Objective To explore a new index for reflecting the topological information of brain functional networks in patients at high risk of Alzheimer disease using characteristics of resting-state functional connectivity strengths(FCS) in patients with amnestic mild cognitive impairment(aMCI). Methods Thirty-one aMCI patients and 42 age, gender and years of education matched normal controls were enrolled between September 2009 and April 2011 in this study. The resting-state functional MRI (rs-fMRI) data of all participants were acquired and preprocessed. Then the whole-brain functional connectivities were constructed for exploring the distribution characteristics of hub regions which had higher FCS values. Using two-sample t test to compare group differences in age, years of education and each neuropsychological assessment. In addition, using Chi-squared test to compare group differences in gender. Group differences in FCS values were analyzed by general linear model. Finally, correlation analyses were used to evaluate the relationships between the FCS values of the brain regions with group differences and behavioral scores in aMCI patients. Results The hub regions of the functional networks in the aMCI patients were mainly located in the association cortices such as the precuneuses, posterior cingulate cortices, medial prefrontal cortices, angular gyri, superior occipital gyri, fusiform gyri and lingual gyri. The distribution models in the aMCI patients were consistent with those in the normal controls. However, the FCS values of these brain regions were significantly lower in the aMCI patients than those in the normal controls. In comparison to the normal controls, the aMCI patients had significantly decreased FCS values in the bilateral fusiform gyri, lingual gyri, superior occipital gyri, left middle occipital gyrus and postcentral gyrus (the cluster was 389, 230, 187 and 107 voxels, respectively;P<0.05, respectively), and they had decreased trends of FCS values in the bilateral posterior cingulate cortices and right insulas. The correlation analysis with uncorrected conditions showed that the FCS values of the left postcentral gyri were correlatid with the clock drawing test (CDT) scores (r=0.436, P=0.026). Conclusions aMCI mainly attacks the hub regions of brain functional networks. The changes of functional connectivities in aMCI may reflect the early pathophysiologic alterations of AD.

Objective To evaluate the effects of an optimized resuscitation bundle on prognosis of emergency patients with septic shock.Methods 65 patients with septic shock,admitted into emergency intensive care unit (ICU),were randomly divided into the treatment group(treated by an optimized resuscitation bundle)and the control group(treated by surviving sepsis campaign classics methods)by using random number table.The scores of sepsis-related organ failure assessment(SOFA) scores,the vasoactive agent application times,the mechanical ventilation times,the stay days of ICU,and 28-day mortality of the two groups were observed and compared.Results 3,7 day after erollment the SOFA score of the treatment group was (9.1 ± 2.5) points,(8.2 ± 2.8) points,respectively,which was lower than that of the control group[(10.1 ± 3.3) points,(9.5 ± 3.1) points] at the same time(t =4.52,3.99,all P ＜ 0.05) ; 8-day mortality rate of the treatment group was 28.1％,which was lower than that of the control group (48.5％) (x2 =12.84,P ＜ 0.05).Conclusion Application of an early optimized resuscitation bundle can significantly improve the prognosis of emergency patients with septic shock.

Objective To investigate the feature of regional grey matter volume changes in relapsing-remitting multiple sclerosis (RRMS) patients by voxel-based morphometry ( VBM) and presume the possible pathophysiological basis.Methods Conventional magnetic resonance imaging (MRI) and T1-weighted three-dimensional MRI were obtained from 32 RRMS and 32 sex- and age-matched normal controls.The comparison of grey matter volume between the two groups was analyzed by statistical analysis software SPM5 and VBM.A Pearson correlational analysis was used to assess correlation between gre matter loss and disease duration,expanded disability status scale (EDSS) and visible brain lesion volume.Results Compared with normal controls,RRMS patients had extensive bilateral grey matter atrophy in thalami (left 2031 and right 1711),caudate (left 815 and right 1031) and parahippocampal gyrus (left 313 and right 467),as well as several cortical regions in frontal,temporal,parietal,and occipital lobes (t value were between 8.853 and 11.163,all P ＜ 0.01).Regional grey matter loss in bilateral thalami ( r value were - 0.596 on left and were - 0.694 on right) and right caudate ( r = - 0.409 ) were strongly negatively correlated with visible brain lesion volume in RRMS (all P ＜ 0.05 ).Conclusions By means of VBM,extensive grey matter atrophy are found in RRMS patients,especially in deep grey matter.Axonal degeneration secondary to visible brain lesions may be a key pathogenesis of grey matter atrophy in RRMS.

Objective To investigate the value of macrophage activity imaging (MAI) in the diagnosis of brain and spinal cord lesions in rat model of multiple sclerosis(MS). Methods Twenty LEW rats were divided into 15 model rats and 5 control rats. MS animal model, experimental autoimmune encephalomyelitis (EAE) was induced by the injection of peptide 35-55 of myelin oligodendrocyte glycoprotein ( MOG35-55 ). MRI was performed on the third day of the acute stage of disease. The brain and spinal cord of rats were scanned by 3.0 T MR scanner( Siemens Trio Tim) with quadrature wrist joint coil.The T2W and T1 W images, Gadolinium enhanced T1 W images in 3D volume were obtained respectively. The MAI were obtained at 24 hours after intravenous injection of ultra small superparamagnetic iron oxide (USPIO) as contrast medium on T2WI. The workstation with special software was used for the reconstruction images of brain and spinal cord of rat in multiple orientations. Results Fifteen MOG35-55-EAE rats model of MS were successfully induced. The great majority lesions of central nervous system in acute stage were located in the brain( 58/63 ) and less in the spinal cord (5/63). The main manifestation of EAE lesions presented was hyperintensity on T2 WI and hypointensity on T1 WI, and some lesions had enhancement after Gd-DTPA injection. The EAE lesions presented as hypointensity on MAI images, but some of them were found to be isointensity on T2 WI. The enhancement pattern was discrepant between USPIO and Gd-DTPA.The sensitivity of depicting lesions of MOG35-55-EAE rat at acute stage were higher on T2WI ( 14/15 ) and MAI ( 13/15 ), and the detection rate was 100% ( 15/15 ) if they were combined. Gd-DTPA enhanced T1 WI had a lower sensitivity (7/15). All the MAI findings were negative in the control rats. Conclusions MAI can complement the drawback of conventional MRI techniques by continuously monitoring the inflammatory activity of EAE lesions, and it could raise the detection rate of EAE lesions by combining with T2WI. Gd-DTPA enhanced T1 WI monitors the breakdown of the blood brain barrier. MAI and Gd-DTPA enhanced MR imaging are complementary in the diagnosis and monitoring of EAE lesions.

at model is an ideal MS model for clinical MRI study.

Objective To explore the feasibility of using clinical whole body MR scanners to investigate the intravital visibility of central nervous system (CNS) lesions in rats of multiple sclerosis (MS). Methods Ten Lewis rats were injected with the peptide 35-55 of myelin oligodendrocyte glycoprotein to make the model of MS. On a Siemens Sonata 1.5T MR scanner equipped with a flexible surface coil, rats brain and spinal cord were examined using T2-weighted and T1-weighted imaging with slice thickness of 1-2 mm. On a Siemens Trio Tim 3.0T MR-scanner equipped with a quadrature wrist coil, rats were examined using T2WI, T1WI and Gd-DTPA enhanced T1WI 3-dimensional imaging with voxel size up to 0.06-0.08 mm~3. Rat brain and spinal cord images in multiple orientations were reconstituted with special software in workstation. Results T2WI and T1WI of the lesions in MS rat brain with high spatial and contrast resolution could be obtained with clinical 3.0T MR scanner, though the image resolution of spinal cord was relatively low. The resolution of 1.5T MR was lower than that of 3.0T. Plaques in CNS of MS rats presented as hyperintense areas on T2WI and hypointense areas on T1WI. Contrast enhancement was observed as hyperintense on T1WI. Conclusion High quality images of CNS lesions canbe obtained with clinical 3.0T MR-scanner in MS rat, which offers a noninvasive access for studying CNS diseases in the rats.

Objective To observe whether repetition time (TR) and field strengths have effects on diffusion indices of brain white matter. Methods Seven rhesuses underwent diffusion tensor MR imaging (DT-MRI) with a series of TRs (from 500 to 6000 ms) at 1.5T and 3.0T MR scanners, respectively. The mean diffusivity (MD), fractional anisotropy (FA), primary (λ1) and transverse eigenvalues (λ2, 3) were measured in region of interest (ROI) at the posterior limb of internal capsule. Pearson correlation analysis and two-way ANOVA were performed. Results None of the diffusion indices was correlated with TR (P＞0.05) when SNR was high enough (SNR>35). FA was significantly higher and the MD and λ2, 3 were significantly lower at 3.0T than those at 1.5T (P＜0.001). No significant difference of λ1 was found between the two field strengths (P＞0.05). Conclusion Field strength may influence diffusion quantification, but not for TR, which should be considered in multi-center studies.

Objective To investigate whether abnormalities can be detected in normal-appearing white matter(NAWM)and normal-appearing white matter(NAGM)in patients with clinically isolated syndrome(CIS)and comparing them to the abnormalities in relapsing-remitting multiple sclerosis(RRMS)by using diffusion tensor imaging(DTI)histogram.To detect the potential relationship between DTI indices of NAWM,NAGM and patient's clinical condition.Methods Nineteen patients with CIS,19 clinically diagnosed RRMS patients and 19 sex-and age-matched healthy volunteers were included in this study.Conventional MRI and DTI images were obtained using Siemens 1.5 T Magnetom sonata scanner.DTI histograms of NAWM and NAGM were obtained after post-processing.The mean value,peak height,peak location of the histogram were used for analysis.All data was statistically processed with SPSS for Windows.Results NAWM average MD was higher and FA was lower in RRMS[MD(0.83±0.04)×10-3mm2/s,FA 0.36±0.03]when compared to CIS[MD(0.79±0.02)×10-3mm2/s,FA 0.40±0.02]and control[MD(0.78±0.02)×10-3mm2/s,FA 0.41±0.01](P＜0.01).But no statistically significant difference was found between CIS and control.The peak height of NAWM average MD histogram was significantly lower in CIS than control(P＜0.05),while the peak location of average FA histogram shifted to the left(P＜0.01).Patients with CIS[(1.08±0.06)×10-3mm2/s]showed significantly higher NAGM average MD than control[(1.03±0.05)×10-3mm2/s](P＜0.05),but,lower than RRMS[(1.18±0.12)×10-3mm2/s](P＞0.01).There were no correlation between DTI indices and EDSS scores in patients with CIS.Moderate correlation between NAGM average MD(r=0.568,P＜0.05)and EDSS scores were found in patient with RRMS.Conclusion NAWM and NAGM abnormalities do occur in CIS which can be detected by DTI.The underlying pathological changes in NAWM and NAGM in CIS may be milder than RRMS as demonstrated by DTI histogram.

Objective Using manganese enhanced MR imaging(ME-MRI)as a standard to validate the accuracy of white matter diffusion tenor tractography(DTT)with different gradients orientations in macaque monkeys.Methods Seven adult male macaque monkeys were scanned for DTY images with different number of gradients orientations.When all data were acquired.3 μl of 0.8 mol aqueous solution of MnCl2 was injected into the primary motor cortex representing forelimb for ME-MRI scanning 48 hours later.On the images of fractional anisotropy(FA),seed region for fiber tracking was chosen according to the subcortical enhanced range on ME-MRI,then the DTT fiber tracts proiecting on axial images of FA were compared with enhancement region on T1WI of ME-MRI.Results Under the calculation method for fiber tracking in the study,different motion-probing gradients orientations led to results consistent with ME-MRI for the brain above the midbrain level.All group's concordance score of fibertracking results were good.Among them,30 and 64 orientation fiber tracking results were optimal.Below the midbrain level,there was significant difference between DTT fiber tracking and ME-MRI fiber tracking. Conclusion Different motion-probing gradients orientations do not influence DTT fiber tracking.But below the midbrain level.the results of DTT fiber tracking were not reliable according to the standard results of ME-MRI fibe tracking.

ObjectiveTo characterize gliomatosis cerebri on magnetic resonance imaging (MRI) and analyze differential diagnosis.MethodsMRI studies of 12 patients with gliomatosis cerebri were reviewed.ResultsTumors involved at least two lobes of the brain in all patients. Widespread invasion with hyperintensity was noted on T2-weighted MR images. No contrast enhancement occurred.Tumors were confirmed with surgery or biopsy.ConclusionGliomatosis cerebri is best detected with MRI.