Large-scale topology and the default mode network in the mouse connectome.

Noninvasive functional imaging holds great promise for serving as a translational bridge between human and animal models of various neurological and psychiatric disorders. However, despite a depth of knowledge of the cellular and molecular underpinnings of atypical processes in mouse models, little is known about the large-scale functional architecture measured by functional brain imaging, limiting translation to human conditions. Here, we provide a robust processing pipeline to generate high-resolution, whole-brain resting-state functional connectivity MRI (rs-fcMRI) images in the mouse.

In vivo mapping of vascular inflammation using multimodal imaging.

Background: Plaque vulnerability to rupture has emerged as a critical correlate to risk of adverse coronary events but there is as yet no clinical method to assess plaque stability in vivo. In the search to identify biomarkers of vulnerable plaques an association has been found between macrophages and plaque stability--the density and pattern of macrophage localization in lesions is indicative of probability to rupture. In very unstable plaques, macrophages are found in high densities and concentrated in the plaque shoulders.

Modulation of T2 relaxation time by light-induced, reversible aggregation of magnetic nanoparticles.

A reversible T2 contrast agent consisting of cross-linked anionic dextran coated iron oxide nanoparticles covalently coupled to a light-sensitive spiropyran (SP)/merocyanine (MC) motif was synthesized and characterized. In aqueous solution, light induced isomerization of the molecular switches between the hydrophobic SP isomer and hydrophilic MC isomer directs the aggregation and dispersion of the nanoparticles, respectively. When in the dark, where the MC form dominates, the probe has a T2 relaxation time of 37.

Synthesis of 64Cu-labeled magnetic nanoparticles for multimodal imaging.

Complementary imaging modalities provide more information than either method alone can yield and we have developed a dual-mode imaging probe for combined magnetic resonance (MR) and positron emission tomography (PET) imaging. We have developed dual-mode PET/MRI active probes targeted to vascular inflammation and present synthesis of (1) an aliphatic amine polystyrene bead and (2) a novel superparamagnetic iron oxide nanoparticle targeted to macrophages that were both coupled to positron-emitting copper-64 isotopes. The amine groups of the polystyrene beads were directly conjugated with an amine-reactive form (isothiocyanate) of aza-macrocycle 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA).

Core/shell quantum dots with high relaxivity and photoluminescence for multimodality imaging.

A series of core/shell CdSe/Zn1-xMnxS nanoparticles were synthesized for use in dual-mode optical and magnetic resonance (MR) imaging techniques. Mn2+ content was in the range of 0.6-6.

Size-controlled synthesis of dextran sulfate coated iron oxide nanoparticles for magnetic resonance imaging.

In the generation of nanoparticles for biological applications, the control over synthetic parameters influencing the particles' physicochemical properties are of great interest due to the strong influence of particle size and surface properties on cellular uptake and biodistribution. We have synthesized dextran sulfate coated particles and systematically evaluated synthetic parameters that may influence the properties of these nanoparticles as potential magnetic resonance (MR) contrast agents. The amount of base, polysaccharide content, ratio of iron salts, and reaction time were optimized to yield approximately 30 nm particles as determined by dynamic light scattering with good MR properties (r(1) = 14.