the open-source software MARIE. 10 The VIE was solved with the aid of the higher-order singular value decomposition (HOSVD), 13 and the VSIE with the aid of the precorrected fast Fourier transform. 51 Both integral equations were solved with the generalized minimal residual algorithm (GMRES) 52 and tolerance 1e − 5.…”

Section: Simulation Settingsmentioning

confidence: 99%

“…Finally, another recent study suggested that the shape of the ICP depends mainly on the topology of the current‐bearing surface, rather than the geometry of the sample 18 . In order to confirm such a hypothesis, and also to provide a practical tool for RF coil design and performance assessment, in this work, we introduce a method to calculate ICP associated with optimal SNR in realistic heterogeneous human head models, using volume 25 and volume‐surface 10 integral equation (VIE, VSIE) methods. Numerical methods to calculate the optimal SNR in heterogeneous head models were proposed in previous studies, 26,27 whereas this work focuses on deriving the corresponding ICP.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7] As the number of RF coil elements increases, so does the prototyping cost of the array. For this reason, electromagnetic (EM) simulations [8][9][10][11] are often used to optimize coil designs before building prototypes. However, despite the use of parallel computing 12 and GPU programming, 13 these simulations remain time consuming, which makes a thorough optimization of complex designs challenging.…”

Section: Introductionmentioning

confidence: 99%

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Computational methods for the estimation of ideal current patterns in realistic human models

Giannakopoulos,

Georgakis,

Sodickson

et al. 2023

Magnetic Resonance in Med

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PurposeTo introduce a method for the estimation of the ideal current patterns (ICP) that yield optimal signal‐to‐noise ratio (SNR) for realistic heterogeneous tissue models in MRI.Theory and MethodsThe ICP were calculated for different surfaces that resembled typical radiofrequency (RF) coil formers. We constructed numerical electromagnetic (EM) bases to accurately represent EM fields generated by RF current sources located on the current‐bearing surfaces. Using these fields as excitations, we solved the volume integral equation and computed the EM fields in the sample. The fields were appropriately weighted to calculate the optimal SNR and the corresponding ICP. We demonstrated how to qualitatively use ICP to guide the design of a coil array to maximize SNR inside a head model.ResultsIn agreement with previous analytic work, ICP formed large distributed loops for voxels in the middle of the sample and alternated between a single loop and a figure‐eight shape for a voxel 3‐cm deep in the sample's cortex. For the latter voxel, a surface quadrature loop array inspired by the shape of the ICP reached of the optimal SNR at 3T, whereas a single loop placed above the voxel reached only of the optimal SNR. At 7T, the performance of the two designs decreased to and , respectively, suggesting that loops could be suboptimal at ultra‐high field MRI.ConclusionICP can be calculated for human tissue models, potentially guiding the design of application‐specific RF coil arrays.

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Section: Methodsmentioning

confidence: 99%