Results 121 to 130 of about 5,501 (303)

Solving Elliptic Interface Problems with Jump Conditions on Cartesian Grids

, 2019
We present a simple numerical algorithm for solving elliptic equations where the diffusion coefficient, the source term, the solution and its flux are discontinuous across an irregular interface. The algorithm produces second-order accurate solutions and
Bochkov, Daniil, Gibou, Frederic
core   +1 more source

Fast and Robust Diffusion Posterior Sampling for MR Image Reconstruction Using the Preconditioned Unadjusted Langevin Algorithm

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose The Unadjusted Langevin Algorithm (ULA) in combination with diffusion models can generate high quality MRI reconstructions with uncertainty estimation from highly undersampled k‐space data. However, sampling methods such as diffusion posterior sampling (DPS) or likelihood annealing suffer from long reconstruction times and the need for
Moritz Blumenthal, Tina Holliber, Jonathan I. Tamir, Martin Uecker   +3 more
wiley   +1 more source

Navier-Stokes Prediction of the Effect of the Skids on the Aerodynamics of Helicopter Fuselage in Forward Flight

, 2006
A series of three-dimensional Navier-Stokes computations were carried out with and without skids to investigate the influence of the skids on the flow field and aerodynamic forces acting on a helicopter fuselage in low Mach number forward flight under ...
Khier, Walid
core  

Multiple‐TE Based Blood–Brain‐Barrier Water Exchange Time Measurement Using a TE‐Resolved 3D TSE Stack‐Of‐Spirals Readout

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To develop a slice‐wise blurring‐free and densely sampled TE‐resolved multiple‐TE (mTE) ASL sequence (TASL) for measuring blood–brain barrier (BBB) water exchange time. Methods A 3D TSE spiral‐readout pCASL sequence was modified to enable TE‐resolved acquisition.
Bo Li, Yiran Li, Xiao Liang, Amnah Mahroo, Manuel Taso, Marta Vidorreta Díaz de Cerio, Lucas Lemos Franco, Yulin Chang, María Asunción Fernández Seara, Matthias Günther, John A. Detre, Ze Wang   +11 more
wiley   +1 more source

BART Streams: Real‐Time Reconstruction Using a Modular Framework for Pipeline Processing

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To create modular solutions for interactive real‐time MRI using reconstruction algorithms implemented in BART. Methods A new protocol for streaming of multidimensional arrays is presented and integrated into BART. The new functionality is demonstrated using examples for cardiac interactive real‐time MRI based on radial FLASH, where ...
Philip Schaten, Moritz Blumenthal, Bernhard Rapp, Christina Unterberg‐Buchwald, Martin Uecker   +4 more
wiley   +1 more source

Vertex Spans of Multilayered Cycle and Path Graphs

Axioms
In this paper, we observe a special class of graphs known as multilayered graphs and their subclasses, namely multilayered cycles and multilayered paths.
Aljoša Šubašić, Tanja Vojković
doaj   +1 more source

Postprocessing‐based interpolation schemes for nested Cartesian finite difference grids of different size

, 2019
Nested Cartesian grid systems by design require interpolation of solution fields from coarser to finer grid systems. While several choices are available, preserving accuracy, stability, and efficiency at the same time require careful design of the ...
Figueroa, Alejandro, Rainald Löhner, Alejandro Figueroa, Lohner, Rainald   +3 more
core   +1 more source

Methods for Uncertainty Quantification in Dictionary Matching to Advance Reliability of Quantitative MRI

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Aims Purpose: Dictionary matching is a standard tool in quantitative MRI (qMRI), but typically lacks uncertainty quantification (UQ). This is critical when advanced reconstructions (e.g., compressed sensing, deep learning) introduce complex‐valued, spatially varying, and temporally correlated noise that violates standard assumptions of ...
Brian Toner, Ute Goerke, Eze Ahanonu, Kevin Johnson, Vibhas Deshpande, Holden H. Wu, Maria I. Altbach, Ali Bilgin   +7 more
wiley   +1 more source

Applications of Dynamic Cartesian Grids Method on Unsteady Flows Involving Moving Boundaries

, 2015
A mesh deformation algorithm for unstructured Cartesian grids is presented. Given a surface deformation, the method efficiently recalculates new locations of high aspect ratio cells that make up the viscous layers of the grid and then deforms the ...
Ji, Chuqun, Zhou, Weijiang, Liu, Xiaowen
core   +1 more source

Short Echo‐Time Spiral MRSI Versus Single‐Voxel Spectroscopy in the Human Brain at 3 Tesla With Semi‐LASER Localization

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Magnetic resonance spectroscopy techniques are widely used to non‐invasively study brain metabolism. Despite advances in magnetic resonance spectroscopic imaging (MRSI), there is a notable absence of research on comparing fast non‐Cartesian MRSI with single‐voxel spectroscopy (SVS), limiting our understanding of its performance and ...
Young Woo Park, Isaac M. Adanyeguh, Pierre‐Gilles Henry, Dinesh K. Deelchand   +3 more
wiley   +1 more source