Gadolinium-based contrast agents (GBCAs) are commonly used for enhancement in MR imaging and have long been considered safe when administered at recommended doses. However, since the report that ...nephrogenic systemic fibrosis is linked to the use of GBCAs in subjects with severe renal diseases, accumulating evidence has suggested that GBCAs are not cleared entirely from our bodies; some GBCAs are deposited in our tissues, including the brain. GBCA deposition in the brain is mostly linked to the specific chelate structure of the GBCA: linear GBCAs were responsible for brain deposition in almost all reported studies. This review aimed to summarize the current knowledge about GBCA brain deposition and discuss its clinical implications.
This study aims to examine how service employees' perceptions of corporate social responsibility (CSR) affect their creativity at work and its mediated link through compassion at work and their ...intrinsic motivation. Working with a sample of 250 hotel employees in South Korea, structural equation modeling is employed to test research hypotheses. The results of this research suggest that employees' perceptions of CSR are positively related to employee creativity. Second, compassion at work mediated the positive relationship between employees' perceptions of CSR and creativity. Third, employees' intrinsic motivation also mediated the positive relationship between employees' perceptions of CSR and employee creativity. Finally, the relationship between employees' perceptions of CSR and employee creativity is sequentially and fully mediated by compassion at work and their intrinsic motivation. The theoretical and managerial implications of the results and limitations of the study are discussed, and future research directions are suggested.
DCE-MRI provides information about vascular permeability and tissue perfusion through the acquisition of pharmacokinetic parameters. However, traditional methods for estimating these pharmacokinetic ...parameters involve fitting tracer kinetic models, which often suffer from computational complexity and low accuracy due to noisy arterial input function (AIF) measurements. Although some deep learning approaches have been proposed to tackle these challenges, most existing methods rely on supervised learning that requires paired input DCE-MRI and labeled pharmacokinetic parameter maps. This dependency on labeled data introduces significant time and resource constraints and potential noise in the labels, making supervised learning methods often impractical. To address these limitations, we present a novel unpaired deep learning method for estimating pharmacokinetic parameters and the AIF using a physics-driven CycleGAN approach. Our proposed CycleGAN framework is designed based on the underlying physics model, resulting in a simpler architecture with a single generator and discriminator pair. Crucially, our experimental results indicate that our method does not necessitate separate AIF measurements and produces more reliable pharmacokinetic parameters than other techniques.
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•Unpaired deep learning for estimating PK parameters using a physics-driven CyeleGAN.•The proposed CycleGAN framework is designed based on the physics model.•Our method does not necessitate AIF measurements and produces reliable PK parameters.
This study aims to investigate the effects of customers' perception of corporate social responsibility (CSR) on their CSR participation intention via customer–company identification (C–C ...identification). The authors also examine how CSR credibility strengthens the customers' CSR perception–C–C identification relationship and the indirect relationship between CSR perception and CSR participation intention through C–C identification. We conducted a survey of 567 South Korean bank customers and performed structural equation modeling to test our hypotheses. C–C identification partially mediated the relationship between customers' CSR perception and CSR participation intention. The positive association between customers' CSR perception and C–C identification was more pronounced when CSR credibility was higher than when it was lower. CSR credibility further moderated the indirect effect of customers' CSR perception and CSR participation intention through C‐C identification. This study deepens CSR research by showing how a cognitive CSR perception leads to a behavioral CSR participation based on a research model.
Purpose
To demonstrate robust myelin water fraction (MWF) mapping using an artificial neural network (ANN) with multi‐echo gradient‐echo (GRE) signal.
Methods
Multi‐echo gradient‐echo signals ...simulated with a three‐pool exponential model were used to generate the training data set for the ANN, which was designed to yield the MWF. We investigated the performance of our proposed ANN for various conditions using both numerical simulations and in vivo data. Simulations were conducted with various SNRs to investigate the performance of the ANN. In vivo data with high spatial resolutions were applied in the analyses, and results were compared with MWFs derived by the nonlinear least‐squares algorithm using a complex three‐pool exponential model.
Results
The network results for the simulations show high accuracies against noise compared with nonlinear least‐squares MWFs: RMS‐error value of 5.46 for the nonlinear least‐squares MWF and 3.56 for the ANN MWF at an SNR of 150 (relative gain = 34.80%). These effects were also found in the in vivo data, with reduced SDs in the region‐of‐interest analyses. These effects of the ANN demonstrate the feasibility of acquiring high‐resolution myelin water images.
Conclusion
The simulation results and in vivo data suggest that the ANN facilitates more robust MWF mapping in multi‐echo gradient‐echo sequences compared with the conventional nonlinear least‐squares method.
While contrast‐enhanced fluid‐attenuated inversion recovery (FLAIR) has long been regarded as an adjunct sequence to evaluate leptomeningeal disease in addition to contrast‐enhanced T1‐weighted ...imaging, it is gradually being used for more diverse pathologies beyond leptomeningeal disease. Contrast‐enhanced FLAIR is known to be highly sensitive to low concentrations of gadolinium within the fluid. Accordingly, recent research has suggested the potential utility of contrast‐enhanced FLAIR in various kinds of disease, such as Meniere's disease, seizure, stroke, traumatic brain injury, and brain metastasis, in addition to being used for visualizing glymphatic dysfunction. However, its potential applications have been reported sporadically in an unorganized manner. Furthermore, the exact mechanism for its superior sensitivity to low concentrations of gadolinium has not been fully understood. Rapidly developing magnetic resonance technology and unoptimized parameters for FLAIR may challenge its accurate application in clinical practice. This review provides the fundamental mechanism of contrast‐enhanced FLAIR, systematically describes its current and potential clinical application, and elaborates on technical considerations for its optimization.
Level of Evidence
3
Technical Efficacy Stage
5
Emerging evidence suggests that the excessive accumulation of iron in subcortical and deep gray matter has been related to dementia. However, the presence and pattern of iron accumulation in vascular ...dementia (VaD) and Alzheimer's disease (AD) are rarely investigated.
To examine and compare the pattern and presence of brain iron accumulation of VaD and AD using quantitative susceptibility mapping (QSM).
Twelve patients with VaD, 27 patients with AD, and 18 control subjects were recruited in this institutional review-board approved study. Susceptibility maps were reconstructed from a three-dimensional multiecho spoiled gradient-echo sequence. Four regions of interest were drawn manually on QSM images, namely the globus pallidus, putamen, caudate nucleus, and pulvinar nucleus of the thalamus. Comparisons of patient demographics, and iron concentrations among the VaD, AD, and control subjects were assessed using analysis of variance and post-hoc analyses. The relationships of age and cognitive state with susceptibility values were assessed using partial correlation analysis.
In VaD and AD, overall susceptibility values were higher than those of control subjects. A significant difference in susceptibility values was found in the putamen and caudate nucleus (p < 0.001 and p = 0.002, respectively). However, susceptibility values did not differ between VaD and AD. Age and cognitive deficit severity were not related to susceptibility values in the VaD and AD groups.
Increased iron deposition in the putamen and caudate nucleus in VaD and AD patients was not associated with age or the severity of cognitive deficits. Further evaluations are needed to determine the temporal changes in iron load and their diagnostic role in dementia pathology.
The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid ...nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.
The aim of the study is to test not only the relative importance effect of employees' external and internal corporate social responsibility (CSR) perceptions on prosocial and proactive behaviors ...(i.e., organizational citizenship behavior OCB and job crafting) but also the impact of the interaction of these two kinds of employee CSR perceptions on proactive behaviors. Survey‐based data were collected from 181 employees at eight luxury hotels located in South Korea. Using a two‐wave longitudinal design, we measured employees' internal and external CSR perceptions, and then their supervisors rated OCB and job crafting one month after. Hierarchical moderated regression model is employed to test research hypotheses. The results showed that employees' internal CSR perceptions are more strongly related to prosocial and proactive behaviors than employees' external CSR perceptions are. Furthermore, the positive relationship between internal CSR perceptions and prosocial and proactive behaviors was more pronounced when external CSR perceptions were high than when they were low. The theoretical and managerial implications of the results and the limitations of the study are discussed, and future research directions are suggested.
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