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The aim of this work was to explore the applicable value of 1H-MRS evaluation on the treatment of Alzheimer's disease (AD) with neural stem cell (NSC) transplantation by quantitative analysis of metabolite changes in the hippocampal area in AβPP/PS1 transgenic (tg) mice. The tg mice (n = 30) aged 12 months were randomized into two subgroups: One receiving NSCs and the other receiving PBS transplantation in the bilateral hippocampal CA1 region. The wild-type mice (n = 15) were used as the control group. 1H-MRS was performed before transplantation and 6 weeks after transplantation to measure the change of N-acetylaspartate (NAA), myo-inositol (mI), glutamate (Glu), choline (Cho), and creatine (Cr) in the hippocampus. Results showed NAA and Glu levels were increased and mI level was decreased in NSC group compared with the PBS group at six weeks after transplantation (p < 0.05). There was no significant difference in NAA and Glu (p > 0.05), and there was significant difference in mI (p < 0.05) between NSC and control groups. However, there was no significant difference in Cho before and after transplantation among the three groups (p > 0.05). Histology showed the number of neurons in the hippocampal CA1 region increased significantly in the NSC group than those in the PBS group (p < 0.05), and the number of astrocytes significantly decreased in the NSC group compared with the PBS group. Ultrastructure showed that the neurons in the NSC group were morphologically normal. In conclusion, 1H-MRS can display intracranial metabolite changes before and after NSC transplantation in tg mice and has a applicable value in evaluating the therapeutic effect of NSCs on AD. [ABSTRACT FROM AUTHOR]

Objective: To obtain the three dimensional visualization model with normal measurements of fetal brain in the second trimester and analyze the developmental changes with gestational age (GA), sexual dimorphisms and cerebral asymmetries., Methods: The brains of 69 fetal specimens of 12 - 22 weeks GA were scanned by 7.0T magnetic resonance imaging (MRI). The developing structures were analyzed and a three dimensional visualization model was rebuilt with Amira 4.1 software., Results: Most sulci, except for postcentral and intraparietal sulcus, were present until 22 weeks GA. And none developed secondary branches. Laminar organization, described as early as 12 weeks GA, was delineated as layers with different signal intensities and became typical after 16 weeks GA. Basal nuclei was distinctly visible. Brains had different growth rates linearly increasing with GA. But neither sexual dimorphisms nor cerebral asymmetries was detected., Conclusions: The initial developmental stage of fetal brain occurs at 12 - 22 weeks GA. The developing structures may be distinctly visualized on 7.0T post-mortem MRI. And the three dimensional visualization model aids greatly in the precise cognition of immature brain.

Objective: To evaluate the controllability and reproducibility of a acute thromboembolic cerebral ischemia model for studying molecular imaging and thrombolysis in mice by 7.0 Tesla magnetic resonance imaging (MRI)., Methods: Twenty-four male C57BL/6J mice were randomly divided into embolic group (n = 14) and sham-operated group (n = 10). To prepare rich fibrin and optimal length of clots and measure diameters of clots under microscope, the clots were injected into internal carotid artery via a microcatheter inserted from external carotid artery to bifurcation of common carotid artery in embolic group. In sham-operated group, phosphate-buffered saline containing bovine serum albumin was injected similarly. At 1, 3 or 24 h after injection of clots or phosphate-buffered saline containing bovine serum albumin, mice underwent 7.0 Tesla magnetic resonance imaging including sequences of magnetic resonance angiography (MRA), diffusion weighted imaging (DWI) and perfusion weighted imaging (PWI) by arterial spin labeling technology (ASL) and T(2) weighted imaging (T(2)WI) so as to evaluate the occlusive rate of middle cerebral artery (MCA) and the change of relative cerebral blood flow (rCBF) and lesion volumes. Triphenyl tetrazolium chloride (TTC) stain was performed at 24 h., Results: The diameters of clots were 162 ± 14 µm. In embolic group at 1, 3 or 24 h after injection of clots, the occlusive rate of MCA was 78.6%, 71.4% and 57.1% respectively. And the values of rCBF decrease in mice showing occlusion of MCA in MRA images. The percents of rCBF value in embolic group were 26% ± 10% at 1 h and 26% ± 15% at 3 h respectively. They were significantly lower than the percents of rCBF value in sham-operated group at the same time points. The percents of infarct volumes at 24 h were 30% ± 4% from T(2)WI images and 30% ± 16% from TTC images. In sham-operated groups, both MRI and TTC images were negative., Conclusion: A murine model of acute thromboembolic cerebral ischemia has been successfully established. The improved method is both stable and feasible. It may be readily evaluated from multi-parameter imaging by 7.0 Tesla magnetic resonance imaging.

Objective: To investigate the methods of manganese enhanced magnetic resonance imaging in 7.0 T magnetic field for tracing corticospinal tract in rat brain in vivo., Methods: 0.4 microl volume of 1 mol/L aqueous solution of MnCl(2) was injected into the primary motor cortex of 9 SD rats under stereotaxis. MRI studies were performed for tracing corticospinal tract and other coherent nerve tracts before injection and 24 hours, 48 hours, 72 hours, 7 days after injection respectively using 7.0T Micro-MRI., Results: Corticospinal tract was visualized perfectly from primary motor cortex, thalamus, cerebral peduncle to pons at different time points after Mn(2+) administration, and the best contrast was achieved after 24-48 h. At the same time, a small quantity of Mn(2+) reached the opposite somatosensory cortex through the corpus callosum., Conclusion: Manganese enhanced MRI visualizes perfectly the transport of Mn(2+) through axoplasmic flow in corticospinal tracts. This method may be used to investigate the change of corticospinal tract and the functional connectivity between two sides of hemisphere in rat brain.