Magnetic Resonance Imaging (MRI)

Ultrasound-triggered phase transition sensitive magnetic fluorescent nanodroplets as a multimodal imaging contrast agent in rat and mouse model

Ultrasound-triggered phase transition sensitive nanodroplets with multimodal imaging functionality were prepared via premix Shirasu porous glass (SPG) membrane emulsification method. The nanodroplets with fluorescence dye DiR and SPIO nanoparticles (DiR-SPIO-NDs) had a polymer shell and a liquid perfluoropentane (PFP) core. The as-formed DiR-SPIO-NDs have a uniform size of 385 ± 5.0 nm with PDI of 0.169 ± 0.011. The TEM and microscopy imaging showed that the DiR-SPIO-NDs existed as core-shell spheres, and DiR and SPIO nanoparticles dispersed in the shell or core.

Publication Type: 
Journal Articles
Journal: 
PLoS One

Facilitation of postischemic reperfusion with alpha-PBN: assessment using NMR and Doppler flow techniques

We examined the effects of the free radical spin trap N-tert-butyl-alpha-phenylnitrone (PBN) on focal cerebral ischemia/reperfusion injury in halothane-anesthetized rats. Ninety minutes after middle cerebral artery occlusion by an intraluminal filament, the artery was reperfused. Intravenous injections of 25 mg/kg PBN 5 min before and 30 min after insertion of the filament significantly attenuated the lesion volume measured 24 h after ischemia.

Publication Type: 
Journal Articles
Journal: 
Am J Physiol

Neural correlates of motor impairment during motor imagery and motor execution in sub-cortical stroke

OBJECTIVE: This study aims at identifying the neural substrates for motor execution (ME) and motor imagery (MI) in patients after stroke and their correlations with functional outcomes.
METHODS: 10 chronic stroke patients with left sub-cortical lesions and 10 unimpaired subjects were recruited. Their cortical processes were studied when they were asked to perform ME and MI unimanually using their unaffected and affected wrists during fMRI.

Publication Type: 
Journal Articles
Journal: 
Brain Inj

Neuroanatomy of adult strabismus: a voxel-based morphometric analysis of magnetic resonance structural scans

Cerebral deficit has been implicated in the genesis of strabismus and in the mechanisms adopted to compensate for the visual disorder. Voxel-based morphometry (VBM) was applied to magnetic resonance images of strabismic adults to detect any abnormal brain anatomy, which could not be easily identified by simple inspection. The gray matter volume in strabismic adults was smaller than that in normal subjects at the areas consistent with the occipital eye field (OEF) and parietal eye field (PEF).

Publication Type: 
Journal Articles
Journal: 
Neuroimage

Hierarchical coding of characters in the ventral and dorsal visual streams of Chinese language processing

Functional and spatial hierarchical organization of increasingly language-like word forms has been proposed for alphabetic languages at the occipitotemporal cortex for visual word recognition. In the logographic Chinese language system, similar functional and spatial hierarchical presentations of brain responses to sublexical orthographic structure are beginning to be explored. In this study, we used whole-brain fMRI to show that a hierarchical coding of increasingly language-like character type is present in multiple Chinese language processing areas.

Publication Type: 
Journal Articles
Journal: 
Neuroimage

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity.

Publication Type: 
Journal Articles
Journal: 
Hum Brain Mapp

Can Cantonese rhymes be used in the assessment of hemispheric dominance for language?

English vowels had been proposed in previous studies to be used as a simple tool for the brain mapping of language. A proper fMRI study of Cantonese rhymes, each of which being a required and fundamental unit of a Cantonese syllable, remains to be carried out. Using an auditory task with Cantonese rhymes which carry no semantic meaning, we observed a minimal amount of positive BOLD signal at the caudate nucleus when Cantonese rhymes were contrasted with their corresponding filtered sounds.

Publication Type: 
Journal Articles
Journal: 
Neurosci Lett

Neural correlates of pair-bonding in a monogamous primate

The neurobiology of social bonding, despite its relevance to human mental health, has been studied primarily in rodents. In this study we used position emission tomography (PET), registered with structural magnetic resonance imaging (MRI) to investigate central glucose uptake in 17 males of a monogamous primate species, the titi monkey (Callicebus cupreus). Twelve pair-bonded males (including six with a lesion of the prefrontal cortex) and five lone males were scanned. The five lone males were re-scanned 48 h after pairing with a female.

Publication Type: 
Journal Articles
Journal: 
Brain Res

Small-animal molecular imaging methods

UNLABELLED: The ability to trace or identify specific molecules within a specific anatomic location provides insight into metabolic pathways, tissue components, and tracing of solute transport mechanisms. With the increasing use of small animals for research, such imaging must have sufficiently high spatial resolution to allow anatomic localization as well as sufficient specificity and sensitivity to provide an accurate description of the molecular distribution and concentration.

Publication Type: 
Journal Articles
Journal: 
J Nucl Med

Simultaneous acquisition of multislice PET and MR images: initial results with a MR-compatible PET scanner

UNLABELLED: PET and MRI are powerful imaging techniques that are largely complementary in the information they provide. We have designed and built a MR-compatible PET scanner based on avalanche photodiode technology that allows simultaneous acquisition of PET and MR images in small animals.

Publication Type: 
Journal Articles
Journal: 
J Nucl Med

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