Paramagnetic ultrasmall gadolinium oxide (Gd(2)O(3)) nanoparticles with particle diameters (d) of approximately 1 nm were synthesized by using three kinds of Gd(III) ion precursors and by refluxing each of them in tripropylene glycol under an O(2) flow. A large longitudinal relaxivity (r(1)) of water proton of 9.9 s(-1) mM(-1) was estimated. As a result, high contrast in vivo T(1) MR images of the brain tumor of a rat were observed. This large r(1) is discussed in terms of the huge surface to volume ratio (S/V) of the ultrasmall gadolinium oxide nanoparticles coupled with the cooperative induction of surface Gd(III) ions for the longitudinal relaxation of a water proton. It is found from the d dependence of r(1) that the optimal range of d for the maximal r(1), which may be used as an advanced T(1) MRI contrast agent, is 1-2.5 nm.

Creating a good image: A probe for combined positron emission tomography (PET) and magnetic resonance imaging (MRI) has high colloidal stability and demonstrates facile conjugation ability. Sentinel lymph nodes are clearly identified in the fusion image (see picture; I: injection site) because of the complementary nature of the techniques, which makes accurate anatomical information and fault‐free diagnosis possible.

A facile one-pot synthesis of d-glucuronic acid-coated ultrasmall Ln(2)O(3) (Ln = Eu, Gd, Dy, Ho, and Er) nanoparticles is presented. Their water proton relaxivities were studied to address their possibility as a new potential MRI contrast agent. We focused on the d-glucuronic acid-coated ultrasmall Dy(2)O(3) nanoparticle because it showed the highest r(2) relaxivity among studied nanoparticles. Its performance as a T(2) MRI contrast agent was for the first time proved in vivo through its 3 T T(2) MR images of a mouse, showing that it can be further exploited for the rational design of a new T(2) MRI contrast agent at high MR fields.

There is no doubt that magnetic resonance imaging contrast agents (MRI CAs) can play a vital role in diagnosing diseases. Therefore, demand for new MRI CAs with an enhanced sensitivity and advanced functionalities is very high. Here, paramagnetic nanoparticles (NPs) are reviewed as new potential candidates for either T(1) or T(2) MRI CAs or both. These include surface coated lanthanide (Ln) oxide NPs (Ln = Gd, Dy, and Ho) and manganese oxide NPs. Surface coating materials should be biocompatible and hydrophilic. Compared to conventional large NPs, these surface coated paramagnetic NPs can be made ultrasmall with core particle diameter ranging from 1 to 3 nm, but their magnetic properties are still sufficient for MRI CAs. At this particle diameter, they can be easily excreted from the body through the renal system, which is prerequisite for in vivo applications. Mixed lanthanide oxide NPs into which a fluorescent Ln material is incorporated will be valuable as multiple imaging agents for both MRI-fluorescent imaging (FI) and MRI-cellular imaging (CL). These paramagnetic NPs can be further functionalized towards target-specific imaging, multiplex imaging, and drug delivery.

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For the application of superparamagnetic iron oxide nanoparticles in biomedical fields for target-specific purposes, they should be ultra small in diameter. We developed a simple one-step synthesis of surface modified ultra small superparamagnetic iron oxide nanoparticles (USPIONs) with an average particle diameter of 1.7 nm in a polar organic solvent. Polyethylene glycol diacid (PEG) surface modified USPIONs synthesized in triethylene glycol were nearly monodisperse in diameter and highly water-dispersible. The PEG surface modified USPIONs were tested for use as magnetic resonance (MR) contrast agents. They had a low r(2)/r(1) relaxivity ratio of 3.4 (r(1) = 4.46 and r(2) = 15.01 mM(-1) s(-1)) and showed clear dose-dependent T(1) and T(2) map images, indicating that they will be useful as both target-specific T(1) and T(2) MR contrast agents due to their ultra small size.

Novel experience and learning new skills are known as modulators of brain function. Advances in non-invasive brain imaging have provided new insight into structural and functional reorganization associated with skill learning and expertise. Especially, significant imaging evidences come from the domains of sports and music. Data from in vivo imaging studies in sports and music have provided vital information on plausible neural substrates contributing to brain reorganization underlying skill acquisition in humans. This mini review will attempt to take a narrow snapshot of imaging findings demonstrating functional and structural plasticity that mediate skill learning and expertise while identifying converging areas of interest and possible avenues for future research.

To verify the usefulness of diffusion tensor imaging (DTI) and fiber tractography (FT) compared with routine magnetic resonance imaging (MRI) in patients with cervical spinal cord injury, and to clarify the relationship between motor and sensory impairments and DTI and FT parameters, we performed routine MRI and DTI on 10 patients with chronic cervical spinal cord injury and on 10 controls. Quantitative parameters of DTI, such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC), were calculated for each cervical cord level. FT parameters of imaginary crossing fiber numbers were also determined at the C3 level, from C3-C6, and from C3-C7, as well as each connection rate. All patients' clinical motor and sensory functions were examined using the International Standards for the Neurological Classification of Spinal Cord Injury (ISCSCI). FA values in the controls and patients were 0.76 ± 0.08 (mean ± standard deviation) and 0.58 ± 0.11, respectively, and ADC values in the controls and patients were 1.29 ± 0.75 × 10(-3) mm(2)/sec and 1.26 ± 0.66 × 10(-3) mm(2)/sec, respectively. In patients with cervical cord injury, abnormal cervical levels detected on routine MRI were not correlated with clinical findings and DTI parameters, but FA of DTI was correlated with motor function, as were imaginary crossing fiber numbers and connection rates of FT. Quantitative DTI and FT analyses were useful in the evaluation of patients with cervical spinal cord injury. The injured cervical spinal cord can be evaluated in more detail and more precisely using DTI and FT, for which findings are correlated with clinical findings such as neurological impairments.