Xiaopeng Zong

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The amide proton transfer (APT) effect has emerged as a unique endogenous molecular imaging contrast mechanism with great clinical potentials. However, in vivo quantitative mapping of APT using the conventional asymmetry analysis is difficult due to the confounding nuclear Overhauser effect (NOE) and the asymmetry of the magnetization transfer effect. Here,(More)
BACKGROUND Certain patterns can induce perceptual illusions/distortions and visual discomfort in most people, headaches in patients with migraine, and seizures in patients with photosensitive epilepsy. Visual stimuli are common triggers for migraine attacks, possibly because of a hyperexcitability of the visual cortex shown in patients with migraine.(More)
This article describes the effects of dexmedetomidine (DEX) - the active ingredient of medetomidine, which is the latest popular sedative for functional magnetic resonance imaging (fMRI) in rodents - on multiple unit activity, local field potential (LFP), cerebral blood flow (CBF), pial vessel diameter [indicative of cerebral blood volume (CBV)], and blood(More)
Chemical exchange between water and labile protons from amino-acids, proteins and other molecules can be exploited to provide tissue contrast with magnetic resonance imaging (MRI) techniques. Using an off-resonance Spin-Locking (SL) scheme for signal preparation is advantageous because the image contrast can be tuned to specific exchange rates by adjusting(More)
Blood-oxygenation-level-dependent (BOLD) fMRI has contributions from venous oxygenation and venous cerebral blood volume (CBV) changes. To examine the relative contribution of venous CBV change (ΔCBV(v)) to BOLD fMRI, BOLD and arterial CBV changes (ΔCBV(a)) to a 40-s forepaw stimulation in six α-chloralose anesthetized rats were measured using a(More)
Quantitative study of perivascular spaces (PVSs) in brain magnetic resonance (MR) images is important for understanding the brain lymphatic system and its relationship with neurological diseases. One of the major challenges is the accurate extraction of PVSs that have very thin tubular structures with various directions in three-dimensional (3D) MR images.(More)
Compressed sensing (CS) may be useful for accelerating data acquisitions in high-resolution fMRI. However, due to the inherent slow temporal dynamics of the hemodynamic signals and concerns of potential statistical power loss, the CS approach for fMRI (CS-fMRI) has not been extensively investigated. To evaluate the utility of CS in fMRI application, we(More)
Noninvasive imaging of perivascular spaces (PVSs) may provide useful insights into their role in normal brain physiology and diseases. Fast MRI sequences with sub-millimeter spatial resolutions and high contrast-to-noise ratio (CNR) are required for accurate delineation of PVS in human. To achieve the optimal condition for PVS imaging at 7T, we carried out(More)
PURPOSE Amide-proton transfer (APT) and amine-water proton exchange (APEX) MRI can be viable to map pH-decreasing ischemic regions. However, their exact contributions are unclear. METHODS We measured APEX- and APT-weighted magnetization transfer ratio asymmetry (denoted as APEXw and APTw), apparent diffusion coefficient, T2 , and T1 images and localized(More)
PURPOSE To evaluate the magnetic susceptibility properties of different anatomical structures within the knee joint using quantitative susceptibility mapping (QSM). METHODS A collagen tissue model was simulated and ex vivo animal cartilage experiments were conducted at 9.4 Tesla (T) to evaluate the B0 orientation-dependent magnetic susceptibility contrast(More)