Ultra-fast multi-parametric 4D-MRI image reconstruction for real-time applications using a downsampling-invariant deformable registration (D2R) model.

Background And Purpose: Motion estimation from severely downsampled 4D-MRI is essential for real-time imaging and tumor tracking. This simulation study developed a novel deep learning model for simultaneous MR image reconstruction and motion estimation, named the Downsampling-Invariant Deformable Registration (D2R) model.

Materials And Methods: Forty-three patients undergoing radiotherapy for liver tumors were recruited for model training and internal validation.

Joint k-TE Space Image Reconstruction and Data Fitting for T2 Mapping.

Objectives: To develop a joint k-TE reconstruction algorithm to reconstruct the T2-weighted (T2W) images and T2 map simultaneously.

Materials And Methods: The joint k-TE reconstruction model was formulated as an optimization problem subject to a self-consistency condition of the exponential decay relationship between the T2W images and T2 map. The objective function included a data fidelity term enforcing the agreement between the solution and the measured k-space data, together with a spatial regularization term on image properties of the T2W images.

Photothermal Thin Films with Highly Efficient NIR Conversion for Miniaturized Liquid-Crystal Elastomer Actuators.

This work presents the development of highly efficient photothermal thin films (PTFs) and the demonstration of their application on miniaturized polymer-based soft actuators. The proposed PTF, which comprises acrylic-based black paint and EGaIn liquid metal (LM) microdroplets, serves as an excellent absorber for efficiently converting near-infrared (NIR) irradiation into heat for actuating liquid-crystal elastomer (LCE) actuators. The introduction of LM microdroplets into the PTFs effectively increases the overall thermal efficiency of PTFs.

Optimal Model Mapping for Intravoxel Incoherent Motion MRI.

In general, only one diffusion model would be applied to whole field-of-view voxels in the intravoxel incoherent motion-magnetic resonance imaging (IVIM-MRI) study. However, the choice of the applied diffusion model can significantly influence the estimated diffusion parameters. The quality of the diffusion analysis can influence the reliability of the perfusion analysis.

Quantitative Comparison of Virtual Monochromatic Images of Dual Energy Computed Tomography Systems: Beam Hardening Artifact Correction and Variance in Computed Tomography Numbers: A Phantom Study.

Objective: The aim of this study was to quantitatively compare the reduction in beam hardening artifact (BHA) and variance in computed tomography (CT) numbers of virtual monochromatic energy (VME) images obtained with 3 dual-energy computed tomography (DECT) systems at a given radiation dose.

Methods: Five different iodine concentrations were scanned using dual-energy and single-energy (120 kVp) modes. The BHA and CT number variance were evaluated.

BDNF Val66Met Polymorphism on Functional MRI During n-Back Working Memory Tasks.

Val66Met polymorphism on the brain-derived neurotrophic factor (BDNF) gene is associated with hippocampal pathology and impaired episodic memory. However, the influence of this polymorphism on working memory (WM) performance and patterns of brain activation is controversial. This study investigated the effects of BDNF Val66Met polymorphism on functional magnetic resonance imaging (fMRI) during n-back WM tasks in healthy middle-aged adults.

Working memory in patients with mild traumatic brain injury: functional MR imaging analysis.

Purpose: To analyze brain activation patterns in response to tests of working memory after a mild traumatic brain injury (MTBI).

Materials And Methods: Research ethics committee approval and patient written informed consent were obtained. Brain activation patterns in response to n-back working memory tasks (n = 1, 2, 3) were assessed with functional magnetic resonance (MR) imaging in 20 patients with MTBI within 1 month after their injury and in 18 healthy control subjects.

Study of onset time-shift and injection duration in DCE-MRI: a comparison of a reference region model with the general kinetic model.

In dynamic contrast-enhanced MR imaging (DCE-MRI), sampling of the arterial input function (AIF) is required for analysis using the general kinetic model (GKM). Alternatively, the recently proposed reference region model (RRM) may be employed to avoid the need of acquiring the AIF. This study aimed to evaluate the influence of the AIF onset-time shift and the injection duration, under various sampling intervals, on physiological parameter estimation in DCE-MRI using the GKM, and to compare the performance between GKM and RRM.