Biomedical subjects

Yasheng Chen

Publications and source records attributed to Yasheng Chen.

4 recordsLinked to original sources

PubMed2026

Proteomic profiling identifies systemic drivers of blood-brain barrier injury in sickle cell disease.

Sickle cell disease (SCD) causes brain injury and cognitive disability. Systemic inflammation and endothelial injury are central to SCD pathophysiology, yet the relationship between systemic drivers of blood-brain barrier (BBB) disruption and brain injury remains understudied. This cross-sectional study assessed whole-brain and regional BBB permeability (Ktrans) using dynamic contrast-enhanced magnetic resonance imaging for 37 adults with SCD in steady state and 37 adults without SCD. Cerebral oxygen extraction fraction (OEF) and white matter mean diffusivity (MD) measured tissue hypoxia and microstructural injury, respectively. The SCD cohort showed elevated Ktrans compared with controls (3.6 × 10-4·min-1 vs 2.58 × 10-4·min-1; 95% confidence interval [CI] median difference, 0.36 × 10-4·min-1 to 1.30 × 10-4·min-1; P< .001), indicating BBB disruption. In SCD, white matter Ktrans was associated with MD (β, 6.25 [95% CI, 1.72-10.77]; P = .008), independent of OEF (β, 0.22 [95% CI, 0.09-0.35]), and silent cerebral infarcts (β, 0.01 [95% CI, 0.00-0.02]). The interaction (P = .037) between Ktrans and OEF on MD suggested a combined, deleterious effect of BBB disruption and hypoxia on microstructural injury. High-throughput plasma proteomics followed by differential expression analysis, and weighted gene correlation network analysis in a subset of 61 participants revealed that 79 proteins associated with BBB permeability belonged to iron homeostasis, response to hypoxia, immune dysregulation, extracellular matrix degradation, lipoprotein homeostasis, and arginine-proline metabolism pathways. All pathways were independently associated with microstructural injury. BBB permeability was a mediator of brain injury for all pathways except extracellular matrix degradation. Targeting specific systemic pathways to protect the BBB may represent a therapeutic approach to preserve brain health in SCD.

Humans↗

PubMed2004

Neuroimaging in human immunodeficiency virus infection.

Human immunodeficiency virus (HIV) is associated with central nervous system (CNS) changes that may affect cerebral blood flow (CBF), metabolism, structure, and diffusion. Each of the available neuroimaging techniques offers unique insight into the neural mechanisms underlying HIV, as well as a potential means of monitoring disease progression and treatment response. The purpose of the article is to provide a review of experimental studies evaluating changes related to HIV with imaging techniques, including single-photon emission computed tomography (SPECT), positron emission tomography (PET), volumetric magnetic resonance imaging (MRI), functional MRI (fMRI), magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), and perfusion MRI (pMRI).

AIDS Dementia Complex↗

PubMed2003

Practical consideration for 3T imaging.

In the past 10 to 15 years, 1.5T has been one of the most commonly used field strengths for day-to-day clinical operations. However, recent advances in high field technology and the increased availability of high field (> 1.5T) human scanners have opened the doors for a variety of exciting improvements in clinical and research applications of MR imaging. In particular, 3T has continued to gain wide acceptance as one of the main field strengths for clinical and research studies. Therefore, in this article the authors focus on the pros and cons of 3T imaging and comparisons between results obtained at 3T and 1.5T.

Brain↗

PubMed2002

A MAP framework for tag line detection in SPAMM data using Markov random fields on the B-spline solid.

Magnetic resonance (MR) tagging is a technique for measuring heart deformations through creation of a stripe grid pattern on cardiac images. In this paper, we present a maximum a posteriori (MAP) framework for detecting tag lines using a Markov random field (MRF) defined on the lattice generated by three-dimensional (3-D) and four-dimensional (4-D) (3-D + t) uniform sampling of B-spline models. In the 3-D case, MAP estimation is cast for detecting present tag features in the current image given an initial solid from the previous frame (the initial undeformed solid is manually positioned by clicking on corner points of a cube). The method also allows the parameters of the solid model, including the number of knots and the spline order, to be adjusted within the same framework. Fitting can start with a solid with less knots and lower spline order and proceed to one with more knots and/or higher order so as to achieve more accuracy and/or higher order of smoothness. In the 4-D case, the initial model is considered to be the linear interpolation of a sequence of optimal solids obtained from 3-D tracking. The same framework proposed for the 3-D case can once again be applied to arrive at a 4-D B-spline model with a higher temporal order.

Heart↗