Quantitative MR-perfusion and -diffusion imaging in a case study of CNS-lymphomas under therapy

Abstract Post-mortem in situ MRI has been used as an intermediate between brain histo(patho)logy and in vivo imaging. However, it is not known how comparable post-mortem in situ is to ante-mortem imaging. We report the unique situation of a patient with familial early-onset Alzheimer’s disease due to a PSEN1 mutation, who underwent ante-mortem brain MRI and post-mortem in situ imaging only 4 days apart. T1-weighted and diffusion MRI was performed at 3-Tesla at both time points. Visual atrophy rating scales, brain volume, cortical thickness and diffusion measures were derived from both scans and compared. Post-mortem visual atrophy scores decreased 0.5–1 point compared with ante-mortem, indicating an increase in brain volume. This was confirmed by quantitative analysis; showing a 27% decrease of ventricular and 7% increase of whole-brain volume. This increase was more pronounced in the cerebellum and supratentorial white matter than in grey matter. Furthermore, axial and radial diffusivity decreased up to 60% post-mortem whereas average fractional anisotropy of white matter increased approximately 10%. This unique case study shows that the process of dying affects several imaging markers. These changes need to be taken into account when interpreting post-mortem MRI to make inferences on the in vivo situation.

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How Does the Spatial Structure of High-Speed Rail Station Areas Evolve? A Case Study of Zhengzhou East Railway Station, China

Applied Sciences ◽

10.3390/app112311132 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11132

Author(s):

Xiaomin Wang ◽

Jingyu Liu ◽

Wenxin Zhang

Keyword(s):

Spatial Structure ◽

High Speed ◽

Rapid Development ◽

Economic Activities ◽

Land Rent ◽

High Speed Rail ◽

Production Factors ◽

Market Factors ◽

And Diffusion

The rapid development of high-speed rail (HSR) and station areas has shortened the spatial and temporal distances among cities, improved the accessibility of cities, and affected the spatial agglomeration and diffusion of populations and of social and economic activities. This has led to spatial reconfiguration of production factors within cities, which has the potential to drive the reconstruction of urban spatial structures. Based on POI and land-use data, this paper defines the spatial scope of the HSR station area and explores the characteristics and influencing factors of its spatial structure from the perspective of industry. The study area i is set at 2000 m. Since the opening of the HSR, the industrial distribution has exhibited a significant circular, multi-core, and axial belt spatial structure. The spatial structure of each sub-industry is different. On the whole, internal and external transport and agglomeration economies have significant impacts on the industrial spatial distribution, and land rent has gradually decreased in importance with the development of HSR station areas. The intensity of the effects of different factors varies among different industries. The mechanisms by which the spatial structure of the station area is formed are discussed and include location accessibility, micro-market factors, node station attributes, the availability of a sufficient amount of undeveloped land, the characteristics and needs of HSR passengers, and policies and systems.

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