Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffu- sion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially in- creased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion co- efficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3-24 hours after infarction. Apparent diffusion coefficient values at remote regions （cerebellum） varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.

Correlation between iron deposition and Alzheimer's disease In vivo preliminary quantitative study with susceptibility-weighted imaging

BACKGROUND： Studies have demonstrated iron deposition in Alzheimer＇s disease （AD） patients. Therefore, quantitative measurements and tracing of iron deposition are important for early detection and treatment.OBJECTIVE： To quantitatively measure iron deposition in the brain and evaluate the relationship between iron deposition and AD using magnetic susceptibility-weighted imaging. DESIGN, TIME AND SETTING： A case-control study was performed at the Department of Radiology, Huashan Hospital of Fudan University from February to July 2008. PARTICIPANTS： A total of 20 AD patients, comprising 11 males and 9 females, with a mean age of 72.5 years （range, 51-80 years）, and 20 healthy volunteers, comprising 10 males and 10 females, with a mean age of 69.9 years （range, 55-78 years）, were selected. AD was diagnosed according to the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer Disease and Related Disorders Association criteria.METHODS： Sagittal T2-weighted images were acquired to locate precise positions of the anterior and posterior commissures. The susceptibility-weighted magnetic resonance images were parallel to the anterior-posterior commissural line through the use of a three-dimensional gradient-echo sequence. All participants underwent measurement of corrected phase （CP） value and Mini-Mental State Examination. Pearson correlation coefficients were used to assess the association between CP values and Mini-Mental State Examination results.MAIN OUTCOME MEASURES： CP values of regions of interest in the hippocampal regions were measured on CP images.RESULTS： CP values were significantly reduced in bilateral hippocampal regions of AD patients compared with normal controls （P〈0.01）, but there were no significant differences between left and right CP values （P〉0.05）. The hippocampal mean CP value positively correlated with the Mini-Mental State Examination score in AD patients and normal controls （r= 0.57, P〈0.01）. CONCLUSION： Susceptibility-weighted imaging can be used to measure CP values to determine iron deposition in the brains of AD patients and could serve as a useful diagnostic tool for AD.

Perfluorooctyl bromide nanoemulsions holding MnO_(2) nanoparticles with dual-modality imaging and glutathione depletion enhanced HIFU-eliciting tumor immunogenic cell death

Tumor-targeted immunotherapy is a remarkable breakthrough,offering the inimitable advantage of specific tumoricidal effects with reduced immune-associated cytotoxicity.However,existing platforms suffer from low efficacy,inability to induce strong immunogenic cell death(ICD),and restrained capacity of transforming immune-deserted tumors into immune-cultivated ones.Here,an innovative platform,perfluorooctyl bromide(PFOB)nanoemulsions holding MnO_(2) nanoparticles(MBP),was developed to orchestrate cancer immunotherapy,serving as a theranostic nanoagent for MRI/CT dual-modality imaging and advanced ICD.By simultaneously depleting the GSH and eliciting the ICD effect via highintensity focused ultrasound(HIFU)therapy,the MBP nanomedicine can regulate the tumor immune microenvironment by inducing maturation of dendritic cells(DCs)and facilitating the activation of CD8^(+)and CD4^(+)T cells.The synergistic GSH depletion and HIFU ablation also amplify the inhibition of tumor growth and lung metastasis.Together,these findings inaugurate a new strategy of tumor-targeted immunotherapy,realizing a novel therapeutics paradigm with great clinical significance.