Results 161 to 170 of about 6,885 (267)

Application of Time-Domain Full Waveform Inversion to Cross-Hole Radar Data Measured at Xiuyan Jade Mine, China. [PDF]

Sensors (Basel), 2018
Liu S, Liu X, Meng X, Fu L, Lu Q, Deng L.   +5 more
europepmc   +1 more source

Beyond Directions: Symmetry‐Aware Rotation Sets for Triaxial Diffusion Encoding by Geometric Filter Optimization

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To improve the accuracy of diffusion‐weighted powder average signals for diffusion encoding with arbitrary b‐tensors. Methods We identify an intrinsic dihedral (D2$$ {D}_2 $$) symmetry of diffusion signals for arbitrary diffusion encoding, which defines their natural signal space (a quotient of 3D rotations).
Sune Nørhøj Jespersen, Filip Szczepankiewicz   +1 more
wiley   +1 more source

Dependence of the Extra‐Cellular Diffusion Coefficient on the Fractions of Neurites and Cell Bodies in Gray Matter

Magnetic Resonance in Medicine, EarlyView.
Purpose The dependence of the long‐time (tortuosity) limit of the extra‐cellular diffusivity on the intra‐cellular volume fraction is of fundamental importance for microstructure modeling. While such dependencies have been explored for the white matter, the tortuosity limit in gray matter is unknown due to complex cell composition and geometry. Here we
Hong‐Hsi Lee, Ali Abdollahzadeh, Hansol Lee, Ricardo Coronado‐Leija, Els Fieremans, Susie Y. Huang, Dmitry S. Novikov   +6 more
wiley   +1 more source

Fast Localized Calibration for Spatial‐Spectral Excitation Without Fly‐Back Gradients

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Standard spatial‐spectral excitation pulses apply a fly‐back gradient between sub‐pulses, limiting, for example, how thin the slices can be (> 4 mm). Without fly‐back gradients, slices can be as thin as 1.7 mm but require a phase calibration for the sub‐pulses with inverted gradients due to system imperfections.
Michael Schär, Sandeep K. Ganji, Robert G. Weiss, Allison G. Hays   +3 more
wiley   +1 more source

Comparative Performance Analysis of an Open Source Motion‐Compensated Cardiac Diffusion Sequence Across Different MRI Systems and Gradient Strengths—A Pilot Study

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose To validate the performance of an open‐source cardiac diffusion sequence framework and to investigate hardware‐based performance differences. Methods Three second order motion compensated sequence files were compiled using Pulseq and applied across different MRI systems to image five volunteers.
Eric Arbes, Ariel Hannum, Johannes Fischer, Qingping Chen, Sebastian Littin, Alexander Maier, Michael Bock, Simon Reiss   +7 more
wiley   +1 more source

Waveform inversion with source encoding for breast sound speed reconstruction in ultrasound computed tomography. [PDF]

IEEE Trans Ultrason Ferroelectr Freq Control, 2015
Wang K, Matthews T, Anis F, Li C, Duric N, Anastasio MA.   +5 more
europepmc   +1 more source

Calibration‐Free Estimation of Cerebrovascular Reactivity From Resting‐State BOLD fMRI Using Reconstructed Respiratory Fluctuations

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Cerebrovascular reactivity (CVR) provides an important index of vascular health and is conventionally quantified using a hypercapnic gas or breath‐hold challenge in conjunction with blood‐oxygen‐level‐dependent functional magnetic resonance imaging (BOLD‐fMRI).
Abdoljalil Addeh, Ethan Church, Muhammad Mahajna, Karen Ardila, Pattarawut Charatpangoon, Alexander D. Cohen, Yang Wang, Rebecca J. Williams, G. Bruce Pike, M. Ethan MacDonald   +9 more
wiley   +1 more source

Incomplete Spoiling Correction for 3D T1$$ {T}_1 $$ Mapping

Magnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose Assess the impact of incomplete spoiling and spatial saturation on T1$$ {T}_1 $$ mapping using the variable flip angle (VFA) spoiled gradient recalled echo sequence (SPGR). Develop a correction for incomplete spoiling that results in an accurate estimate of T1$$ {T}_1 $$, essential for quantitative MRI applications.
Gabriela Belsley, Damian J. Tyler, Matthew D. Robson, Elizabeth M. Tunnicliffe   +3 more
wiley   +1 more source

Estimating the critical angle of top near‐surface layers on the Moon

Near Surface Geophysics, EarlyView.
Abstract Near‐surface characterization of the lunar subsurface is essential for future exploration and infrastructure development, particularly for the construction of underground habitats that provide protection against radiation and micrometeorites. However, conventional seismic approaches for estimating subsurface properties typically rely on prior ...
Nelson Ricardo Coelho Flores Zuniga, Deyan Draganov   +1 more
wiley   +1 more source